This study aims to address the challenges associated with rockfall assessment and monitoring, focusing on the coastal cliffs of “Navagio Shipwreck Beach” in Zakynthos. A complete time-series analysis was conducted using state-of-the-art methodologies including a 2020 survey using unmanned aerial systems (UASs) and two subsequent surveys, incorporating terrestrial laser scanning (TLS) and UAS survey techniques in 2023. Achieving high precision and accuracy in georeferencing involving direct georeferencing, the utilization of pseudo ground control points (pGCPs), and integrating post-processing kinematics (PPK) with global navigation satellite system (GNSS) permanent stations’ RINEX data is necessary for co-registering the multitemporal models effectively. For the change detection analysis, UAS surveys were utilized, employing the multiscale model-to-model cloud comparison (M3C2) algorithm, while TLS data were used in a validation methodology due to their very high-resolution model. The synergy of these advanced technologies and methodologies offers a comprehensive understanding of rockfall dynamics, aiding in effective assessment and monitoring strategies for coastal cliffs prone to rockfall risk.

This manuscript presents a multidisciplinary study that proposes a methodology for delineating and categorizing vulnerability at rockfall risk areas to avoid human injuries and infrastructure damage caused by rockfalls. The presented workflow includes (i) classical geological mapping, (ii) the interpretation of high-resolution satellite data for observing the spatial distribution of fallen boulders, (iii) analytical hierarchy processing of spatial information within a Geographical Information System (GIS) platform, (iv) close-range remote sensing campaigns with Unmanned Aerial Systems (UASs), and (v) integrated simulation of rockfall events. This methodology was applied to Kalymnos Island, which belongs to the Dodecanese Islands complex of the southeastern Aegean Sea in Greece. It is characterized by unique geomorphological features, including extensive vertical limestone cliffs that span the island. These cliffs make it one of the world’s most densely concentrated areas for sport climbing. The results highlighted the areas that the local authorities need to focus on and suggested measures for increasing the safety of climbers and infrastructure.

We find ourselves in an ever-evolving environment, where the past fifty years have marked a pivotal moment in scientific thinking. This shift is particularly evident in the scientific approach to analyzing natural-induced hazards. Geohazards annually contribute significantly to loss of life and property, with mass movements standing out as widespread occurrences globally. The study of extreme events and their repercussions on landscape stability is a critical area in environmental research. In this paper, we showcase the advancements in the integration of Artificial Intelligence (AI) and Remote Sensing (RS) for improved landslide assessments, leveraging developments in Earth Observation (EO) data analysis. We highlight the application of Object-Based Image Analysis (OBIA), which have not traditionally been tailored for landslide studies but have proven effective in this context. The framework enables the translation of complex real-world landslide scenarios into analyzable objects through segmentation algorithms, applying subsequent classifications via rule-based or advanced Machine Learning (ML) algorithms. We demonstrate how ML has the potential to revolutionize geoscience data analysis and address major societal concerns presented by landslide hazards by tapping into the vast reserves of geoscience data. ML algorithms, particularly Random Forest (RF), integrated into an Object-Based Image Analysis (OBIA) workflow, demonstrated adaptability for sub-zone landslide mapping on a local scale. Given the increasing frequency of extreme meteorological events driven by climate change, the integration of UAV datasets, Structure from Motion (SfM), and advancements in OBIA and AI can respond effectively by enabling precise and accurate analysis of landslide and rockfall failures. Our results affirm that rotational landslides and their thematic sub-zones were adequately recognized and mapped through the ML procedure.

The Eastern Anatolia suffered devastation following two major earthquakes on 6 February 2023 causing collapse of numerous structures and resulting in tens of thousands of human casualties, injuries, and displacements. This research endeavors to elucidate factors related to building properties and earthquake environmental effects (EEEs) that control the grade and distribution of structural damage in southeastern Turkey. The outcomes delineated herein originate from post-event field surveys conducted by the authors shortly after the earthquakes. The field surveys encompassed geological mapping techniques alongside novel methodologies, such as the utilization of Unmanned Aerial Systems (UAS).In terms of building construction characteristics, deficiencies such as inadequate compliance with building codes, arbitrary urban planning solutions, and inferior construction practices represent primary factors that contributes significantly to the disaster. Regarding geological factors, both primary and secondary EEEs played a significant role in controlling the severity and distribution of building damage. Primary EEEs, in particular coseismic surface ruptures along segments of the East Anatolian Fault (EAF), intersected with urban regions exhibited severe to severe structural damage (e.g. Gölbaşı, Balkar, Sekeroba, Nurdağı, İslahiye, Hassa towns etc.). Liquefaction along with lateral spreading and subsidence near water bodies (sea, existing and former lakes and rivers in the affected area) resulted in damage indicative of compromised building foundation load-bearing capacity (e.g. İskenderun, Gölbaşı and Antakya cities). Typical damage included sinking and tilting of buildings, damage due to pounding of adjacent structures, as well as outspread multi-layer and pancake-type collapse. Earthquake-triggered landslides (ETILs) predominantly affected mountainous and semi-mountainous villages. The collision of the mobilized rock fragments with adjacent structures and the presence of structures within the landslide boundaries are the main mechanisms of building damage due to ETILs. The synergy of high landslide susceptibility and liquefaction potential resulted in destruction in several urban centers of the earthquake-affected area (e.g. Kahramanmaraş city).

Kalymnos Island features extensive vertical limestone cliffs that span throughout the entire onshore area, establishing it as one of the world's premier locations for sports climbing. Drawing thousands of tourists and climbers annually, Kalymnos captivates with its unparalleled natural beauty and unique geomorphological relief. The absence of vegetation and the prevalence of large limestone vertical cliffs contribute to a distinctive geological setting, showcasing detached boulders throughout the island and positioning it as an ideal site for studying rockfall events worldwide. To investigate this peculiar geological landscape, contemporary close-range remote sensing techniques such as UAS images photogrammetric processing, terrestrial LiDAR point clouds, and high-resolution satellite imagery within a GIS platform are employed. This integrated approach facilitates the creation of detailed terrain models and enables the identification of spatial boulder distribution on the downslope areas of steep carbonate cliffs. Moreover, the diachronic study of the detected high-risk locations delineated the surface changes at the foot of the steep slopes where several back analyses were performed. Utilizing these quantitative techniques provides valuable information for designing protective measures for the stability of the slopes, highlighting the safe climbing routes for the athletes and the infrastructure at the cliff bases. Strategies involve anchoring individual rock blocks, removing unsafe rock masses, and implementing restraining nets or dynamic rockfall barriers at strategic locations along the route trail to mitigate risks effectively.

Coastal cliffs are one of the cases of steep terrains naturally vulnerable to a range of erosional processes, with rockfalls emerging as one of the most prevalent and hazardous. Although predicting rockfall occurrences remains challenging due to multi-faceted triggering factors such as extreme weather events, seismic activity, erosion, and human actions, technological advancements offer promising avenues for developing more robust and effective risk assessment methodologies. Light Detection and Ranging (LiDAR), photogrammetry from Unmanned Aerial System images, and satellite imagery, coupled with the evolution of artificial intelligence, have revolutionized the field of rockfall assessment by enabling precise detection and quantification of 3D topographic changes, offering insights into rockfall dynamics.

The projected increase in frequency of flood extremes, attributed to climate change, poses a significant threat to coastal regions throughout the Mediterranean. Consequences encompass extensive geomorphological changes, infrastructural degradation, property damage, pollution of the aquatic environment, and other adverse socio-economic impacts, also threating the blue economy—a vital economic driver of the region. Acknowledging the pivotal role of coastal areas as critical nodes for both economic activities and ecologically valuable natural landscapes, it becomes imperative to deepen our understanding of the mechanisms and extents to which extreme flood events can impact these vulnerable coastal zones. This work focuses on exploring the impacts on the coastline of recent extreme storm events in the Eastern Mediterranean. The study aims to explore and classify the typology of effects, the severity of impacts and examine their spatial distribution as means to contribute to an improved understanding of extreme storm and flooding consequences in the region.

The projected increase in the frequency of extreme flood events in the Eastern Mediterranean region signifies profound societal impacts of various types beyond the actual inundated areas and across different sectors. However, the extent and complexity of the various cascade effects remain inadequately understood. This work focuses on collecting new evidence on the types and extent of these cascade effects drawing on recent and historical flood disasters in the region, in an effort to improve our understanding of the nature, the extent, the propagation mechanisms and the consequences of these far-rearching repercussions, Additionally, the study examines the interplay between various impacts to provide insights useful for enhancing preparedness and response strategies to mitigate the associated risks.

The largest part of earthquake debris is generated by the collapse during the strong ground motion and the urgent demolition of severely damaged structures during the emergency response and recovery. One of the first and most significant actions during the response and recovery phases is the management of the disaster debris. It constitutes one of the most important challenges for all involved in disaster management, as it poses significant hazards to both the environment and the public health in the affected area. The hazards are attributed to the occurrence of hazardous materials in collapse and demolition debris.Many such challenges and related hazards emerged in the southeastern Türkiye in early February 2023, when two major earthquakes of magnitude 7.8 and 7.5 struck a densely built-up area comprising 11 provinces with many large urban centers such as large cities and towns and extensive rural areas with countless villages.The synergy of the strong ground motion combined with the generation of extensive primary effects, such as coseismic surface ruptures, and the triggering of secondary effects, including liquefaction and landslides among others, resulted in tens of thousands of totally and partially collapsed buildings and large parts of residential areas being flattened. This fact led to a volume of debris considered as the largest since the 1994 Northridge earthquake, an earthquake debris volume difficult to manage even in organized countries.During post-event field surveys conducted by the authors in the affected area, several disposal sites set up in the most affected provinces were detected and checked for suitability. The field surveys comprised the deployment of Unmanned Aircraft Systems (UAS) in the disaster field and the use of satellite imagery back in the laboratory for assessing properties of sites and their surrounding areas as well as for monitoring implemented debris management activities. It is concluded that all sites had characteristics that did not allow them to be classified as safe sites for earthquake debris treatment and disposal. This is mainly attributed to their proximity to areas, where thousands of people live and work on a daily basis. As regards the environmental impact, these sites were operating within or close to surface water bodies. This situation reveals a rush for rapid debris removal and recovery resulting in serious omissions in the preparation of disaster management plans and concessions in their implementation. In this context, effective debris management measures are also proposed: (i) sorting of hazardous materials, (ii) appropriate treatment for chemicals and heavy metals, (iii) 3R (reuse, reduce, recycle) activities, (iv) systematic monitoring of environmental parameters and hazardous substances, (v) storage in sites with safe operation standards, (vi) strict application of international best practices and procedures for limiting asbestos adverse effects on public health.

On 6 February 2023, East Anatolia was devastated by two major earthquakes resulting in hundreds of thousands of collapses and tens of thousands of human casualties, and injured and homeless people. These high numbers are attributed to the extensive heavy and very heavy structural damage corresponding to damage grades 4 and 5 in terms of the European Macroseismic Scale EMS-98 that were caused in the earthquake-affected area.The obvious reasons that contributed to the disaster comprised the large magnitude of the earthquakes, the generation of the first earthquake during the night that found the majority of the population in their homes, the demographic characteristics of the region that include densely built-up and populated areas as well as the proximity of many residential areas to the ruptured faults. Furthermore, the synergy of significant factors, which are strongly related to the seismotectonic setting of the area, the earthquake environmental effects (EEEs) and the characteristics of the affected structures resulted in one of the largest earthquake disasters in the modern history of the country.The aim of this study is to highlight the factors related to building properties and the generation of EEEs that control the grade and the spatial distribution of building damage in the studied earthquake-affected areas of southeastern Turkey. The results of this study are based on field surveys conducted by the authors shortly after the earthquakes (7 to 11 February) and after almost 2 months (31 March to 6 April). The field survey comprising conventional methods of geological mapping and modern and innovative methodologies such as deployment of Unmanned Aerial Systems (UAS).In regards to the building construction properties, the loose enforcement of the building code, the random urban planning solutions and the poor construction standards are the main construction deficiencies that led to one of the largest disasters in Turkey’s recent history.Regarding geological factors, the triggering of primary and secondary EEEs largely shaped the grade and distribution of damage. Where coseismic surface ruptures intersected with the built environment, heavy to very heavy structural damage was observed. This was evident in many cases along the ruptured segments of the East Anatolian Fault Zone. Liquefaction observed close to waterbodies caused damage typical of building foundation load-bearing capacity loss. The earthquake-triggered landslides affected mainly mountainous and semi-mountainous settlements characterized with pre-earthquake high related susceptibility. The high susceptibility to generation of EEEs was extensively confirmed in many cases resulting in extensive damage.

Understanding the geochemistry and contamination of rivers affected by anthropogenic activities is paramount to water resources management. The Asopos river basin in central Greece is facing environmental quality deterioration threats due to industrial, urban and agricultural activities. Here, the geochemistry of river sediments and adjacent soil in terms of major and trace elements (Al, Ca, Mg, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) and the geochemical composition of surface water in terms of major ions, trace elements and nutrients along the Asopos river basin were determined. In addition, this study characterized potential nitrate sources through the analysis of stable isotope composition of NO3− (δ15Ν-ΝΟ3− and δ18Ο-ΝΟ3−). Results indicated that specific chemical constituents including nutrients (NO2−, NH4+, PO43−) and major ions (Na+, Cl−) were highest in the urban, industrialized and downstream areas. On the other hand, nitrate (NO3−) concentration in river water (median 7.9 mg/L) showed a decreasing trend from the upstream agricultural sites to the urban area and even more in the downstream of the urban area sites. Ionic ratios (NO3−/Cl−) and δ15Ν-ΝΟ3− values (range from +10.2 ‰ to +15.7 ‰), complemented with a Bayesian isotope mixing model, clearly showed the influence of organic wastes from septic systems and industries operating in the urban area on river nitrate geochemistry. The interpretation of geochemical data of soil and river sediment samples demonstrated the strong influence of local geology on Cr, Fe, Mn and Ni content, with isolated samples showing elevated concentrations of Cd, Cu, Pb and Zn, mostly within the industrialized urban environment. The calculation of enrichment factors based on the national background concentrations provided limited insights into the origin of geogenic metals. Overall, this study highlighted the need for a more holistic approach to assess the impact of the geological background and anthropogenic activities on river waters and sediments.

Plastiras artificial lake is formed upstream of an 83 m-high arched dam, at an altitude of 795.20 m above msl. A hydroelectric power plant constructed back in 1959, started functioning in 1960 with an average annual electricity production of 180 GWh. Moreover, its water provides potable supply, after treatment, to surrounding towns and essential agricultural irrigation to 140,000 acres of land. The 23.5 km² lake and its surroundings are extensively used for environmental recreational activities and the local ecosystem is sensitive to human activities and environmental factors.Recently the region was affected by two extreme weather events, in 2020 and 2023, evidently causing extensive mass wasting phenomena in the surrounding drainage basins and torrent discharge points into the lake. Especially after the “IANOS” Medicane (September 17-18, 2020), a systematic monitoring of the lake and its drainage was decided. A synergy of methodologies with state-of-the-art equipment was used, to evaluate the volumes of terrigenous sediment brought into the lake, drastically reducing the water storage capacity of the dam. The reference dataset was a single and multibeam survey carried out back in 2009, accompanied by a photogrammetric mapping of the lake coast at the maximum lake water level.Our 2023 surveys encompass more than 14,000 images which were acquired with a Trinity F90 UAS, flying at a relative height of 160 meters, covering a 200-meter-wide zone around the coast of the lake, with a 70% overlap between the images. Image capturing of the latter took place during the lowest lake water level so that most of this zone would be revealed from the water's surface. The establishment of 15 Ground Control Points (GCPs) at certain locations around the lake increased the spatial credibility of the extracted 2.5 cm resolution Digital Terrain Model. For co-registration reasons, the same GCPs were also used as references during the multibeam survey, which was conducted at transects parallel and vertical to the shoreline routes, 20-90 meters apart, pending on the lake depth, to achieve a complete swath coverage of the lake bottom. The multibeam-sounding survey was carried out at near maximum lake water level, with continuous hourly monitoring of the water level and the water speed of sound.Both methodologies resulted in point-clouds which were unified, and a DTM of the entire lake bottom was constructed, representing the full extent of the water body during the highest water level. The latter was compared to the 2010 dataset and a significant change in the water volume was detected reaching almost 4 million m3. This is clearly related to the volume of sediments brought into the lake, by both sediment gravity flows entering the lake especially within the torrent inlets along the west coast while finer suspended sediment mostly settles in the deepest areas towards the dam.

Disasters arising from geophysical hazards have the potential to trigger extensive structural damage upon the built environment within the impacted area. A substantial proportion of debris generated from earthquakes is a consequence of structural collapse during the ground motion, coupled with the urgent demolition of severely damaged and unstable structures in the course of emergency response and recovery. Among the foremost and pivotal measures undertaken during disaster management is the effective management of the generated debris. This task stands as one of the paramount challenges faced by those involved, given its inherent hazards to both the natural environment and public health. These hazards emanate from the presence of hazardous materials within debris from collapses and demolitions.Numerous challenges and associated hazards emerged in southeastern Turkey after two devastating earthquakes on 6 February 2023 with Mw=7.8 and Mw=7.5 respectively. These seismic events affected a densely populated region encompassing 11 provinces, which included numerous sizable urban centers, such as large cities and towns, along with extensive rural areas comprising countless villages.The convergence of intense ground motion, accompanied by the occurrence of widespread primary effects, such as coseismic surface ruptures, and the triggering of secondary effects, including mainly but not limited to liquefaction and landslides, culminated in the total or partial collapse of tens of thousands of structures and the extensive leveling of residential areas. This fact gave rise to a debris volume deemed the largest since the 1994 Northridge earthquake and challenging to manage, even within well-organized nations.In the course of post-event field surveys conducted by the authors within the earthquake-stricken area, various disposal sites established in the most severely affected provinces were identified and assessed for suitability. The field surveys included the utilization of Unmanned Aircraft Systems (UAS) in the disaster-affected areas, complemented by the examination of satellite imagery in the laboratory to evaluate the characteristics of the sites and their immediate surroundings and to monitor the ongoing debris management activities.The findings indicate that none of the identified sites possessed attributes qualifying them as safe for the treatment and disposal of earthquake debris. Primarily, this inadequacy is attributed to their close proximity to areas densely populated with thousands of residents who engage in daily activities. Furthermore, from the environmental viewpoint, these sites operated either within or in close proximity to surface water bodies. This situation reveals a rush for rapid debris removal and recovery resulting in serious omissions in the preparation of disaster management plans and concessions in their implementation. Consequently, recommendations for effective debris management measures are also proposed in the context of this research based on existing scientific knowledge and operational expertise.

On September 4, 2023, Storm Daniel moved inland from the Ionian Sea, intensifying due to the warmth of the post-summer Mediterranean Sea, resulting in intense rainfall and thunderstorms over the Balkans. Central Greece was particularly affected, experiencing the highest daily rainfall totals recorded in the region.The storm caused widespread devastation, especially in the Thessaly region, with significant impacts including intense erosion, mass movement phenomena triggered by rainfall, damages from strong winds, inundation, agricultural land damage, loss of life and injuries, impacts on residences and businesses, as well as a substantial toll on the environment and cultural sites.This study focuses on Storm Daniel and its effects in Thessaly, Greece, by creating a database of distinct impact elements based on field surveys and public records. Through this archive, the study explores the range of its impacts, developing a systematic categorization to provide an in-depth understanding of the types and mechanisms of these impacts.Examining extreme storms through post-flood surveys and emphasizing their impacts can enhance our comprehension of associated risks. This knowledge will facilitate more accurate predictions and strategic planning for such events, contributing to improved emergency management and recovery efforts. Anticipating the impacts becomes crucial, particularly in the context of the projected increase in the frequency of such events due to climate change, thereby strengthening our preparedness.

On 6 February 2023, the Eastern Anatolia experienced significant devastation due to two major seismic events, leading to the collapse of hundreds of thousands of structures and causing tens of thousands of human casualties, injuries, and homeless people. The substantial magnitude of these impacts is attributed to the extensive occurrence of heavy and very heavy structural damage, categorized as damage grades 4 and 5 according to the European Macroseismic Scale EMS-98, within the earthquake-affected area.The discernible factors contributing to the disaster encompassed the substantial magnitude of the earthquakes, the occurrence of the initial seismic event during nighttime, thereby locating a considerable portion of the population within their residences, and the demographic attributes of the region characterized by densely constructed and populated zones, coupled with the close proximity of numerous residential areas to the ruptured faults. Additionally, the confluence of significant factors, closely associated with the seismotectonic context of the region, the effects of earthquake environmental effects, and the characteristics of the impacted structures, culminated in one of the most extensive earthquake disasters in the recent history of Turkey.This study aims to highlight the factors controlling associated with building properties and the manifestation of earthquake environmental effects that govern the severity and spatial dispersion of structural damage within the earthquake-affected regions under study in the southeastern Turkey. The findings presented herein derive from field surveys undertaken by the authors in the immediate aftermath of the seismic events (7th to 11th February) and subsequently, almost two months later (31st March to 6th April). The field surveys included conventional techniques of geological mapping alongside innovative methodologies, including the deployment of Unmanned Aerial Systems (UAS).With regard to building construction characteristics, insufficient adherence to building codes, arbitrary urban planning solutions, and substandard construction practices constitute primary deficiencies contributed to the disaster. Concerning geological factors, the generation of both primary and secondary earthquake environmental effects significantly influenced the intensity and distribution of damage. Locations where coseismic surface ruptures intersected with built-up areas exhibited heavy to very heavy structural damage, as evidenced along the ruptured segments of the East Anatolian Fault Zone. Liquefaction proximal to water bodies resulted in damage indicative of building foundation load-bearing capacity. Earthquake-triggered landslides predominantly impacted mountainous and semi-mountainous villages and areas characterized by pre-existing susceptibility. The substantial susceptibility to EEEs generation was extensively corroborated in numerous cases, leading to widespread damage. The presented information highlights the pivotal role of such studies in informing hazard mitigation and facilitating disaster risk reduction measures.

The evolution of technology, particularly the integration of Unmanned Aerial Systems (UAS), earth observation datasets, and historical data such as aerial photographs, stand as fundamental tools for comprehending and reconstructing surface evolution and potential environmental changes. In addition, the active geodynamic phenomena in conjunction with climate crisis and the increasing frequency of extreme weather phenomena can cause abrupt events such as rockfalls and landslides, altering completely the morphology on both small and large scales.This study deals generally with the temporal evolution of landscapes and specifically focuses on the detection and quantification of a significant rockfall event that occurred at Kalamaki Beach on Zakynthos Island, Greece – a very popular summer destination. Utilizing UAS surveys conducted in July 2020 and July 2023, this research revealed a rockfall that has significantly altered the coastal morphology. During this period, two severe natural phenomena occurred, one of which could potentially be the cause of this rockfall event. Initially, the Mediterranean hurricane (‘medicane’) ‘Ianos’ made landfall in September 2020, affecting a large part of the country including the Ionian Islands. The result was severe damage to property and infrastructures, along with human casualties, induced by intense precipitation, flash flooding, strong winds, and wave action. Second, in September of 2022, an ML=5.4 earthquake struck between Cephalonia and Zakynthos Islands in the Ionian Sea, triggering considerable impact in both islands. The study employs satellite images postdating these natural disasters, to detect the source of the rockfall in Kalamaki Beach. Additionally, historical analog aerial images from 1996 and 2010 were used as assets for understanding the surface’s evolution. For the quantitative analysis, we applied 3D semi-automated change detection techniques such as the M3C2 algorithm, to estimate the volume of the rockfall.The results provide insights into the complex interplay between natural disasters and geological processes, shedding light on the dynamic nature of landscapes and the potential implications for visitor-preferred areas.This research not only contributes to our understanding of landscape evolution but also underscores the importance of integrating modern and historical datasets to decipher the dynamic processes shaping the Earth's surface. The methodology proposed, serves as a valuable approach for assessing and managing geological hazards in coastal regions affected by both climatic events and geodynamic activities.

The island of Crete represents a portion of the forearc above the northward-dipping Hellenic subduction zone. Crete’s subaerial exposure offers the opportunity to study deformation processes in the forearc area of the rapidly subducting African plate towards the North underneath Eurasia.The examination of river incision patterns and the distribution of morphological discontinuities based on high-resolution digital topographic datasets yields abundant indicators of recent tectonic activity and deformation. The results from the processing of tectonic geomorphology indices (SL, AF, Ksn etc.) leads to the conclusion that the mid-Miocene E-W trending Messara basin in Central Crete is still evolving in the hanging wall of the Southern Crete extensional detachment fault. Several maps generated in a GIS environment display the spatial distribution of tectonic geomorphology indices, and the combination of them clearly points out the contemporary extensional tectonic regime intercalated with transtensional zones trending N-S, normal to the Messara development, which is in agreement with a general pull-apart basin pattern. The tectonic activity is confirmed by the latest seismic excitation, including the recent shallow (~12km depth) strong seismic events that took place the last two years (Arkalochori on Sept.2021, Mires on May 2023), the epicentres of which are located within the Messara basin area, and south of the south-dipping detachment fault trace. The history of the supra-detachment basin started during Middle Miocene, shortly after the compressional phase of the alpine units’ nappe stacking at the southern part of the Hellenic Arc system. The continuous subsidence of its hanging wall provided accommodation space for an individual Messara basin trending E-W. The rearrangement movements of several fault blocks that bound it are clearly imprinted on the tectonic geomorphology indices’ values, presented in this work.

Badlands are among the most intricate and complex types of erosion landscapes typically formed from soft sedimentary rock, such as shale, clay, and sandstone, which can be intensively eroded by precipitation processes. The erosion produces steep slopes, deep canyons, and peculiar geomorphological features that are highly related to this type of landforms. The SE part of Zakynthos Island, located at the Ionian Sea (western Greece), is characterized by such kind of landscape dominated by high inclined marly sandstone formations, of Pliocene age. Besides their high contribution to the geo-diversity of the Island, the Gerakas Badlands are characterized by ecological significance since they host a nesting site for the endangered loggerhead sea turtle, within the National Marine Park of Zakynthos. The study of badlands can offer insights into the processes and mechanisms of erosion since due to their unique rock properties, including their high clay content, low organic matter, and low infiltration capacity, they are exceptionally vulnerable to erosion. Therefore, their relatively rapid reshaping and the processes that affect these geomorphological features could be measured with innovative techniques and equipment. We describe a methodology based on the advancement of technological means and particularly the use of Unmanned Aerial Systems (UAS) which provides detailed information on micro-topography, erosion patterns, and other key features by applying change detection over time.The period needed for monitoring badlands to identify erosion patterns can vary depending on various factors such as the scale of the study area, the climate conditions, and the specific objectives of the study. In this case, the data acquisition was accomplished in two phases three years apart, which were used to create a series of DSMs along with ortho-photo-mosaics, for quantifying the badlands surface topographic changes, before and after at least one severe weather phenomenon (e.g., Medicane Ianos, Sept 2020).

This study presents a comprehensive overview of Greece's geomorphology at a 1:1,000,000 scale, aiming to integrate and interpret the geological and geomorphological factors responsible for the formation and evolution of its landscape. It represents a pioneering cartographic synthesis, bringing together diverse data sources and employing semi-automated GIS techniques. The production of the geomorphological map relied on an extensive literature review of previous studies covering Greece's terrestrial and coastal areas at varying scales. Leveraging high-resolution topography provided by the Hellenic Cadastre and the 1:50,000-scale geological maps from the Institute of Geology and Mineral Exploration of Greece, a spatial geodatabase was established. Several secondary layers, including hillshade, slope-aspect, and red relief image maps, were combined with Google Earth Imagery to delineate landforms across the entire Greek territory. The resulting map offers a comprehensive depiction of landforms originating from both endogenic and exogenic processes. It encompasses structural landforms, fluvial erosional and depositional features, gravity-induced landforms, coastal, karst, volcanic, glacial and periglacial landforms, as well as anthropogenic elements.Additionally, accompanying maps and tables provide essential topographic parameters, geotectonic context, and climatic characteristics. The findings underscore the heterogeneity of Greece's geomorphological environments, shaped primarily by active tectonics and exogenic processes. The map serves as a valuable tool for stakeholders involved in land management, offering crucial insights for informed decision-making. Furthermore, it provides a solid foundation for interdisciplinary research, facilitating investigations spanning fields such as geology, geography, environmental sciences, and more. Overall, this comprehensive geomorphological map represents the latest advancements in the study of Greece's landscape.With its wealth of information and its interdisciplinary relevance, it serves as a vital reference for researchers, educators, and practitioners, fostering a deeper understanding of Greece's dynamic landforms and supporting sustainable land management practices.

On 6 February 2023, East Anatolia was devastated by two major earthquakes resulting in hundreds of thousands of collapses and tens of thousands of human casualties. This paper investigates the factors related to building properties and earthquake environmental effects (EEEs) that contributed to the building damage grade and distribution in southeastern Turkey. In regards to the building construction properties, the loose enforcement of the building code, the random urban planning solutions and the poor construction standards are the main construction deficiencies that led to one of the largest disasters in Turkey’s recent history. Regarding geological factors, the triggering of primary and secondary EEEs largely shaped the grade and distribution of damage. Where coseismic surface ruptures intersected with the built environment, heavy to very heavy structural damage was observed. This was evident in many cases along the ruptured segments of the East Anatolian Fault Zone (EAFZ). Liquefaction observed close to waterbodies caused damage typical of building foundation load-bearing capacity loss. The earthquake-triggered landslides affected mainly mountainous and semi-mountainous settlements characterized with pre-earthquake high related susceptibility. The high susceptibility to generation of EEEs was extensively confirmed in many cases resulting in extensive damage. The provided information highlights the importance of such studies for hazard mitigation and disaster risk reduction.

Earth Observation (EO) is widely recognized as a powerful tool for Climate Change and Sustainability Education (CCSE); however, the uptake of EO data in schools is still limited due to technical, motivational, or informational barriers. A major factor for the exploitation of EO in schools is the availability of curriculum-relevant pedagogical content that is attractive and personally meaningful to learners. Here, we examine whether an EO-based learning scenario developed for primary schools and implemented by EO novice teachers and students, based solely on written instructions, can serve as an effective entry point for incorporating EO into schools and addressing CCSE objectives. Our study showed that: (a) cloud-based EO tools are suitable for EO-novice teachers and students, who quickly become familiar with them and grasp basic EO concepts; (b) the combined use of EO-based and place-based learning helps students bridge the local and the global perspective of Climate Change (CC) impacts; (c) EO-based educational material stimulates students’ interest for satellites and EO technology; (d) the phenomenon-based approach grabs students’ attention, provokes their curiosity, and acts as a springboard for scientific inquiry on CC impacts; and (e) our scenario’s learning approaches promoted teachers’ upskilling and intra-school collaboration.

Light Detection And Range (LiDAR) data have been used in numerous case studies, related to fast-developing landslides and rockfalls, producing remarkably precise Digital Terrain Models (DTMs). When these models are coupled to classic near-surface geophysical methods, they result in the high-accuracy mapping of the open surface and subsurface morphology, an essential element for a modern coastal management study. In this work, we introduce the diachronic monitoring and detection of alterations on the surface of the active fault of Psatha (Greece), via a multiple-phase study within a period of 11 years, by using terrestrial LiDAR scans and Electrical Resistivity Tomography (ERT). The successful combination of these techniques is being used to reveal and quantify the landscape evolution involving the surface alterations at the fault adjacent coastal zone, the sea intrusion, and even the coastline displacement, in any coastal area characterized by similar features.

The cave of Alistrati, is located in the Prefecture of Serres, Northern Greece near the foothills of Mount Menoikio, in the area of Petroto. This area is structured by crystalline limestones, where the development of a complex and multilevel karst system is favored. An extensive geomorphological survey was carried out for the accurate mapping of the karst surface above the cave, using UAS. For the investigation of a possible lateral extension of the existing karstic conduit, a detailed surface geophysical investigation was carried out. More specifically, three geophysical techniques were implemented: a) the Electrical Resistivity Tomography (ERT), b) the Ground Penetrating Radar (GPR) technique and c) the Very-Low Frequency (VLF) method. These 13 lines of the three geophysical techniques are fully matched at 4 locations and were join-interpreted, yielding remarkable findings. The comparative results of the above geophysical techniques, as well as their 3D presentation, highlight similar geophysical anomalies, evaluated as different types of karst system structures. Therefore, the combined geophysical survey has indicated the existence and interconnection of the first two karst levels of the area, up to a depth of 50m, as well as the possible extension of the Alistrati karstic conduit to the northeast.

On 6 February 2023, southeastern Turkey was struck by two major earthquakes that devastated 11 provinces. Tens of thousands of buildings collapsed and more were later demolished. During post-event field surveys conducted by the authors, several disposal sites set up in the most affected provinces were detected and checked for suitability. Based on field observations on the properties of sites and their surrounding areas as well as on the implemented debris management activities, it is concluded that all sites had characteristics that did not allow them to be classified as safe for earthquake debris management. This inadequacy is mainly attributed to their proximity to areas, where thousands of people reside. As regards the environmental impact, these sites were operating within or close to surface water bodies. This situation reveals a rush for rapid recovery resulting in serious errors in the preparation and implementation of disaster management plans. In this context, measures for effective debris management are proposed based on the existing scientific knowledge and operational experience. This paper aims to highlight challenges during earthquakes debris management and related threats posed to public health and the environment in order to be avoided in future destructive events.

Many issues arise from the recession of sea cliffs, including threats to coastal communities and infrastructure. The best proxy to study cliff instability processes is the cliff face evolution. Unfortunately, due to its verticality, this proxy is difficult to observe and measure. This study proposed and compared three remote sensing methods based on structure-from-motion (SfM) photogrammetry or stereorestitution: boat-based SfM photogrammetry with smartphones, unmanned aerial system (UAS) or unmanned aerial vehicle (UAV) photogrammetry with centimetric positioning and Pléiades tri-stereo imagery. An inter-comparison showed that the mean distance between the point clouds produced by the different methods was about 2 m. The satellite approach had the advantage of covering greater distances. The SfM photogrammetry approach from a boat allowed for a better reconstruction of the cliff foot (especially in the case of overhangs). However, over long distances, significant geometric distortions affected the method. The UAS with centimetric positioning offered a good compromise, but flight autonomy limited the extent of the monitored area. SfM photogrammetry from a boat can be used as an initial estimate for risk management services following a localized emergency. For long-term monitoring of the coastline and its evolution, satellite photogrammetry is recommended.

On October 30, 2020, 11:51 UTC, a large shallow earthquake of moment magnitude Mw7.0 ruptured the eastern Aegean Sea area and affected several Greek islands, mainly Samos, as well as the Izmir area, western Turkey. A moderate damaging tsunami followed the earthquake and inundated many coastal zones in the area. At 12:15 UTC, the Greek Civil Protection sent to the residents of the eastern Aegean Sea Greek islands a tsunami alert via SMS through the single European emergency phone number 112. It has been the first time that a tsunami warning was publicly issued in the frame of the North-East Atlantic and Mediterranean Tsunami Warning System (NEAMTWS/IOC/UNESCO) since the system became operational during the summer of 2012. Through an on-line questionnaire survey conducted soon after the event we investigated the impact the tsunami 112 alert message had among the population. The aim of this study is to assess the effectiveness of the 112 number as a tool for tsunami early warning, to look after possible weaknesses that may need future improvements and to better understand the level of tsunami risk awareness among the population. The response received from 344 citizens clearly indicates that the particular tsunami alert in general had positive impact to the message recipients, but highlights several weaknesses of the tsunami emergency management chain in Greece and demonstrates some aspects of the 112 system that need improvement.

In this paper, we present a systematic GIS-based approach for producing updated, upscaled, unified and reevaluated maps for the Ionian Islands of Greece, which is an area of great geological interest. In particular, Cephalonia and Lefkada are two islands with an increased and intense seismicity. Therefore, a common GIS geodatabase was produced for handling the geoinformation of the area. New upscaled (scale 1:50,000) geotechnical and seismotectonic maps of these islands were produced based on older ones. On the other hand, the corresponding maps of the islands, based on the categories of the Greek antiseismic code and Eurocode 8, were produced in an effort to correlate them. Beyond that, all the available isoseismal maps of the earthquakes that hit the Ionian Islands were gathered in an effort to evaluate them and to find possible correlations with the other types of maps. Based on the correlation results, the consideration of the Vs30 parameter in the Greek antiseismic code is proposed for a better categorization of the geological formations.

The geosites of Lemnos represent local touristic products that, beyond their high aesthetic value, display significant scientific links to the geological past as well as prehistory and history, archaeology, mythology and religious heritage of the island. The unique wealth of Lemnos geosites in combination with the abundance of archaeological sites, cultural monuments and museums composes the basis of what we define here as “Geo-Archaeo-Routes”: certain routes that can be geographically defined, offered, guided and finally followed by the touristic masses. The outcome of the performed quantitative Lemnos geosite assessment enables decision making, thus providing a toolbox useful for sustainable Geo-Archaeo-tourism development at a local level and forms the basis for designing “Geo-Archaeo-Routes”. “Geo-Archaeo-Routes” are particularly favorable of environmentally friendly alternative types of tourism, attracting naturalists, hikers, fans of cultural or religious tourism and many others who represent a major part of the touristic needs of the 21st century. The established hiking and road “Geo-Archaeo-Routes” on Lemnos Island may represent a distinctive touristic product as they offer a high level of “nalture” entertainment, blending “nature with culture” in the framework of a holistic geotouristic approach.

Despite being relatively rare, Mediterranean tropical-like cyclones, also known as Medicanes, induce significant impacts on coastal Mediterranean areas. Under climate change, it is possible that these effects will increase in frequency and severity. Currently, there is only a broad understanding of the types and mechanisms of these impacts. This work studied Medicane Ianos (September 2020) and its effects on the Ionian Islands, in Greece, by developing a database of distinct impact elements based on field surveys and public records. Through this archive, the study explored the range of Ianos’ impacts to develop a systematic categorization. Results showed different types of effects induced on the natural and the built environment that can be grouped into 3 categories and 39 sub-categories in inland and coastal areas, indicating an extensive diversity of impacts, ranging from flooding and geomorphic effects to damages in various facilities, vehicles and infrastructure. The systematic description of the typology of Medicanes’ effects presented in this study is a contribution to a better understanding of their consequences as means to improve our ability to prepare for, respond to, and recover from them, a necessary stepping stone in improving the overall preparedness of both the general public and relevant authorities.

Coastal erosion induced either by a natural process and/or human intervention has been the subject of extensive investigations due to their negative socio-economic impact. ILIDA-KIT is an innovative and multi-parametric decision-making tool for successful management of coastal erosion and the impacts of storms. Thus, within the framework of the ILIDA-KIT tool, beach zone sectors of the west and south coast of Peloponnesus (Greece) (i.e. Helonitis Gulf, Kyparissiakos Gulf and Messiniakos Gulf) have been investigated with geophysical means, aiming to the quantification of the sediment budget that is essential for the confrontation of the phenomenon. The geophysical research aims to identify the thickness and the characteristics of the uppermost lithostarigraphic substratum of the selected beach zone sectors, whose common characteristic is the presence of dunes at the backshore zone. Apart of the other geophysical techniques (e.g. electrical resistivity tomography (ERT), transient electromagnetic soundings (TEM), vertical electrical soundings (VES)) that have been applied, the present contribution provides the preliminary results concerning the application of the ground penetrating radar (GPR) technique. The GPR electromagnetic method was implemented to profiles normal to the shoreline contributing to (a) the quantification of the erodible part of the beach zone and (b) the determination of the base of the sand dunes.

The present-day geotectonic regime of Crete Island is mainly controlled by the processes occurring along the seismically active Hellenic subduction zone, e.g., the fast convergence between Africa - Eurasian plates (at a rate of 36 mm/yr) and the simultaneous SSW-ward retreat of the subducting slab. The result is a large south-facing orogenic wedge extending from the southern coast of Crete up to the Hellenic subduction trench to the South. Contractional structures (thrusts, folds, and duplexes) have formed in the deeper parts of the wedge and caused the thickening of the crust. This has led to substantial regional uplift and extension of the upper part of the wedge. Hence, two significant arc-parallel and arc-normal sets of active normal faults crosscut the Cretan mainland, affecting the entire alpine nappe pile. These faults have created a characteristic basin and range topography expressed through impressive E-ESE and N-NNE horst and graben structures bounded by fault zones with segments ranging from 5 to more than 20 km. Detailed fault mapping of the Mirabello Gulf – Ierapetra Basin depression revealed a dominant NNE-SSW fault system, occupying the central and northern part, and a subordinate E-W to ESE-WNW system, observed mainly along the southern coastal zone. In the ESE margin, the deformation is localized mainly along the 30 km long NNE-SSW Kavousi – Ieraptera fault zone. On the other hand, in the WNW margin, the deformation is distributed in a larger population of relatively minor faults, organizing in more complex second-order horst and graben structures. In the southern part of the Ierapetra Basin, the E-W to ESE-WSW faults are significantly less and concern 2-3 specific zones. Specific morphological structures such as the remarkable range high, the deep V-shaped gorges, the large scree thickness, and the prominent post-glacial fault scarps produced along the basin margins indicate the intensive activity of these faults during the Quaternary. The NNE-SSW fault system seems to be younger and more active, given that i) intersects the E-W or ESE-WNW faults of the southern part, ii) produces significant fault scarps and polished fault surfaces in the cemented scree along the fault zone, and iii) kinematically is compatible with the recent and present-day focal mechanisms (e.g., the 2021 Arkalochori earthquakes). In conclusion, the Ierapetra Basin has formed and developed through an overall E-W extension parallel to the present-day geometry of the arc.

Post-fire geomorphic processes and associated risks are an important threat in Mediterranean environments. Currently, post-fire mass movement prediction has limited applications across the Mediterranean despite the abundance of both forest fires and landslide/debris flow disasters. This work applies a debris flow generation likelihood model to evaluate the probability of mass movement phenomena in different catchments of a burnt area, after a catastrophic fire near Schinos (Attica, Greece) in 2021. Then, it uses field observations from the area, recording mass movement phenomena after high-intensity rainfall events, to validate the results. The findings show that the model is successful in determining the probability of debris flow generation in the 21 basins of the study area, ranging from 0.05 to 0.893. The probability values show a statistically significant correlation (sig. = 0.001) with the actual debris flow occurrences in the area, and satisfactory results in terms of the model’s predictive ability, functioning well within the particular geo-environmental characteristics of the Mediterranean environment. The results establish the reliability of the approach as a tool to assess mass movement risks in a region with an abundance of post-fire related hazards and disastrous events.

This paper presents the methodology of an applied geophysical and remote sensing research at river deltas for their subsurface and surface structure and its application in the deltaic plain of Pineios River (Thessaly, Greece). The scope is to primarily calculate the thickness of deltaic post alpine deposits, with the contribution of Transient Electromagnetic Method (TEM), but also identify the surficial characteristics (biotic/ abiotic) of the area with the appropriate combination of spectral bands and spectral indices. Regarding the remote sensing approach, some geomorphological features were outlined. This was managed from six false color composites of the area, produced by combining spectral bands and additional five false color composites by combining several spectral indices. • The results of the TEM method along with their statistical analysis provided important information regarding the spatial distribution and thickness of the lithological units along the deltaic plain • The combination of spectral bands 8, 7, 6 seems to adumbrate the hydrographic network of the area and even detects possible changes in the inflow. • The combination of spectral indices MSAVI2, WV-BI, WV-WI was helpful enough to geomorphological mapping of the deltaic plain.

Geomorphological and sedimentological indicators are often used to reconstruct not only coastal evolution, but also relative sea level changes. In this work, we studied the coastal sediments of Psatha bay (Alkyonides Gulf, Greece) and beachrock outcrops in order to reconstruct the coastal evolution of the area. The drillings analysis included stratigraphy, sediment texture and radiocarbon dating. Detailed mapping of the beachrocks was accomplished using DGPS-GNSS, as well as mineralogical analysis and OSL dating of beachrock samples. The new beachrock index points indicate a sea level that fell by 0.64 ± 0.13 m since 2200 ± 210 years BP and by 0.95 ± 0.13 m since 4160 ± 320 years BP, as a direct result of its location near the uplifting footwall of Psatha fault, suggesting further a rate of tectonic uplift of ~0.26 mm/yr for the late Holocene.

Extreme weather events can trigger various hydrogeomorphic phenomena and processes including slope failures. These shallow instabilities are difficult to monitor and measure due to the spatial and temporal scales in which they occur. New technologies such as unmanned aerial systems (UAS), photogrammetry and the structure-from-motion (SfM) technique have recently demonstrated capabilities useful in performing accurate terrain observations that have the potential to provide insights into these geomorphic processes. This study explores the use of UAS-aided photogrammetry and change detection, using specialized techniques such as the digital elevation model (DEM) of differences (DoD) and cloud-to-cloud distance (C2C) to monitor and quantify geomorphic changes before and after an extreme medicane event in Myrtos, a highly visited touristic site on Cephalonia Island, Greece. The application demonstrates that the combination of UAS with photogrammetry allows accurate delineation of instabilities, volumetric estimates of morphometric changes, insights into erosion and deposition processes and the delineation of higher-risk areas in a rapid, safe and practical way. Overall, the study illustrates that the combination of tools facilitates continuous monitoring and provides key insights into geomorphic processes that are otherwise difficult to observe. Through this deeper understanding, this approach can be a stepping stone to risk management of this type of highly-visited sites, which in turn is a key ingredient to sustainable development in high-risk areas.

Lefkada and Corfu old towns are located in the western part of Greece, in the Ionian Sea. Their proximity to the Hellenic subduction zone (HSZ) is the reason for their intense seismicity. The main goal of this study was the estimation of the geotechnical characteristics of the subsurface, with the contribution of applied geophysical techniques. Therefore, seismic refraction tomography (SRT) and multichannel analysis of surface waves (MASW) were applied. A total of thirty-three (33) seismic and geoelectrical profiles were performed in both towns in order to evaluate the geotechnical characteristics of the subsurface formations. Additionally, subsurface resistivity distributions were investigated with the application of electrical resistivity tomography (ERT). Some important elastic moduli were calculated through the combination of estimated seismic wave velocities and laboratory density measurements. The horizontal distribution of seismic velocities and mechanical properties (σ, E, K, G) of Corfu town was illustrated in maps, for the depth of 5 m. The geophysical interpretation also revealed that Lefkada’s subsurface consists of only one compact geological formation, with little or no variation of its geophysical-geotechnical characteristics. Beyond that, the ground type classifications for the two towns were determined according to the European Committee for Standardization Eurocode 8, based on Vs30 values.

The coastal area of Myrtos beach, is a very popular Natura protected area at the Northern part of Cephalonia Island, in W. Greece, which suffered severe damages during the Medicane named after “Ianos”, that affected the Greek territory in September 2020. Most of the steep slope area, which hosts the road that leads to the the beach area itself were extensively covered by debris due to mudflows, interrupting aggressively the road connection with the inland network. The use of Unmanned Aerial Systems proved to be an ideal way of mapping quite small areas, with limited access to road networks. The generation of ultra-high resolution spatial products seems to be optimal for mapping and quantifying mass movements that cover areas ranging from less than one square kilometer up to few square kilometers. The aim of such a multi-temporal study, which is described herein, contains aerial image data collection and analysis, before and after the catastrophic event. It is leading to the quantification of the surface topographic changes, by generating a time series of point clouds, after creating several terrain models along with ortho-photo-mosaics, based on Structure-from-Motion photogrammetric techniques. The digital comparison of the co-registered photogrammetric products showed that significant surface alterations have taken place due to the 2020 Medicane. The diachronic point clouds led to the detection and quantification of elevation changes, mainly at the central part of the area of interest, whereas the elevation values of the point clouds were found rather altered, before and after “Ianos”, either positively (deposition) or negatively (erosion), delineating the areas that suffered surface changes.

Precision Agriculture (PA) tends to become a contemporary trend nowadays, as agriculture constitutes a really big part of economy with great social impact around the world. Among the advantages of using Precision Agriculture (PA) are the decrease in cost, time and human resources. Aerial remote sensing data processing and interpretation is a modern way of recognizing and classifying vegetation, within high resolution and precision imagery outputs, which can be utilized for further image processing and classification such as in Normalized difference vegetation index NDVI, Modified Chlorophyll Absorption Ratio Index, MCARI, and Modified Soil-Adjusted Vegetation Index, MSAVI. The application of such thematic products may lead to the best decisions for the most prominent ways of interference during the entire cultivation process. Using unmanned aerial systems (UAS), onboard sensors and GNSS for better precision and of course high residual multispectral images with several bands which can give precious information after being post processed, the data acquisition phase has become relatively easy and with the lowest cost, not to mention the frequent update upon request. In this work, we present a multispectral flying platform. The proposed solution is based on a commercial Quantum Trinity F90+ drone equipped with a combination of a high-resolution RGB camera UMC R10C and a multispectral MicaSense RedEdge-MX camera.

Τhis study aims to investigate to what extent the drainage systems of the northern part of Evia Island, in Central Greece, reflect the contemporary tectonic regime of the area. The effects of tectonic activity have been detected and described by performing a landscape morphological analysis of the drainage systems, followed by a field survey for validating the results. The Relative Declivity Extension (RDE) index, which is based on the Stream Length (SL) gradient index, was calculated along the channels of 189 drainage basins of the study area, using the Knickpoint Finder tool integrated into ArcGIS desktop. The Hack RDE index is defined by the ratio of the RDEs index (which refers to a stretch) and the RDEt index (which refers to the total length of a river) was applied, and its calculation identifies the knickpoints based on anomaly values detection along the longitudinal profiles of the rivers. Furthermore, knickpoint analysis was carried out along the channels of the drainage networks of the northern part of the Evia Island and the corresponding anomaly maps were designed. A total of 2,486 knickpoints were identified and the greatest anomalies (139 points), named first-order anomalies (RDE>10), seem to correspond to a recently shaped or rejuvenated landscape, indicative of intense neotectonic activity. In some cases, the spatial distribution of knickpoints delineates a NW-SE trending yielding the structural control of the study area. The comparison of the results with the lithological map of the area showed that about 30% of the knickpoints are lithologically controlled. The identification of zones of neotectonic activity and consequently the existence of active faults is highly correlated with the distribution of knickpoints and their core density, the drainage density, the drainage asymmetries, and other morphometric indices such as the hypsometric integral, along with the earthquake epicentres, and the morpho-lineament density. The overall analysis showed a positive correlation of the concentration of the derived knickpoints with both active structures and tectonic activity rates. The results were consistent with field observations, which were mainly focused on waterfall landforms. Our study proves that the landscape evolution of the northern part of the Evia Island is considerably affected by the recent activity of normal fault zones, whereas the drainage systems react to the changes of base-level providing insights on active tectonics.

Technical advancements have widened the limits of remote sensing and Terrestrial Laser Scanning technology in studying underground cavities. Furthermore, the use of Unmanned Aerial Systems has proven to be a significant advantage in the study of caves, as under certain circumstances during the data processing, it is plausible to combine TLS and UAS data for generating a complete 3D model, representing surface and subsurface simultaneously. The use of state-of-the-art laser scanning equipment either terrestrial or handheld accompanied by total station measurements on a series of ground control points, has resulted in the scanning and detailed mapping the entire Melissani and Drogarati caves, in Cephalonia Island, in Greece, including hidden cavities. This study attempted not only to delineate a new methodology for compiling a highly detailed cave map, but also to identify structural discontinuities and faults for further investigation of the influence of rock failures in causing rock falls and further damage in the caves. Both show caves attract many visitors and since they are located at an area of very high seismicity, where large earthquakes occur very frequently, the risk is rather high. The methodology is based on the synergy of equipment in different working levels, since the cave environment is by far one of the most difficult cases to survey, led to hazard identification in high detail and accuracy throughout the cavity. The fieldwork includes the generation of a unified point cloud for the underground cavity, generated by scanning at several bases inside the cave and by entering smaller cavities by holding the mobile scanner. The bundling of the partial point clouds is possible since the proposed methodology includes the establishment of a dense network of Ground Control Points, which are measured with Total Station equipment for gaining actual coordinates. After the merging of the partial scans were combined into a single point cloud, the methodology continues with further processing including filtering and noisy points removal. Moreover, the final product is combined with the point cloud that was generated after the photogrammetric processing and the methodology is completed with exporting the results in file formats that can be imported in several geotechnical or discontinuity recognition software for further interpretation. The results along with the produced 3D models could be utilized to determine areas susceptible to different failure types. The assessment of rock stability within a cave by combined innovative equipment, techniques, and research methods could be considered by the management authorities for the maintenance and/or re-design the tourist routes.

This study presents the preliminary results of selected samples from Aggelokastro section, Argolida, Greece. The section is comprised of a ~200m thick carbonate sedimentary succession, capped by ~50m of clastic sediments of the “schist-sandstone-chert” formation. The entire sedimentary sequence belongs to the Sub-Pelagonian type B Unit, member of the tectonostratigraphic terrain H3, equivalent to the non-metamorphic Pelagonian platform (Papanikolaou, 1990; Papanikolaou, 2021). In total 12 thin sections were produced from selected samples and studied under the microscope. Each sample was characterized according to the Standard Microfacies (SMF) scheme of Flugel (2010). The results show significant diversion between paleoenvironmental conditions and are divided into three main parts (see Fig. 1): -          Lower formation: shallow water carbonate succession with densely packed peloidal packstones-grainstones with coated benthic foraminifera (Orbitopsella and others), gastropods and echinoids (SMF 11, platform margin shoals or platform margin reef) and wackestones with gastropods, benthic foraminifera and algae (SMF 8, open marine-interior platform) -          Middle formation: transitional (slope) environment carbonates, represented by a polymictic breccia grading to wackestone with subangular-subrounded lithoclasts and bioclasts (shell debris, radiolaria, benthic foraminifera and large bivalve shells) (SMF 4, slope or toe-of-slope) and -          Upper formation: deep marine environment carbonates, including Ammonitico Rosso facies, represented by wackestones-packstones with spicules, thin shelled bivalves, radiolaria and planktonic foraminifera (SMF 1 and 3, deep shelf or deep sea). Additionally, smear slides from the “flysch-like” succession point to a deep marine clastic environment with rare or absent carbonate material. The defined Standard Microfacies show a clear deepening upward trend, marking the rifting of the carbonate platform. Regarding geological age considerations, the lower formation should be considered as Early Jurassic (late Sinemurian – middle/late Plienbachian) due to the presence of Orbitopsella sp. (Ogg et al., 2016). The Ammonitico Rosso facies of the upper formation is tentatively attributed to Middle Jurassic, similarly to the dating of radiolarites above the carbonate platform (Danelian and Robertson, 1995) in Beotia area. Lastly, the “flysch-like” clastic succession is generally considered of Late Jurassic-Early Cretaceous age, according to Papanikolaou (1990).

A strong, shallow earthquake occurred near Heraklion (Crete, Greece) on 27 September 2021. The earthquake produced significant ground deformation in the vicinity of Arkalochori village but without any evidence for surface ruptures of primary origin. We used geodetic (InSAR and GNSS) data to map motions of the Earth’s surface that occurred during and shortly after the earthquake. A 14 cm subsidence of the GNSS station ARKL and a maximum of 19 cm distance from the SAR satellite were recorded. The measured surface displacements were used to constrain the rupture geometry and slip distribution at depth. Our best-fitting inversion model suggests that the rupture occurred on a 13 km-long planar normal fault striking N195° E dipping 55° to the northwest, with major slip occurring to the east and updip of the hypocentre. The fault tip is located 1.2 km beneath the surface. The maximum coseismic slip occurred in the uppermost crust, in the depth interval of 4–6 km. A decrease in the fault offsets toward the Earth’s surface is likely caused by an increased frictional resistance of the shallow layers to rapid coseismic slip. Satellite observations made in the first month after the earthquake detected no post-seismic deformation (i.e., below one fringe or 2.8 cm). The seismic fault may be identified with the Avli (Lagouta) segment of the NNE-SSW striking, west-dipping, 23 km-long neotectonic Kastelli Fault Zone (KFZ). Part of the rupture occurred along the Kastelli segment, indicating a fault segment linkage and a history of overlapping ruptures along KFZ. Based on geological data and footwall topography we estimate an average slip rate between 0.17–0.26 mm/yr for the KFZ. The Arkalochori earthquake is a paradigm example for the on-going extension of Heraklion basin (central Crete) in the WNW-ESE direction, which is almost orthogonal to the E-W Messara graben and other active faults along the south coast of Crete.

Field geological mapping is the initial step of preliminary research in mining. However, in the last decades, the rapid progress of remote sensing data processing and its use for reconnaissance of geological outcrops for the purpose of locating possible mining sites gained increasing attention due to the significant time and cost savings. In this study, a new methodology, focused on mapping ferronickel (Fe–Ni) laterite deposits by using Sentinel-2 satellite data, is introduced. It describes a novel spectral index (called laterite spectral index (LSI)) that enhances laterite surface outcrops. To the best of our knowledge, LSI is the first spectral index tailored for this task, concerning minerals that are simultaneously rich in Fe and Ni. The LSI was applied on a continuum removed image by taking advantage of the spectral features present in two specific spectral areas of 490–560 nm and 842–945 nm. The entire methodology was tested and validated on four different excavation sites in eastern Central Greece based on known drillholes. In all excavation sites, the proposed LSI compared favorably with other relative spectral indices proposed in the literature for the detection of Fe-bearing minerals or Fe-oxides.

The current study aims to clarify the structural regime of the deltaic valley of Pineios river (Thessaly, Greece). The structural control of a deltaic area is usually a crucial parameter for its Palaio-geographical evolution and the latter needs to be clear for the contemporary conservation of such a sensitive ecotope environmentally. The investigation of the concealed subsurface tectonic structures was accomplished through the combined interpretation of gravity measurements, VES and TEM soundings. The standard gravity data reduction has been carried out and the residual anomaly was isolated with the contribution of the Fourier filters. The Euler deconvolution has been applied, providing the corresponding depth solutions between 159.8 and 1716.6 m. In the context of the qualitative interpretation, we produced several structural maps (THDR, VDR, Tilt and Theta) in order to enhance the edges of density sources that may reflect fault zones. Severe indications for the delineation of fault zones of the area were provided by these maps. Moreover, 3D density models of the area have been constructed illustrating the subsurface density distribution, up to depths of 3370 m. A main zone of lower densities in the central part of the delta has been revealed, surrounded by three zones of higher densities. Afterwards, the densities of the majority of the existing geological formations were determined with laboratory measurements from geological specimens. Therefore, three geophysical-geological profiles have been constructed, based not only on the gravity modelling but also on the geological interpretation of the geoelectrical layered models from the VES and TEM measurements. In conclusion, concealed and unknown tectonic structures of the Pineios deltaic valley have been identified beneath the surface.

Cephalonia, located in the middle of the central Ionian Islands, has been affected by destructive earthquakes during both the instrumental and the historical period. Despite the fact that it is widely studied from several scientific viewpoints, limited research has been conducted so far regarding the earthquake-triggered landslides (ETL) and the related susceptibility. In the context of the present study, an inventory with 67 ETL from 11 earthquakes that occurred from 1636 to 2014 is presented. Given this record, the study further examines the ETL susceptibility exploiting 10 landslide causal factors in the frame of a GIS-based Analytic Hierarchy Process (AHP). Four factors (i.e., slope, PGA, tectonic structures and lithology) were associated in a higher degree to the locations where ETL occurred on the island. Based on the comparison of the ETL inventory and the landslide susceptibility index (LSI) map, the distribution of ETL in Cephalonia is not random, as their majority (82%) were generated within high to critically high susceptible zones. This fact, along with the AUC values of 80.3%, reveals a fair-to-good accuracy of the landslide susceptibility assessment and indicate that the contribution of the studied variables to the generation of ETL was effectively determined

The Arkalochori village in central Crete was hit by a large earthquake (Mw = 6.0) on 27 September 2021, causing casualties, injuries, and severe damage to the infrastructure. Due to the absence of apparent surface rupture and the initial focal mechanism solution of the seismic event, we initiated complementary, multi-disciplinary research by combining seismological and remote sensing data processing, followed by extensive field validation. Detailed geological mapping, fault surface measuring accompanied with tectonic analysis, fault photorealistic model creation by unmanned aerial system data processing, post-seismic surface deformation analysis by DInSAR image interpretation coupled with accurately relocated epicenters recorded by locally established seismographs have been carried out. The combination of the results obtained from these techniques led to the determination of the contemporary tectonic stress regime that caused the earthquake in central Crete, which was found compatible with extensional processes parallel to the Hellenic arc.

The complexity of show caves and the problems arising through human interaction with them, require interdisciplinary approaches capable of synthesizing a range of parameters such as knowledge, methods and provided tools to promote geo-ethical thinking and geoscientists contribution for sustainable management. Show caves are tourist/commercial caves which have been accessible to the public with artificial lighting, shaped paths, guided tours, open hours and they are considered as heritage sites. The concept of heritage is a complex idea, controversial and culturally constructed, depending on the personal and collective background and experiences of the members of a society. Heritage is often artificially divided into natural and cultural, but regarding the “show caves” as entities, the boundaries are indistinguishable. Moreover, show caves suffer successive degradation for several interconnected reasons. This work analyzes proposals for compilation of protocols and general management that may involve educational institutes, management agencies, policy makers and stakeholders based on remotely monitored parameters and scientific data collection, for feeding assessment and evaluation tools. The main scope is to arouse a wider dialogue of the interested parts with the aim to form the basis for the creation of a European legislation for protecting these sensitive but also complex environments through geo-conservation and geo-ethics approaches.

On September 27, 2021, an Mw=6.0 earthquake struck the central part of Crete Island (southern Greece) and in particular the Heraklion Region. This event was preceded by an extended foreshock sequence started on early July 2021 and it was followed by an Mw=5.3 aftershock on the following day. Taking into account the spatial distribution of foreshocks and aftershocks and the focal mechanism of mainshock as well as the active faults of the earthquake-affected area, it is evident that the seismic activity is strongly related to the NNE-SSW striking W-dipping faults of the Kasteli fault zone located along the eastern margin of the Neogene to Quaternary Heraklion Basin. The latter has been filled with Miocene to Holocene post-alpine deposits. A field reconnaissance conducted by the authors in the earthquake-affected area shortly after the mainshock revealed that the earthquake-triggered effects comprised mainly rockfalls and slides, as well as ground cracks within or close to landslide zones. These effects were located within the hanging-wall of the KFZ. The affected sites are mainly composed of Miocene deposits and they are characterized by pre-existing instability conditions and high susceptibility to landslides. Far field effects were also observed south of the earthquake-affected area and in particular in the southern coastal part of Heraklion Region. In regards to the spatial distribution of the earthquake-induced building damage, the vast majority was caused in villages and towns founded on Miocene and Holocene deposits of the hanging-wall. Damage was not reported in settlements located in the footwall, which is composed of alpine formations. The dominant building types of the earthquake-affected area comprise: (i) buildings with load-bearing masonry walls made of stones and bricks with clay or lime mortar, mainly constructed without any anti-seismic provisions and (ii) buildings with reinforced-concrete frame and infill walls constructed according to the applicable seismic codes. The former suffered the most severe structural damage including partial or total collapse in many villages founded on post-alpine deposits of the hanging-wall of KFZ. The latter responded satisfactory during the mainshock and were less affected with only non-structural damage including cracking, detachment of infill walls from the surrounding reinforced concrete frame, peeling of concrete and short-column failures. From the abovementioned, it is concluded that the impact of the 2021 Arkalochori earthquake was limited to the hanging-wall of the causative fault zone and in particular to residential areas founded on post-alpine deposits and to slopes highly susceptible to failure within the Heraklion Basin.

Mediterranean tectonically-active coastal areas are a highly-dynamic environment balancing internal tectonic dynamics with external geomorphic processes, as well as manmade influences. Especially in touristic areas characterized by high built-up pressure and land value, where these dynamics are even more concentrated, the evolution of coastal environments needs careful and high-resolution study to identify localized risk and the processes they derive from.Recently, new advanced remote sensing techniques such as Unmanned Aerial Systems (UAS)- and Terrestrial Laser Scanners (TLS)-aided monitoring have improved our capabilities in understanding the natural processes and the geomorphic risks (i.e. mass movement phenomena).An integrated study comprising Unmanned Aerial Vehicles (UAV) and Light Detection And Ranging (LIDAR) sensors was conducted in coastal areas of the southern Ionian Islands (Western Greece) aiming to the mitigation of earthquake-triggered landslide risk and to responsible coastal development. Located at the northwesternmost part of the Hellenic Arc, this area is characterized by high seismicity and has been affected by destructive earthquakes mainly due to the Cephalonia Transform Fault Zone (CTFZ), which constitutes one of the most seismic active structures in the Eastern Mediterranean region. One of the most common environmental effect triggered by these earthquakes are landslides distributed along fault scarps in developed and highly visited coastal areas. Furthermore, this area is highly susceptible to hydrometeorological hazards inducing intense geomorphic processes, including Medicanes among others.These technologies allow a highly-detailed view of landslide processes, providing insights on the structures and factors controlling and triggering failures along coastal scarps as well as highlighting susceptible zones and high-risk areas with accuracy and mitigating adverse effects with precision and clarity. Overall, by providing a better understanding of the risks the approach used allows a more sustainable development of these coastal segments enhanced by risk mitigation.The study was conducted in the framework of the project “Telemachus - Innovative Operational Seismic Risk Management System of the Ionian Islands”, co-financed by Greece and the European Union (European Regional Development Fund) in Priority Axis “Environmental Protection and Sustainable Development” of the Operational Programme “Ionian Islands 2014–2020”.

Seismicity in the Ionian Sea (W. Greece) is mainly generated along the Cephalonia–Lefkada Transform Fault Zone (CLTFZ) in the central Ionian, and on the northwestern termination of the Hellenic subduction margin in the south. Joint pre-, co- and post-seismic ground deformation and seismological analysis is performed at the broad Ionian area, aiming to homogeneously study the spatiotemporal evolution of the activity prior to and after the occurrence of strong (M > 6) earthquakes during the period of 2014–2018. The 2014 Cephalonia earthquakes (Mw6.1 and Mw5.9) were generated on a faulting system adjacent to CLTFZ, causing local ground deformation. The post-seismic sequence is coupled in space and time with the 2015 Lefkada earthquake (Mw6.4), which occurred on the Lefkada segment of the CLTFZ. Co-seismic displacement was recorded in the broader area. Seismicity was concentrated along the CLTFZ, while its temporal evolution lasted for several months. The 2018 Zakynthos earthquake (Mw6.7) caused regional deformation and alterations on the near-velocity field, with the seismicity rate remaining above background levels until the end of 2021. In the northern Ionian, convergence between the Apulian platform and the Hellenic foreland occurs, exhibiting low seismicity. Seismic hazard assessment revealed high PGA and PGV expected values in the central Ionian.

Coastal areas constitute a very dynamic environment, balancing between numerous natural and anthropogenic processes liable to sometimes hazardous geomorphic phenomena. Especially in tectonically active coastal regions and areas of high economic value, slope failures can have significant impacts and therefore need careful and detailed examination. This work uses Unmanned Aerial System (UAS)-aided photogrammetry and Terrestrial Laser Scanning (TLS) in tectonically active segments of the coastal zone of the Ionian Islands in Greece, to explore how their capabilities can help to improve our understanding of the structural integrity of the slopes. Results show that the two approaches are able to extract large numbers of discontinuity facets, in a more practical, rapid and safe way than conventional methods of rock slope stability analysis extending to unreachable yet important parts of the slope. Through this holistic record of the structural condition of the slope the two applications allow the identification of segments that are more prone to instability and failure. In this way, they improve our understanding of the prioritization of interventions aiming to enhance the prevention of slope failures, mitigating the associated risk and improving local development in these high-value locations.

Geological heritage or geoheritage refers to the total of geosites, i.e., areas of high geological interest in a given area. Geosites have a high potential of attracting geotourists, thus contributing to the development of the local economy. Assessing sites of geological interest can contribute to their promotion, as well as their preservation and protection. Greece’s geotectonic position in the convergent zone between the African and Eurasian plates has contributed to the existence of a considerable wealth of geosites, with the particularly active geotectonic region of the Ionian Sea characterized as a geoheritage hotspot. The purpose of this study is the selection of several such sites from the islands of Lefkas, Meganisi, Kefalonia and Ithaki and their assessment regarding their scientific, environmental, cultural, economic and aesthetic value. The most representative sites for the individual disciplines of geology (e.g., geomorphology, tectonics, stratigraphy and palaeontology) have been chosen, mapped and assessed, while indicative georoutes are proposed, which could aid the island’s geotouristic promotion to geologist and non-geologist future visitors.

Structure-from-motion photogrammetric processing and laser scanning technology have given us more tools to study environments such as caves with their complex and unique morphology. In this case study, we combine two innovative techniques to generate the complete 3D model of a show cave (Koutouki, Peania Greece) and calculate the rock thickness between the cave and the open surface. We used a Handheld Laser Scanner (HLS) for acquiring points with coordinate information covering the entire cave and an Unmanned Aerial System (UAS) for acquiring data covering the open-air surface above the cave. The absolute and exact placement of the point cloud within a geographic reference frame allow the three-dimensional measurements and detailed visualization of the subsurface structures. By processing of the multi-source data (UAS and HLS) we managed to make a quantitative analysis of the terrain. After a series of processing steps and analyses we managed to calculate with high accuracy several dimension such as the cavity vacuum, the speleothem volume, the elevation differences across the entire cave etc. The final product is a high-resolution information layer with measurements of the rock thickness between the roof of the underground karstic landform and the open-surface topography.

The accurate extraction of a coastline is necessary for various studies of coastal processes, as well as for the management and protection of coastal areas. Very high-resolution satellite imagery has great potential for coastline extraction; however, noises in spectral data can cause significant errors. Here, we present a newly developed Coastal Extraction Tool (CET) that overcomes such errors and allows accurate and time-efficient automated coastline extraction based on a combination of WorldView-2 (WV-2) multispectral imagery and stereo-pair-derived digital surface model (DSM). Coastline extraction is performed and tested on the Iž-Rava island group, situated within the Northern Dalmatian archipelago (Croatia). Extracted coastlines were compared to (a) coastlines extracted from state topographic map (1:25,000), and (b) coastline extracted by another available tool. The accuracy of the extracted coastline was validated with centimeter accuracy reference data acquired using a UAV system (Matrice 600 Pro + MicaSense RedEdge-MX). Within the study area, two small islets were detected that have not been mapped during the earlier coastline mapping efforts. CET proved to be a highly accurate coastline mapping technique that successfully overcomes spectral-induced errors. In future research, we are planning to integrate data obtained by UAVs infrared thermography (IRT) and in situ sensors, measuring sea and land surface temperatures (SST and LST), into the CET, given that this has shown promising results. Considering its accuracy and ease of use, we suggest that CET can be applied for automated coastline extraction in other large and indented coastal areas. Additionally, we suggest that CET could be applied in longitudinal geomorphological coastal erosion studies for the automated detection of spatio-temporal coastline displacement.

Nickel laterites constitute a significant proportion of world nickel reserves. In Greece, LARCO GMMSA exploits the domestic laterite deposits, operating in Locris area and Euboea island (Central Greece) and in Kastoria area (Northern Greece). During the last decades, the use of remote sensing technology in geological mapping has gained significant attention worldwide. In particular, multispectral/hyperspectral imagery is one of the most widespread and standard source of data for the recognition of spatial and/or spectral patterns in mineral/ore exploration. To this purpose, the development of suitable state-of-the-art processing algorithms, either at pixel level or at sub-pixel level, is of crucial importance. In particular, spectral unmixing (SU) is currently a very powerful method that allows sub-pixel level processing in order to assess spectral information regarding different lithologies that co-exist within a pixel. The aim of SU is the decomposition of the spectral signatures of mixed pixels onto a space spanned by a set of spectral signatures (represented as vectors) corresponding to pure physical materials (endmembers). The latter are retrieved either from spectral libraries or they are extracted from the image itself by detecting the relatively “purest” pixels via suitable algorithms. The resulting decomposition coefficients are indicative of the degree of each endmember’s presence within each pixel. It should be noted here, that in contrast to other scalar-based approaches (e.g. spectral indices), SU is a vector-based processing that provides richer representational capabilities. The most widely used assumption in SU is that each pixel’s spectral signature can be written as a linear combination of the spectral signatures of its endmembers (linear mixing hypothesis). In this study, we investigate the ability of SU to reliably map FeNi laterite outcrops. The study area is the Tsouka laterite excavation in Central Greece, operated by LARCO GMMSA. More specifically, linear SU is applied to a Sentinel-2 satellite image. The dataset is atmospherically corrected, spatially resampled to 10m pixel size and subset to the excavation area. For the needs of SU, two endmembers are used, namely a laterite endmember and a non-laterite endmember. The former corresponds to the average spectral signature of selected pixels of pure laterite composition. The latter represents both the other two existing lithologies, namely Cretaceous limestones and ophiolites. The SU resulting abundance maps show that Sentinel-2 succeeds to satisfactorily map the FeNi laterite. The proposed method is fast, low-cost and non-destructive and can contribute to the research of LARCO GMMSA for new exploitable ores.

Lasithi is the easternmost regional unit on Crete Island (Greece), south of which lies the Hellenic Arc. The broader offshore study area is dominated by reverse and strike-slip faulting, while active normal faults are mapped on land. Detailed research of the latter suggests that the northern and central parts of Lasithi are affected by arc-parallel extension, whereas the southern part by arc-normal extension. The NNE-SSW striking faults are more frequent and form horst and graben or half-graben macro-structures. These faults usually consist of two or more segments accompanied by post-glacial scarps and clear evidence of recent reactivations. The E-W to ESE-WNW striking faults are scarcer and mainly observed along the southern coastal zone or offshore. Compared to the NNE-SSW strikingfaults, they present fewer active traces. Significant events in the study area include the 8th August1303 (M≈8.0) earthquake and the 1st July 2009 (Mw=6.4) earthquake that occurred south of Crete, triggering a small tsunami. A probabilistic seismic hazard assessment is performed for Lasithi. The maximum expected ground motion parameters (PGA, PGV and PGD) for mean return periods of 475and 950 years are determined using the SHARE 2013 zones and seismicity model. Greek GMPEs that consider type of faulting and soil type were applied. Optimum results are obtained through a logic-tree approach, which considers all GMPEs. The Uniform Hazard Spectrum for Agios Nikolaos, Sitia and Ierapetra are presented and compared with the elastic design spectra proposed by the Greek National Building Code and Eurocode 8.

Landslides are a critical geological phenomenon with devastating and catastrophic consequences. With the recent advancements in the geoinformation domain, landslide documentation and inventorization can be achieved with automated workflows using aerial platforms such as unmanned aerial vehicles (UAVs). As a result, ultra-high-resolution datasets are available for analysis at low operational costs. In this study, different segmentation and classification approaches were utilized for object-based landslide mapping. An integrated object-based image analysis (OBIA) workflow is presented incorporating orthophotomosaics and digital surface models (DSMs) with expert-based and machine learning (ML) algorithms. For segmentation, trial and errors tests and the Estimation of Scale Parameter 2 (ESP 2) tool were implemented for the evaluation of different scale parameters. For classification, machine learning algorithms (K- Nearest Neighbor, Decision Tree and Random Forest) were assessed with the inclusion of spectral, spatial, and contextual characteristics. For the ML classification of landslide zones 60% of the reference segments have been used for training and 40% for validation of the models. The quality metrics of Precision, Recall, and F1 were implemented to evaluate the models’ performance under the different segmentation configurations. Results highlight higher performances for landslide mapping when DSM information was integrated. Hence, the configuration of spectral and DSM layers with the RF classifier resulted in the highest classification agreement with an F1 value of 0.85.

Climate change education (CCE) fosters the skills and behavioral patterns of students in regards to climate-related challenges and risks. Despite its importance, the integration of CCE in schools is challenging due to the interdisciplinary nature of climate science and the obstacles and demands of everyday school reality. Here, we examine the case of satellite Remote Sensing (RS) for Earth Observation (EO) as an innovative tool for facilitating CCE. We focus on Greece, a country that, despite being a hot spot for climate change, shows a low level of CCE integration in schools and awareness for EO-based educational resources. Based on interviews with in-service teachers, our research reveals the following: (a) there is a high interest in how satellites depict environmental phenomena; (b) EO is considered an efficient vehicle for promoting CCE in schools because it illustrates climate change impacts most effectively; (c) local natural disasters, such as intense forest fires and floods, are more familiar to students and, thus, preferable for teaching when compared to global issues, such as the greenhouse effect and sea level rise; and (d) educators are in favor of short, hands-on, EO-based activities (also known as “activity-shots”), as the most useful material format for integrating climate change topics in their everyday teaching practice.

Sr isotopes have been applied as a provenance tracer in archaeology for over three decades providing unprecedented insights into past human mobility at an individual level. However, their successful application requires a comparison to the bioavailable Sr isotopic composition characteristic for the areas where finds were unearthed or are suspected to originate from (referred to as baseline). Due to financial reasons or other limitations many studies only take a few baseline samples within or in close proximity to the archaeological site for reference purposes. This can introduce large uncertainties to the interpretation of human 87Sr/86Sr data especially in geologically complex areas. Here, we present Sr concentrations and isotopic data of modern environmental proxies (plants, soils and water) sampled at 52 sites across the Peloponnese, Greece, and compare them to previously published 87Sr/86Sr data to evaluate the need for extensive regional baselines. The bioavailable Sr isotopic composition of the Peloponnese is characterised by a wide range in 87Sr/86Sr values (0.7077 – 0.7237). The distribution of the 87Sr/86Sr data corresponds well with the surface lithology, suggesting a dominance of Sr derived from the bedrocks. The 87Sr/86Sr baselines defined by the environmental samples taken from areas characterised by clastic and chemical surface sediments are calculated as comparatively unradiogenic, narrow 87Sr/86Sr ranges of 0.70832 ± 0.00053 (x̅ ± 2σ) and 0.70835 ± 0.00089 (x̅ ± 2σ), respectively. In contrast, the areas characterised by metamorphic outcrops are characterised by more radiogenic 87Sr/86Sr signals with wider 87Sr/86Sr baseline ranges of 0.70906 ± 0.00116 (x̅ ± 2σ) and 0.71429 ± 0.01133 (x̅ ± 2σ) for marbles and schists, respectively. These significantly extend the bioavailable 87Sr/86Sr baseline data of the Peloponnese compared to previously published data (0.70841 ± 0.00092; x̅ ± 2σ). This emphasises the importance of regionally extensive sampling in geologically complex areas, such as the Peloponnese, to reduce uncertainties in the application of Sr isotopes as a tracer for past human mobility.

The study of environmental changes in coastal areas provide useful information for past conditions and constitute a powerful tool for accurate palaeogeographic reconstructions. Several coastal landforms are present on the coastal zone, with different response to environmental change. Coastal wetlands and lagoons are particularly sensitive to local paleoenvironmental changes and provide an excellent opportunity to reconstruct the evolution of the coastal zone evolution and the sea level changes. In this context, the aim of this work is to elucidate the coastal evolution of Psatha bay, Alkyonides Gulf, Greece, through coastal drillings and geomorphological sea level markers. The study area is located at the eastern end of Corinth Gulf, in the Gulf of Alkyonides. Psatha is bounded by active neotectonic structures, which have been a determining factor in its development. In this work we adopt a multiproxy approach through the study of coastal drillings and beachrocks. We coupled detailed beachrock mapping, microstratigraphic analysis and luminescence dating to study beachrock outcrops found up to 1 m above the present sea-level. For the palaeoenvironmental reconstruction, multiproxy analyses were undertaken, which included sedimentological analysis of the core, paleontological analysis of macrofauna and microfauna and radiocarbon dating. The results of this work will contribute to the better understanding of a coastal site in a tectonically active area and the relative sea level changes.

Sr isotopes are a powerful tool used for provenancing in many disciplines, but their successful application requires the availability of robust Sr baselines of potential target areas. This study presents 87Sr/86Sr signatures and Sr concentrations of water, plants and soil leachates from the Peloponnese peninsula, Greece, to establish the first comprehensive bioavailable Sr isotope baseline for this region. Additionally, this study aims to evaluate which proxy is most suitable to characterise bioavailable Sr in a geologically complex area also exposed to foreign aeolian Sr sources. Our recorded bioavailable Sr isotope signatures correspond well with the surface lithologies characteristic of the Peloponnese. Unradiogenic 87Sr/86Sr ratios and a narrow isotope range (0.70779 - 0.70955) characterise the bioavailable Sr signatures of the sedimentary deposits and more radiogenic and isotopically variable values (0.70791 - 0.72370) were measured for metamorphic and igneous rock outcrops. The differences in 87Sr/86Sr values measured between proxies of one site are comparatively low for samples from the sedimentary and igneous deposits, while the overall spread in 87Sr/86Sr values is wider for samples from metamorphic deposits. We propose to define bioavailable 87Sr/86Sr baseline ranges as the average bioavailable 87Sr/86Sr ratio of all proxies of each lithology ± its double standard deviation (x̅ ± 2σ). This results in narrow baselines for the sedimentary outcrops of 0.70832 ± 0.00053 (n=58) for clastic sediments and 0.70835 ± 0.00089 (n=29) for chemical sediments. The metamorphic deposits are characterised by wider bioavailable 87Sr/86Sr baselines of 0.70906 ± 0.00116 (n=4) and 0.71429 ± 0.01133 (n=13) for marble and schist, respectively. The bioavailable Sr baseline for igneous rock outcrops is also characterised by a comparatively wide range with 0.70950 ± 0.00259 (n=7). The wide range in inter- and intra-site specific bioavailable 87Sr/86Sr variation observed in this study emphasise the need for comprehensive multi-proxy sampling strategies within geologically-complex areas.

The results of structure from motion photogrammetry and SAR interferometry as complementary techniques for measuring ground deformation induced by the massive open-pit landslide in Amyntaio, Greece (June 10, 2017), is presented in this paper. This unexpected slide damaged the entire westernmost marginal area of the pit, significant number of buildings, and infrastructures of the nearby village of Anargiri. The described methodology includes the generation of a multi-temporal dataset (from Sept. 2017 to Sept. 2018) of very high-resolution surface topography (at 10 cm), based on the analysis of imagery collected by Remotely Piloted Airborne Systems (RPASs). Satellite observations involved interferometric processing of TerraSAR-X data for a complementary estimation of ground displacement rates. Height differences from consecutive aerial photography campaigns as well as space-borne measurements provided valuable information on the evolution of the deformation and its spatial characteristics during the post-event period, an important aspect for future hazard and risk considerations.

We present a GIS-based crowdsourcing application that was launched soon after the first COVID-19 cases had been recorded in Greece, motivated by the need for fast, location-wise data acquisition regarding COVID-19 disease spread during spring 2020, due to limited testing. A single question was posted through a web App, to which the anonymous participants subjectively answered whether or not they had experienced any COVID-19 disease symptoms. Our main goal was to locate geographical areas with increased number of people feeling the symptoms and to determine any temporal changes in the statistics of the survey entries. It was found that the application was rapidly disseminated to the entire Greek territory via social media, having, thus, a great public reception. The higher percentages of participants experiencing symptoms coincided geographically with the highly populated urban areas, having also increased numbers of confirmed cases, while temporal variations were detected that accorded with the restrictions of activities. This application demonstrates that health systems can use crowdsourcing applications that assure anonymity, as an alternative to tracing apps, to identify possible hot spots and to reach and warn the public within a short time interval, increasing at the same time their situational awareness. However, a continuous reminder for participation should be scheduled.

Remote sensing techniques and laser scanning technology have given us the opportunity to study indoor environments, such as caves, with their complex and unique morphology. In the presented case study, we used a handheld laser scanner for acquiring points with projected coordinate information (X, Y, Z) covering the entire show cave of Koutouki; including its hidden passages and dark corners. The point cloud covers the floor, the walls, and the roof of the cave, as well as the stalactites, stalagmites and the connected columns that constitute the decoration of the cave. The absolute and exact placement of the point cloud within a geographic reference frame gives us the opportunity for three-dimensional measurements and detailed visualization of the subsurface structures. Using open - source software, we managed to make a quantification analysis of the terrain and generated morphological and geometric features of the speleothems. We identified 55 columns by using digital terrain analysis and processed them statistically in order to correlate them to the frame of the cave development. The parameters that derived are the contours, each column height, the speleothem geometry and volume, as well as the volume of the open space cavity. We argue that by the demonstrated methodology, it is possible to identify with high accuracy and detail: the geomorphological features of a cave, an estimate of the speleogenesis, and the ability to monitor the evolution of a karstic system.

The spatial and temporal scale of flash flood occurrence provides limited opportunities for observations and measurements using conventional monitoring networks, turning the focus to event-based, post-disaster studies. Post-flood surveys exploit field evidence to make indirect discharge estimations, aiming to improve our understanding of hydrological response dynamics under extreme meteorological forcing. However, discharge estimations are associated with demanding fieldwork aiming to record in small timeframes delicate data and data prone-to-be-lost and achieve the desired accuracy in measurements to minimize various uncertainties of the process. In this work, we explore the potential of unmanned aerial systems (UAS) technology, in combination with the Structure for Motion (SfM) and optical granulometry techniques in peak discharge estimations. We compare the results of the UAS-aided discharge estimations to estimates derived from differential Global Navigation Satellite System (d-GNSS) surveys and hydrologic modelling. The application in the catchment of Soures torrent in Greece, after a catastrophic flood shows that the UAS-aided approach succeeded in determining peak discharge with high accuracy. The technique proved to be particularly effective, providing flexibility in terms of resources and timing, although there are certain limitations to its applicability. The application highlighted important advantages and certain weaknesses of these emerging tools in indirect discharge estimations, which we discuss in detail.

The improvement of the accuracy of Structure-from-Motion photogrammetric products is discussed in this paper. In most cases it depends on the number and distribution of ground control points (GCPs) for block orientation, although the placement and precise measuring of GCPs are often time-consuming in a UAS project. This paper presents the evaluation of two approaches including Post Process Kinematic (PPK) and Network Real Time Kinematic (NRTK) methods aiming to avoid GCPs establishment, taking advantage of a real time positioning service, where differential corrections are sent from a network of Reference stations directly to the UAS.

The general understanding of the major tectonic structures that are traced on Crete Island is of great importance to decipher the geodynamic regime of the leading edge of the overriding Aegean microplate and consequently Eurasia’s southernmost active margin. The aim of this multi-disciplinary methodology is to provide useful information for more reliable mapping of buried structures, which in turn supplement the dynamic and kinematic model of this key area of high interest. Several indicators for the existence of oblique fault block displacement were identified with the use of earth observation data, as strike slip faulting expressions on the surface are more efficiently identified by vertical observations. Tectonic structures which are usually created along lateral displacements require different working scales. Hence, earth observation data (satellite images, aerial photographs) with various spatial characteristics need to be included. Therefore, the methodology presented in this paper involves high spatial resolution digital elevation models and several remote sensing multispectral datasets, in many cases merged with higher spatial resolution panchromatic aerial photographs. The co-registration and ortho-rectification of all datasets proved to be a very significant part of this work in order to produce high resolution coloured 3D scenes at selected sites in central Crete, where the observed N-S trending strike slip fault zones crosscut arc parallel low angle normal faults and higher angle fault scarps. Additionally, deep seismic reflection datasets along the major geomorphic structure of Messara basin were combined and highlighted the strike slip mechanism, since the continuation of the sub-vertical structures in depth has become clearer after the exact positioning of the sections and further interpretation.

Unmanned Aircraft Systems (UAS) can be used to enhance monitoring of a wide range of environmental parameters, including acquiring data on various types of hydro-geomorphic phenomena. Their capabilities to provide on demand images and videos of high resolution, are particularly useful in the case of flash flood phenomena, which occur in spatial and temporal scales that do not favor traditional monitoring processes. In this work, flow velocity is estimated using aerial imaging acquired by means of an Unmanned Aircraft Vehicle (UAV) as well as ground observations during the catastrophic flash flood event of November 2017 in Mandra, Greece. In these imaging detailed tracing of various floating objects and particles such as light trash, debris etc. was carried out using multiple high-resolution video frames with specific time marks. Water velocity estimations were also cross-examined using flood mark-derived velocity hydraulic heads extracted by ground observations after the flood. The analysis was applied at a variety of locations across the study area, leading to a map of velocities for parts of the floodplain. Velocity values varied significantly depending on location, reaching up to 10m/s. The UAS proved to be very useful for the collection of important information for an extended area during the flood since a large portion of it was inaccessible due to road closures and safety issues. Nevertheless, the approach comes with certain limitations, including flight regulations, safety precautions and that rainfall is at a level that allows the deployment of a UAV during a flash flood. The findings show that the integration of aerial with ground observations in post-flood analysis contributes the completeness and accuracy of datasets regarding specific flash flood parameters and in the future could become a useful source of information, especially in data-poor regions.

The goal of this study is to create a high-resolution grid of precipitation indices for the wider Greek region using real data from meteorological stations for the 1980-2010 period. Under the risk of increased extreme events caused by climate change, it is important to be able to have a high-resolution gridded extreme precipitation indices in order to overcome the lack of density of observations in both time and space. The development of such a grid can be used to validate model outputs and inform decision makers to better mitigate the damage from extreme precipitation. The first step of the analysis is to calculate the extreme precipitation indices based on daily observations derived from more than 100 meteorological stations covering a wide range of altitudes and spatial climate patterns existing in Greece. Thereafter, the extreme indices will be multilinearly downscaled to a 12-meter resolution grid. The geophysical parameters used in the downscaling procedure consists of altitude, latitude, longitude, slope, aspect, solar irradiance and Euclidian distance from the water bodies. The altitude information came from the highly accurate 12-meter resolution TanDEM-X Elevation Model, which is a product generated from the TerraSAR-X satellite mission data. The resulting high-resolution patterns will give insight of the spatial and temporal variability of extreme precipitation, over the complex terrain of the wider Greek region.

Three main aquifer systems developed on Kythira Island (Greece) include (Pagounis, 1981; Pagounis & Gertsos, 1984, Danamos, 1991; Koumantakis et al., 2006; Filis et al., 2019):

• The porous aquifer system in Neogene and Quaternary formations.
• The karst aquifer system in the carbonate formations of the Pindos and Tripolis Units.
• The aquifer system (both shallow and deep) in the fractured hard rocks mainly of the Phyllites – Quartzites Unit.

The main discharge of the aquifer systems takes place in coastal and submarine brackish springs around the island, except for its northern part where the Phyllites – Quartzites Unit outcrops and its central part where springs of small capacity discharge the carbonate formations of the Pindos Unit. Precipitation is the direct recharge of the three aforementioned aquifer systems while indirectly lateral discharge occurs in places between adjacent and tangential aquifer systems and from the streams runoff as well. In the area of Mylopotamos village four springs discharge the karst aquifer of the Pindos Unit within the channel of Kako Laghadi stream forming downstream the known “Neraida or Fonissa waterfall”. Moreover, along the dell of Kako Laghadi stream 22 watermills were built, among the plane trees and the ivy. The most significant of the aforementioned springs is the Kamari spring (+282.28 meters a.s.l.) which emerge at the thrust fault between the overlying permeable carbonates and the underlying impermeable flysch formation of the Pindos Unit. The discharge of the Kamari spring presents annual fluctuation which varies from app. 45-50 m3/h (during winter) to total recession (during summer), due to restriction of the precipitation and the prolonged drought and overpumping of its recharge area mainly with boreholes. The inactive municipal borehole of Mylopotamos village (+299.15 meters a.s.l.) is located app. 310 meters SSE of the Kamari spring within its recharge area (karst aquifer of the Pindos Unit). This borehole of a total depth of 40 meters penetrates carbonates of the Pindos Unit which thickness exceeds 100 meters in that area. Monthly measurements of the Kamari spring discharge and the water table head in the inactive borehole demonstrate clear and direct hydraulic correlation between them. The Kamari spring presents outflow only in the case when the water level head of the borehole exceeds +282.28 meters. This means that the water level head in the borehole should not exceed 16.87 meters from the earth surface. Taking into account all the aforementioned, the Kamari spring is designated as an overflow spring. Finally, microbiological analysis from the Kamari spring showed qualitative degradation, due to human activities in the wider area (Pagounis, 1981; Filis et al., 2019).

The state-of-the-art in surveying of open surface the last few decades is based on Point Cloud processing and interpretation. Lately, similar technology tends to be used for indoor surveying as well. One of the extreme applications is the use of the exact same technology in underground karstic cavities, evolving the methodology used in cave mapping. Geometric and morphometric analysis of the caves or any containing components (speleothems) include various techniques aiming at quantifying their dimensions in order to determine the characteristics and consequently the relationship between the cavity morphology and the surrounding structural, lithological and hydrogeological properties. The purpose of this research is to combine high resolution topographic data acquired with different instruments for both the underground morphology of a karstic cave (Koutouki, Peania, Greece) and the open-air surface above it. The described methodology is based on photogrammetric processing of Unmanned Aerial System image data and the extraction of a point cloud recorded with the use of a handheld laser scanning system. The latter resulted a 3D model of the cave and led to the production of a digital relief for the roof of the cave, which in turn was combined with the digital terrain model of the open-air surface above the cave. The final product is a high-resolution information layer with measurements of the rock thickness between the roof of the underground karstic structure and the open-surface topography with high accuracy.

During the period 24-25 November 2019 a low pressure system with organised convective storms has affected Greece as it crossed the country from west to east. The system, which was name Gyrionis, after a name used in the Greek mythology, has produced heavy rainfall, with increased lightning activity and local hailstorms. In the area of western Attica the maximum rainfall has been reported with 92 mm of on 24 November and additional 115 mm in 25 November, adding to a storm total of 206 mm, which caused flash floods in the town of Kineta. The storm caused overflowing of local torrents draining the south slopes of Geraneia Ori, inducing significant damages in property and infrastructure mainly within the town and across the coastal zone. Field surveys showed that a wildfire that burned through almost the entire catchment of the main torrent (named Pikas) on 2018, played a crucial role in flooding and its impact on the town. At critical locations along the river, vegetation debris and eroded material of various grain sizes, including boulders, diminished dramatically the hydraulic capacity of the river, intensifying flooding in the downstream areas, which formed an alluvial fan. Based on comparison of pre- and post-flood aerial photography of the burned area, a major source of this deposited material was identified as burned trees still standing after the fire, uprooted from the river banks of the main channel and carried away together with additional soil debris. The material was jammed at a crucial location near the apex of the alluvial fan causing floodwaters to overflow and inundate significant parts of the fan’s apron, a geomorphological setting that increased the extent and impact of flooding further. Overall, the case of Kineta, is a characteristic case of post-wildfire flash flooding, in which the fire effects are critical in the enhancement of subsequent flooding phenomena.

The Ionian Islands are located in the northwestern part of the Hellenic Arc and constitute one of the most seismically active areas in the Mediterranean. Building a geospatial database including all the available geo-information layers was the initial step for identifying and delineating the earthquake-related environmental effects by using various mapping algebra techniques and algorithms. Landslide, liquefaction and tsunami related inventories were created. Real time recording network of sensors such as meteorological instruments, seismographs, accelerometers etc was designed to trans pond data telemetrically and feed a dynamically interactive geodatabase, which in turn act as a smart tool for declaring an area as vulnerable to a specific hazard. The abovementioned approach can contribute to the reduction of the consequences after a disastrous event, as it will provide useful information to the civil protection authorities for increased alertness during an ongoing threat. The identification of the risk areas by using various methods has become significant in recent years due to the fact that among others it serves as a valuable tool for revealing and highlighting sites of significant hazards. In this study we present a smart tool, specially developed for recording and taking under consideration any changing parameters that affect the susceptibility of an area to any of the studied geo-hazards and highlight it on a digital real time updateable map.

Geological failures from massive rockfall failures to small landslides of few cubic meters are a major geological hazard in many parts of the world. Based on the latest developments, close-range photogrammetry and individually UAV photogrammetry and Light Detection and Ranging systems have become indispensable tools for geo-experts in order to provide ultra high-resolution 3D models of the failure site. TLS suffers from the fact that is sometimes tricky to capture the holistic area of interest from the ground, while some areas may often be obscured by vegetation or negative inclinations. The science of photogrammetry has long been used to accurately detect and characterize landslide and rockfall failures. Due to the continuously increasing spatial resolution capability of new generation sensors, traditional pixel-based approaches are not capable to cope with the level of detail resulted from those sensors. Mostly, landslides present complex and dynamic geomorphological features with great heterogeneity in their spatial, spectral and contextual properties dependent on the specific failure mechanism. In the current study, an object-based 3D approach for the automated detection of landslide and rockfall hazard is presented based on detailed topographic photogrammetric point clouds and 3D analysis. Recent trends show that close photogrammetry will play a vital role on the geological and engineering geological assessments concerning geo-failures. The results show that object-based approach is closer to human interception due to integration of contextual and semantic, spectral and spatial information rather than translating pixel’s spectral information solely. The current procedure provides a detailed objective quantification of landslide characteristics and automated semantic landslide modelling of the case site.

The increased development of computer vision technology combined with the increased availability of innovative platforms with ultra-high-resolution sensors, has generated new opportunities and fields for investigation in the engineering geology domain in general and landslide identification and characterization in particular. During the last decade, the so-called Unmanned Aerial Vehicles (UAVs) have been evaluated for diverse applications such as 3D terrain analysis, slope stability, mass movement hazard and risk management. Their advantages of detailed data acquisition at a low cost and effective performance identifies them as leading platforms for site-specific 3D modelling. In this study, the proposed methodology has been developed based on Object-Based Image Analysis (OBIA) and fusion of multivariate data resulted from UAV photogrammetry processing in order to take full advantage of the produced data. Two landslide case studies within the territory of Greece, with different geological and geomorphological characteristics, have been investigated in order to assess the developed landslide detection and characterization algorithm performance in distinct scenarios. The methodology outputs demonstrate the potential for an accurate characterization of individual landslide objects within this natural process based on ultra high-resolution data from close range photogrammetry and OBIA techniques for landslide conceptualization. This proposed study shows that UAV-based landslide modelling on the specific case sites provides a detailed characterization of local scale events in an automated sense with high adaptability on the specific case site.

The identification of the earthquake environmental effects by using various methods has become significant in recent years due to the fact that among others it serves as a valuable tool for revealing and highlighting sites of significant earthquake-related hazards. In the frame of the project entitled "Tilemachos - Innovative Operational Seismic Risk Management System of the Ionian Islands" included in the Priority Axis "Environmental Protection and Sustainable Development" of the Operational Programme “Ionian Islands 2014-2020”, the landslide, liquefaction and tsunami hazards in the Ionian Islands are analyzed and assessed by combining different methods. Landslide, liquefaction and tsunami inventories for all Ionian Islands were initially created. Along with the inventories, different thematic maps were used and combined in order to test the earthquake-induced landslide and liquefaction susceptibility and the tsunami hazard of the Ionian Islands. The main result is the identification of sites of significant earthquake-related hazards in the Ionian Islands. This study and its results could constitute a basic guide for the future urban design and planning and the sustainable local development since all scientists and agencies competent to the prevention and management of natural disasters can be informed and guided.

Late years, innovative close-range Remote Sensing (RS) technology such as Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are widely applied in the field of geoscience due to their efficiency in collecting surface data. Detection and mapping of landslide and rockfall events using RS products has been proved to be an effective approach to provide landslide inventories. However, most of the studies are lacking valuable semantic information about landslide elements and how they react with the surrounding environment. The proposed methodology was divided in five main working phases. The first phase includes designing and execution of an optimal UAV flight planning to collect accurate 3D data. During the second phase, the pre-processing and raw data preparation such as point cloud filtering and elimination of ambiguities is taking place, while at the next phase an image segmentation using the 3D point cloud RGB information is created. The main task was focused on identifying the specific landslide elements by using an object-based approach. A sequence of image-based processes was applied, including multi-scale object segmentation, spectral, morphometric and contextual information extraction aiming to detect the landslide among other features. The next phase was set up for object classification in meaningful and homogeneous landslide classes (e.g. scarp, depletion zone, accumulation zone) which are spatially connected by introducing contextual information. The proposed methodology presents the effectiveness and efficiency of UAV platforms to acquire accurate data from intense relief environments and complex surface topographies.

The synergy of different methods was used for the creation of an earthquake-induced landslides (EIL) inventory for the Ionian Islands. More specifically, post-earthquake field surveys were conducted shortly after recent earthquakes (2003 and 2015 in Lefkada, 2014 in Cephalonia and 2018 in Zakynthos) in order to obtain detailed field information of the EIL among other earthquake effects. The available literature on historical earthquakes were reexamined with emphasis on their environmental effects and especially EIL. Remote sensing products including satellite imagery and orthophotos were interpreted. All qualitative and quantitative information related to EIL and derived from the aforementioned steps were inserted in a database especially designed and developed in GIS environment for the purpose of this study and the respective inventory map was produced. This landslide inventory map was used and combined with other thematic maps in order to test the earthquake-induced landslide susceptibility (LS) of the Ionian Islands. The Analytical Hierarchical Process was applied along with the Weighted Linear Combination method in the frame of a multi-criteria decision analysis for the calculation of the spatial distribution of the Landslide Susceptibility Index (LSI). Along with the inventory, morphological data were derived from a TanDEM-X elevation model of the Ionian Islands based on data produced by TanDEM-X and TerraSAR-X satellite pair. Lithological and geological data were digitized from previous already published geological and neotectonic maps updated with corrections from field mapping for the purpose of this study. Land use and soil thickness were derived from the 2018 version of Corine Land Cover. Road network was digitized from the topographic maps of the Hellenic Military Geographical Service, while rainfall data was collected from the database of the National Meteorological Service. Data classification of each factor according to their estimated LS followed, by using the reverse ranking method, where 1 is the least and 10 is the most susceptible. Each category was normalized to 100% and the final raster thematic maps of landslide controlling factors were produced. Finally, using numerical weight for each factor, which was assigned by the Analytic Hierarchy Process using Pairwise Comparison Method and according to the weighted linear combination, a map was generated where each cell has a certain LSI value. The higher the LSI value, the higher the LS, whereas lower LSI value means lower LS. The resulted map, classified with natural breaks method, constitutes the earthquake-induced LS map of the Ionian Islands with five LS categories: very low, low, moderate, high and very high LS. Comparison of the EIL inventory map and the LS map show that the EIL in the Ionian Islands are structurally controlled as the majority of them have been generated along morphological discontinuities formed by active faults or inactive thrusts and overthrusts.

The disastrous phenomenon of aseismic ground fissures along the eastern Thessaly basin has deteriorated since 1989. The main reason for these fissures is the over-pumping, which leads to differential vertical compaction of the aquifer system and subsidence on the land surface. In this paper, we present the results of a combined geophysical survey applied in the area (VES and TEM soundings), in order to investigate the subsurface geological conditions. The geological regime of the area is comprised of the alpine basement, transgression formations and finally a package of post-alpine deposits with respectful thickness. A peudo-3D representation of resistivity maps for several depths of investigation was produced. Additionally, a dataset of deep boreholes was used for the calibration of the geophysical data. All the borehole and sounding interpreted data were grouped into three categories in order to produce the Lithology Model of the area. The alpine bedrock was adumbrated only at the southeast and central part of the basin, where we do not observe ground fissures. The absence of alpine bedrock for depths up to 300 meters, the thick and coarse-grained deposits and finally the over-pumping seem to contribute to the creation of the ground fissures.

In the presented case study, we combined re-mote sensing techniques and lidar technology by using a handheld laser scanner in order to generate a complete 3D model of the Koutouki Cave, at Peania, Greece. Using open – source software we made a quantification anal- ysis of the terrain and generate morphological features of the speleothems with high accuracy and detail in order to estimate the speleogenesis and monitor the evolution of the cave.

The study of the east dipping N-S mountain front of Olympus Mt that is presented in this work, was based on the interpretation of high-resolution digital elevation model (DEM), as the main dataset for calculating various tectonic geomorphology indices, through quantitative techniques. Since the fluvial network maintains its connection to the tectonic forcing and therefore contains potentially useful information about variations in rock uplift rates across the landscape, we used a highly detailed one generated from the DEM in order to calculate various indices and extract quantitate information. Calculations were made in a GIS platform by using the Ks index, the drainage basin asymmetry index and the geometry of the triangular facets on the front of the mountain, alongside the fault zone delineating the mountain. The results extracted by combining the previous methodologies are in agreement with the observations which were made during the fieldwork, that there is no uniform uplift along the main Olympus fault zone.

The generation of rock cavities and especially of those created under karstic procedures is a matter of research for the last decades. A high-resolution subsurface morphology could be produced after scanning the entire cave with state-of-the-art equipment based on Light Detection And Range technology. A handheld laser scanner was used for acquiring points with projected coordinate information (X,Y,Z) covering the entire show cave of Koutouki (Athens, Greece), including its hidden passages and dark corners. The point cloud covers the floor, the walls and the roof of the cave, as well as the stalactites, stalagmites and the connected columns that constitute the decoration of the cave. The absolute and exact placement of the point cloud within a geographic reference frame gives us the opportunity for three-dimensional measurements and detailed visualization of the subsurface structures.

Detection and mapping of landslide and rockfall events using remote sensing products has been proved to be an effective approach to provide landslide inventories. However, most of the studies are lacking valuable semantic information about landslide elements and how they react with the surrounding environment; natural and man-made primitives. In addition, post classification object-based approaches have been proved to result in better accuracy compared with the pixel-based. Lately, innovative close-range remote sensing technology such as Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are widely applied in the field of geoscience due to their efficiency in collecting data about terrain morphology rapidly. This research aims to demonstrate the applicability of UAV technology for automated semantic labeling in managing landslide and rockfall hazard in mountainous environments during emergency situations. SfM photogrammetry in addition to high accuracy RTK-GNSS ground control point establishment, is used to provide detailed 3D point clouds describing the surface morphology of the landslide and rockfall elements. The proposed methodology was divided in five main working phases. The first phase includes designing and execution of an optimal UAV flight planning to collect accurate 3D data. During the second phase, the pre-processing and raw data preparation such as point cloud filtering and elimination of ambiguities is taking place, while at the next phase an image segmentation using the 3D point cloud RGB information is created. The main task was focused on identifying the specific landslide elements by using an object-based approach. Based on Object-Based Image Analysis (OBIA), a sequence of image-based processes was applied, including multi-scale object segmentation, spectral, morphometric and contextual information extraction aiming to detect the landslide among other features. The next phase was set up for object classification in meaningful and homogeneous landslide classes (e.g. scarp, depletion zone, accumulation zone) which are spatially connected by introducing contextual information in the ruleset. The proposed methodology presents the effectiveness and efficiency of UAV platforms to acquire accurate photogrammetric datasets from intense relief environments and complex surface topographies by providing a holistic assessment and characterization of the failure site based on semantic classification of the landslide and rockfall objects. Results have demonstrated the capabilities of combining UAV platforms with computer-based methods for rapid and accurate identification of valuable semantic information subjectively and even from inaccessible areas of the landslide and rockfall body.

Fires affecting large areas usually create a mosaic of recovering plant communities reflecting their pre-fire composition and local conditions of burning. However, post-fire recovery patterns may also reveal the effects of landscape heterogeneity on the natural regeneration process of plant communities. This study combines field data and remote sensing image interpretation techniques to assess the role of various landscape characteristics in the post-fire recovery process in a mountainous region of Greece burned by a severe wildfire. Remote sensing techniques were used to accurately map secluded, large burned areas. By introducing a temporal component, we explored the correlation between post-fire regeneration and underlying topography, soils and basement rock. Pre-fire forest cover was reduced by more than half 8 years after fire. Regarding the dominant pre-fire forest trees, Abies cephalonica did not regenerate well after fire and most pre-fire stands were converted to grasslands and shrublands. In contrast, Pinus nigra regenerated sufficiently to return to its pre-fire cover, especially in areas underlain by softer basement rock. The use of different time series of high-resolution images improved the quality of the results obtained, justifying their use despite their high cost.

The use of techniques of two different origin were compared and combined aiming to map the seagrass meadows at shallow waters of South Evoikos Gulf, in central Greece. The high spatial and spectral resolution of WorldView-2 satellite images and its ability of water penetration, offers a positive approach for sea bottom mapping, in a relatively high resolution. In addition, the ground truth fieldwork survey with side scan data acquisition revealed that it was in impressively high agreement with the outcomes from the remote sensing data interpretation.

For several years, Greece has set as a priority the strengthening of maritime tourism, such as the tourism of yachts for which tourist marinas have been created. The most important marinas of the country include the “Glyfada Marina”, whose works began on the coastal front after 1960, thus changing the area’s shape and planning. The main objective of the present work is to investigate the improvement measures and prospects for the development of the “Glyfada Marina” consisting of four basins, being one of the most beautiful and developed marinas in the country since it is an important attraction for tourist yachts. For this reason, on-site visits to the port area were carried out, both on the sea and on the coastal part of the coastal zone, in order to record the current situation, so as to reach as accurately as possible the characteristics and the range of the internal port works and facilities of the aforementioned tourist port. Furthermore, any deficiencies or failures that need improvement are presented, labeled and classified in order to continue unhindered activities in the marina area. Finally, improvement and upgrading measures are proposed that can contribute positively to the tourist and economic development of the port and the municipality of Glyfada in general. 

Coastal zone monitoring is essential in order to understand their evolution and incorporate sustainable coastal management practices. Frequent data collection is essential but often surveys can be costly and time-consuming. Several costly and time-consuming tools and techniques have been developed during the last few years for change detection and monitoring, allowing for both qualitative and quantitative analysis. In this study we present the ability of an off-the-shelf Unmanned Aerial Systems (UAS) coupled with Structure-from-Motion (SfM) photogrammetry to map and measure coastal features (e.g. shorelines). The UAS surveys taken place over three campaigns during Autumn 2017 (November), Spring 2018 (March) and Autumn 2018 (October) in Pinios river deltaic coast. The demonstrated UAS-SfM methodology produced remote sensing data with great spatial resolution which could be used to visually identify important parameters for coastal research and management at a fraction of thecost of other available techniques and. Even an off-the-shelf UAS is suitable for repeat surveys to assess spatial and temporal changes at small spatial extents and to better comprehend how these may be related with site-specific natural processes along the coast.

Late years, innovative close-range remote sensing technology such as Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are widely applied in the field of geoscience due to their efficiency in collecting data about surface morphology. Their main advantage stands on the fact that conventional methods are mainly collecting point measurements such as compass measurements of bedding and fracture orientation solely from accessible areas. The current research aims to demonstrate the applicability of UAVs in managing landslide and rockfall hazard in mountainous environments during emergency situations using object-based approach. Specifically, a detailed UAV survey took place in a test site namely as Proussos, one of the most visited and famous Monasteries in the territory of Evritania prefecture, in central Greece. An unstable steep slope across the sole road network results in continuous failures and road cuts after heavy rainfall events. Structure from Motion (SfM) photogrammetry is used to provide detailed 3D point clouds describing the surface morphology of landslide objects. The latter resulted from an object-based classification approach of the photogrammetric point cloud products into homogeneous and spatially connected elements. In specific, a knowledge-based ruleset has been developed in accordance with the local morphometric parameters. Orthomosaic and DSM were segmented in meaningful objects based on a number of geometrical and contextual properties and classified as a landslide object (scarp, depletion zone, accumulation zone). The resulted models were used to detect and characterize 3D landslide features and provide a hazard assessment in respect to the road network. Moreover, a detailed assessment of the identified failure mechanism has been provided. The proposed study presents the effectiveness and efficiency of UAV platforms to acquire accurate photogrammetric datasets from high-mountain environments and complex surface topographies and provide a holistic object-based framework to characterize the failure site based on semantic classification of the landslide objects.

The purpose of this research is to combine two state-of-the-art technologies in surveying for extracting the rock thickness above a cavity. By combining Lidar technology for indoor surveying and photogrammetric processing of Unmanned Aerial Systems (UAS – drones) data, we managed to calculate and project with high accuracy the rock thickness of the roof of the underground environment of Koutouki Cave (Peania, Greece). Usually, cave systems are complex and unique because of their distinctive geometry and compound geomorphology along with natural harsh conditions such as constrained accessibility, limited light, high humidity and possible existence of water. Such environments make mapping difficult and further complicated (Kershaw, 2012). Nowadays, the state-of-the-art in surveying of open surface is based on LiDAR technology. Lately, similar technology has started to be used for indoor surveying and consequently in cave mapping, especially where the underground space allows it. Our research was based on the use of a recently released piece of equipment introducing a lightweight mobile handheld laser scanning system (GeoSLAM ZEB – REVO) that has the ability to produce a quite dense point cloud within an underground cavity. The x, y, z point cloud is generated while the operator walks through the cave (Zlot and Bosse, 2014). The specifications of this equipment include a 360o rotation, a (class 1 eye safe) 100Hz laser – making 100 rotations per second with the collection of 43,200 points per second. The maximum effective range is around 25-30m for indoor environment and data over 30m are usually excluded.

The quantification of the amount of the expected eroded material that will migrate towards lower elevations after a forest fire is one of the most crucial and practical information needed from the local authorities, in order to design post-fire stabilization measures and actions. It is one of the greatest challenges in natural resources and environmental planning and computer simulation models are becoming increasingly popular in predicting soil loss for various land use and management practices. Quite a few models along with their modifications are being developed aiming to fulfil the need for accurate quantification of soil erosion risk. Depending on the availability and the quality of the spatial data, which have to be imported into the various models as parameters, different methodologies are followed. Geraneia Mt is an extended mountain range at the west outskirts of Attica, central Greece, reaching the altitude of 1351 m, part of which has been designated as Natura 2000 site and is characterized by almost vertical slopes of carbonate rocks. The mountain was almost completely burned by a wild fire in late July 2018, which consumed most of its Pinus halepensis forests. The ridge of the protected area, covered by endemic fir Abies cephalonica forest was also affected by the fire. The soil covers carbonate rocks which comprise the higher elevations and the vertical slopes of the mountain as debris and loose deposits crop out at the south-facing mountain front which was greatly affected by the fire. Several erosion risk spatial models were applied on the protected area of Geraneia Mt in order to compare the sensitivity of their results and evaluate the risk of the affected habitat to be deteriorated. For each model, the most sensitive model parameters were calibrated and predicted soil loss amounts were compared. A qualitative and quantitative estimation was achieved and the advantages and disadvantages of each model had been identified.

The use of Very High Resolution (VHR) satellite imagery at various applications is gaining more and more popularity due to the growing number of offered data and the increasing spectral properties. WorldView-2 is the first commercial VHR multi-spectral satellite providing imagery in eight different sensors having bands that range from the visible to near-infrared (0.40-1.04 μm). The integration of the “Coastal” band (0.40-0.45 μm) in the 8-band WorldView series of satellite imagery data, which was followed by the addition of the similar wavelength band 1 (0.43 - 0.45 µm) in the Landsat-8 Operational Land Imager (OLI), gave a great boost to applications related to shallow water depths. The fundamental principle underlying the methods used to study the sea bottom from remotely sensed imagery is that different wavelengths of the solar light penetrate the water body to different depths (Phinn et al. 2008). The ability to accurately determine the seagrass at underwater regions is of great importance for the biodiversity of the submarine environment. The use of certain spectral wavelength data tends to be the most cost effective way of monitoring the marine habitats by mapping the sea bottom type along with several other jobs like modeling coastlines or even navigating through shallow aquatic areas by studying the bathymetry (Fornes et al. 2006).

The Ingessana hills in the southern Blue Nile of Sudan consist of serpentinised and highly silicified dunites in contact with the intruding Bau granite. The observed chromite mineralization zones are associated with NE-SW trending shear-zones. The mineralization associated with ophiolitic belts includes podiform chromite, asbestos, talc, and base metal (Cu, Ni, Co) mineralization. We applied Linear Spectral Unmixing algorithm on a 10m spatial resolution Sentinel-2 images in order to detect and map the chromite mineralization and the associated mineralization of ophiolitic belts. The resulting abundance maps show the capability of Sentinel-2 for detailed mineral mapping and detection of potential chromite ore deposit locations.

Developing educational material based on satellite remote sensing technologies, information and methods, is a key trend in modern pedagogy of Earth System Sciences. Here, we present “MICE”, a classroom activity on Melting ICe Effects, that utilizes remote sensing information to demonstrate the value of Earth Observation (EO) as a context to teach the STEM (Science, Technology, Engineering and Mathematics) school curriculum. The activity focuses on the subject of polar ice melting as a main climate change effect and the different impact of land and sea ice melting on sea level rise. Students, have the opportunity to discover the above experimentally and subsequently, to observe the diachronic change on polar ice through sequences of satellite images and discover the positive climate feedback on global warming. The activity was translated and adapted to the Greek curriculum from the freely available classroom resources of the European Space Agency (ESA, “Teach with Space” collection). MICE, has been enriched with Greek scientific material, including up-to-date information on climate impacts, localized for the extended region. As part of an evolutionary process, the activity was pilot-tested with 6th grade primary school students and adjusted according to the trial findings. This work is considered as the first step towards the development of original Greek educational material that will utilize EO and climate change as the context to teach STEM school curriculum, capitalizing on the pedagogical role satellite remote sensing and inquiry-based teaching methods, can play.

The spatial and temporal scale of flash flood occurrence provides limited opportunities for measurements and observations using of conventional monitoring networks. These observational difficulties, often accompanied by a lack of instrumental data have turned the focus to event-based, post-disaster studies. Post-flood surveys are particularly useful, as they provide the opportunity to observe aspects of hydrological behaviour of catchments under rare runoff conditions and extreme meteorological forcing, by capitalizing on field evidence. Recently, unmanned aerial vehicles (UAVs) and the Structure for Motion (SfM) technique have been used to enhance field surveys and monitoring related to different aspects of disasters. The simple consumer-grade equipment required, its enhanced observation capabilities and certain conveniences they offer in field surveys indicate a strong potential of these technologies in many aspects of flash floods, especially given the opportunistic nature of their study. This work explores further this potential, aiming to demonstrate the application of UAVs in post-flood peak flow estimation. The research team surveyed two selected cross sections after the catastrophic 2017 flood of Mandra, developing a high resolution (2.7cm) digital surface model (DSM) using UAV imagery and the Structure from Motion technique (SfM). The detailed DSM was used to study channel geometry and flow obstructions, extract cross sections and calculate the cross sectional area and wetted perimeter. Water energy slope was defined with the use of high water marks that were placed on the DSM on the appropriate elevation. Peak discharge in the two ungauged sections were estimated at 170m3/s and 140m3/s (with a range to account for the uncertainty inherent in the dynamic nature of Manning coefficient), using the slope-conveyance method, indicating a unit peak discharge of approximately 9-10m3/s/km2. Following recommendations described in relevant literature on the integration of survey observations by means of hydrological modelling, we applied a spatially distributed hydrologic model to simulate discharge at the surveyed cross-sections (the Kinematic Local Excess Model (KLEM)) and other checks, all of which were in agreement, with the peak flow estimates provided by the UAV-aided survey analysis. The UAV allowed the collection of aerial imagery in a rapid way from an extensive area, despite that a large portion of it was inaccessible due to road closures and safety issues. In addition, detailed DSMs created using aerial imagery and the SfM technique was found to be particularly useful for studying channel geometry, obstructions and other characteristics of flow as well as for measuring cross sectional areas on demand, even at a later time, when the channel had changed due to human intervention (e.g. cleanup using heavy machinery) and water flow. These capabilities fit to the opportunistic context of studying flash flood events in the sense that UAVs can rapidly collect information within the short time frame that it is available. Nevertheless, it has to be noted that combination of ground with aerial observations is preferable.

The purpose of the study is the determination of the shoreline changes and the sediment processes along the beach of Marathon Bay, which is located at northeast Attica. In the wider on shore area the Schinias National Park, at the northeast of the bay, the Olympic Rowing Centre, military bases, archeological sites, museums etc. are encountered. The area is also characterized by high touristic activity during summer. In the area there are specific locations and constructions endangered due to coastal retreat. A lagoon was established in the study area 3.500 years BP (Pavlopoulos et al., 2006) as it is characterized by low elevations, gentle slopes and fine sediments. A survey of the coastal and marine geomorphology was carried out by acoustic scanning of the seafloor with an echo sounder and sonar side scan topographical sections perpendicular to the shoreline along with collection and analysis of surface sediments. The quantification of long-term shoreline displacements was carried out by comparing historical and contemporary aerial photographs (1945, 1960, 1969, 1988, 1996, 2001, 2010) along with very high resolution satellite imagery (2012, 2014, 2015, 2016, 2017, 2018), not to mention the tracing of the coastline (2013) with Real Time Kinematics equipment (RTK-GNSS). The quantification of long-term shoreline displacements was made with the use of the add-on application of Digital Shoreline Analysis System (DSAS) within the GIS platform ArcMap 10.6 (Thieler et al., 2009). This was accomplished by drawing 261 transects (every 50 meters), except those neighboring anthropogenic structures, perpendicularly to the historical shorelines from a stable baseline (Tsokos et al., 2018). At each transect the rate of displacement was measured.

Three main aquifer systems developed on Kythira Island include (Pagounis, 1981; Pagounis & Gertsos, 1984, Danamos, 1991; Koumantakis et al., 2006):

• The porous aquifer system in Neogene and Quaternary formations.
• The karstic aquifer system in the carbonate formations of the Pindos and Tripolis units.
• The aquifer system (both shallow and deep) in the fractured hard rocks mainly of the Phyllites – Quartzites unit.

The main discharge of the aquifer systems takes place in coastal and submarine brackish springs around the island, except for its northern part where the Phyllites – Quartzites unit outcrops and its central part where springs of small capacity discharge the carbonate formations of the Pindos unit. The municipal water supply of Kythira has been reinforced by a series of projects and interventions, focusing on the summer touristic period, when water demand surpasses by far water availability, mainly consisting of new deep boreholes. Precipitation is the direct recharge of the three aforementioned aquifer systems while indirectly lateral discharge occurs in places between adjacent and tangential aquifer systems and from the streams runoff as well. On August 4, 2017 a shrub, rather a forest fire broke out close to the island hospital; it expanded rapidly due to strong winds blowing in the area and raged out of control for four days, inducing considerable damage. The size of the fire-affected area was about 20km2, 16km2 mainly of shrub and 4km2 of agriculture land. For the detailed evaluation of the geo-environmental impact of the aforementioned fire to the aquifer systems of the Kythira Island concerning the quantitative and qualitative degradation seventeen municipal water points were finally selected for further hydrogeological study. The water points monitoring network were used in September 2017, June 2018 and October 2018 for measurements of the water tables heads and springs discharges while water samples were collected and chemical, trace elements and microbiological analysis were carried out. The impact of the fire on the quantity of the aquifer systems of the wider fire-affected area could not be fully clarified and there was indirect evidence of their recharge (it remains unknown its rate compared to the recharge before the August 2017 fire) during the three field trips such as:

• Fluctuation of the measurements of the water table heads.
• Fluctuation of the measurements of springs discharges.
• Fluctuation of the measurements of boreholes hydrometers.
• Changes to the hydrochemical facies of the Piper’s, Durov’s and Stiff’s diagrams of the collected water samples.

The results and the evaluation of the chemical and trace elements showed that there was no impact of the fire on the quality of the wider fire-affected area aquifer systems. However, microbiological analysis from the Mylopotamos spring showed qualitative degradation, due to human activities in the wider area preexisting the August 2017 fire (Pagounis, 1981). For the sustainable water resources management of the wider fire-affected area new projects were proposed in order to prevent phenomena that favors the runoff instead of infiltration which lead to the restriction of the recharge of the three main aquifer systems, such as works of artificial recharge.

Mediterranean Temporary Ponds (MTPs) are shallow water bodies which are characterized from a short wet period and their small size (Zacharias et al., 2007). MTPs of Europe have are under an effective protection status, as a result of their identification as a priority habitat (Annex I code 3170*) in the EU Directive 92/43/EEC (Habitats' Directive). These ponds are very delicate ecosystems regarding their hydrological and geochemical characteristics. Due to their small size, they are open to random destruction or other unpredictable dangers. Although small in size, MTPs are complex ecosystems where topography, soil, water and hydrological conditions and microorganisms are closely connected (Zacharias et al., 2007; Stamatakis et al., 2015). The conservation and restoration of such ecosystems is very difficult because of their unique characteristics. The most common threats for MTPs include destruction of the hosting area through human and animal pressures, hydrological disturbance, fire and generally changes in ecological conditions resulting in an increase of competitive plants, nutrition influx, toxic contaminants and wastes, sedimentary deposit filling, exotic-invasive fauna and flora and negative effects from domesticated or hunted fauna (Dimitriou et al., 2006).

A variety of remote sensing tools have been extensively used in the past years for landslide detection and mapping purposes. In addition, detection and mapping of landslide and rockfall events using remote sensing products has been proved to be an effective approach to provide landslide inventories (Scaioni et al., 2014). However, most of the studies are lacking valuable semantic information about landslide elements and how they react with the surrounding environment; natural and man-made primitives. In addition, post classification object-based approaches have been proved to result in better accuracies compared with the pixel-based (Martha et al., 2011). Lately, innovative close-range remote sensing technology such as Unmanned Aerial Vehicle (UAV) photogrammetry and Terrestrial Laser Scanning (TLS) are widely applied in the field of geoscience due to their efficiency in collecting data about terrain morphology rapidly. Their main advantage stands on the fact that conventional methods are mainly collecting point measurements such as compass measurements of bedding and fracture orientation only from areas that were accessible. Aerial platforms are capable to overcome technical issues such as potential occlusions and unfavorable incidence angles due to their ability to capture imagery from multiple positions and with different angles. Nowadays, UAVs tend to be more flexible and powerful tools for landslide and rockfall investigations compared to TLS, due to their low-cost and ease of transportability in harsh environments but also with technology advances such as maintaining of Real Time Kinematic (RTK) positioning. An important factor of their usefulness is their capability to offer unprecedented spatial resolution over wide inaccessible areas, maintain a variability of different sensors (optical, laser, thermal, multispectral) and great ability to reach remote areas and acquire data as close as the user defines. UAVs applications are widely used in post-disaster situations for emergency support, in infrastructure monitoring, in natural resources management, in geohazard monitoring etc. (Corominas et al., 2016; Vassilakis et al., 2019). The latter proves that UAV market has been rapidly growing over the last decade and in future more applications will be introduced in the public. Thus, rapidness and efficiency of Structure-from-Motion (SfM) technology in landslide management provides numerous advantages such as creating landslide inventory maps providing 3D information of large areas.

The Copernicus EO Programme offers information services based on vast amounts of satellite and in-situ data. This information content which is freely and openly available to all users, can directly impact teaching and learning systems by providing insights of our planet never available before. Specifically, the Copernicus ecosystem can enable students to develop a keen awareness of the intricate interrelationships that exist in the real world environment. The incorporation of Copernicus services and data in all levels of education is an ongoing effort which has been initiated with the establishment of the Copernicus Academy Network. Here, we present an application of Copernicus services into the Greek upper primary school curriculum, delivered in the form of “ready-to-use” hands-on activities. We use case studies from the latest natural disasters which have raised public awareness and are believed to be concrete examples of local events that are personally relevant to students, thus engaging them in an experiential learning process. The activity shown is related to the Athens’ devastating forest fires during the summer of 2018 (Mati, Kineta forest fires). We use the Sentinel-hub EO Browser tool to approach the issue of forest fires in urban compare to rural sites. Through simple concepts developed from these examples, the students are introduced to science subjects such as the interaction of light with matter, the reflection of light by different land surfaces, and the extinction of the radiation by atmospheric constituents. The interdisciplinary approach used in the suggested classroom activities promotes the UNESCO vision for education that helps students better understand the world in which they live by addressing the complexity and interconnectedness of environmental problems and thus promoting sustainable development concepts. Future work includes the use of additional natural phenomena and disasters or man-made emergency situations monitored by Copernicus in order to further promote a holistic approach in teaching and learning of Earth System Sciences. (e.g. floods, oil spills, algal blooms, desert dust outbreaks, volcanic eruptions etc.).

The aim of this study is to calculate the displacement rates of the coastline at the western part of the island, which is characterized of the escarpment coast. The shape of this coastal zone is caused mainly by tectonism which is very frequent in this wider area (Valkaniotis et al., 2018). The western coast of the island from Cape Agios Ioannis (NW) to the southernmost point of the peninsula, Cape Doukato is steep and precipitous, as a result of the high seismicity of the Ionian Sea area (Bornovas, 1964). Along this side of the island, several landslides and rock falls are observed. The situation changes only at the northern part of the island, with a distinctive coastal landform over the narrow zone called "Zostiras" (Leivaditis & Verikiou - Papaspyridakou, 1986). This work was conducted using two different types of data. Historical analogue panchromatic aerial images of high resolution (Zuidam and Van Zuidam-Cancelado, 1979) and contemporary digital high resolution multi-spectral satellite images were combined for extracting the coastline at the time period of acquisition. The acquisition of the aerial photographs took place during 1945 and 2010, while the satellite images where acquired during 2016, 2017 and 2018 (Figure 1). In all cases the images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at each time period. All the data were imported in a Geographic Information System platform, where they were subjected into comparison and geo-statistical analysis (Tsokos et al., 2018). Several transects were drawn normally to the coast and the distance between them was set at every 200 m as the relative displacement of the coastline was calculated for each one of them. In a way to achieve this, an extension of the ESRI ArcGIS v.10.6.1 software was employed as published by USGS and named Digital Shoreline Analysis System v.5 (DSAS). The DSAS extension (Thieler et al., 2009) lets the user define a constant straight line in a specific distance from the shoreline and take transects perpendicular to it among the evolving coastlines. The measurements give quantitative information on the change of the position of the shoreline, as well as more useful statistical data. Even if this seems to be an arbitrary value, it worked rather sufficiently at this almost 12 km long segment of the shoreline as it can be characterized as rather curvy and either a smaller value would result an oversampled area with transects intersect each other mixing the calculations or a larger value would result quite sparse transect locations without any representative outcome.

The present study compiles new and literature data in a GIS platform aiming to (a) evaluate the extent and magnitude of Cr contamination in a Mediterranean region (Assopos-Thiva and Central Evia (Euboea) Basins, Greece); (b) combine spatial distribution of Cr in soil and groundwater with land use maps; (c) determine geochemical constraints on contamination by Cr; and (d) provide information that will be useful for better management of land use in a Mediterranean type ecosystem in order to prevent further degradation of natural resources. The spatial diversity of Cr distribution in soils and groundwater throughout the C. Evia and Assopos-Thiva Basins is considered. It is attributed to both natural Cr sources (Cr-bearing peridotites, affecting primarily soil) and human (industrial) activities (the dominant source of groundwater contamination). A combination of the spatial distribution of metals in soil and land use maps was used to define the specific areas of agricultural land use with elevated heavy metal contents. Furthermore, the combination of the spatial distribution of Cr in groundwater and land use maps allows for definition of specific areas of industrial land use with elevated Cr concentrations (Inofita, south Assopos-Thiva Basin). Despite the good correlation (r = 0.75) between Cr(VI) and the strong oxidant NO3− in C. Evia, the lower standard potential (E0) values for NO3− compared to those for Cr2O72− (the latter is a stronger oxidant than the former) suggest that NO3− is not an oxidant of Cr. This detailed assessment and presentation of the available analytical data for soil and groundwater in Assopos-Thiva and C. Evia Basins on a land use map provides information for land management decision makers.

A web - interactive application which spreads geo-environmental information over the internet and also accepts and manages real time rural data is described in this paper. Story Maps context has been chosen for this reason, since this is considered to be a new and innovative Web-based Geographic Information System application method for using it as a mean for organizing and presenting new digital geographic information by combining interactive maps with multimedia and other apps simultaneously in one platform. The protected area of Kallidromo Mt. (central Greece) was chosen as a case study, due to its environmental sensitivity since it is characterized as Natura protected area and also because of the availability of several kinds of geospatial data.

Mediterranean temporary ponds (MTPs) constitute priority habitats under the European Union Habitats Directive, inhabited by several rare endemic species and subjected to unstable environmental conditions. Lakes and pond act as early indicators of climate change, in which alpine ecosystems are especially vulnerable. The study area is located in a mountainous Natura 2000 site of Central Greece, designated as “National Forest Park of Mt Oiti” (Ethnikos Drymos Oitis), which hosts a number of MTPs. Field sampling of soil and water carried out in four MTPs during dry and wet periods between 2012 and 2014. Electrical Resistivity Tomography (ERT) technique was used for the delineation of the subsurface geological structure. This study aims to present the current ecological status of Mt Oiti MTPs with respect to their geo-environmental characteristics, emphasizing to their indirect correlation with plant species richness. Moreover, this paper aims to address the lack of basic ecological background on MPTs network of Mt Oiti concerning their characteristics along with the pressures received from various activities. MTPs of Mt Oiti were classified according to their ecological status, by identifying the habitats’ threats and defining their geological structure, mineralogy and physiochemical parameters of each pond.

The results of Structure-from-Motion techniques in order to quantify the ground surface deformation due to the massive landslide that occurred at the lignite open pit in Amyntaio, Greece on June 10th 2017, are presented in this paper. This unexpected slide damaged the entire westernmost marginal area of the pit, significant number of buildings and infrastructures (incl. road network, powerlines, biological treatment, houses etc.) of the nearby village of Anargiri, as well as agricultural land at the head of the landslide. We generated a very high-resolution surface topography and corresponding co-registered ortho-rectified images covering a total area of 2 km2 by analyzing images acquired from Remotely Piloted Airborne Systems (RPASs). A high resolution (0.13 m) Digital Surface Model (DSM) was produced after photogrammetric processing, serving as a reference dataset for comparison with other surveys realized in December 2017 and September 2018. We compared the centimeter-resolution DSMs acquired during the post landslide periods, quantified the overall ground deformation and finally delineated regions of potential risk.

The long-term change of the shoreline location is a phenomenon, which is highly factored in the design of construction projects along the coastal zone. Especially, beach erosion is characterized as one of the major problems at coastal areas and it is of high importance as a quite significant percentage of social development is concentrated in a relatively narrow zone not far from the waterfront. This study presents a methodology that aims to quantify the shoreline displacement rate by involving the processing of different types of remote sensing datasets such as aerial photographs, satellite images and unmanned aerial system data coupled with in-situ observations and measurements. Several photogrammetric techniques were used in order to orthorectify and homogenize a time series of remotely sensed data acquired from 1945 to 2017, representing a rapidly relocating coastal zone at the southern part of Corinth Gulf (Greece), as a case study. All images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline at the time period of each acquisition. The data were imported in a Geographic Information System platform, where they were subjected to comparison and geostatistical analysis. High erosion rates were calculated, reaching the order of 0.18 m/year on average whilst extreme rates of 0.70 m/year were also observed in specific locations leading to the segmentation of the coastal zone according to its vulnerability and consequently the risk for further development as well as the effectiveness of measures already taken by the authorities.

Urbanization has a significant impact on the surface environment and land surface temperature (LST) can be used as reliable indicator of the Surface Urban Heat Island effect that is caused by it. Here, the relationship between LST and the Athens urban landscape is investigated, using very high resolution airborne nighttime LST image data, obtained during the ESA’s 2009 THERMOPOLIS campaign for three typical summer days (warm day, day with strong Etesian winds and heat wave day). The landscape is represented by the percentage of built-up area coverage per spatial unit provided the European Settlement Map (ESM), spatially averaged on the European Urban Atlas land use map, both provided by Copernicus Land Monitoring Service. It is found that the LSTs exhibit statistically significant differences among the different urban land cover/land use (LCLU) classes, but also among the different days for the same LCLU. A modelled global relationship between LST and landscape can be constructed, though hot and cold spots exist, which indicate clustered areas with higher and lower LSTs. The hotspots coincide with the city centre area of dense fabric and the deviations are maximized with unfavourable meteorological conditions, i.e. heat waves and windless days.

A multidisciplinary analysis comprising neotectonic mapping, morphotectonic indices, applied geophysics and remote sensing techniques was applied in the area affected by the 2008 NW Peloponnese (Western Greece) in order to map the recently-recognized E-W striking Pineios River normal fault zone with a high degree of accuracy, and to better understand its contribution to the evolution of the ancient region of Elis during Holocene time.Quantitative constraints on deformation caused by the faulting were applied through the application of morphometric and morphotectonic indices including drainage network asymmetry, longitudinal river profiles and valley floor slope changes, the river sinuosity index (SI) of modern channels as well as mountain front indices including mountain front sinuosity (Smf) and percentage of faceting along mountain front (F%). All of the aforementioned indicated that the Pineios fault zone is a highly active structure.The study area consists mainly of a succession of Pliocene to Holocene sediments. Already published 230Th/238U dating of corals from the upper layers of the sequence indicates a Tyrrhenian age for samples spanning three complete sections from the footwall of the Pineios fault zone. The deposition ages were determined to be 103 ka for the Psari section (at an elevation of 40-45 m above a.s.l.), 118 ka for the Neapolis section (at an elevation of 60–65 m a.s.l.) and 209 ka for the Aletreika section (at an elevation of 140–145 m a.s.l.). The sampling sites that are located north of Pineios fault zone should be located on a single fault block because there is no sign of tectonic disruption between them. The ages of these dated samples correspond to oxygen isotope stages 5.3, 5.5 and 7.3. These stages represent high sea-level stands for the Mediterranean Sea and especially for the western coast of Peloponnese. In particular, at 103 ka sea-level was ~13 m below present sea-level, at 118 ka it was ~1 m below present sea-level and at 209 ka it was ~7 m below present sea-level. From the age of each sample and the sea-level change that has occurred since deposition, uplift rates for the footwall of the Pineios fault zone were calculated as ~0.26 mm/yr for the Psari area, ~0.50 mm/yr for the Neapoli area and ~0.64 mm/yr for the Aletreika area. The maximum uplift rate of 0.64 mm/yr occurs in close proximity to the fault zone. The areas with lower uplift rates are located much further to the north. Because all sample locations are inferred to be within the same fault block, this implies back tilting of the fault block toward north, in full agreement with the rotational block-faulting inferred from structural studies based on fieldwork in the surrounding area.

The purpose of the study is the determination of the morphodynamical processes and the changes of the shoreline of Marathon Bay, which is located at northeast Attica. The area was lagoon 3.500 years BP (Pavlopoulos et al.2006) and it is characterized by low elevations and smooth slopes. The survey of the coastal and marine geomorphology was carried out by acoustic scanning of the seafloor with an echo sounder and sonar side scan topographical sections perpendicular to the shoreline and collection and analysis of surface sediments. The quantification of long-term shoreline displacements (Thieler et al. 2009) was carried out by comparing historical and recent aerial photographs (1945, 1960, 1969, 1988, 1996, 2001, 2010,), satellite imagery (6/2015, World View 2) and the imprint of the coastline (3/2013) with real time kinematic digital global positioning system (RTK DGPS). The estimation of rate and volume of the sediments transportation was realized by a hydrodynamical model (MIKE 21 Flow Model FM). At the north section of the area, near the estuary of Kainourio stream, and the lagoon’s draining channel, the maximum rates of coastal retreat are noticed (̴0,35m/year). The exposition of the coast to the southern waves, the reduced sediment supply from local rivers, due to the Marathon’s Dam and secondly of the morphology of their riverbeds, they have been filled because of the sea level rise the last 50yrs (IPCC, 2007). The lack of sediment supply, the sediment's composition and the morphological appearance of the submarine basin at the northeast of the Bay are mainly responsible for the coastal retreat along with the sea level rise.

n July 25 and August 26 2016 wildfires broke out in the southwestern and central-western part of Chios Island(NE Aegean Sea, Greece), respectively. The first affected an area of approximately 47km2 and burned throughalmost 90% of olive groves and mastic trees, while the second broke out in a forested area and affected approximately6.6km2 of forest and farmland.A research aiming at the post-fire landslide susceptibility (LS) mapping of both areas was conducted. Morphologicaldata (slope, aspect, curvature, drainage network) derived from a 5m-DEM model of the areas was used.Lithological and geological data (lithology, tectonic structures) were digitized from previous field work maps.Land cover was derived from Worldview-2 satellite images before and after the fire events. Soil thickness was derivedfrom field survey observations within the fire-affected areas, road network from OpenStreetMap and rainfalldata resulted from related measurements derived from Chios meteorological station. Post-fire landslide inventorywas created after an extensive field survey of both areas before the beginning of the rainfall period (October 2016)and before the end of winter season (February 2017).Data classification of each factor according to their estimated LS followed, by using the reverse ranking method,where 1 is the least susceptible and 10 is the most one. Each category was normalized to 100% and the final rasterthematic maps of landslide controlling factors were produced. Finally, using numerical weight for each factor,which was assigned by the Analytic Hierarchy Process using Pairwise Comparison Method and according to theweighted linear combination, a map was generated where each cell has a certain post-fire LS index (LSI) value.The higher the LSI value, the higher the LS, whereas lower LSI value means lower LS.This procedure was repeated twice, first using pre-fire land cover and secondly using the severity of the fire events.The resulted maps, classified with natural breaks method, constitute the final pre- and post-fire LS maps of theaffected areas with five LS categories: very low, low, moderate, high and very high.Comparison of these two final maps showed, more or less, the same LS areas, but with LSI value enhanced. Thevalidated results showed good agreement between post-fire landslide occurrence and the produced post-fire LS maps.

Although forest fires are an integral part of Mediterranean forest ecosystems, they constitute one of the most devastating natural hazards in the region. Apart from the direct consequences, fires induce well-documented longer term effects in the geomorphological and hydrological processes, influencing environmental factors that in turn can affect the occurrence of other natural hazards, such as floods and mass movement phenomena.This work focuses on the forest fire of 2007 in Peloponnese, Greece that burnt 1773 km2, causing 78 fatalities and very significant damages in property and infrastructure and went down as the largest fire in the country’s record. It examines the occurrence of flood and mass movement phenomena, before and after this mega-fire and studies different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency.Observational evidence based on several data sources collected during the period 1989-2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively.Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends.Although no major land use changes has been identified and chlorophyll is shown to recover 2 years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed changes in hydrogeomorphic response of the fire affected basins.The findings of this work are strong indications that future climatic change, with more frequent and severe droughts and storms will be a disastrous combination for the Mediterranean region.

Remote sensing techniques offer the opportunity to study fire effects and vegetation recovery dynamics across large areas, providing essential information for effective management strategies development over fire-prone landscapes. Chios, the fifth largest of the Greek islands, has experienced recurring forest fires during the recent years, resulting to significant risk of environmental degradation. During the summer of 2016, the island experienced two severe wildfires, with the biggest one recorded in the southern part of the island. The affected area was mostly covered by maquis and phrygana (formations of low shrubs) (40.9%), while pine forests (Pinus brutia) represented 15.5% of the burned area. The aim of this study was to estimate and analyze the state of post-fire vegetation recovery in the island of Chios following major fire events occurred during the summer of 2016. A post-fire 8-band WorldView-2 image was used for burned area mapping by employing a geographic object-based classification approach, followed by field campaign for assessing post fire vegetation recovery, which was conducted during summer 2017 by establishing reference plots in the main pre-fire vegetation types (maquis, shrublands and pine forest areas) within the fire-affected area. A series of single and multi-temporal spectral indices including Normalized Burn Ratio, Normalized Difference Vegetation Index, Enhanced Vegetation Index and Soil Adjusted Vegetation Index, were derived from multi-temporal Sentinel-2 images. A random forest modelling procedure was performed for estimating post fire vegetation recovery within the burned area, as well as the areas of high risk erosion. We identified dNDVI, EVI and the second red edge band of Sentinel-2 as the most important spectral variables for predicting vegetation recovery within pre-fire areas. In the case of pre-fire areas with maquis, post-fire NBR, EVI and NDVI were selected as best predictors. Finally, the results revealed that vegetation recovery is more pronounced within the pre-fire pine forest areas, while topographic and geological sub-strata factors were also found significant in defining post-fire vegetation recovery.

Apart from direct consequences, forest fires induce water related effects related to geomorphological and hydrological processes, triggering floods and mass movement phenomena. This work focuses on the forest fire of 2007 in Peloponnese, Greece that to date corresponds to the largest fire in the country’s record. It examines the occurrence of flood and mass movement phenomena, before and after this fire and analyses different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency. Observational evidence collected during the period 1989-2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively. Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends. Although no major land use changes has been identified and chlorophyll is shown to recover 2 years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed increase in flood and mass movement frequency in the fire affected areas.

The aim of this study is to spatially assess fire severity and to explore the relationship between the Normalized Vegetation Index (NDVI) derived from WorldView- 2 imagery and the field-based fire severity index “Composite Burn Index” (CBI) on a recent large fire that occurred on the island of Chios, Greece, in 2016. The statistical analysis indicated a relatively strong linear relationship between the NDVI and the CBI (R2 = 0.71). Predictive local thresholds of NDVI values have been determined for accurate thematic classification and mapping of fire severity classes. The overall classification accuracy based on NDVI from WorldView-2 was relatively high (71%), pointing to the potential of using such data for mapping forest fires in the Mediterranean as well as for assessing their severity. The application of the classification thresholds calculated in this study over other forest fire events on similar ecosystem types, could support the rapid assessment of fire severity and hence could enable the decisions needed for proper post-fire management.

The thermal comfort conditions in a complex urban area is influenced by the surrounding structures and obstacles which modify the incoming radiation fluxes. A measure of this modification is the sky view factor (SVF), which could be estimated in each point of a selected area if a high resolution digital elevation model (DEM), or other urban morphological data including the manmade infrastructure, are available. The goal of this study is to model the continuous SVF for a complex building environment in the campus of National and Kapodistrian University of Athens, based on a high resolution DEM (0.09 m). For this purpose, we applied the structure-from-motion (SfM) technique, which takes advantage of the interpretation of ultra-high resolution colour images acquired by remotely piloted airborne systems, also known as drones or unmanned aerial vehicles. A quantitative analysis, by applying statistical metrics, yields perfect agreement between modelled and observed SVF values, over the examined area. The proposed methodology could be applied for human-biometeorology research in micro scale complex urban environments.

Although forest fires are considered an integral part of Mediterranean forest ecosystems, they nevertheless constitute one of the most devastating natural hazards. Apart from the direct consequences, fires induce longer term effects in the geomorphological and hydrological processes, influencing environmental factors that in turn can affect the occurrence of other natural hazards, such as floods and mass movement phenomena. This work focuses on the forest fire of 2007 in Peloponnese, Greece that burnt 1773 km2, causing 78 fatalities and very significant damages in property and infrastructure and went down as the largest fire in the country’s record. It examines the occurrence of flood and mass movement phenomena, before and after this mega-fire and studies different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency.Observational evidence based on several data sources collected during the period 1989-2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively. Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends. Although no major land use changes has been identified and chlorophyll is shown to recover 2 years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed changes in hydrogeomorphic response of the fire affected basins.

Even though rare, mega-fires raging during very dry and windy conditions, record catastrophic impacts on infrastructure, the environment and human life, as well as extremely high suppression and rehabilitation costs. Apart from the direct consequences, mega-fires induce long-term effects in the geomorphological and hydrological processes, influencing environmental factors that in turn can affect the occurrence of other natural hazards, such as floods and mass movement phenomena. This work focuses on the forest fire of 2007 in Peloponnese, Greece that to date corresponds to the largest fire in the country's record that burnt 1773 km2, causing 78 fatalities and very significant damages in property and infrastructure. Specifically, this work examines the occurrence of flood and mass movement phenomena, before and after this mega-fire and analyses different influencing factors to investigate the degree to which the 2007 fire and/or other parameters have affected their frequency. Observational evidence based on several data sources collected during the period 1989–2016 show that the 2007 fire has contributed to an increase of average flood and mass movement events frequency by approximately 3.3 and 5.6 times respectively. Fire affected areas record a substantial increase in the occurrence of both phenomena, presenting a noticeably stronger increase compared to neighbouring areas that have not been affected. Examination of the monthly occurrence of events showed an increase even in months of the year were rainfall intensity presented decreasing trends. Although no major land use changes has been identified and chlorophyll is shown to recover 2 years after the fire incident, differences on the type of vegetation as tall forest has been substituted with lower vegetation are considered significant drivers for the observed increase in flood and mass movement frequency in the fire affected areas.

Fires of 2007 have consumed large areas of Black pine and endemic fir forests in Greece. The current research aims at examining the role of geomorphology and lithology that govern the soil properties upon the post-fire vegetation recovery at the landscape level. A case study from Taygetos Mt, a large part of which was burned in 2007, is presented. Based on the interpretation of a high spatial and spectral resolution satellite image (WorldView-3, 4/2015), GIS thematic layers have been created showing unburned and regenerated patches over various lithological types. A network of sites was selected for field sampling representing various combinations of the above. Data on recovery of the main tree species as well as on total vegetation cover were collected. Results prove the relationship between regeneration ability and plant species traits as well as the existence of unburned patches near the burned ones. Black pine had regenerated from seeds dispersed from cones that have remained intact on unburned or scorched trees, close enough to the burned patches, while Greek fir presented remarkably low regeneration, lacking of any response mechanism. Plant species recovery seems to be controlled by the geology as it was found weaker in plots overlying carbonate, permeable, not easily erodible formations as compared to that observed over clastic, impermeable, erodible formations of schists, even for the same species. In conclusion, post-fire vegetation recovery at the landscape level seems to be a complex process controlled not only from species biology but also from the landscape features.

Combining geological and geomorphological data together with geodetic SAR interferometry (InSAR) measurements an attempt has been made to investigate the vertical deformation of the Itea-Amfissa basin at the northern part of the Corinth rift. The north–south trending basin has been developed normally to the east – west trending Corinth Rift and on the hanging wall of the Itea-Amfissa detachment. In the stratigraphy of the Itea–Amfissa supra-detachment basin, two sequences can be distinguished; the lower marine polymict conglomerate of Early–Middle Miocene age and the upper terrestrial monomict carbonate breccia of Late Miocene age. The unconformity between them has been uplifted to the north of the basin up to the elevation of 1100m and subsided below sea level at its southern part. Remnants of low-relief surfaces are retained on top of the upper terrestrial sequence, that permit to reconstruct the paleo-landscape of the basin and to measure the spatial distribution of its vertical deformation after compensating the erosional isostatic adjustment. The exact delineation of the paleo-landscape, involved detailed mapping as well as quantitative analysis of geomorphological features caused by river incision, based on measurements of several tectonic geomorphology indices. Geodetic InSAR estimates of vertical ground displacements, combining almost 10 years of ascending and descending ENVISAT data, were also utilized both for refinement of delineated surfaces as well as for validation of geology-based deformation trends. Interferometric results were constrained to the geologic time frame, considering the well-defined long-term deformation trend of a doline, proven to be sinking over the last 6000 years. It is shown that over the last 10 years the largest uplift rates are observed within the Itea-Amfissa basin, while the coastline regions follow a more complex spatial deformation pattern of successive submergences and uplifts. The synthesis of geological and geomorphological data indicates that the Itea-Amfissa extensional basin from its development in the Middle-Late Miocene and throughout Plio-Quaternary, has been tilted towards south, while contemporary geodetic measurements from InSAR confirm that the basin is still uplifting with regard to its surrounding mountains and coastal areas.  

Mt Taygetos (2407m), located at southern Peloponnese (Greece) suffered a large fire during the summer of 2007. The fire burned approximately 45% of the area covered by the endemic Greek fir (Abies cephalonica) and Black Pine (Pinus nigra) forest ecosystems. The aim of the current study is to examine the potential differences on post-fire vegetation recovery imposed by the lithology as well as the geomorphology of the given area over sites of the same climatic and landscape conditions (elevation, aspect, slope etc.). The main lithologies consist of carbonate, permeable, not easily erodible formations (limestones and marbles) and clastic, impermeable (schists, slate and flysch) erodible ones. A time-series of high spatial resolution satellite images were interpreted, analyzed and compared in order to detect changes in vegetation coverage which could prioritize areas of interest for fieldwork campaigns. The remote sensing datasets were acquired before (Ikonos-2), a few months after (Quickbird-2) and some years after (Worldview-3) the 2007 fire. High resolution Digital Elevation Model was used for the ortho-rectification and co-registration of the remote sensing data, but also for the extraction of the mountainous landscape characteristics. The multi-temporal image dataset was analyzed through GEographic-Object Based Image Analysis (GEOBIA). Objects corresponding to different vegetation types through time were identified through spectral and textural features. The classification results were combined with basic layers such as lithological outcrops, pre-fire vegetation, landscape morphology etc., supplementing a spatial geodatabase used for classifying burnt areas with varying post-fire plant community recovery. We validated the results of the classification during fieldwork and found that at a local scale, where the landscape features are quite similar, the bedrock type proves to be an important factor for vegetation recovery, as it clearly defines the soil generation along with its properties. Plant species recovery seems to be controlled by the local lithology as it was found weaker in plots overlying limestones and marbles, comparing to that observed over schists, even for the same species. In conclusion, post-fire vegetation recovery seems to be a complex process controlled not only from species biology, but also from the geological features.

Recent global changes seem to have affected fire regimes by inducing more severe larger fires in the thermomediterranean vegetation zone but also more frequent incidents in territories of higher altitudes. Cephalonia island hosts Mt Ainos, one of the most important National Parks of Greece, focal geographical area of the non-fire adapted endemic fir Abies cephalonica. The island has suffered several fires in the past. The aim of this work is to introduce a framework for assessing spatial fire risk and exposure of biodiversity hot spot areas, using Cephalonia as a pilot case study. Fuel parameters in representative vegetation types were measured across the island for models development as well as for collecting training and validation points for satellite data classification. The Minimum Travel Time algorithm, as it is embedded in FlamMap spatial fire simulation software, was applied in order to assess critical fire behavior parameters and exposure of the island’s biodiversity hotspots under three different meteorological and fuel moisture scenarios simulating predicted climate changes. In addition, the risk of change in the island's ecological value due to biodiversity loss was studied under the same scenarios. According to the analysis, loss of all biodiversity values was found under the severe meteorological and fuel moisture scenario and was estimated to be higher in the endemic fir forests. The outputs of this study may be used as an application of quantitative and probabilistic risk assessment for biodiversity conservation planning, prioritization and management of high value natural and cultural resources.

Fires of 2007 have consumed large areas of Black pine and Greek fir forests in Peloponnese, Euboea and Attica. Most studies that followed, focused on the natural regeneration potential or the need for reforestation. The current research aims at examining the role of geomorphology and lithology that govern the soil properties upon the post-fire vegetation recovery at the landscape level. A case study from Taygetos Mt, a large part of which was burned in 2007, is presented. Based on the interpretation of a high spatial and spectral resolution satellite image (WorldView-3, 4/2015), several GIS thematic layers have been created showing unburned and regenerated patches over various lithological types. A network of sites was selected for field sampling representing various combinations of the above. Data on vegetation cover and recovery of the main tree species were collected. Results prove the interrelationship between regeneration and species traits as well as the existence of unburned patches near the burned ones. Recovery seems to be controlled by the geology of the plots as it was found weaker in plots overlying carbonate, permeable, not easily erodible formations as compared to that observed over clastic, impermeable, erodible formations of schists, even for the same species. In conclusion, post-fire vegetation recovery at the landscape level seems to be a complex process controlled not only from species biology but also from the landscape features and its fire history.

Within this study we introducea framework for assessing spatial fire risk and exposure to three important habitat types in Cephalonia island, Greece.Existing maps were used for plot allocation in orderto measure several fuel parameters in representative natural fuel complexes for site-specific fuel models development, as well as for collecting training and validation points for satellite data classification. The spatial extent of the fuel types and the canopy cover were delineated using a Landsat 8 OLI image acquired on 23-7-2015and the Support Vector Machines-(SVMs) machine learning algorithm. Subsequently, The Minimum Travel Time (MTT) algorithm, as it is embedded in FlamMap spatial fire simulation software, was applied in order to assess critical fire behavior parameters and exposure of Cephalonia's habitats under three different meteorological and fuel moisture scenarios. The outputs of this study may be used as an application of quantitative and probabilistic risk assessment for habitats conservation planning, prioritization and management of high value natural and cultural resources.

On July 17, 2015 a forest fire that broke out in the southern part of Epidavros Limira peninsula (Laconia, southeastern Peloponnese), expanded rapidly due to strong winds blowing in the area and raged out of control for two days, inducing substantial damage to agriculture, livestock farming, buildings and infrastructure and causing one fatality. Innovative GIS-based methods were developed and implemented for the first time in a fire-affected area in Greece for mapping the post-fire erosion, flood and landslide hazards and risks. Geomorphological, geological, tectonic, hydrological, meteorological and land-use data along with a WorldView-2 satellite image and post-fire field observations were evaluated and used. A newly developed method was applied for assessing the erosion hazard. Analytic Hierarchy Process and Weighted Linear Combination methods were used for assessing the post-fire landslide susceptibility. The HEC-RAS model was used for hydraulic simulation and assessment of flood risk under post-fire conditions. Post-fire erosion, flood and landslide hazard and risk maps were constructed for the affected area delineating locations with very low, low, moderate, high or very high hazard and risk of erosion, flood and landslide respectively. The developed methodology is a useful post-fire hazard and risk assessment tool and can be applied by state authorities to assess the geo-environmental impact of fire disasters in areas with similar environmental conditions.

The Aegean-west Anatolian orocline formed due to mainly post-15 Ma opposite rotations of its western and eastern limbs, which contributed to the opening of the Aegean back-arc basin. Stretching lineations in exhumed metamorphic complexes in this back-arc basin mimic the regional vertical axis rotation patterns and suggests that the oppositely rotating domains are bounded by the ‘Mid-Cycladic Lineament’, the tectonic nature of which is enigmatic. Some authors have proposed this lineament to be extensional fault accommodating orogen-parallel extension, while others considered it a transform fault. The island of Paros hosts the only exposure of the Mid-Cycladic Lineament: the northwest of the island contains E-trending and the southeast contains N trending stretching lineations. Here, we show new paleomagnetic results from isotropic, ~16 Ma granitoids that intruded both domains. These demonstrate that the trend difference resulted from post-16 Ma ~90° clockwise and 10° counterclockwise rotation of the northwest and southeast blocks, respectively. We show that a greenschist facies, semi-ductile to brittle, low-angle, southeast dipping normal fault zone, here identified as the Elitas Shear Zone that we interpret as the Mid-Cycladic Lineament accommodates this rotation difference on Paros. We conclude a two-stage exhumation history for Paros that is consistent with regional Aegean reconstructions. Between ~23 and 16 Ma, the metamorphic rocks of Paros exhumed from amphibolite-facies to greenschist facies conditions along a top-to-the-north detachment. The Elitas shear zone then started to exhume the northwestern clockwise rotating domain from below the southeastern, counterclockwise rotating domain since 16 Ma. We demonstrate at the only location at which a structure coinciding with Mid-Cycladic Lineament is exposed, it is extensional in nature, consistent with geometrical predictions that Aegean oroclinal bending must have been accommodated by combined orogen-normal and orogen-parallel extension.

Corinth Canal is an important technical construction with a significant role in marine and land transportation for Greece. Whilst the main highway of the Corinth bridge is well monitored there is no similar monitoring scheme for landslide failures of the canal walls. This work presents an in-house developed real-time early warning landslide triggering system using wireless sensor network (WSN) nodes. Specifically, for the detection of different types of landslide processes (drift, slide and fall) a set of corresponding MEMS (Micro-Electro-Mechanical Systems) sensors (accelerometer, inclinometer, magnetometer) will be used. These sensors along with radio transmission unit and microprocessor comprise a WSN node. The option for in-situ processing (i.e transmitting only alerts) is possible in order to decrease the communication costs. In conjunction with the proposed WSN system, high accuracy geodetic techniques are used with terrestrial laser scanning (TLS) measurements. TLS is augmenting the point-based system to a spatial -based monitoring system. The paper describes the use of WSN node as triggering device in order to alert the users to begin TLS measurements. A description of the network topology is given along with the implementation of the system in selected control points on the canal walls. Real results are shown and the performance of the system is discussed.

The long term change of the shoreline is a phenomenon, which is factored in the design of construction projects along the coastal zone. This study presents a meth-odology that aims to quantify the shoreline displacement rate. The described meth-odology involves the interpretation of different remote sensing data types, which make up a quite dense time series of representations for the coastline spanning from 1987 to 2012. The representation of the shoreline is based on geometrically corrected (ortho-rectified), historical, analogue, panchromatic, high resolution aerial photos of the area (1987, 1996) and latest generation, digital, multispectral, high resolution satellite images (2000, 2008, 2012). In all cases the images were digitally processed and optically optimized in order to produce a highly accurate representation of the shoreline in each time period. All the data were imported in a Geographic Information System platform, where they were subjected to comparison and geo-statistical analysis. A large number of sections perpendicular to the coast (every 100 meters) was drawn and the relative motion of the coastline was calcu-lated for each of them. The average rate of the calculated erosion is in the order of 24mm/year whilst extreme rates of 1m/year were also observed in specific posi-tions.

In tectonically active areas, such as in the northwest Peloponnese of western Greece, geomorphic processes are strongly influenced by active faulting; in many cases such faults cannot be easily identified. In this paper we apply multidisciplinary analysis (morphotectonic indices, neotectonic mapping, geophysical surveys and remote sensing techniques) to map the recently-recognized east–west trending Pineios River normal fault zone with a high degree of accuracy, and to better understand its contribution to the evolution of the ancient region of Elis during Holocene time. Fault activity seems to be related to frequent changes in river flow patterns and to displacements of the nearby shoreline. We argue that fault activity is the main reason for migration of Pineios river mouth as documented for several time periods during historical time. Quantitative constraints on deformation caused by the faulting were applied through the application of the morphotectonic indices proposed in this paper, including drainage network asymmetry and sinuosity, and mountain front sinuosity, all of which indicate that this is a highly active structure. Slip rates calculated to be as high as 0.48 mm/yr for the last 209 ka (based on previously published dating) were verified by applied geophysical methods. The fault surface discontinuity was identified at depth using vertical electrical resistivity measurements and depositional layers of different resistivity were found to be clearly offset. Displacement increases toward the west, reaching an observed maximum of 110 m. The most spectacular landform alteration due to surface deformation is the north–south migration of the river estuary into completely different open sea areas during the late Quaternary, mainly during the Holocene. The sediment transport path has been altered several times due to these changes in river geometry with and the most recent seeming to have occurred almost 2000 years ago. The river estuary migrated to its contemporary position along the southern coast, settled on the hanging wall, inducing retrograding of the northern coast, and settled on the foot wall, with rates reaching the order of 0.52 m/yr, as concluded from historical and recently-acquired remote sensing data.

The aim of the present study is to investigate the morphodynamic regime of the coastal area of Xylokastro (north coast of Peloponnese), in order to identify and evaluate the processes controlling its formation and evolution. Within this concept, a number of factors have been considered and evaluated; near-shore morphometry and granulometry along shore-normal profiles, the direction and potential volumes of long- and cross-shore sediment transport the decadal and future trends of coastline displacement, the available information for terrestrial sediment influx and the geological processes operating in the broader coastal region of Xylokastro (i.e. subaqueous slides) as well as human interference. On the basis of these results, the formation and evolution of this coastal stretch seems to be governed primarily by the neotectonic activity and relative change of sea level rise, and secondarily by the wave-induced near-shore sediment transport; the role of the latter could be enhanced substantially by human intervention (i.e. construction of marina, seafront walls). Moreover, the expected eustatic increase in sea level by the year 2100, could cause a coastline retreat up to 9 m (SLR=0.38 m) or >19 m (SLR≥1 m).

Aim Although all five of the major mediterranean-climate ecosystems (MCEs) of the world are recognized as loci of high plant species diversity and endemism, they show considerable variation in regional-scale richness. Here, we assess the role of stable Pleistocene climate and Cenozoic topography in explaining variation in regional richness of the globe's MCEs. We hypothesize that older, more climatically stable MCEs would support more species, because they have had more time for species to accumulate than MCEs that were historically subject to greater topographic upheavals and fluctuating climates. Location South-western Africa (Cape), south-western Australia, California, central Chile and the eastern (Greece) and western (Spain) Mediterranean Basin. Methods We estimated plant diversity for each MCE as the intercepts of species–area curves that are homogeneous in slope across all regions. We used two down-scaled global circulation models of the Last Glacial Maximum (LGM) to quantify climate stability by comparing the change in the location of MCEs between the LGM and present. We quantified the Cenozoic topographic stability of each MCE by comparing contemporary topographic profiles with those present in the late Oligocene and the early Pliocene. Results The most diverse MCEs – Cape and Australia – had the highest Cenozoic environmental stability, and the least diverse – Chile and California – had the lowest stability. Main conclusions Variation in plant diversity in MCEs is likely to be a consequence not of differences in diversification rates, but rather the persistence of numerous pre-Pliocene clades in the more stable MCEs. The extraordinary plant diversity of the Cape is a consequence of the combined effects of both mature and recent radiations, the latter associated with increased habitat heterogeneity produced by mild tectonic uplift in the Neogene.

A series of methodologies are described in this paper aiming to quantify the natural hazard due to the coastal changes at a deltaic fan. The coastline of Istiaia (North Evia, Greece) has been chosen for this study as several areas of accretion and erosion have been identified during the past few decades. We combined different types of datasets, extracted from high resolution panchromatic aerial photographs and traced the contemporary shoreline by high accuracy surveying with Real Time Kinematics (RTK) GPS equipment. The interpretation of all shorelines required geo-statistical analysis in a Geographical Information System. A large number of high resolution morphological sections were constructed normally to the coast, revealing erosional and depositional parts of the beach. Retreating and extension rates were calculated for each section reaching the values of 0.98 m/yr and 1.36 m/yr, respectively. The results proved to be very accurate, allowing us to expand the developed methodology by using more complete time-series of remote sensing datasets along with more frequent RTK-GPS surveying.

The Sparta Fault system is a major structure approximately 64 km long that bounds the eastern flank of the Taygetos Mountain front (2407 m) and shapes the present-day Sparta basin. It was activated in 464 B.C., devastating the city of Sparta. This fault is examined and described in terms of its geometry, segmentation, drainage pattern and post-glacial throw, emphasising how these parameters vary along strike. Qualitative analysis of long profile catchments shows a significant difference in longitudinal convexity between the central and both the south and north parts of the fault system, leading to the conclusion of varying uplift rate along strike. Catchments are sensitive in differential uplift as it is observed by the calculated differences of the steepness index ksn between the outer (ksn < 83) and central parts (121 < ksn < 138) of the Sparta Fault along strike the fault system. Based on fault throw-rates and the bedrock geology a seismic hazard map has been constructed that extracts a locality specific long-term earthquake recurrence record. Based on this map the town of Sparta would experience a destructive event similar to that in 464 B.C. approximately every 1792 ± 458 years. Since no other major earthquake M ~ 7.0 has been generated by this system since 464 B.C., a future event could be imminent. As a result, not only time-independent but also time-dependent probabilities, which incorporate the concept of the seismic cycle, have been calculated for the town of Sparta, showing a considerably higher time-dependent probability of 3.0 ± 1.5% over the next 30 years compared to the time-independent probability of 1.66%. Half of the hanging wall area of the Sparta Fault can experience intensities ≥ IX, but belongs to the lowest category of seismic risk of the national seismic building code. On view of these relatively high calculated probabilities, a reassessment of the building code might be necessary.

In this paper we present a combination of several near surface geophysical investigation techniques with high resolution remote sensing image interpretations, in order to define the groundwater flow paths and whether they can be affected by future seismic events. A seasonal spring (Amvrakia) located at the foot of Meteora pillars near the village of Kastraki (Greece) was chosen as a test site. The Meteora conglomeratic formations crop out throughout the study area and are characterized by large discontinuities caused by post Miocene till present tectonic deformation [Ferriere et al. 2011, Royden and Papanikolaou 2011]. A network of groundwater pathways has been developed above the impermeable marls underlying the conglomeratic strata. Our research aims to define these water pathways in order to investigate and understand the exact mechanism of the spring by mapping the exposed discontinuity network with classic field mapping and remote sensing image interpretation and define their underground continuity with theΒ contribution of near surface geophysical techniques. Five Very Low Frequency (VLF) profiles were conducted with different directions around the spring aiming to detect possible conductive zones in the conglomeratic formations that the study area consists of. Moreover, two Electrical Resistivity Tomography (ERT) sections of a total length of 140m were carried out parallel to the VLF profiles for cross-checking and verifying the geophysical information. Both techniques revealed important conductive zones (<200 Ohm m) within the conglomerate strata, which we interpret as discontinuities filled with water supplying the spring, which are quite vulnerable to displacements as the hydraulic connections between them might be easily disturbed after a future seismic event.

New paleomagnetic data from Early Miocene to Pliocene terrestrial sedimentary and volcanic rocks in Central Greece constrain the history of vertical-axis rotation along the central part of the western limb of the Aegean arc. The present-day pattern of rapid block rotation within a broad zone of distributed deformation linking the right-lateral North Anatolian and Kephalonia continental transform faults initiated after Early Pliocene time, resulting in a uniform clockwise rotation of 24.3±6.5° over a region >250 km long and >150 km wide encompassing Central Greece and the western Cycladic archipelago. Because the published paleomagnetic dataset requires clockwise rotations of >50° in Western Greece after ∼17 Ma, while our measurements resolve no vertical-axis rotation of Central Greece between ∼15 Ma and post-Early Pliocene time, a large part of the clockwise rotation of Western Greece must have occurred during the main period of contraction within the external thrust belt of the Ionian Zone between ∼17 and ∼15 Ma. Pliocene initiation of rapid clockwise rotation in Central and Western Greece reflects the development of the North Anatolia–Kephalonia Fault system within the previously extended Aegean Sea region, possibly in response to entry of dense oceanic lithosphere of the Ionian Sea into the Hellenic subduction zone and consequent accelerated slab rollback. The development of the Aegean geometric arc therefore occurred in two short-duration pulses characterized by rapid rotation and strong regional deformation.

Pineios River is the 3 rd longest river in Peloponnese and flows in Kyllini wider area which is located close to the Hellenic Arc-Trench system. This is one of the most seismically and tectonically active regions in Greece with a great number of changes in the morphogenetic events taking place during the neotectonic period, as well as the last 100 ky. Prior to the 18 th century A.D., the lower alluvial Pineios River flowed north of the Kyllini peninsula and into the Ionian Sea southwest of Kotichi Lagoon, but the river now flows southward into a deltaic swamp and dune region, burying a former lagoon-barrier coastal zone. From this, it becomes apparent that this river is not monotonous in appearance and therefore is not completely controlled by hydrology and hydraulics. In fact, the lower alluvial Pineios River has reacted to major geological controls, surface deformation and uplift movements caused by the activity of the recently mapped Pineios normal fault zone and salt tectonics in Kyllini peninsula resulting in the river flow diversion from north to south at completely different open sea areas. The effects of the geological, tectonic and neotectonic activity and the impact of the human presence and influence on the lower Pineios River are presented in this paper in order to determine the causes of the diversion of the lower (alluvial) Pineios River (NW Peloponnese, Greece) and shoreline displacements.

Rapid northeast-vergent subduction along the Hellenic trench, at ~ 35 mm/yr, exists in concert with widespread extensional and strike-slip faulting within the upper plate lithosphere of western Greece. Integration of regional geomorphic, geologic, seismic, GPS, remote sensing and field data demonstrates that young and active deformation in the area, extending from the Hellenic subduction boundary near Kephalonia to the Gulf of Corinth, consists of an interconnected network containing highly localized zones of deformation. These bound a series of crustal fragments with relatively little internal deformation. These deformation zones merge to form triple junction-like features at the western end of the Gulf of Corinth and in the Amvrakikos Gulf. At the western end of the Corinth Gulf, most of its 14 ± 2 mm/yr of extension is relayed to the northwest along a prominent zone of left-slip and extension through Lake Trichonis and the Amphilochia fault zone (11 ± 2 mm/yr). The remaining displacement across the western Gulf of Corinth is relayed into 7 ± 2 mm/yr of right-slip on the southwest-striking Achaia fault zone, which traverses the northwestern margin of the Peloponnesus. A second triple-junction like feature occurs in the Amvrakikos Basin, where the left-slip Amphilochia fault zone, the right-slip Kephalonia transform fault (15 ± 2 mm/yr) and the convergent thrust front of northern Hellenides (4 ± 2 mm/yr) are joined. Thus the extensional deformation in the Gulf of Corinth can be shown to be connected to convergence and subduction along the Hellenic trench through a series of discrete deformation zones that are not dissimilar from those observed in the global plate tectonic system.

The revised tectono-stratigraphy of Crete and especially of the "Phyllites-Quartzites" complex demonstrated the distinction of the probable Paleozoic low-medium grade metamorphic rocks of the Arna unit from the underlying Permo-Triassic phyllites and associated carbonate sediments (Trypali facies) of Western Crete unit as well as the overlying Permo-Triassic phyllites and associated sediments of the Tyros/Ravdoucha Beds at the base of the Tripolis unit. The pre-existing mixture of the above tectono-stratigaphic units in a single complex created a number of misinterpretations as far as stratigraphy, metamorphism and interpretation of low angle faults as thrusts or detachments. Especially in cases where the inferred tectonic contact concerns the transition between the Tyros Beds and the base of the Tripolis carbonate platform there is no structural omission and therefore the contact represents a minor disharmonic sliding surface and not a detachment. Based on the revised tectono-stratigraphic analysis the determination of the structural omission for each tectonic contact was possible and several detachments were described for the first time. Footwall rocks of the detachments comprised several tectonic units usually from the lower nappes and hanging wall rocks comprised several tectonic units usually from the upper nappes. The detachment may separate not only metamorphosed units in the footwall (Mani, Western Crete, Arna) from non metamorphosed units in the hanging wall (Tripolis, Pindos and higher nappes) but also all other possible combinations from the Cretan nappe pile. Extension in Crete started in the Middle-Late Miocene with the formation of extensional detachment faults. The reported extensional structures of Oligocene to Early Miocene age do not correspond to crustal extension of Crete but to localized shear zones related to nappe stacking and the exhumation of metamorphic rocks. Extensional detachments in Crete form a tectonic horst through two oppositely dipping E-W-trending zones; one dipping north, related to the opening of the Cretan basin, and the other dipping south, related to the formation of the Messara supra-detachment basin. The deformation history of units within Crete can be summarized as: (i) compressional deformation producing arc-parallel east-west-trending south-directed thrust faults in Oligocene to Early Miocene time; (ii) extensional deformation along arc-parallel, east-west-trending detachment faults in Middle Miocene time, with hanging wall motion to the north and south; and (iii) Late Miocene-Quaternary transtensional deformation along high-angle normal and oblique normal faults that disrupt the older arc-parallel structures.

The city planning of Heraklion in Crete included the construction of the new Courthouse building at the eastern part of the town where several active fault have been mapped during an earlier microzonation study. The significance of the new building required detailed studies for the exact tracing of the faults and the period of their latest activation. The proposed methodology included trenching across the fault traces which are either controlling a morphological discontinuity or covered by human activities. Sampling for radiocarbon and optical luminance dating was carried out aiming for the exact age of the ruptured strata by the active faults. The combination of the described methodologies resulted the modification of the city plan, as constructions were designed to be built on the fault trace.