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.

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.

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).

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.

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 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 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.

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.

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.

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.

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.

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.

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.

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.