Publications by Year: 2023

2023
Mavroulis S, Argyropoulos I, Vassilakis E, Carydis P, Lekkas E. Earthquake Environmental Effects and Building Properties Controlling Damage Caused by the 6 February 2023 Earthquakes in East Anatolia. Geosciences [Internet]. 2023;13(10):303. https://doi.org/10.3390/geosciences13100303Abstract
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.
Asimakopoulou P, Nastos P, Vassilakis E, Antonarakou A, Hatzaki M, Katsigianni O, Papamatthaiou M, Kontoes C. Climate Change Education through Earth Observation: An Approach for EO Newcomers in Schools. Sustainability [Internet]. 2023;15:14454. https://www.mdpi.com/2071-1050/15/19/14454Abstract
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.
Mavroulis S, Mavrouli M, Vassilakis E, Argyropoulos I, Carydis P, Lekkas E. Debris Management in Turkey Provinces Affected by the 6 February 2023 Earthquakes: Challenges during Recovery and Potential Health and Environmental Risks. Applied Sciences [Internet]. 2023;13(15):8823. https://doi.org/10.3390/app13158823Abstract
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.
Katsora C, Vassilakis E, Konsolaki A, Alexopoulos JD. Diachronic Monitoring of Psatha Active Fault at a Costal Zone, by Combining Near Surface Geophysical Methods. In: NSG2023, 29th European Meeting of Environmental and Engineering Geophysics. Vol. 2023. Edinburg, Great Britain: European Association of Geoscientists & Engineers; 2023. pp. 1-5. https://doi.org/10.3997/2214-4609.202320153Abstract
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.
Giannopoulos IK, Alexopoulos JD, Mitsika GS, Konsolaki A, Dilalos S, Vassilakis E, Voulgaris N. A Preliminary Geophysical Investigation Regarding the Possible Extension of Alistrati Cave in Serres Greece. In: NSG2023, 29th European Meeting of Environmental and Engineering Geophysics. Vol. 2023. Edinburg, Great Britain: European Association of Geoscientists & Engineers; 2023. pp. 1-5. https://doi.org/10.3997/2214-4609.202320045Abstract
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.
Bessin Z, Jaud M, Letortu P, Vassilakis E, Evelpidou N, Costa S, Delacourt C. Smartphone Structure-from-Motion Photogrammetry from a Boat for Coastal Cliff Face Monitoring Compared with Pléiades Tri-Stereoscopic Imagery and Unmanned Aerial System Imagery. Remote Sensing [Internet]. 2023;15(15):3824. https://doi.org/10.3390/rs15153824Abstract
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.
Katsetsiadou K-N, Triantafyllou I, Papadopoulos GA, Lekkas E, Lozios S, Vassilakis E. Crowdsourcing data interpretation for the response to the first public tsunami alert in the Mediterranean sea, after the October 30th, 2020 earthquake (Mw7.0), Samos, Greece. International Journal of Disaster Risk Reduction [Internet]. 2023:103867. https://doi.org/10.1016/j.ijdrr.2023.103867Abstract
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.
Alexopoulos JD, Dilalos S, Giannopoulos I-K, Filis C, Vassilakis E, Voulgaris N. The Combination of Updated Geotechnical, Seismotectonic and Isoseismal Maps of the Ionian Islands (Greece). Geosciences [Internet]. 2023;13(7):218. https://doi.org/10.3390/geosciences13070218Abstract
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.
Triantaphyllou MV, Firkasis N, Theodora T, Vassilakis E, Spyrou E, Koukousioura O, Oikonomou A, Skentos A. “Geo-Archaeo-Routes” on the Island of Lemnos: The “Nalture” Experience as a Holistic Geotouristic Approach within the Geoethical Perspective. Geosciences [Internet]. 2023;13(5):143. https://doi.org/10.3390/geosciences13050143Abstract
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.
Diakakis M, Mavroulis S, Filis C, Lozios S, Vassilakis E, Naoum G, Soukis K, Konsolaki A, Kotsi E, Theodorakatou D, et al. Impacts of Medicanes on Geomorphology and Infrastructure in the Eastern Mediterranean, the Case of Medicane Ianos and the Ionian Islands in Western Greece. Water [Internet]. 2023;15:1026. https://doi.org/10.3390/w15061026Abstract
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.
Alexopoulos J, Giannopoulos I, Mitsika G, Gkosios V, Konsolaki A, Vassilakis E, Poulos S. Ground Penetrating Radar for inspecting the core and base of coastal sand dunes. In: 2nd International Conference International Scientific Conference on Design and Management of Harbor Coastal and Offshore Works. Thessaloniki, Greece; 2023. pp. 0172 .Abstract
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.
Soukis K, Lozios S, Vassilakis E, Antoniou V, Laskari S. Active extensional tectonics along the Mirabello Gulf – Ierapetra Basin depression (Eastern Crete, Greece). In: EGU General Assembly 2023. Vienna, Austria; 2023. pp. EGU23-12210. https://doi.org/10.5194/egusphere-egu23-12210Abstract
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.
Diakakis M, Mavroulis S, Vassilakis E, Chalvatzi V. Exploring the Application of a Debris Flow Likelihood Regression Model in Mediterranean Post-Fire Environments, Using Field Observations-Based Validation. Land [Internet]. 2023;12(3):555. https://doi.org/10.3390/land12030555Abstract
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.
Mitsika GS, Alexopoulos JD, Vassilakis E, Dilalos S, Poulos S. Investigation of the physical-geographical characteristics of river delta with geophysical and satellite data. The case study of Pineios River, Greece. MethodsX [Internet]. 2023:102033. https://doi.org/10.1016/j.mex.2023.102033Abstract
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.
Karkani A, Evelpidou N, Saitis G, Tsanakas K, Drinia H, Vassilakis E, Karymbalis E, Batzakis D-V. Coastal Evolution and Relative Sea Level Changes at Psatha (Alkyonides Bay, Greece). Journal of Marine Science and Engineering [Internet]. 2023;11(1):199. https://doi.org/10.3390/jmse11010199Abstract
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.
Kotsi E, Vassilakis E, Diakakis M, Mavroulis S, Konsolaki A, Filis C, Lozios S, Lekkas E. Using UAS-Aided Photogrammetry to Monitor and Quantify the Geomorphic Effects of Extreme Weather Events in Tectonically Active Mass Waste-Prone Areas: The Case of Medicane Ianos. Applied Sciences [Internet]. 2023;13(2):812. https://doi.org/10.3390/app13020812Abstract
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.