In the early months of 2025, a significant seismic activity was recorded in the area between Santorini and Amorgos, raising concerns about the potential occurrence of a major earthquake and a possible tsunami. The objective of this study is to assess the earthquake-triggered tsunami hazard in the Santorini-Amorgos Tectonic Zone (SATZ) by simulating tsunami processes using the MOST (Method of Splitting Tsunami) numerical model, implemented through the ComMIT (Community Model Interface for Tsunamis). High-resolution bathymetry and topography were employed to model tsunami generation, propagation, and onshore inundation. A total of 60 simulations were conducted using a deterministic approach based on worst-case scenarios. The analysis considered six major active faults with two kinematic types, pure normal and oblique-slip, and assessed tsunami impact on five selected coastal study areas. The simulations results showed potential maximum run-up values of 4.1 m in Gialos (Ios), 2.7 m in Kamari (Santorini), 2.4 m in Perissa (Santorini), 1.5 m in Katapola (Amorgos), and 2.3 m in Chora (Astypalaea), in some cases affecting residential zones. Inundation flows also impacted the main ports of Gialos, Katapola, and Chora, highlighting the exposure of critical infrastructure. Although earthquake-triggered tsunamis represent a potential hazard in the SATZ, the results indicated that it is unlikely to cause a widespread disaster in the study areas.

We use the Worldwide Bioclimatic Classification system to identify changes in the bioclimatic characteristics of Greece between the present and the recent past, by comparing two reference periods: 1961-1990 and 1991-2020. This classification system, developed by Rivas-Martínez et al. (2011), defines the relationship between climatic variables, expressed through bioclimatic indices, and the corresponding distribution of natural vegetation. It generates distinct climatic units known as isobioclimates, which represent specific combinations of macrobioclimates, thermotypes, and ombrotypes. These isobioclimates link climate to ecosystems and allow the characterization of environmental diversity across spatial and temporal scales. The climate input for the system consists of mean, maximum, and minimum monthly temperatures and accumulated monthly precipitation. For this study, we use the ERA5-Land monthly mean data sets from the Copernicus Climate Data Store (CDS), averaged over the two study periods. Calculation of bioclimatic indices and mapping of the isobioclimates are performed using ArcGIS. Preliminary results indicate a shift in the isobioclimatic structure of Greece towards warmer thermotypes and drier ombrotypes. These changes are mostly evident in southern and lowland regions and may reflect increasing aridity and temperatures, suggesting an intensification of ecological stress and wildfire risk, with potential consequences for biodiversity. This work will be extended with the use of regional climate model projections to explore possible future bioclimatic changes in Greece, that will help to assess how climate change may affect vegetation types and inform strategies for ecosystem management in the coming decades.

Landslides represent a persistent hazard in Mediterranean en-vironments, necessitating reliable monitoring techniques for risk assessment. Recent advancements in 3D close-range re-mote sensing, particularly through the integration of Un-manned Aerial Systems (UAS) and Terrestrial Laser Scanning (TLS), have enhanced our ability to capture surface changes. Object-based analysis offers a robust framework for seg-menting and classifying landslide features from high-resolution spatial data, improving the detection and under-standing of landslide processes and rockfall dynamics be-yond traditional pixel-based methods. This work describes the use of repeated UAS and TLS surveys at several active landslide and rockfall sites, referring to the challenges that arose and the solutions that were provided. Point clouds were processed to generate high-resolution digital elevation models (DEMs), and object-based techniques were applied for sys-tematic segmentation and classification of landslide objects. Data fusion was performed following rigorous co-registration procedures, drawing on ground control points to align da-tasets from different sensors. Spatial and geomorphological attributes were extracted from classified objects for temporal change detection and feature analysis. UAS-derived models demonstrated efficient coverage and high surface detail, while TLS data provided increased point density and vertical accuracy in targeted sectors. Object-based analysis enabled the identification and delineation of distinct landslide fea-tures, such as scarps, displaced blocks, and accumulation zones, with improved accuracy compared to manual delinea-tion. The combined UAS-TLS approach reduced data gaps and enhanced the representativeness of classified objects. The segmentation process, however, was sensitive to vegeta-tion cover and point density variations, requiring parameter optimization for each dataset. Integrating advanced data analysis with fused UAS-TLS datasets improved the identifi-cation and monitoring of morphological changes, facilitating a more process-based understanding of landslide and rockfall dynamics. The object-based framework allowed for con-sistent feature extraction across temporal sequences, support-ing detailed change analysis and the recognition of geomor-phological evolution patterns. Challenges included managing data heterogeneity and ensuring segmentation reliability across varying surface conditions. This study demonstrates that combining object-based analysis with multi-sensor 3D data acquisition enhances landslide and rockfall feature de-tection and temporal analysis, providing a scientific basis for more effective landslide hazard assessment and management in Mediterranean terrains.

Understanding the subsurface structural framework of mines is critical for ensuring operational safety. Especially in room and pillar marble quarries, where extraction strategies need continuous optimization and reorientation and since benching creates rooms with considerable heights, ensuring structural stability is crucial for the safety of personnel and equipment. This study presents a novel application of ground-based Li-DAR (Light Detection and Ranging) technology for high-resolution structural mapping within an active marble quarry. By deploying terrestrial laser scanning across key excavation galleries, we generated detailed 3D point clouds that reveal hidden discontinuities and fault systems with a non-invasive, rapid, and precise methodology, capable for representing de-tailed three-dimensional models of the quarry interiors. We used a Leica P50 scanner for acquiring point data in this marble quarry, covering an area of 8,800 m2. A volume of 46,900 m3 was mapped in high detail by setting up 9 bases, accompanied with the measurement of 12 ground control points (GCPs), which were utilized for the transform of al-most 960 million points into real coordinates.The resulting point cloud data were processed using ad-vanced geospatial software to generate 3D models and ex-tract structural features such as joints, faults, bedding planes, and correlate them with existing geological models, which were derived from classical surface mapping of outcrops. The analysis revealed several previously undocumented sub-surface structures that have direct implications for resource estimation, selection of support measures and operational planning. The high spatial resolution of LiDAR enabled the identification of subtle features that are typically missed by conventional surveying techniques.This study demonstrates that ground-based LiDAR is a pow-erful tool for subsurface structural mapping in marble quar-rying, offering significant advantages in terms of accuracy, safety, and efficiency.

The geotectonic units of the External Hellenides Carbonate Platform are characterized by continuous sedimentation from the Triassic onward. This was terminated by widespread synorogenic flysch sequences of great thicknesses, deposited in foreland basins during the collision stage extending from the Paleogene up to Pliocene in the most external parts. A comprehensive dataset concerning the synorogenic Messinian-Pliocene locations of the Hellenic territory and the available published calcareous nannofossil biostratigraphic results, has been constructed, aiming to standardize the available data and provide realistic biochronologic estimations, according to the available and updated astrobiochronological approaches (e.g., Lourens et al., 2004; Raffi et al., 2006; Backman et al., 2012; Agnini et al., 2017). In addition, a series of new locations with their unpublished calcareous nannofossil biostratigraphic determinations (e.g., Triantaphyllou, 2017; Triantaphyllou et al., 2025), are incorporated to the dataset, providing a useful framework for geodynamic interpretations and correlations in the eastern Mediterranean and beyond. The geographical distribution of all the existing data is presented in a series of geological maps arranged according to each nannofossil biozone. The presented dataset contributes to a better understanding of the spatiotemporal impact on biostratigraphic assignments of the different geological-geotectonic origin deposits, practically dating the most recent evolution stages of the Hellenic arc, as also of the factors limiting the distribution and controlling the presence of the widely used nannofossil biostratigraphic indices in the eastern Mediterranean realm. Most of the micropaleontological/geological material associated with the constructed nannofossil biostratigraphy dataset, is already incorporated into the Micropaleontology Collection at the Laboratory of Historical Geology and Biogeosciences, NKUA.

The study presents a geomorphological overview of Greece at a 1:1,000,000 scale, marking the first national cartographic synthesis effort to interpret geological and geomorphological factors shaping the country's landscape. The geomorphological map was developed through a literature review of prior studies at varying scales and semi-automated GIS techniques. High-resolution topographic data and 1:50,000 geological maps were integrated into a spatial geodatabase. Secondary layers, including a hillshade map, slope-aspect map, and red relief image map, were created and combined with Google Earth imagery to delineate landforms. These were categorized by primary formative processes into structural, fluvial, gravity-induced, coastal, karst, volcanic, glacial and periglacial. Additional maps and tables were produced, detailing topographic parameters, geotectonic setting, and climatic regime. The results highlight Greece's diverse geomorphological environments, shaped by active tectonics and surface processes. The map represents recent geomorphological advancements and serves as a management tool for stakeholders and a reference for interdisciplinary research.

The anticipated rise in extreme flood events in the Eastern Mediterranean region indicates an increase in significant societal impacts that have the potential to extend beyond the flooded areas and affect multiple sectors. Despite the criticality of understanding storm and flood risk and how they propagate in modern interconnected societies, the scope and complexity of storm- and flood-triggered cascading effects are still poorly comprehended. This study explores the effects created by the extreme Storm Daniel, occurring in Thessaly, Greece in 2023, aiming to gather new evidence on the types and scale of these cascading effects by analyzing its impacts in the region through fieldwork and official data collection. The results, as a contribution to existing knowledge on cascade effects, provide insights into the nature, the extent, the propagation mechanisms, and the consequences of these triggering events leading to diverse cascade effects. The study identifies the interactions between different phenomena following this extreme storm event to offer a better understanding of how impacts propagate, and therefore a better understanding of future challenges connected with this type of cascading hazards framework, ultimately contributing to predicting and mitigating associated risks.

(1) Background: The present study examines the effects of fire on the ecosystem services of forest ecosystems in Greece. Being a Mediterranean country, Greece has been affected by fires of increasing intensity and frequency in recent years; (2) Methods: Information was extracted from 56 articles published in the period January 1997–March 2024 that were selected after an extensive literature review; (3) Results: An increasing trend in the number of published articles over time was observed. Studies on regulating and maintenance services prevailed. The majority of studies reported on thermo-Mediterranean ecosystems, with Pinus halepensis Mill forests being the most common ecosystems affected by fires. The effects of fire were primarily negative on provisioning and cultural services, as well as on the control of erosion rates, regulation of the hydrologic cycle, atmospheric composition, and climate regulation. Most effects on plant diversity were found to be positive, while positive and neutral effects were also recorded for pollination. The most pronounced negative or positive effects were noted for the first two years after the fire. The spatial mapping of the results showed that the areas most affected by the fires in Greece are Eastern Attica, Euboea, Western Attica, and most regional units of the Peloponnese; (4) Conclusions: In the era of climate change and changing fire regimes in the Mediterranean, there is a need to further research the impact of fire on ecosystem services, as this will help in the better protection and management of the most vulnerable forest ecosystems.

Flash floods have been responsible for some of the most catastrophic events globally. The extensive range of effects and the varying severity of impacts present significant challenges in accurately understanding the damage caused by a flood event, thereby hindering our capacity to predict future consequences. When evaluating flood impacts and their severity, most existing approaches rely on qualitative descriptions (e.g., major, catastrophic, etc.) or examine the impacts from a single perspective or discipline, such as economic losses. In this study, the Flash Flood Impact Severity Scale (FFISS) is employed to evaluate, map, and categorize the impacts of two flash floods that occurred in the Lilas River in Greece in 2009 and 2020. The goal of this application is to analyze the varying severity levels and how one flood event can influence the impacts of a subsequent event. The methodology involved extensive fieldwork, including the collection of ground-based and aerial observations using UAV technology to document the impacts. These observations were subsequently georeferenced, followed by applying the Flash Flood Impact Severity Scale (FFISS) and creating detailed maps to assess and evaluate the severity of impacts associated with the two flood events. The results indicate that, despite the higher water levels during the second flood, areas previously affected show lower severity values. This reduction is attributed to the community’s gradual adaptation, improvements in infrastructure, and significant local widening of the river channel. Conversely, newly flooded areas during the second event exhibit high severity levels. Overall, applying the FFISS reveals spatial patterns of impact severity, offering insights into the local nature of floods while suggesting a potential reduction in overall risk during the post-flood period.

Extreme weather events, increasingly frequent in the Mediterranean due to climate change, pose significant risks by triggering hydrogeomorphic processes such as slope failures. These phenomena, particularly prevalent in tectonically active and steeply sloped coastal areas, present challenges for monitoring due to their spatial and temporal dynamics.Unmanned aerial systems (UAS) and advanced photogrammetric techniques, including structure-from-motion (SfM) and multi-view stereo (MVS), have emerged as transformative tools for capturing high-resolution terrain data. This study employs UAS-aided photogrammetry alongside change detection methods, such as digital elevation models of differences (DoD) and cloud-to-cloud distance (C2C), to analyze geomorphic changes induced by extreme storms in highly visited and geologically dynamic coastal areas in Greece.The findings reveal the utility of UAS in providing detailed morphometric measurements, delineating areas of erosion and deposition, and identifying high-risk zones. These capabilities facilitate a deeper understanding of geomorphic processes, enabling informed risk assessment and management strategies. The study underscores the potential of integrating UAS and photogrammetry for continuous monitoring in regions with high socioeconomic and environmental value. This approach not only supports sustainable development by minimizing disruptions but also enhances safety standards in vulnerable, high-exposure coastal areas. Through this methodological framework, the research contributes to addressing the pressing need for resilient hazard management in the context of evolving climatic conditions.

The increasing frequency and severity of extreme storms and floods in the Eastern Mediterranean under climate change pose significant challenges for modern societies. These events often trigger cascading effects that extend far beyond the immediate disaster zone, disrupting interconnected systems such as power, transportation, and communication networks. Despite advancements in flood risk management and growing awareness of cascading hazards, the mechanisms driving these interdependencies and their broader impacts remain poorly understood. This study investigates the cascading effects triggered by the catastrophic Storm Daniel, which struck Thessaly, Greece, in September 2023, as a case study to explore the nature, scale, and ways of impact propagation.This work also provides an analysis of cascading effects, based on evidence on historical storm and flood disaster impacts in the Mediterranean region, identifying the interactions between primary hazards (flooding, landslides, erosion) and secondary consequences as well as the diverse sectors that suffer impacts. The analysis reveals different propagation mechanisms of these effects, highlighting the vulnerability of interconnected systems as well as the vulnerability of the natural and the built environment. The cascading effects identified underscore systemic risks of modern societies posed by extreme events, particularly in urban areas with dense, interdependent, and critical infrastructure.The findings contribute to the growing body of literature on cascading disasters, addressing critical knowledge gaps in understanding how extreme weather events propagate through modern societal systems. These insights are particularly relevant in the context of climate change, which is expected to amplify the frequency and intensity of such events.

In early 2024, the largest full-scale exercise (FSE) for earthquakes and related geohazards in Greece was implemented in Crete Island (southern Greece). Crete is characterized by intense seismicity with historical and recent destructive earthquakes with considerable impact on both the natural and built environment and subsequently on the population. The uniqueness of this FSE lies in the creation and coordination of a multi-agency, multijurisdictional, and multidisciplinary environment in which a multitude of central, regional, and local stakeholders and a large percentage of the total population of Crete actively participated. This paper constitutes a descriptive study focusing on the main steps of the exercise management cycle comprising planning, implementation, and evaluation of the FSE. Furthermore, emphasis is given on its purpose and objectives, its main events and subsequent incidents, the participants and their roles, as well as the material developed and distributed to the participants. Through this study, the implemented actions for increasing preparedness of the Civil Protection mechanism in case of earthquakes and related geohazards are highlighted aiming to inform the scientific community and operational staff and to contribute to the seismic risk reduction of regions worldwide with similar seismotectonic and demographic characteristics with Crete. Furthermore, suggestions are made for the integration of multi-hazard episodes in the FSE scenario in order that the Civil Protection authorities will be prepared to handle the synergy of hazards of different types that may arise during a post-earthquake period that create compounding challenges during the emergency response and further increase recovery time.

Flash floods have been the cause of some of the most devastating events worldwide. The wide diversity of the effects, as well as the variety in the severity of the impacts, lead to major obstacles in obtaining a realistic understanding of the damages caused by a flood event, thus hampering at the same time our ability to predict future impacts. In assessing flood impacts and their severity, most existing methods use a qualitative characterization (e.g., major, catastrophic, etc.) or view the impacts from a single viewpoint or discipline (e.g., economic losses). In this study, we apply the Flash Flood Impact Severity Scale (FFISS) to assess, map, and classify the impacts of two flash floods from the Lilas River in Greece in 2009 and 2020. This application aims to discuss the different severity levels in terms of how one flood can affect the impacts of the next event. The methodology encompasses comprehensive field research, including the collection of ground-based and aerial observations utilizing UAV technology to document the impacts. These observations are subsequently georeferenced, followed by application of the Flash Flood Impact Severity Scale (FFISS) and generation of detailed maps to assess and evaluate the severity of the impacts associated with the two flood events. The results show that despite the higher water stage of the second flood, the impacts in previously hit areas indicate lower severity values, attributed to the gradual adaptation of the community and its infrastructure, as well as significant local widening of the river channel. On the contrary, high severity remains an issue in newly flooded areas during the second event. Overall, the application of the FFISS can show the spatial patterns of severity impacts, providing insights into the nature of floods locally but also indicating a potential reduction in the overall risk in the post-flood period.