GeoHazards

Analyses of thermokarst hazard risk are becoming increasingly crucial in the context of global warming. A significant aspect of thermokarst research is the mapping of landscapes based on their vulnerability to thermokarst processes. The exponential growth of remote sensing data and the advent of novel techniques have paved the way for the creation of sophisticated techniques for the study of natural disasters, including thermokarst phenomena. This study applies machine learning techniques to assess the vulnerability of tundra landscapes to thermokarst by integrating supervised classification using random forest with morphometric analysis based on the Topography Position Index. We recognized that the thermokarst landscape with the greatest potential for future permafrost thawing occupies 20% of the study region. The thermokarst-affected terrains and water bodies located in the undegraded uplands account for 13% of the total area, while those in depressions and valleys account for 44%. A small part (6%) of the study region represents areas with stable terrains within depressions and valleys that underwent topographic alterations and are likely to maintain stability in the future. This approach enables big geodata-driven predictive modeling of permafrost hazards, improving thermokarst risk assessment. It highlights machine learning and Google Earth Engine’s potential for forecasting landscape transformations in vulnerable Arctic regions. Full article

The 2024 cut-off low-pressure (DANA) event had a devastating impact on the province of Valencia (Spain), resulting in 227 fatalities. This extreme weather event highlighted the urgent need to enhance education on flood risk and prevention, particularly through geography lessons in schools. This paper presents a didactic experience conducted during the 2024–2025 academic year at a primary school in Alicante (Valencian Community, Spain), within the sixth-grade subject of “Natural, Social, and Cultural Environment Studies”. The initiative aimed to increase knowledge of the causes of flooding and safety measures, with a particular focus on the DANA event of 29 October 2024. Through hands-on and collaborative activities, the project sought to raise awareness of the importance of risk prevention and management. Ultimately, this educational approach aspires to foster a more resilient society, one that is better prepared to face the challenges posed by current and future climate change scenarios. Full article

An attempt is made at recognizing the main effects of the strong 1939 earthquake in the Easternmost Anatolian Fault on the seismic activity in key Mediterranean tectonic zones. The major earthquake trends since 1800 indicate that, in the decades following 1939, both the number and intensity of significant earthquakes increased in the central and western NAF, the western Anatolia, the Crete–Rhodes Arc, the Peloponnesus, Sicily, and even the Tell zones. In contrast, seismicity experienced a sharp decline in the Serbo-Macedonian, Epirus-Albanides, and Calabria zones. These findings provide additional constraints on the geodynamic and tectonic framework and on the role played by post-seismic relaxation in the Mediterranean region. Full article

Landslides in Ecuador are one of the most common deadly events in natural hazards, such as the one on 26 March 2023. A large-scale landslide occurred in Alausí, Chimborazo province, causing 65 fatalities and 10 people to disappear, significant infrastructural damage, and the destruction of six neighborhoods. This study presents a detailed case analysis of the anthropogenic factors that could have contributed to the instability of the affected area. Field investigations and a review of historical, geological, and social information are the basis for analyzing the complex interactions between natural and human-induced conditions. Key anthropogenic contributors identified include unplanned urban expansion, ineffective drainage systems, deforestation, road construction without adequate geotechnical support, and changes in land use, particularly agricultural irrigation and wastewater disposal. These factors increased the area’s susceptibility to slope failure, which, combined with intense rainfall and past seismic activity, could have caused the rupture process’s acceleration. The study also emphasizes integrating geological, hydrological, and urban planning assessments to mitigate landslide risks in geologically sensitive regions such as Alausí canton. The findings conclude that human activity could be an acceleration factor in natural processes, and the pressure of urbanization amplifies the consequences. This research underscores the importance of sustainable land management, improved drainage infrastructure, and land-use planning in hazard-prone areas. The lessons learned from Alausí can inform risk reduction strategies across other mountainous and densely populated regions worldwide, like the Andean countries, which have similar social and environmental conditions to Ecuador. Full article

This study develops a landslide susceptibility zoning map for the Zipaquirá–Pacho road corridor in Cundinamarca, an area prone to frequent landslides. Two statistical methods—Weight of Evidence (WoE) and Information Value (IV)—were used alongside various causal factors to generate the map using GIS software (ArcGIS Pro 3.5.0 software.). A landslide inventory with 101 points was compiled through fieldwork and Google Earth image analysis. Of these, 70% were used to build the models, while the remaining 30% were reserved for validation, ensuring spatial representativeness. The resulting susceptibility maps classified the area into five categories: “very high”, “high”, “moderate”, “low”, and “very low.” For WoE, 19.62% of the area was classified as “very high” and 19.71% as “high”, while for IV, the respective values were 17.57% and 26.55%. Notably, 88% of the identified landslides occurred in “high” and “very high” zones. Model validation using the AUC (Area Under Curve) metric yielded an efficiency of 81%, confirming the reliability of both methods for landslide prediction. The study’s findings are essential for supporting mitigation strategies and serve as valuable input for local authorities and stakeholders involved in risk management and infrastructure planning. Full article

Traditional seismic risk assessments often require specialized expertise and extensive computational time, making probabilistic seismic risk evaluations less accessible to practitioners and decision-makers. To reduce the barriers related to applications of quantitative seismic risk analysis, this paper develops a Quick Loss Estimation Tool (QLET) designed for rapid seismic risk assessment of Canadian buildings. By approximating the upper tail of a seismic hazard curve using an extreme value distribution and by integrating it with building exposure-vulnerability models, the QLET enables efficient computation of seismic loss curves for individual sites. The tool generates seismic loss exceedance probability curves and financial risk metrics based on Monte Carlo simulations, offering customizable risk assessments for various building types. The QLET also incorporates regional site proxy models based on average shear-wave velocity in the uppermost 30 m to enhance site-specific hazard characterization, addressing key limitations of global site proxy models and enabling risk-based seismic microzonation. The QLET streamlines hazard, exposure, and vulnerability assessments into a user-friendly tool, facilitating regional-scale risk evaluations within practical timeframes, making it particularly applicable to emergency preparedness, urban planning, and insurance analysis. Full article

This research addresses the increasing vulnerability of coastal urban areas to climate change, with a particular focus on the increased risk of overtopping and coastal flooding events in Praia da Vitória, Azores. This study, conducted within the LIFE-GARACHICO project, aims to develop a holistic and flexible management approach to coastal flood risk. The methodology included a comprehensive risk assessment that combined a vulnerability analysis (considering factors such as population, land use, and infrastructure) with the probability of coastal inundation events (using oceanographic data and models). Public risk perception was assessed through surveys to understand residents’ awareness and preferences. A response protocol for overtopping events was developed with civil protection officials, and the HIDRALERTA early warning system was implemented. The risk assessment showed a mostly acceptable risk with some undesirable areas, resulting from a mostly low probability and medium vulnerability. Public surveys indicated that residents had experienced flooding but felt unprepared and preferred softer management measures such as access restrictions and early warning systems. The response protocol developed and integrated into HIDRALERTA responds to these preferences. This study concludes that this integrated framework improves coastal risk management, increases public awareness and confidence, and provides a flexible and sustainable model for coastal risk management. Full article

In recent years, numerous satellite-based systems have been developed to monitor and study volcanic activity from space. This progress reflects the growing demand for accurate and timely monitoring to reduce volcanic risk. Observing volcanoes from a satellite perspective provides key advantages, enabling continuous data acquisition and near-real-time assessment of volcanic activity. Multispectral sensors operating across various regions of the electromagnetic spectrum can detect thermal anomalies associated with lava flows, pyroclastic flows, ash plumes, and volcanic gases. Traditional hotspot detection techniques based on fixed thresholds often miss subtle anomalies on a global scale. In contrast, advanced machine learning algorithms offer a data-driven alternative. We designed and implemented the V-STAR application (Volcanic Satellite Thermal Anomalies Recognition) on Google Earth Engine (GEE) to leverage cloud computing for processing large geospatial datasets in real time. It employs supervised machine learning, specifically Random Forests, to adapt to evolving volcanic conditions. This enhances the accuracy and responsiveness of volcanic monitoring, offering valuable insights into potential eruptive behavior. Here, we present V-STAR as a robust and accessible tool that integrates satellite data and advanced analytics. Through its intuitive interface, V-STAR provides a comprehensive visualization of key volcanic features. The resulting analyses reveal hidden patterns in thermal data, contributing to improved disaster risk reduction strategies associated with volcanic hazards. Full article

The morphologic dating of single-event fault scarps along the dextral strike-slip Valley Fault System (VFS) yielded distinct clusters of relative ages (kt), which we interpret as evidence of independent surface ruptures. The boundaries between structural and geometric segments of the East Valley Fault (EVF) appear to have been nonpersistent during the recent rupture cycle. We associate the youngest cluster with the largest historical earthquake (M > 7 in 1863) felt in Manila, which is believed to have come from three segments of the EVF. Thus, future multiple-segment events, M > 7, could occur on the EVF. Our results do not support rupturing of the entire length of the West Valley Fault (WVF), but its northern segment (segment I) is capable of generating an M > 7 earthquake. This is the first time that diffusivity and relative ages of fault scarps are determined from this part of the world and is one of the few studies applying analysis of recent fault scarps to rupture segmentation studies. The recent scarps along the WVF’s segment II are due to aseismic creep and occur along pre-existing tectonic structures. Continued groundwater overextraction within the creeping zone could induce seismicity and modulate the natural timing of future earthquakes along the WVF. Full article

Post-earthquake fires are typically of great concern for fire protection services, which are expected to be in high demand immediately after a strong earthquake. The post-earthquake functionality of fire stations is necessary after strong earthquakes to reduce potential fire damage and improve emergency services. A reliable assessment of the seismic vulnerability and expected damage for fire stations is therefore a necessary step towards the identification of the most vulnerable structures and the prioritization of seismic retrofit activities. This article presents the development of a methodology for the damage assessment of fire stations based on earthquakes scenarios. The framework is based on four models: seismic hazard, inventory, fragility and impact. The seismic hazard model represents ground shaking in terms of intensity measure at each station using a ground motion prediction equation for Eastern Canada. The inventory model categorizes all the fire stations in building classes based on construction material and seismic code level. The fragility model associates building classes with fragility functions that provide the relationship between intensity measure and expected damage probabilities. The impact model converts damage probabilities into a mean damage state. All Montreal fire stations were selected as case study demonstrations. Simulations were conducted by varying the epicenter location and magnitude for a total number of 345 scenarios. Simplified relationships that correlate the earthquake magnitude and expected damage were developed. The study showed that, for magnitude 6 earthquakes, 45% of stations on average would sustain at least moderate damage. The methodology is particularly useful for emergency planning and prioritization of seismic retrofit activities. Full article

The aim of the present research is to analyze community participation in disaster risk management due to tailings dam failures (DRM-TDF). Conceição do Mato Dentro, Minas Gerais State (Brazil) was used as case study. The aims of the study are to help developing more effective DRM-TDF strategies and to strengthen community participation in decision making, and in mapping and categorizing vulnerabilities (criticality and support capacity) by assessing current practices and prioritizing future strategies. Semi-structured questionnaires were applied to community leaders and open interviews were carried out with DRM experts for information collection purpose. The collected responses were categorized based on vulnerabilities by taking into account criticality (communities) and support capacity (public management and mining entrepreneurs). SWOT analysis identified “Weaknesses” (criticality) and “Threats” (support capacity), whereas Pareto analysis highlighted the most critical aspects. The results indicate that public policies and the Brazilian legal framework have made limited contributions toward achieving the Sendai Framework guidelines and the Sustainable Development Goals. A review of current practices is necessary to safeguard the rights of affected communities through their meaningful participation in decision-making processes. Full article

A revision of the submarine instability processes offshore the Campania region is presented herein based on the literature data and Multibeam bathymetric and seismic profiles previously acquired by the CNR ISMAR of Naples (Italy). Among others, the objectives and perspectives of this research include the following: the chrono-stratigraphic framework of the submarine instability events and their correlation with the trigger geological processes, including the seismicity, the volcanism and the tectonic activity; density reversal has not been detected as a control factor; the implementation of technologies and database for the acquisition and the processing of morpho-bathymetric, seismo-stratigraphic and sedimentological data in the submarine slopes of Campania, characterized by submarine gravitational instabilities. Other main tasks include producing thematic geomorphological maps of the submarine slopes associated with instability phenomena. The principles of slope stability have been revised to be independent of the slope height. In submarine slopes mainly composed of sand, the stability depends on the slope inclination angle concerning the horizontal (β), equal or minor to the internal friction angle of loose sand (ϕ). Based on this research, it can be outlined that the submarine instability processes offshore of Campania mainly occur along the flanks of volcanic edifices, both emerged (Ischia) and submerged (Pentapalummo, Nisida, Miseno, Procida Channel), on steep, tectonically-controlled sedimentary slopes, (southern slope of Sorrento Peninsula, slope of the Policastro Gulf), and on ramps with a low gradient that surround wide continental shelves (Gulf of Salerno). Full article

After the subsidence phase that followed the 1982–1984 bradyseismic crisis, a gradual ground uplift at Campi Flegrei caldera resumed in 2005, while volcanic-tectonic earthquakes have steadily increased in frequency and intensity since 2018, with a significant intensification observed since 2023. This rise in seismic activity enabled a new tomographic study using data collected from 2020 to June 2024. In this work, 4161 local earthquakes (41,272 P-phases and 14,683 S-phases) were processed with the tomoDDPS code, considering 388,166 P and 107,281 S differential times to improve earthquake locations and velocity models. Compared to previous tomographic studies, the 3D velocity models provided higher-resolution images of the central caldera’s structure down to ~4 km depth. Additionally, separate inversions of the two 2020–2022 (moderate seismicity) and 2023–2024 (intense seismicity) datasets identified velocity variations ranging from 5% to 10% between these periods. These changes observed in 2023–2024 support the existence of two pressurized sources at different depths. The first, located at 3.0–4.0 km depth beneath Pozzuoli and offshore, may represent either a magma intrusion enriched in supercritical fluids or an accumulation of pressurized, high-density fluids—a finding that aligns with recent ground deformation studies and modeled source depths. Additionally, the upward migration of magmatic fluids interacting with the geothermal system generated a secondary, shallower pressurized source at approximately 2.0 km depth beneath the Solfatara-Pisciarelli area. Overall, these processes are responsible for the recent acceleration in uplift, increased seismicity and gases from the fumarolic field, and changes in crustal elastic properties through stress variations and fluid/gas migration. Full article

A tsunami can cause significant economic losses for tourism areas like Batukaras Village, which is located on the southern coast of Java Island. This paper seeks to elaborate on the calculation of economic losses in tourism areas due to damage to buildings, loss of land production, and loss of income, based on high-resolution geospatial data. The data are derived from UAV photogrammetry surveys and high-resolution tsunami run-up models. The tsunami worst-case scenario run-off model provides an inundation area of 43 ha with 185 buildings and 24.4 ha of productive land. The estimated losses from the tsunami disaster amounted to IDR 208.79 billion, consisting of 49.63 billion from building damage, 6.73 billion from productive land, and 152.43 billion from the tourism sector. These results show that the tsunami disaster will severely affect tourism areas, because the tourism sector makes up 73% of the total economic losses. Reductions in the amount of economic loss, in addition to spatial planning near the coastline to reduce the number of impacted buildings and productive land, can be achieved by accelerating the recovery period so that economic activities after the tsunami disaster can be carried out immediately, including in the tourism sector. Full article

Sediment disasters, triggered by heavy rainfall, have resulted in significant human casualties and economic damage annually worldwide. Therefore, the promotion and implementation of disaster prevention strategies have emerged as crucial measures to mitigate the human and financial losses inflicted by these disasters. This article examines case studies in the mountainous regions of China and Japan, encompassing terrain conditions, local disaster risk factors, and residents’ awareness of disaster prevention, as well as their living conditions. The CAUSE model was employed to cultivate a relationship of mutual trust and cooperation with the residents through activities that promote disaster prevention and reduction. Feedback was also collected from the residents. In addition, relevant disaster prevention personnel were organized to participate in disaster prevention technical training, and feedback was collected through questionnaires (CAUSE is an acronym derived from the first letter of Confidence, Awareness, Understanding, Satisfaction with proposed Solutions, and Enactment). From the above inspection and analysis techniques used in the case studies in China and Japan, it is confirmed that disaster prevention and promotion work is closely linked. This analysis underscores the importance, necessity, and effectiveness of promoting disaster prevention at the local level. Furthermore, it offers crucial technical support for the local government’s efforts in disaster reduction and prevention. Full article

The Muong La–Bac Yen–Cho Bo fault is one of the seismic faults in the northwest region of Vietnam. Neo-tectonic activities and exogenous processes have influenced the drainage system and topographic–geomorphologic features on both walls of the fault. The results of topographic analysis and geomorphological indices have confirmed the active tectonics of the fault during the Neo-tectonic period (Pliocene–Quaternary, about 5 million years). The valley floor width-to-height ratio (V_f) of less than 0.5 indicates the “rejuvenation” of the streams and the obvious influence of tectonic activities on the two walls of the studied fault. The Hypsometric curve (HC) in the study area has a straight–convex shape and the basins on the northeast wall have hypsometric integral index values ranging from 0.46 to 0.481, which are lower and more convex than those of the southwest wall. The Mountain-front sinuosity index (S_mf) from 1.92 to 3.28 along the foot slope of the Hoang Lien Son range (the segment from Than Uyen to Bac Yen and Phu Yen) and the highly variable stream-length gradient index (SL) value on the northeast wall signify the relative tectonic uplift on the northeast wall of the fault. The deformed geomorphological indications (steep cliffs, slip surfaces, etc.) in the field confirm the active tectonics of the Muong La–Bac Yen–Cho Bo fault during the Neo-tectonic period. Full article

Debris flows are one of the most common and frequent natural hazards in mountainous environments. For this reason, there is a need to develop monitoring systems aimed at better understanding the initiation and propagation mechanisms of these phenomena to subsequently adopt the most reliable mitigation measures to safeguard anthropic assets and human lives exposed to the impact of debris flows in alluvial fan areas. However, the design of a responsive monitoring system cannot overlook the need for a thorough understanding of the catchment in which debris flows occur. This knowledge is essential for making optimized decisions regarding the type and number of sensors to include in the monitoring system and ensuring their accurate and efficient placement. In this paper, it is described how the preliminary characterization of an Alpine catchment and the geo-hydrological processes that have historically affected it—such as the lithological and geomechanical classification of the catchment’s bedrock, the identification and description of sediment source areas, the characterization of debris flow occurrence and quantification of the triggering causes—contribute to the optimal design of a monitoring system. Additionally, the data recorded from the sensors during a debris flow event in summer 2024 validate and confirm the results obtained from previous research. Full article

Slope failure, as a natural disaster, can cause extensive human suffering and financial losses worldwide. This paper introduces a new soil moisture extended cohesive damage element (SMECDE) method to predict railway slope failure under heavy rainfall. A correlation between rainfall intensity and soil moisture content is first established to create an equivalence between the two. Considering slope failure mechanisms dominated by the loss of soil or the cohesion of slope materials due to heavy rainfall infiltration, the soil moisture decohesion model (SMDM) is developed using previous experimental data to express how soil cohesion varies with different soil moistures and depths. The SMDM is incorporated into the extended cohesive damage element (ECDE) method to fundamentally study slope failure mechanisms under varying soil moisture levels and depths. The proposed SMECDE approach is used to predict the failure propagation of a selected railway embankment slope at the critical soil moisture or rainfall intensity. This SMECDE failure prediction is validated using relevant data from previous fieldwork and meteorological reports on the critical rainfall intensity at the site. Additionally, the corresponding slope damage scale prediction is validated with a large plastic deformation analysis using the commercial FEM package ABAQUS. Full article

In 2011, a M 5.7, earthquake struck near Mineral, Virginia, about 130 km southwest of Washington, D.C., prompting studies on paleoliquefaction to better understand the earthquake potential of the Central Virginia seismic zone and the hazard it poses to the Mid-Atlantic region. Researchers identified earthquake-induced liquefaction features along the Appomattox and Rapidan rivers, dated sediment and estimated the ages of these liquefaction features as well as features previously found along several other rivers in the seismic zone, and evaluated scenario earthquakes to constrain the locations and magnitudes of past earthquakes. Evidence suggests that historical earthquakes (M 5.25–5.5) in 1758, 1774, and 1875 C.E. caused liquefaction along the Appomattox, James, and Pamunkey Rivers, and a paleoearthquake (M 6.5–6.75) around 2640 ± 80 yr B.P. near Wyndham Forest caused liquefaction along the Appomattox River and across the seismic zone. Similarly, an earthquake (M 5.5–5.75) around 1690 ± 50 yr C.E. may have triggered liquefaction along the Rapidan River. Full article