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Background: The Mediterranean Sea is a region characterized by high seismic activity, with at least 200 tsunami events recorded from the fourth century to the present twenty-first century. Numerous studies have been conducted to understand past tsunami events, earthquake–tsunami generation, tsunami recurrence periods, tsunami vulnerability zones, and tsunami hazard mitigation strategies. Therefore, gaining insights into future trends and opportunities in Mediterranean Sea tsunami research is crucial for significantly contributing to all relevant aspects. This study aims to assess such trends and opportunities through a scientometric analysis of publications indexed by Web of Science from 2000 to 2023. Results: Based on a selection of 329 publications, including research articles, review articles, book chapters, and conference papers, published between 2000 and 2023, Italy has the highest number of publications and citations in this field. The number of publications has increased significantly, especially after the 2004 Indian Ocean, 2011 Tohoku, and 2018 Palu tsunamis. According to the keyword analysis, the terms "tsunami", "earthquake", "hazard", "wave", "Mediterranean", "coast", and "tectonic" were the most frequently used in these publications. Research themes consist of four classifications: motor themes, such as seismic hazard; specific but well-developed themes, like tsunamiite; emerging or disappearing themes, for example, climate change; and general or basic themes, such as equations and megaturbidite. The number of publications related to the motor theme classification continued to grow throughout 2000–2023. Topics from 2011–2023 are more complex compared to 2000–2010, characterized by the emergence of new keywords such as evacuation planning, risk reduction, risk mitigation, building vulnerability, coastal vulnerability, climate change, probabilistic tsunami hazard assessment (PTVA-3 and PTVA-4). However, topics that were popular in the 2000–2010 period (e.g., paleotsunami deposits, earthquake, and tsunami propagation analysis) also increased in 2011–2023. Conclusions: Research topics with high centrality and density such as seismic hazard will continue to develop and prospect. The cluster network of this topic includes seismoturbidites, sedimentary features, tsunami modeling, active faults, catalog, and historical earthquakes. [ABSTRACT FROM AUTHOR]

Geoenvironmental Disasters - an open access journal of the International Consortium on Geo-disaster Reduction (ICGdR) - is being published since 2014. This contribution aims at characterising 115 papers published in the first five volumes of the journal (2014–2018) and outlining some future perspectives. It is shown what research topics (types of natural hazards and disasters) are a subject of published papers, what methods are employed to investigate them and what is the geographical focus. Further, it is shown who publishes research results in Geoenvironmental Disasters, international cooperation network and the impact of published papers. Based on these findings, we conclude that Geoenvironmental Disasters became established journal for disseminating results of research on diverse typers of natural disasters in various geographical environments accross the globe, and we opine that further advancement of the journal might be achieved by onward indexing efforts. [ABSTRACT FROM AUTHOR]

Background: The world population is still growing. The growing population caused a changes in the trend of selecting settlements location. Due to the limited flat land, people were starting to form settlements in a hilly or mountainous area which is prone to landslide. The community used to move from place to place to avoid landslides, however, it is no longer possible to implement those actions. While a lot of research has been conducted to assess the vulnerability and risk of settlements to disasters, there needs to be more research on developing settlements in landslide-prone area and their impact on disaster management. Results: High social influences can be found in the development of landslide-prone settlements of Giripurno Village. The community shows a high consideration on relatives in deciding their settlement location. Moreover, high consideration of kinship and social activity affects the arrangement of spaces in the house and directly affects the amount of space occupancy. Layout of houses in Giripurno Village were found to have large living room to accommodate family and community gatherings. Although high social dependences of one community can be beneficial in the disaster emergency response and recovery, it can also hinder the disaster mitigation effors by allowing development in an unsafe area, thus increase the risk of disasters. Conclusion: This paper discuss about how the social factors can relate to the disaster management with an emphasis on the development of settlements. This paper also highlight the aspects of space occupancy which is rarely being discussed in the disaster management related research. The result obtained by this study could provide important insight into the future disaster management in the landslide-prone settlements area. [ABSTRACT FROM AUTHOR]

Background: Granular flows are common on the Qinghai–Tibet Plateau and the Hengduan Mountains in China, and their dynamic process processes have obvious erosional and entrainment effects. On the one hand, the volume of the granular flow increases by a factor of several or ten, which significantly increases its ability to cause a catastrophe; on the other hand, the eroded loose material affects the granular flow dynamics process and changes its state of motion. Methods: In this paper, the dynamic mechanism of granular flow erosion and entrainment is investigated by DEM simulation. Purpose: The effects of different substrate materials and substrate boundary conditions on granular flow erosion and entrainment are analyzed, and the effects of material mixing caused by erosion and entrainment on the state of motion of granular flow are discussed. It was verified that the kinetic mechanisms of granular flow erosion and entrainment includes impact erosion, ploughing, and shear abrasion. Results: And discovered that small matrix particle size, small matrix boundary friction, and small matrix thickness lead to stronger ploughing and shear abrasion; Large matrix fractal dimensions result in stronger ploughing and weaker shear abrasion, and the granular flow does not entrain large amounts of material to the accumulation zone. Meanwhile, the dynamics of erosion and entrainment of granular flow were investigated, and the results showed that: 1. The greater the erosion rate, the greater the velocity and kinetic energy of the granular flow, the greater the distance traveled, and the smaller the apparent friction angle (i.e., the greater the mobility). 2. The amount of small granules in a granular flow changes its fluidity, the more small granules there are, the more fluid it is. 3. The fit reveals that the substrate fractal dimension has the strongest effect on the velocity and kinetic energy of granular flow, followed by substrate thickness and substrate boundary friction. [ABSTRACT FROM AUTHOR]

Background: Earthquakes and landslides pose significant threats to human safety and property, necessitating early warning systems. However, the high construction costs of earthquake early warning systems present a challenge. Purpose: Landslide warnings are more prevalent, so linking them to earthquake warnings could address cost concerns. Hence, it is crucial to validate the feasibility of utilizing GNSS landslide monitoring as assistance for earthquake early warning systems. Methods: This paper analyzes acceleration anomaly data from 31 GNSS landslide monitoring points near the epicenter of the May 2, 2023, MW = 5.2 Baoshan earthquake in Yunnan. The response time was determined as the time difference between an earthquake's occurrence and GNSS's acceleration anomalies. This calculation helps measure the time delay and sensitivity between these two events. Data were obtained from the geological disaster monitoring and early warning management system. Results: GNSS landslide monitoring showed high sensitivity to nearby earthquakes. The fastest response time among the 31 data points was 8 seconds, while the slowest was 56 seconds, all falling within the one-minute mark. A linear correlation was found between acceleration anomaly response time and distance from the epicenter, indicating the feasibility of GNSS landslide monitoring-assisted earthquake monitoring. Conclusion: A proposal is made for a GNSS landslide monitoring cluster to establish a multi-dimensional landslideearthquake disaster warning system. This approach offers new methods for combining earthquake and landslide early warning systems, leveraging existing infrastructure for cost-effectiveness and enhancing disaster preparedness. [ABSTRACT FROM AUTHOR]

Background: The Bangkok Basin has been known from non-instrumental observations of the local population to be subject to ground motion amplification due to the deep alluvial sediments and basin geometry. This study analyzes available seismic data to confirm that basin effects are significant in the Bangkok Basin. The paper contributes to the evaluation of basin effects by characterizing the engineering ground motion parameters and HVSR curves for the Bangkok basin which produce lengthening of ground motion duration with respect to nearby rock sites, albeit with very low ground motions. For this purpose, we analyzed ground motion records from seismic stations located within the Bangkok alluvial basin from 2007 to 2021. Recorded peak horizontal ground acceleration (PGA) for seismic stations inside the basin always exceeded 1 cm/s2 during eight earthquakes with Mw ≥ 5.5. Of these, two were intraslab events and six were shallow crustal earthquakes. These recorded ground motions shook high-rise buildings in Bangkok even though their epicentral distance exceeded 600 km. Methods: Several time and frequency domain analyses (such as analysis of residual, HVSR, Hodogram plots, etc.) are used on the ground motion records in the Bangkok basin to determine the frequency content of recorded ground motion and to demonstrate the significance of surface waves induced by the deep basin in altering the engineering ground motion amplitudes. In addition, centerless circular array microtremor analysis is used to determine the depth of sedimentary basin to the bedrock. Results: Based on comparisons from those stations located outside the Bangkok basin, we observed the capability of alluvial deposits in the Bangkok basin to amplify ground motion records by about 3 times. We observed that there is a unique site amplification effect between 0.3 and 0.1 Hz due to local surface waves and other moderate amplifications between 2 and 0.5 Hz due to a soft layer like other deep alluvial basins in other metropolitan areas. Conclusion: We noticed that there is a unique site amplification effect between 0.1 and 0.3 Hz and smaller peaks around 2 and 0.5 Hz consistent with expectations for site amplification effects associated with deep basins. Moreover, we noticed the presence of low frequencies content of the surface wave generated within the basin which deserved further studies using the 2D/3D ground motion modelling through basin topography and velocity models. [ABSTRACT FROM AUTHOR]

Background: On September 5, 2022, an Ms 6.8 earthquake occurred in Luding County, Ganzi Tibetan Autonomous Prefecture, Sichuan, China. The casualties and economic losses caused by the earthquake are huge. Most of the landslides triggered by this earthquake are small and medium-sized rock collapses and destructive debris flows, with a small number of large-scale landslides. Results: There are 5007 coseismic landslides in the Luding earthquake VII-degree area and above, with a total area of 17.36 km2. The landslides are generally distributed along the NW-SE direction. The highest landslide area density is 13.8%, and the highest point density of the landslide is 35.73 km2. High-density area is mainly concentrated in the IX-degree area and the northeast side of the seismogenic fault. Coseismic landslides are more likely to develop in the area with the slope more than 40°, the slope direction of 67.5-112.5 degree, and vegetation coverage of 40–50%. More landslides are developed in granite areas and forest areas. The closer distance to active faults, the more the coseismic landslides develop. The correlation between coseismic landslide development and the distance from the active faults is better than that between coseismic landslide development and the distance from the seismogenic faults. Conclusion: The landslide database used in this paper is the most perfect at present, and the research results have also been verified by fieldwork. This is also the first applied study of this landslide inventory, which indirectly confirmed the accuracy of the inventory. The results obtained in the manuscript will provide an important guideline for future disaster prevention and mitigation in southwest China. [ABSTRACT FROM AUTHOR]

Coal mining has a significant impact on the movement of the overburden, leading to potential safety hazards in the working face. In this paper, a similarity simulation experiment was conducted to investigate the migration of overburden during the mining process of a specific working face in the Liuzhuang Coal Mine located in southern China. Sand and gravel were used to simulate the geological environment of each rock stratum. The deformation of the stratum was monitored using strain gauges, the fracture and displacement changes of the overburden stratum were recorded using cameras, and the characteristics of roof collapse was monitored using infrared thermal imager. The experimental model fully simulated the situation of the working face, and the actual working face size was obtained by enlarging the model by 100 times. The experiment found that during the initial stage of mining, there was no significant subsidence of the roof. In the course of the advancement of the working face, the primary roof intermittently fractured behind the working face, with subsequent propagation of upper cracks in an upward direction. The overburden rock layer above the goaf experienced continuous compaction, leading to the gradual closure of the separation layer. Simultaneously, new cracks constantly emerged in front of the working face, resulting in the progressive stabilization of the height of the crack zone. The stress measurements at each point exhibit a pattern of initial increased, followed by decrease, and ultimately stabilization. By considering the stress variation law of the overburden rock, the stress changes in key layers of the bedrock during mining could be categorized into four zones: the stress stable zone, stress increasing zone, stress reducing zone, and compaction stable zone. During the initial phase of coal seam mining, the presence of rock layers provided support, resulting in minimal subsidence of the overburden rock. However, as the mining operation progressed, the disturbance force and collapse of the overburden rock leaded to further downward subsidence. When the working face reached the stop line, the collapsed overburden rock gradually consolidates, resulting in a deceleration of energy release and the formation of a pressure relief zone. Consequently, the overburden rock above the working face underwent a slight additional subsidence, reaching its maximum level. A short cantilever rock beam structure was formed in the experiment. This study will provide valuable reference for future coal mining and serve as a vital theoretical basis for roof control in deep coal seam mining. [ABSTRACT FROM AUTHOR]

Background: The Cameroon Volcanic Line (CVL) is an oceanic-continental megastructure prone to geo-hazards, including landslide/mudslide, gully erosion and flash floods targeted in this paper. Recent geospatial practices advocated a multi-hazard analysis approach supported by artificial intelligence. This study proposes the Multi-Geoenvironmental Hazards Susceptibility (MGHS) tool, by combining Analytical Hierarchy Process (AHP) with Machine Learning (ML) over the North-Moungo perimeter (Littoral Region, Cameroon). Methods: Twenty-four factors were constructed from satellite imagery, global geodatabase and fieldwork data. Multicollinearity among these factors was quantified using the tolerance coefficient (TOL) and variance inflation factor (VIF). The AHP coefficients were used to weigh the factors and produce a preliminary map per Geoenvironmental hazard through weighted linear combination (WLC). The sampling was conducted based on events records and analyst knowledge to proceed with classification using Google Earth Engine (GEE) cloud computing interface. Classification and Regression Trees (CART), Random Forest (RF) and Gradient Boosting Regression Trees (GBRT), were used as basic learners of the stacked hazard factors, whereas, Support Vector Regression (SVR), was used for a meta-learning. Results: The rainfall was ranked as the highest triggering factor for all Geoenvironmental hazards according to AHP, with a coefficient of 1, while the after-learning importance assessment was more varied. The area under receiver operating characteristic (AUROC/AUC) was always more than 0.96, and F1-score is between [0.86–0.88] for basic classifiers. Landslides, gully erosion and flash floods showed different spatial distributions, confirming then their probability of co-occurrence. MGHS outputs clearly displayed two and three simultaneous occurrences. Finally, the human vulnerability assessed with population layer and SVR outputs showed that high human concentrations are also the most exposed, using the example of Nkongsamba's extract. Conclusions: Combining AHP with single learners, then a meta-learner, was efficient in modelling MGHS and related human vulnerability. Interactions among geo-environmental hazards are the next step and city councils are recommended to integrate results in the planning process. [ABSTRACT FROM AUTHOR]

This paper reflects on the progress of tsunami preparedness in a coastal community in Aceh, Indonesia, nearly two decades after the catastrophic 2004 Indian Ocean Tsunami. The research employs a comprehensive approach to thoroughly evaluate and comprehend the community's preparedness, its correlation with local perceptions of tsunami risk, and delves into the prevalence of tsunamis in the area, with a specific emphasis on the significant impact of the 2004 Indian Ocean Tsunami on the coastal community of Aceh. To investigate the community's readiness and the potential impacts of tsunamis at the study site, tsunami simulations were performed using the shallow water equation within the COMCOT (Cornell Multi-grid Coupled Tsunami) model. These simulations assessed run-up and inundation scenarios, thereby providing justification for the potential tsunami impact in the area. Modelling the scenario of tsunami in the region is important to measure the potential impact and estimation time for community to prepare the evacuation plan. In addition to the numerical modeling, a mixed-method approach was employed, involving the distribution of questionnaires and conducting in-depth interviews with 150 respondents directly on-site. These assessments yielded valuable insights into community perspectives on tsunami risk and their preparedness measures. The findings contribute to the development of effective strategies for disaster management by integrating local knowledge, experiences, and socialization programs. The study emphasizes the significance of ongoing endeavors to enhance community preparedness and mitigate the consequences of tsunamis. [ABSTRACT FROM AUTHOR]

Background: Consolidation of clays could be a very time-consuming procedure. However, preloading can increase the speed of consolidation; applying an electric field can accelerate this procedure significantly. The efficiency of the electroosmosis approach has been studied for different types of clays previously. At the same time, there is no information about the performance of the EO method for Tabriz gray clay. Methods: This paper investigates the effects of the EO technology on Tabriz gray clay using a modified oedometer consolidation apparatus. The achieved results of the EO consolidation of the Gray clay of Tabriz are compared with the standard Kaolin clay (KC-which produced industrially). Three different electrodes (Iron, Copper, and Aluminum) are employed to study about effects of the electrode type, and two different voltages (12 V and 24 V) are applied to assess the impact of the input electric field on the settlement of samples. Results: It is shown that the copper electrode leads to maximum volumetric strains while the iron electrode results in minimum volumetric strains. In addition, it is shown that the larger input voltage leads to larger settlements. The results indicate that the EO approach is more efficient for the Gray clay of Tabriz in comparison to the KC, where gray clay shows larger settlements while subjected to an electric field. Unconfined compression tests are also applied to some samples, and the EO method's influence on the samples' strength is discussed. Conclusions: The achieved results demonstrated that the EO method can be efficiently used to improve the consolidation and strength properties of the gray clay of Tabriz. Highlights: Effects of the electro-osmosis (EO) method on the consolidation properties of the grey clay of Tabriz were investigated. A modified oedometer apparatus was developed to assess efficiency of the EO method for gray clay of Tabriz. EO induced settlements of the grey clay of Tabriz were compared with the settlements of Kaolin clay. Effects of the different electrodes on the EO induced settlements were evaluated. Effects of the EO on the unconfined strength of clays were investigated. [ABSTRACT FROM AUTHOR]

Background: In recent years, the technology of blocking and grouting of has been widely used in the treatment of groundwater inrush in tunnels in China's mines. Studies have been carried out on the aggregates pouring under hydrodynamic conditions; however, there is lack of studies of the grout propagation in the pouring aggregate mass, which formed in the earlier stage. This paper presents an experimental investigation of grout propagation in poured aggregates with flowing water, which focused on the second stage, i.e., the grouting stage, after the first stage of aggregates pouring in the salvage of an inundated underground tunnel. Results: In this work, a visualized tunnel replica with flowing water was adopted to investigate the main effects of sealing efficiency, water pressure variation, propagation mechanism during grouting in the poured aggregates with different grain sizes and flowing water conditions. A series of experiments with orthogonal array design were carried out, and the propagation of cement/sodium silicate and the change characteristics of fluid pressure in the tunnel were obtained. The results show that the main effects on the sealing efficiency of grouting in poured aggregates with flowing water in a descending order is cement/sodium silicate ratio, relative density of aggregates, particle size distribution of aggregates, and final water pressure difference of both ends of aggregates segment. The cementation form of grouted aggregates has four types; T shape, H shape, O shape and shell shape. The main mode of grout propagation includes three types; permeation filling mode, compaction- permeation mode, and compaction-fracturing mode, which reflects the influence of grain size, density of aggregates and grouting pressure. The variation of water pressure can be divided into four categories; overall ascending type, step ascending type, concave type, and convex type. The curve type mainly depends on water pressure, water flowrate, relative density and grain size of aggregates, gel time, propagation mechanism of grout. Conclusion: The flow rate after grouting has decreased by approximately 60% to 86% compared to that before grouting, bulk hydraulic conductivity decreased by more than 80%, reflecting a great improvement of the sealing efficiency in the grouting stage after the pouring stage. The research on grout propagation in different graded aggregate mass has guiding significance for the design and construction of a rapid disaster treatment after groundwater inrush. [ABSTRACT FROM AUTHOR]

Landslides involving sensitive clays are recurrent events in the world's northern regions and are especially notorious in eastern Canada. The two critical factors that separate sensitive clay landslides from traditional slope stability analysis are the highly brittle behavior in undrained conditions (strain-softening) characteristic of progressive or retrogressive failures and the large deformations associated with them. Conventional limit equilibrium analysis has numerous shortcomings in incorporating these characteristics when assessing landslides in sensitive clays. This paper presents an extensive literature review of the failure mechanics characteristics of landslides in sensitive clays and the existing constitutive models and numerical tools to analyze such slopes' stability and post-failure behavior. The advantages and shortcomings of the different techniques to incorporate strain-softening and large deformation in the numerical modeling of sensitive clay landslides are assessed. The literature review depicts that elastoviscoplastic soil models with non-linear strain-softening laws and rate effects represent the material behavior of sensitive clays. Though several numerical models have been proposed to analyze post-failure runouts, the amount of work performed in line with sensitive clay landslides is very scarce. That creates an urgent need to apply and further develop advanced numerical tools for better understanding and predicting these catastrophic events. [ABSTRACT FROM AUTHOR]

This research paper aims to model Mass Movements Susceptibility (MMS) in the province of Tétouan. First, we identified the characteristics and spatial mapping of the different types of MM (collapse, mudflows, and complex landslides) by means of the interpretation of satellite images and from fieldwork. Subsequently, we selected the predictive parameters controlling the occurrence of MM e.g. lithology, land use, fault density, hydrographic network density, slope degrees, slope aspects, and elevation. We used the heuristic method for Modeling Mass Movements Susceptibility (MMMS). The choice of this method compared to other methods (fractal, factorial, and neurons) is justified by the possibilities of intervention and the judgment of the expert who relies on the ground truth to select the parameters, to identify the classes, and to assign the weights to each one; unlike to other methods with steps that are done automatically and randomly. The results of the validation of the susceptibility map correspond to 70% compared to the field data and it includes five susceptibility classes (not susceptible, low, moderate, high, and very high). Indeed, the originality of this paper relies on the fact that the creation of our susceptibility map will eventually indicate the areas of roads, dwellings, the extension of urbanization, and dams, which are located in areas at risk of MM. Our map is also a powerful decision-making tool to conduct management plans and to guide the selection of sites to build new projects; which help mitigate the socio-economic impacts usually encountered when mass movements in Tétouan province are triggered. [ABSTRACT FROM AUTHOR]

The joint event of 21st International Symposium on Geo-disaster Reduction (21st ISGdR) was held onsite and online during 5–8 August 2023 in Shanghai, China. This symposium focused on the theme of "A new era for safe and resilient coastal and marine systems", providing a platform for academics, researchers and practitioners from different countries to discuss the research progress and exchange ideas on the reduction of disasters. The symposium consisted of keynote lecture, invited lectures and other presentations in parallel session. [ABSTRACT FROM AUTHOR]

The flood protection embankments of Hungary and Europe face numerous challenges. Some dike bases were constructed more than 200 years ago; since then, they have been elevated and extended. Because of these iterative adaptations, the dikes bear many construction errors, which can trigger failures and slides. Due to climate change, droughts and low-water periods of the rivers in central Europe are becoming more frequent. As a result of these effects, the water balance of the dikes can alter and desiccate in the long term. The most staggering fissures appeared on dikes built from clays susceptible to volume change. The General Directorate of Water Management ordered a comprehensive survey of dike pavement cracks in Hungary. This was one of the most extensive surveys of such kind. Hungary has some 4400 km of primary flood protection embankments, out of which 1250 km is paved. There are multiple reasons why the pavement of an embankment can crack. The main features of crack patterns related to clays with shrink-swell potential are identified. The results of international studies and the present survey are synthesised. The main objective of this paper is to draw a correlation between drought (aridity) zones, plasticity index of the soil samples, and crack thickness. [ABSTRACT FROM AUTHOR]

A landslide early warning system based on monitoring acoustic emission (AE) generated by slope movements has been developed that can deliver alerts direct to a community at risk, with relevance to low- and middle-income countries. The Community Slope SAFE (Sensors for Acoustic Failure Early-warning) (CSS) approach uses steel waveguides driven into the slope to transmit detected high frequency noise (AE) to a sensor at the ground surface. CSS gives a measure of slope displacement rate. Continuously measured AE is compared to a pre-defined trigger level that is indicative of decreasing slope stability (i.e., landslide initiation), and a visual and audible alert automatically generated so that a community can follow a pre-defined course of action (e.g., evacuation). This paper describes the CSS approach and details a field trial of the system at two sites in Hakha, Chin Sate, Myanmar. The trial, which included training a group of youth Landslide Response Volunteers to install and operate the CSS system, increased landslide awareness and knowledge in the Hakha community, delivered the required real-time continuous operation, and demonstrated the practicality of using the CSS system for community landslide protection. [ABSTRACT FROM AUTHOR]

This paper presents an experimental investigation of the plugging efficiency of aggregate pouring through multiple boreholes under flowing water conditions into an inundated mine tunnel. Aggregate pouring into an inundated mine tunnel has been widely used and constitutes the premise for the salvage of flooded underground mines through further grouting. However, corresponding in-depth research is relatively limited due to the concealment of underground engineering. A visual experimental setup for aggregate pouring into a tunnel replica was built based on the theory of similarity between sediment movement and slurry pipeline transportation. Four factors, each with four levels, including the aggregate particle size (0.25–0.5, 0.5–1, 1–2 and 2–5 mm), distance between boreholes (0.5, 0.75, 1 and 1.5 m), initial water flow rate (0, 1.5 × 10−2 m/s, 2.4 × 10−2 m/s and 3 × 10−2 m/s) and tunnel inclination (0°, 3°, 5° and 8°) were selected in orthogonal experiments to investigate the plugging efficiency. Range and variance analysis of the four-level orthogonal array experimental results indicated that the factors influencing the plugging efficiency, varying between 83.96 and 98.15%, could be ranked in descending order as the initial water flow rate, aggregate particle size, distance between boreholes and tunnel inclination. The former two factors yielded a more significant influence than that of the latter two factors. The measured water pressure difference ranging from 16 to 32% between the front and back ends of the formed aggregate mass in the pouring process indicated that there remained a high resistance to water flow, even if the aggregate mass was not capped but reached a certain length. Plugging criteria for aggregate pouring into horizontal and inclined tunnels were then proposed. Moreover, the optimal distance between boreholes to form an effective bulkhead was determined, which could be defined as the distance between boreholes when the aggregate mass exhibits the fastest build-up and the plugging capacity is reached. [ABSTRACT FROM AUTHOR]

Full understanding the interaction mechanisms between flow-like landslides and the impacted protection structures is an open issue. While several approaches, from experimental to numerical, have been used so far, it is clear that the adequate assessment of the hydromechanical behaviour of the landslide body requires both a multiphase and large deformation approach. This paper refers to a specific type of protection structure, namely a rigid barrier, fixed to the base ground. Firstly, a framework for the Landslide-Structure-Interaction (LSI) is outlined with special reference to the potential barrier overtopping (nil, moderate, large) depending on the features of both the flow and the barrier. Then, a novel empirical method is casted to estimate the impact force on the barrier and the time evolution of the flow kinetic energy. The new method is calibrated by using an advanced hydro-mechanical numerical model based on the Material Point Method. The validation of the empirical formulation is pursued referring to a large dataset of field evidence for the peak impact pressure. Both numerical and empirical methods can appropriately simulate the physical phenomena. The performance of the newly proposed empirical method is compared to the literature methods and its advantages are outlined. [ABSTRACT FROM AUTHOR]

This paper examines the environmental and economic impact of cloudburst-triggered debris flow and flash flood in four villages of Uttarkashi district, Uttarakhand Himalaya. On 18th July 2021 at 8:30 p.m., a cloudburst took place on the top of the Hari Maharaj Parvat, which triggered a huge debris flows and flash floods, affecting 143 households of four villages of downstream areas. Immediately after the cloudburst occurred, the authors visited four affected villages—Nirakot, Mando, Kankrari, and Siror. A structured questionnaire was constructed and questions were framed and asked from 143 heads of affected households on the impact of debris flows and flash floods on people's life, settlements, cowsheds, bridges, trees, forests, and arable land in and around the villages. The volume of debris, boulders, pebbles, gravels, and mud was assessed. It was noticed that all four villages got lots of destructions in terms of loss of life—people and animals, and property damage—land, crops, and infrastructural facilities. This study shows that the location of the settlements along with the proximity of the streams, which are very violent during the monsoon season, has led to the high impact of debris flow on the affected villages. We suggest that the old inhabited areas, which are located in the risk zones, can be relocated and the new settlements can be constructed in safe places using suitability analyses. [ABSTRACT FROM AUTHOR]

Background: Landslide size distribution is widely found to obey a negative power law with a rollover in the smaller size, and has been exploited by many researchers to inspect landside physics or to assess landslide erosion and landslide hazard. Yet, sample size has effect on the statistics of landslide size even though we manage to avoid complications associated with landslide datasets and statistical treatments. Results: In this paper, a series of stochastic simulations were implemented to explicitly and systematically quantify the effect of sample size. The results show that, the errors of parameters estimated based on small sample size can be considerably large. For a sample size of 100, the relative error of the estimated landslide erosion rate that has a probability of 50 % can approach 100 %. In addition, small sample size also obscures the statistical significance of the variances in parameters between different subsets of the same dataset. Although inconsistency was found regarding how the power exponent varies with rainfall intensity, numerical results suggest that the variance observed in a dataset with a small sample size may be not statistically significant. Conclusions: This paper not only reveals the potential effect of sample size on exploiting landslide size distribution but also presents procedures for quantifying this issue in future studies. [ABSTRACT FROM AUTHOR]

This paper proposes a three-phase method that combines multi-source (i.e. topographic, thematic, monitoring) input data in a GIS environment to rank—at small (1:250,000) scale—administrative units (e.g. municipalities) based on their exposure to slow-moving landslide risk within a selected area (e.g. a region) and, accordingly, detect those primarily requiring mitigation measures. The method is applied in the Calabria region (southern Italy) where several municipalities are widely affected by slow-moving landslides that systematically cause damage to buildings and infrastructure networks resulting in significant economic losses. The results obtained are validated based on the information gathered from previous studies carried out at large (municipal) scale. The work undertaken represents a first, fundamental step of a wider circular approach that can profitably facilitate the decision makers in addressing the issue of the slow-moving landslide risk mitigation in a sustainable way. [ABSTRACT FROM AUTHOR]

As climate change continues, wildfire outbreaks are becoming more frequent and more difficult to control. In mid-July 2017, a forest fire spread from the forests to the city of Split in Croatia. This unpredictable spread nearly caused emergency systems to collapse. Fortunately, a major tragedy was avoided due to the composure of the responsible services and the help of citizens. Citizens helped to extinguish the fire and provided a large amount of disaster-related information on various social media platforms in a timely manner. In this paper, we addressed the problem of identifying useful Volunteered Geographic Information (VGI) and georeferenced social media crowdsourcing data to improve situational awareness during the forest fire in the city of Split. In addition, social media data were combined with other external data sources (e.g., Sentinel-2 satellite imagery) and authoritative data to establish geographic relationships between wildfire phenomena and social media messages. This article highlights the importance of using georeferenced social media data and provides a different perspective for disaster management by filling gaps in authoritative data. Analyses from the presented reconstruction of events from multiple sources impact a better understanding of these types of events, knowledge sharing, and insights into crowdsourcing processes that can be incorporated into disaster management. [ABSTRACT FROM AUTHOR]

Natural disasters have been a significant hurdle in the economic growth of middle-income developing countries. Thailand has also been suffering from recurring flood disasters and was most which are severely affected during the 2011 floods. This paper aims to identify the various factors that impact the speed of disaster recovery among the Small and Medium Enterprises (SMEs) severely affected by the floods in Pathumthani province in central Thailand, and how it is related to its speed decision of neighbours SMEs. The methodology adopts a spatial econometric model, to analysis and understand each of the chosen factors' impact. The findings include the impact of disaster resilience, mitigation and planning at the SME level as well as the government level. The absence of accurate perception of actual risk, flood insurance and disaster management planning before the 2011 floods had contributed to the severity of the impacts during the 2011 floods. [ABSTRACT FROM AUTHOR]

Background: Since the high-rise buildings and deep underground structures dramatically increases in urban area, the decent design and construction of deep excavations is essential before these structures are actually built up. The building area is very susceptible to the changes of their geo-environment, and even minor insecurity of a deep excavation may lead to a catastrophic failure of structures and deformation of the ground. Therefore, the adverse influence of deep excavation on the surrounding environment should be monitored and controlled stringently. Results: Based on the real case of deep excavation in Xuzhou, China, a FDM numerical model, which was accomplished by FLAC-3D, was developed to evaluate the deformation of retaining piles and ground surface under various excavation support systems. The original pile-anchor support system was simulated as well as the proposed quincunx double-row piles support system. For the original support system, the deformations were discussed by comparing the numerical results with monitoring data. For the proposed support system, orthogonal tests were designed to evaluate the influence of multiple factors on the effectiveness of excavation support. The optimum solution for the proposed support system was obtained through orthogonal tests. Conclusion: Results show that the pile space is the primary factor for the excavation-induced deformations, which can be reflected by the lateral displacement of retaining piles and the settlement around the excavation, while the row space has insignificant influence on the deformations. The conclusions of this paper can contribute to the design of similar projects and avoid excessive deformation of the ground during excavation in the future. [ABSTRACT FROM AUTHOR]

Background: The concepts of disaster risk reduction and disaster risk management involve the development, improvement, and application of policies, strategies, and practices to minimize disaster risks throughout society. Nowadays, preserving architectural heritage and ancient monuments from disasters is an important issue in the cultural life of modern societies. The 'health' of a building/structure may be evaluate by its deterioration or damage level: monitor the aging and promptly detect relevant damages, play a central role, and structure dynamic characterization and microtremor analysis are considered powerful techniques in this field. A wide bibliography about structures/buildings seismic dynamic characterization is counterpoised to a missing one about their seismic response during conservation/safety works. This paper focus on the seismic response and monitoring of a historical masonry embankment wall during the conservation works carried out after a riverbank landslide that seriously damaged it. Results: The H/V results of the acquired traces show that main resonance frequency of the masonry embankment wall is between 4 Hz and 15 Hz, in agreement with the frequency range of roughly 10-meters-high, squat and monolithic structure. The whole monitoring period can be divided into three intervals corresponding to three different kind of workings: i) piling work; ii) parapet breakdown, excavation, embankment arrangement and foot wall consolidation; iii) backfill and restoring of the original condition, ordinary construction activities. The maximum peak component particle velocity substantial increase during the second period. All the stations have a higher energy content in the 10-20 Hz frequency range, but the spectra analysis clearly shows that the NS component, perpendicular to the wall, is the most stressed one. Moreover, despite the considerable distance from the August 24 Central Italy earthquake epicentre, the earthquake waveform is clearly recognizable at each station. In fact, the energy is focused around 2 Hz and the signals show directivity neither for the spectrum nor for the H/V. Conclusion: This work may contribute to characterize the vibrations induced by piling work at close range, and help to define the maximum acceptable vibration pattern for such structures, since literature is missing of such case studies. The maximum peak component particle velocity values clearly showed the work advancement. This paper also shows how the H/V technique is a valuable method to estimate the resonant frequency not only of buildings, but also of a squat and monolithic structure like the Lungarno Torrigiani masonry embankment wall. [ABSTRACT FROM AUTHOR]

The joint event of 20th International Symposium on Geo-disaster Reduction (20th ISGdR) was held onsite and online during 16–19 August 2022 in Kanazawa City, Ishikawa Prefecture, Japan. This symposium focused on the theme of "the reduction of the disasters triggered by geological and geophysical factors on the earth and beyond", providing a platform for academics, researchers and practitioners from different countries to discuss the research progress and exchange ideas on the reduction of disasters. The symposium consisted of keynote lecture, invited lectures and other presentations in parallel session. A technical trip to Hakusan Tedorigawa Geopark was conducted on August 19. [ABSTRACT FROM AUTHOR]

Background: Tunisia is one of countries most affected by desertification. Sustainability of its resources, particularly agricultural ones, is closely dependent on it. Studies have multiplied to understand this phenomenon and consequently try to reduce its consequences on society. In recent decades, attempts have been made to find methods of forecasting and predicting desertification. Today, with significant progress made in remote sensing and GIS techniques, there is a better control of data from field, environment and society. This now makes it possible to produce documents that are much more accurate and reliable than before. This paper aims to assess sensitivity to desertification in a region of central Tunisia using remote sensing tools, GIS and guidelines of MEDALUS (Desertification and Land Use in the Mediterranean) model. Integration of different parameters with weighted values in a GIS system resulted in indices of climate, soil, vegetation and management. Result: In almost all cases, indices reveal the preponderance of soils, vegetation, climate and management of moderate and especially poor quality. Overlaying the four indices by multiplying them according to model equation yields the final sensitivity index map. This index shows that study area is in an advanced stage of desertification since most of its surface area (82%) is in critical class. The rest is considered as fragile. Whole region is therefore placed in of high sensitivity classes of desertification. This situation is linked to a very poor vegetation cover, unstructured and low-developed soils, cultural practices based on tillage and high livestock numbers in regard to low natural grazing resources. It is also due to a farming system not taking into account soil natural vulnerability. Conclusion: As natural resources, in current context of exploitation, cannot regenerate so quickly, pressure on environment is remarkable, exacerbating at the same time desertification problem. Continuing with current practices with clear signs of degradation may make situation irreversible in near future. Therefore, immediate action is necessary to stop degradation and preserve future generations' resources. [ABSTRACT FROM AUTHOR]

Local authorities i.e. government officials working at the district level and below and elected representatives of municipalities are the steering body of local-level disaster response mechanism in Nepal. The effectiveness of response operation moreover depends on their competency. This paper investigates their disaster response knowledge, preparedness, and perception, and to identify gaps and suggest recommendations. The prevailing competency of Nepalese local authorities doesn't warrant an effective response during the time of disaster. They lack awareness and preparedness. Amidst their positive perception towards the need of disaster response capacity building, in the void of an effective mechanism, the government has failed to enhance their competency. The national investment for disaster response competency building is meager in Nepal. The country heavily relies on foreign aid. The present capacity-building mechanism should be redressed from the newer dynamic. [ABSTRACT FROM AUTHOR]

This paper briefly discusses on the recent scenario in sustainable development goals and disaster risk reduction initiatives. Recent reports state that achievement of the target of SDG on 2030 is questionable however several strategies are placed internationally and locally. It raises the issue on paradigm shift in public awareness through citizen disaster science education, which will provide basic science behind any disaster of their locality that help in taking decisions in reducing exposure, improving preparedness and reaction, response and recovery to any disaster. [ABSTRACT FROM AUTHOR]

This study focuses on two weak points of the present procedure to carry out microzoning study in near-field areas: (1) the Ground Motion Prediction Equations (GMPEs), commonly used in the reference seismic hazard (RSH) assessment; (2) the ambient noise measurements to define the natural frequency of the near surface soils and the bedrock depth. The limitations of these approaches will be discussed throughout the paper based on the worldwide and Italian experiences performed after the 2009 L'Aquila earthquake and then confirmed by the most recent 2012 Emilia Romagna earthquake and the 2016–17 Central Italy seismic sequence. The critical issues faced are (A) the high variability of peak ground acceleration (PGA) values within the first 20–30 km far from the source which are not robustly interpolated by the GMPEs, (B) at the level 1 microzoning activity, the soil seismic response under strong motion shaking is characterized by microtremors' horizontal to vertical spectral ratios (HVSR) according to Nakamura's method. This latter technique is commonly applied not being fully compliant with the rules fixed by European scientists in 2004, after a 3-year project named Site EffectS assessment using AMbient Excitations (SESAME). Hereinafter, some "best practices" from recent Italian and International experiences of seismic hazard estimation and microzonation studies are reported in order to put forward two proposals: (a) to formulate site-specific GMPEs in near-field areas in terms of PGA and (b) to record microtremor measurements following accurately the SESAME advice in order to get robust and repeatable HVSR values and to limit their use to those geological contests that are actually horizontally layered. [ABSTRACT FROM AUTHOR]

Background: Landslide-affecting factors are uncorrelated or non-linearly correlated, limiting the predictive performance of traditional machine learning methods for landslide susceptibility assessment. Deep learning methods can take advantage of the high-level representation and reconstruction of information from landslide-affecting factors. In this paper, a novel deep learning-based algorithm that combine classifiers of both deep learning and machine learning is proposed for landslide susceptibility assessment. A stacked autoencoder (StAE) and a sparse autoencoder (SpAE) both consist of an input layer for raw data, hidden layer for feature extraction, and output layer for classification and prediction. As a study case, Oda City and Gotsu City in Shimane Prefecture, southwestern Japan, were used for susceptibility assessment and prediction of landslides triggered by extreme rainfall. Results: The prediction performance was compared by analyzing real landslide and non-landslide data. The prediction performance of random forest (RF) was evaluated as better than that of a support vector machine (SVM) in traditional machine learning, so RF was combined with both StAE and SpAE. The results show that the prediction ratio of the combined classifiers was 93.2% for StAE combined with RF model and 92.5% for SpAE combined with RF model, which were higher than those of the SVM (87.4%), RF (89.7%), StAE (84.2%), and SpAE (88.2%). Conclusions: This study provides an example of combined classifiers giving a better predictive ratio than a single classifier. The asymmetric and unsupervised autoencoder combined with RF can exploit optimal non-linear features from landslide-affecting factors successfully, outperforms some conventional machine learning methods, and is promising for landslide susceptibility assessment. [ABSTRACT FROM AUTHOR]

Landslide Hazard Zonation (LSH) maps play a key role in landuse planning particularly in landslide prone areas. LSH mapping is globally accepted one for analyzing the area for landslide susceptibility. Different approaches were followed by many researchers in India to prepare landslide hazard zonation mapping depending upon their need and requirement. The Nilgiris district in Western Ghats of India is one of the severe to high landslide hazard prone areas of India. Many agencies have carried out research on LSH mapping for the Nilgiris district with different scales. A systematic study of inventory and zonation was 122carried out in 1980's by government agencies. However there is no proper updation or documentation on landslides after 1980's in the district The purpose of this paper is to review the existing landslide-related studies in the district of The Nilgiris and review the district's existing landslide hazard map with updated information. Landslide hazard maps in The Nilgiris were compiled in the GIS platform from various authenticated sources. Data on landslides from 1824 to 2014 were collected and a spatial database on landslides was created. A detailed inventory was analyzed and used for revision of the district's landslide hazard impact on the 2009 landslides.. Based on the landslide inventory and densely populated areas and repeated landslides at the same locations, the most landslide hazard areas were identified. [ABSTRACT FROM AUTHOR]

In this paper, we estimate the seismogenic energy during the Nepal Earthquake (25 April 2015) and studied the ground motion time-frequency characteristics in Kathmandu valley. The idea to analyze time-frequency characteristic of seismogenic energy signal is based on wavelet transform which we employed here. Wavelet transform has been used as a powerful signal analysis tools in various fields like compression, time-frequency analysis, earthquake parameter determination, climate studies, etc. This technique is particularly suitable for non-stationary signal. It is well recognized that the earthquake ground motion is a non-stationary random process. In order to characterize a non-stationary random process, it is required immeasurable samples in the mathematical sense. The wavelet transformation procedures that we follow here helps in random analyses of linear and non-linear structural systems, which are subjected to earthquake ground motion. The manners of seismic ground motion are characterized through wavelet coefficients associated to these signals. Both continuous wavelet transform (CWT) and discrete wavelet transform (DWT) techniques are applied to study ground motion in Kathmandu Valley in horizontal and vertical directions. These techniques help to point out the long-period ground motion with site response. We found that the long-period ground motions have enough power for structural damage. Comparing both the horizontal and the vertical motion, we observed that the most of the high amplitude signals are associated with the vertical motion: the high energy is released in that direction. It is found that the seismic energy is damped soon after the main event; however the period of damping is different. This can be seen on DWT curve where square wavelet coefficient is high at the time of aftershock and the value decrease with time. In other words, it is mostly associated with the arrival of Rayleigh waves. We concluded that long-period ground motions should be studied by earthquake engineers in order to avoid structural damage during the earthquake. Hence, by using wavelet technique we can specify the vulnerability of seismically active region and local topological features out there. [ABSTRACT FROM AUTHOR]

Background: The landslides of the flow-type are dangerous and also challenging to study. A wide literature has been investigating the principal mechanisms governing each stage in which these phenomena can be ideally subdivided: failure, post-failure and propagation. However, holistic contributions and general overviews are very rare. In addition, a number of numerical methods have been issued and validated so that new chances exist to efficiently model those threats. The paper focuses on two classes of rainfall-induced landslides of the flow-type, namely debris flows and debris avalanches. The principal numerical methods are reviewed for modelling the landslide initiation and propagation and are later used for analyzing a series of benchmark slopes and real case histories which are successfully simulated. Results: The rainfall from ground surface and water spring from the bedrock are key factors for slope instability. Pore water pressure plays a relevant role also during the propagation stage. The entrainment of further material makes the propagation patterns complex due to lateral spreading and slow-down of the front of flows. It is shown that the used models are capable to provide useful indications even for combined channelized and unchannelized flows. Conclusions: Notwithstanding the complexity of flow-like landslides and the related challenges in modelling, the understanding and forecasting of such natural hazards is achievable with a satisfactory confidence. Among the key factors, rainfall, pore water pressure and bed entrainment deserves a special attention. Further improvements are expectable as the numerical models are becoming more efficient. Thus, more accurate descriptions of local effects will be possible and also additional mechanisms will be eventually analysed. [ABSTRACT FROM AUTHOR]

Background: This paper reviews the classical and some particular factors contributing to earthquake-triggered landslide activity. This analysis should help predict more accurately landslide event sizes, both in terms of potential numbers and affected area. It also highlights that some occurrences, especially those very far from the hypocentre/activated fault, cannot be predicted by state-of-the-art methods. Particular attention will be paid to the effects of deep focal earthquakes in Central Asia and to other extremely distant landslide activations in other regions of the world (e.g. Saguenay earthquake 1988, Canada). Results: The classification of seismically induced landslides and the related 'event sizes' is based on five main factors: 'Intensity', 'Fault factor', 'Topographic energy', 'Climatic background conditions', 'Lithological factor'. Most of these data were extracted from papers, but topographic inputs were checked by analyzing the affected region in Google Earth. The combination and relative weight of the factors was tested through comparison with well documented events and complemented by our studies of earthquake-triggered landslides in Central Asia. The highest relative weight (6) was attributed to the 'Fault factor'; the other factors all received a smaller relative weight (2-4). The high weight of the 'Fault factor' (based on the location in/outside the mountain range, the fault type and length) is strongly constrained by the importance of the Wenchuan earthquake that, for example, triggered far more landslides in 2008 than the Nepal earthquake in 2015: the main difference is that the fault activated by the Wenchuan earthquake created an extensive surface rupture within the Longmenshan Range marked by a very high topographic energy while the one activated by the Nepal earthquake ruptured the surface in the frontal part of the Himalayas where the slopes are less steep and high. Finally, the calibrated factor combination was applied to almost 100 other earthquake events for which some landslide information was available. This comparison revealed the ability of the classification to provide a reasonable estimate of the number of triggered landslides and of the size of the affected area. According to this prediction, the most severe earthquake-triggered landslide event of the last one hundred years would actually be the Wenchuan earthquake in 2008 followed by the 1950 Assam earthquake in India - considering that the dominating role of the Wenchuan earthquake data (including the availability of a complete landslide inventory) for the weighting of the factors strongly influences and may even bias this result. The strongest landslide impacts on human life in recent history were caused by the Haiyuan-Gansu earthquake in 1920 - ranked as third most severe event according to our classification: its size is due to a combination of high shaking intensity, an important 'Fault factor' and the extreme susceptibility of the regional loess cover to slope failure, while the surface morphology of the affected area is much smoother than the one affected by the Wenchuan 2008 or the Nepal 2015 earthquakes. Conclusions: The main goal of the classification of earthquake-triggered landslide events is to help improve total seismic hazard assessment over short and longer terms. Considering the general performance of the classification-prediction, it can be seen that the prediction either fits or overestimates the known/observed number of triggered landslides for a series of earthquakes, while it often underestimates the size of the affected area. For several events (especially the older ones), the overestimation of the number of landslides can be partly explained by the incompleteness of the published catalogues. The underestimation of the extension of the area, however, is real - as some particularities cannot be taken into account by such a general approach: notably, we used the same seismic intensity attenuation for all events, while attenuation laws are dependent on regional tectonic and geological conditions. In this regard, it is likely that the far-distant triggering of landslides, e.g., by the 1988 Saguenay earthquake (and the related extreme extension of affected area) is due to a very low attenuation of seismic energy within the North American plate. Far-distant triggering of landslides in Central Asia can be explained by the susceptibility of slopes covered by thick soft soils to failure under the effect of low-frequency shaking induced by distant earthquakes, especially by the deep focal earthquakes in the Pamir - Hindukush seismic region. Such deep focal and high magnitude (> > 7) earthquakes are also found in Europe, first of all in the Vrancea region (Romania). For this area as well as for the South Tien Shan we computed possible landslide event sizes related to some future earthquake scenarios. [ABSTRACT FROM AUTHOR]

Background: This study presents a 4-year (January 2019–April 2023) X-band radar network-based bow echo observation over Great Bandung Indonesia. This study provides insight into the temporal and spatial variability of bow echo distribution and presents the atmospheric condition associated with the bow echo events. Temporal analysis is categorical into monthly, seasonally, and diurnal. The analysis was performed using X-band radar network and reanalysis data (ERA5). Result: At least 26 bow echoes were identified across the Bandung basin from X-band radar network during the study period. From this total number of bow echoes, the observation of initiation modes is primarily generated from a weakly organized cell, with few coming from the squall line. The bow echo mostly evolved from noon until afternoon. The rainy season (December–January–February) and transition season (March–April–May) is the most frequent period of bow echo occurrence, with March being the most active month. Nevertheless, this study also found bow echo occurrence in the dry season (June–July–August). For the spatial analysis, the studied area is divided into two regions representing the eastern and western part of Bandung basin. The eastern region recorded the most intense occurrences with 14 events. The movement of bow echo in this region covered a shorter distance (average distance only 4.56 km), with all initiation modes occurring inside the region. The atmospheric condition within this region has less moisture flux, with higher CAPE and slightly higher surface temperature. Meanwhile, in the western region have different characteristics with higher moisture flux, a slight effect of CAPE and CINH, with longer distance and zonal movement direction of bow echo displacement. Conclusion: These conditions indicate that local convection is the dominant mode of bow echo initiation mode in the eastern region of Bandung basin. Meanwhile, the monsoon effect influences the bow echo initiation mode in the western region. Given that the observed 4-year bow echo has different characteristics from previous studies of bow echo in mid latitudes, developing different criteria for bow echo detection in the tropics is crucial. [ABSTRACT FROM AUTHOR]

Introduction: On November 21, 2022, a magnitude Mw 5.6 earthquake struck Cianjur Regency in the West Java Province of Indonesia. It was followed by at least 512 aftershocks that persisted from November to June 2023. This seismic event occurred in an area previously unrecognized as an active fault zone. The consequences of this earthquake in Cianjur were severe, leading to both loss of life and extensive structural damage. The substantial damage to buildings was likely a result of abrupt alterations in the local topography due to surface deformation effects. Objectives: This research endeavor aims to spatially determine the patterns of ground surface deformation and its relationship with local geomorphological setting due to earthquakes in Cianjur in 2022. Methods: In this study we conduct seismological analysis of 45 seismic stations, statistical analysis of mainshock and aftershocks data, RADAR Sentinel-1 imagery and employed the DInSAR methodology. Field survey was also conducted to determine the geomorphological characteristics in the study area. Results: The outcomes disclosed that the deformation encompassed both subsidence and uplift. The results signify that there was subsidence deformation in the vicinity of Cianjur and its environs during the primary earthquake on November 21, 2022, with an average deformation value of approximately -5 cm. In contrast, the measured deformation during the aftershocks exhibited uplift deformation, with an average value of 10 cm. The examination of deformation patterns amid the 2022 Cianjur earthquake sequence detects elevated deformation values in the vicinity of Cugenang district, with an orientation running from northwest to southeast. The geomorphological investigation conducted indicates that the region of Cianjur encompasses a variety of landforms, such as volcanic, structural, fluvial, and denudational. These landforms exhibit distinct responses to seismic activities. Co-seismic hazards, such as landslides frequently occur as a consequence of seismic events in mountainous terrain. Main Conclusions: Spatio-temporal variation of ground deformation could arise from various causes, such as the number and distribution of aftershocks, stress redistribution, fault interactions, secondary effects, and local geological settings. The mainshocks release accumulated stress along a fault, resulting in particular types of deformation, whereas aftershocks may redistribute stress exhibiting on adjacent faults. Secondary effects triggered by aftershocks, coupled with local geological and geomorphological conditions, further contribute to the diverse patterns of ground deformation observed during seismic events. The results of the study revealed that ground deformation had the greatest impact on fluvial, volcanic, and denudational processes, resulting in notable subsidence and uplift in specific regions. The occurrence and magnitude of co-seismic landslides were triggered by both mainshock and aftershock events, which occurred on weathered geological materials. These effects were further amplified by the simultaneous presence of the rainy season. Implications: The knowledge gained from this research can be applied to evaluate the impacts of earthquakes and to proactively reduce future risks. [ABSTRACT FROM AUTHOR]

Background: Three groups of factors related to topography, geology and hydrology have influence on the triggering of shallow landslides in soil material. In this paper a single representative factor ( T-factor) for the topography is proposed, which can be used to define threshold values for the possibility of shallow soil slides. This study was carried out in the Dayi area, Guizhou Province, China. During a heavy rainfall event on June 6, 2011, 230 shallow soilslides were triggered. In some slopes, no shallow landslides were triggered even though some of the topographical factors point to unstable high probability. Results: We isolated and analyzed the influence of the topography on the triggering of shallow landslides in catchments with almost identical hydrological and geological conditions and propose a new T-factor as a topographical indicator which is a combination of the slope angle, the upslope contributing area, the cross-section, and the free-face of a (potential) shallow landslide. Higher T-factor values are related to higher probabilities of shallow landsliding. The probability assessment with the topographical factor T was successfully validated in other areas of the USA and Japan. Conclusions: Without information on the geological and rainfall conditions, a quick and primary prediction of shallow landsliding using the topographical factor T is proposed. Additionally a new R-factor is proposed as a rainfall indicator, which is a combination of the 1 hour rainfall and cumulative rainfall before the landslide event and the annual rainfall. Higher R-factor values are generally related to higher probabilities of shallow landsliding. The primary probability factor P, which is the combination of T and R, gives a final indication of the probability of shallow landsliding. [ABSTRACT FROM AUTHOR]

Background: Drying and rewetting process, frequently occurred during climatic changes, is an important process in soil aggregate slacking and dissolution. The severer interference of human activities on global climate makes the extreme climate scenarios like drought and rainstorm occur frequently. Therefore, there is necessity to further our understanding on the impact of the drying-wetting cycles and initial water content on the breakdown of soil aggregates. The typical yellow-brown earth composed of water-stable and water-unstable aggregates is selected. Variations of water-stable aggregate size distributions after drying-wetting cycles are measured by wet sieving, under variable initial water content and cycles respectively. Results: Drying-wetting cycles cause a significant aggregate slaking, especially within the first two cycles. After that, most aggregates show more slacking resistant. The variation curves of the proportion of water-stable aggregates with the size 1-5 mm shows a coexistence of slaking process and supplement. The critical initial water content (about 24%) and turning point (with the aggregate size of 0.3 mm) are proposed to describe the effects of initial water content on size distribution of water-stable aggregates. Overall, the increase of initial water content strengths the water stability. In addition, the mathematical model for the relative leakage ratio based on the drying-wetting cycle, initial water content and size distribution are established. Conclusions: The findings reported in this paper may be capable of supporting the intensive study for the breakdown mechanism and assessing the leakage potential under the influence of climate change. However, there exists a certain mismatch between the drying-wetting cycles in the tests and in practice, mainly in the frequency and intensity, which should be paid more attention. [ABSTRACT FROM AUTHOR]

We use Visible Infrared Imaging Radiometer Suite (VIIRS) nightlight data to model the impact of the 2015 Nepal earthquakes. More specifically, the data—showing nightlight emissions—are used to examine the extent to which there is a difference in nightlight intensity between cells damaged in the earthquake versus undamaged cells based on (1) mean comparisons; and (2) fixed effect regression models akin to the double difference method. The analysis is carried out for the entire country as well as smaller regions in and around the Central area and Kathmandu, which were the hardest hit areas. Overall, the regressions find a significant and negative effect from the initial shock, followed by a positive net effect from aid and relief efforts, which is consistent with what one would expect to find. However, the mean analysis results are inconclusive and there is substantial noise in the nightlight measurements due to how the values are produced and persistent cloud cover over Nepal. [ABSTRACT FROM AUTHOR]

Background: Operational large-scale flood monitoring using publicly available satellite data is possible with the advent of Sentinel-1 microwave data, which enables near-real-time (at 6-day intervals) flood mapping day and night, even in cloudy monsoon seasons. Automated flood inundation area identification in near-real-time involves advanced geospatial data processing platforms, such as Google Earth Engine and robust methodology (Otsu's algorithm). Objectives: The current study employs Sentinel-1 microwave data for flood extent mapping using machine learning (ML) algorithms in Assam State, India. We generated a flood hazard and soil erosion susceptibility map by combining multi-source data on weather conditions and soil and terrain characteristics. Random Forest (RF), Classification and Regression Tool (CART), and Support Vector Machine (SVM) ML algorithms were applied to generate the flood hazard map. Furthermore, we employed the multicriteria evaluation (MCE) analytical hierarchical process (AHP) for soil erosion susceptibility mapping. Summary: The highest prediction accuracy was observed for the RF model (overall accuracy [OA] > 82%), followed by the SVM (OA > 82%) and CART (OA > 81%). Over 26% of the study area indicated high flood hazard-prone areas, and approximately 60% showed high and severe potential for soil erosion due to flooding. The automated flood mapping platform is an essential resource for emergency responders and decision-makers, as it helps to guide relief activities by identifying suitable regions and appropriate logistic route planning and improving the accuracy and timeliness of emergency response efforts. Periodic flood inundation maps will help in long-term planning and policymaking, flood management, soil and biodiversity conservation, land degradation, planning sustainable agriculture interventions, crop insurance, and climate resilience studies. [ABSTRACT FROM AUTHOR]

Introduction: The current research investigates into the application of various thunderstorm indices to predict severe thunderstorm occurrences during the monsoon season across four distinct regions in India. Methods: The study assesses the prediction model's efficacy using various skill scores and the Weather Research and Forecasting (WRF) model has been integrated for 30 h with double moment microphysics scheme NSSL-17 which accurately reproduces vertical and meteorological measures. Objective: Furthermore, it investigates fifteen thunderstorm indices derived from the ERA5 dataset to identify the most effective index for forecasting severe thunderstorms. Results: The results indicate that combining thunderstorm indices with skill scores, such as the Heidke Skill Score and True Skill Statistic, enhances the accuracy of severe thunderstorm predictions in the Indian monsoon season. The accurate predictions rely on determining optimal thresholds for each index. The study emphasizes the importance of using multiple indices rather relying solely on single measure for predicting severe thunderstorms. Advanced indices like the Energy Helicity Index (EHI) and Supercell Composite Parameter (SCP) perform well in forecasting extreme severe thunderstorms due to their strong reliance on wind shears. The EHI (> 1), and SCP (≥ 3.5), STP (≥ 1.2) along with low SRH at 3 km (100 m2/s2), indicated no evidence of helicity or tornado activity during the event. On the other hand, the CAPE, K Index, and VT Index demonstrate robust predictive capabilities for non-severe category thunderstorms. Conclusions: Integrating numerous thunderstorm indices improves meteorologists' forecasts, ensuring public safety. Based on this work, future research can improve severe weather forecasting models' accuracy and reliability. [ABSTRACT FROM AUTHOR]

Background: In August 2004 a series of debris flows caused significant disruption to the Scottish (strategic) Trunk Road Network. The subsequent Scottish Road Network Landslides Study identified a number of sites considered to be at highest risk. Some of these sites have been the subject of formal quantitative assessment of the risk from debris flow to mobile road users in vehicles. The A82 in Glen Coe has the added complication that two car parks have developed on debris fans exposing significant numbers of people to the risk while, they are essentially static and largely outside their vehicles. Methodology: The risk to road users is determined using a previously developed probabilistic methodology for mobile road users (mobile elements at risk) and a new and related methodology developed for static road users (static elements at risk) is described and applied. Within the latter, an entirely new metric of Annual Average Daily Visits is used to allow the temporal component of the probability of a landslide impacting a person to be determined given the occurrence of an event. Results: While Personal Individual Risk is at an acceptable level, including for frequent users, the risk presented to society as a whole presents a rather different picture; this is largely due to the number of visitors. The results assess the overall, societal risk for mobile elements at risk as As Low As reasonably Practicable, being at a similar level to other sites, albeit with a higher risk associated with higher numbers of fatalities. The results for the static elements at risk on the other hand suggest that the risks are classified as Unacceptable for higher numbers of fatalities. The assessment of the total societal risk, for mobile and static elements at risk, at the A82 Glen Coe suggests As Low As Reasonably Practicable for low numbers of fatalities but classify as Unacceptable for higher numbers of fatalities (around 20 to 250). [ABSTRACT FROM AUTHOR]

A huge number of sinkhole events has been recorded in different Italian urban areas, with an occurrence frequency largely increasing in the last decades, sometimes even causing loss of human lives. The main reason for such catastrophic events is the presence of man-made underground cavities, excavated within soft rocks, several decades ago and then abandoned, at shallow depths. Here, the possibility of interaction with overlying buildings and infrastructures and the corresponding sinkhole hazard is relatively high. In such contexts, the low mechanical properties of the soft rock formations where the cavities have been excavated, like those formed of calcarenites, which outcrop in large areas of Southern Italy, and their high susceptibility to weathering processes, represent one of the most important predisposing factors for instability. Therefore, assessing the stability of underground cavities is crucial for land management and planning purposes. The mechanically-based stability charts developed by Perrotti et al. (Int J Geomech 18(7):04018071, 2018) have proved to be a valid tool for preliminary stability assessment and, although allow to identify an eventual proneness of the cave to instability, they do not provide quantitative assessment about the safety margin itself. In that regard, this study intends to present the most recent outcomes obtained in the development of the methodology and is aimed at promoting an enhanced way for their application, so that the charts can become an operative tool for preliminary sinkhole hazard assessment in similar regions in the world. [ABSTRACT FROM AUTHOR]

Background: Ground failures in a slope due to gravity, are commonly known as landslides. Depend on the compositional, geological, and structural characteristics of the unstable initiation zone and the erosional composition of the propagation zone decide the complete particle size distribution of the moving mass and its gradation. This information is most important for the study of downslope movement. Only laboratory sieve analysis cannot fulfil this target because the natural debris contains a wide range of particle sizes, especially boulders. The combined method of scaled image analysis and laboratory sieve analysis or the combined method of line-grid analysis and laboratory sieve analysis was proposed to fulfil the requirement. To study the proposed combined methods, five different locations within the downslope propagation zone from the Aranayake landslide in Sri Lanka were surveyed and analyzed. In image analysis, the high-resolution scaled image of deposited debris was analyzed by computer-based image analysis for particle sizes. Small particles were addressed by the laboratory sieve analysis using the representative debris sample taken from the same location. If the boulder sizes within the debris are too big to address this method, then the Line-grid method was performed. The particles in every 0.5 m along a measured line of debris deposition were measured in this method. If the selected location contains small particles that cannot measured manually, the representative sample was used for the laboratory sieve analysis to fulfil this range. Results: The results of three locations indicated a 40% distribution of < 10 mm and a 60% distribution of > 10 mm representing the general distribution of the debris. Two distributions deviated from the general distribution that was surveyed and analyzed from special locations of the "near boundary of flow path" and "slope change zone" of the landslide. Conclusions: The combined methodology yielded successful results of complete particle size distribution for the wide range of particle sizes in debris. The variation of the particle size distribution curves of debris along the downslope depositions is planned to be used for the study of downslope propagation, damage zone assessment studies, and predicting the representative composition of future failures. [ABSTRACT FROM AUTHOR]

The joint event of 19th International Symposium on Geo-disaster Reduction (19ISGdR) and High-Level Academic Forum on Disaster Mitigation and Integrated Risk Defense on the Plateau was held on 11–15 July in Xining, Qinghai Province, China, focusing on the theme of "Geological disaster and integrated risk defense". This event consisted of keynote lectures, invited lectures, and Youth forum, which provided a platform for scientists, industrial professionals and young scholars to share their research progress and exchange novel ideas on geo-disaster reduction in a hybrid way of offline and online. A post-symposium field trip for three days was also conducted in the joint area between Qinghai-Tibet plateau and Loess plateau. [ABSTRACT FROM AUTHOR]

This paper expands the previous efforts by other researchers to present a quantitative and deterministic approach for terrain analysis. This study evaluates both spatial and temporal factors contributing landslides utilizing Light Detection and Ranging (LiDAR) point clouds in conjunction with the frequency ratio model (PFR) than has previously been used in the Alborz Mountains. The study area is Marzan Abad of the Alborz Mountain in Iran. The significance of this study is the performance of a high-resolution digital elevation model (DEM) derived from LiDAR point clouds in order to provide detailed information in improving landslide susceptibility evaluation. This study discusses how we improve the quality of landslide susceptibility evaluation. We apply the PFR model to consider the effect of landslide-related factors associated with Google Earth's high-resolution images and field observations. The LiDAR point cloud data and GIS-based analysis have allowed performing high quality ways of landslide hazard assessments using inventory dataset as compared to previous studies. We contributed an improved landslide inventory map of the Mazandaran Province. We used image elements interpretation from the available ASTER DEM (30 m), LiDAR-DEM (5 m), and the Google Earth high spatial resolution images in conjunction with the field observations. This study evaluates factors such as geology, geomorphology, landuse, soil, slope, and distance from roads and drainage to represent, manipulate, and analyze factors. Also, we evaluated the performance success of the rate curve of landslides susceptibility. The results have indicated an improved landslide susceptibility map from LiDAR-derived DEMs implementing the PFR model with 92.59% of accuracy performance as compared to the existing data and previous studies in the same region. Furthermore, this study reveals that all considering factors have relatively positive effects on the landslides susceptibility mapping in the study, however, the most effective factor on the landslide occurrence is the lithology with 13.7%. [ABSTRACT FROM AUTHOR]

Background: In April 2016, Kumamoto City, Japan, and its surroundings were hit by a sequence of strong and devastating earthquakes including two significant events, one on April 14, 2016, at 21:26 JST (Mw6.2) and the other on April 16, 2016, at 01:25 JST (Mw7.0). These disasters caused 120 fatalities (including indirect fatalities), 2337 people injured and 177,914 residential houses were damaged. This paper aims to ascertain the damage to residential houses and buildings caused by liquefaction during this earthquake and suggests possible mitigation methods. Results: Field reconnaissance was conducted in the target area on May 27-30, 2016. The post-earthquake inclination angle and the tilt direction of 68 affected houses and buildings in the liquefied sites in Kumamoto City were measured by using a laser rangefinder (Leica DISTO D 510). Ground structure and condition were also determined from topographic maps, bore data and the calculated liquefaction resistance factor, F. Conclusions: Based on this investigation, the inclination angle of the houses in the target area seems to be related to the type of building structure and their foundation as well to the local ground composition. The tilt direction has a tendency to be associated with the location of the nearby river. The results presented could be useful to develop future liquefaction mitigation measures for detached residential houses. [ABSTRACT FROM AUTHOR]

Background: Strong earthquakes are among the prime triggering factors of landslides, which may block rivers, forming landslide dams. Some of these dams may pose serious threats to people and property due to upstream inundation and downstream dam-breach flooding. Evaluating the stability and potential hazard of landslide dams is significant for the mitigation measures, but remains challenging. The 2008 Wenchuan earthquake ( M 7.9) in China triggered numerous landslides over a broad area, some of which dammed rivers, posing severe threats to downstream settlements. Our previous study created one of the most complete landslide dam inventories including detailed geomorphic parameters of 828 landslide dams induced by the Wenchuan earthquake. This paper presents the study of a number of representative landslide dams associated with the 2008 Wenchuan earthquake. Results: The coseismic landslides were classified into rock/debris avalanches, debris flows, rock/debris slides and rock falls. According to dam composition material and sedimentological features, landslide dams were categorized into three types: dams mainly composed of large boulders and blocks; dams composed of unconsolidated fine debris; and dams with partly intact rock strata at the base topped by large boulders and blocks or soil with rock fragments, showing two-layered or three-layered depositional structure. This classification is linked to the typology of damming landslides and considered to be a preliminary indicator of dam stability. In addition, dam stability also largely depends on valley morphometry as well as landslide runout distance and mechanism. The post-earthquake debris flow damming events induced by subsequent rainfalls are also introduced. It was found that there is still a large amount of loose sediment remaining on the slope, which may continue promoting heavy debris flows and dams in the coming years or decades. Conclusions: The classification of landslide dams proposed in this study can be used as a preliminary indicator of dam stability. More reliable assessment requires a geotechnical approach taking into account a variety of dynamic loading scenarios, and also relies on knowledge about the accurate dam and barrier-lake geometry. There is still a large amount of loose sediment remaining on the slopes, which may be reactivated and remobilized during the heavy post-earthquake rainstorms. Therefore, predicting the post-earthquake debris flows and evaluating their potential for damming rivers are still of great concern and remain as a main challenge. [ABSTRACT FROM AUTHOR]