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On 1 January 2024, a massive earthquake struck the Noto Peninsula in Japan, and the resulting tsunami significantly damaged the nearby coasts. This study focuses on Iida Bay, located on the peninsula that suffered severe coastal damage. We observed a tsunami waveform in Iida Bay from video analysis owing to the lack of instrument data. This, combined with the waveform observed outside the bay, was used to correct the initial sea‐surface displacements produced by a prior source model. We successfully reproduced the observed waveforms with corrected displacements and investigated how the tsunami propagated and amplified in the bay. Alongshore wave propagation and superposition were identified as crucial factors in this tsunami event. Plain Language Summary: On 1 January 2024, a large earthquake struck the Noto Peninsula in Japan, generating a tsunami that significantly impacted the nearby coasts. Post‐event surveys revealed severe damage to Iida Bay, located on the peninsula. To investigate tsunami propagation and amplification, we analyzed the images of the recorded video of the tsunami along with a numerical simulation. According to our results, the tsunami maximized during the subsequent waves rather than during the primary wave in the bay. Waves propagating along the shore developed after the primary wave of the tsunami, and some of these waves propagating from opposite sides of the bay overlapped at a specific location in the bay, where significant inundation was observed ∼20 min after the arrival of the primary wave. Key Points: Generation, propagation, and amplification characteristics of a tsunami following the 2024 Noto Peninsula Earthquake were investigatedSignificant sea‐surface displacements were concentrated in the northeastern part of the source areaWaves propagating in alongshore directions and their superposition greatly contributed to coastal damage in Iida Bay [ABSTRACT FROM AUTHOR]

This experimental study focused on the measurement and analysis of the impact force caused by a tsunami bore on a coastal structure. The bore wave was produced by a dam break mechanism. The water depth in the reservoir and the location of the coastal structures were varied to simulate different impact scenarios. The time history of the force resulting from the impact of the bore wave on the coastal structure was measured. The propagation of the bore wave along the flume was recorded and the video recordings were converted into digital data using an image-processing technique in order to determine the flow depth variations with time. The hydrostatic forces and the corresponding depth and time-averaged hydrodynamic forces as well as the maximum hydrodynamic forces were acquired for each scenario. The ratio of hydrodynamic to hydrostatic forces were obtained, and it was observed that the calculated averaged ratio was within the recommended design ratio. The results indicate that an increase in the reservoir level caused an increase in the magnitude and intensity of the impact forces, however, the relationship was non-linear. Moreover, it was found that the location of the structure did not play a significant role on the intensity of the impact forces. [ABSTRACT FROM AUTHOR]

The overtopping-inundation process of a tsunami results in the collisions of drifting objects on the coast, which damage structures, thereby increasing the risk of collapse. This study conducted laboratory experiments on the collision between a drifting container caused by the overtopping-inundation process of a solitary wave and a fixed port crane's leg. The movement trajectory and velocity of the container as well as the collision velocity by solitary wave inundation, were analyzed using motion analysis software. Overall, increasing solitary wave scale, collision velocity, and drifting object weight and decreased distance between the two objects tended to increase the collision force. However, different experiment results were also obtained due to pitching in objects that fully floated without bottom friction owing to the solitary wave bore. This resulted in line-to-surface collisions. Thus, surface-to-surface contact occurred under the incomplete floating condition owing to the difficulty because of interference with the bottom; however, the collision force decreased under complete floating conditions owing to line-to-surface contact. Therefore, the contact condition according to the floating behavior must be considered a parameter while predicting the collision forces of drifting objects. Thus, surface-to-surface contact occurred under the incomplete floating condition owing to the difficulty because of interference with the bottom; however, the collision force decreased under complete floating conditions owing to line-to-surface contact. Therefore, the contact condition according to the floating behavior must be considered a parameter while predicting the collision forces of drifting objects. [ABSTRACT FROM AUTHOR]

On January 1, 2024 at 16:10:09 JST, an Mj 7.6 earthquake struck the Noto Peninsula in the southern part of the Sea of Japan. This location has been experiencing an earthquake swarm for more than three years. Here, we provide an overview of this earthquake, focusing on the slip distribution of the mainshock and its relationship with the preceding swarm. We also reexamined the source areas of other large earthquakes that occurred around the Sea of Japan in the past and compared them with the Matsushiro earthquake swarm in central Japan from 1964 to 1968. The difference between the Matsushiro earthquake swarm and the Noto earthquake swarm is the surrounding stress field. The Matsushiro earthquake swarm was a strike-slip stress field, so the cracks in the crust were oriented vertically. This allowed fluids seeped from the depths to rise and flow out to the surface. On the other hand, the Noto area was a reverse fault stress field. Therefore, the cracks in the earth's crust were oriented horizontally. Fluids flowing underground in deep areas could not rise and spread over a wide area in the horizontal plane. This may have caused a large amount of fluid to accumulate underground, triggering a large earthquake. Although our proposed mechanism does not take into account other complex geological conditions into consideration, it may provide a simple way to explain why the Noto swarm is followed by a large earthquake while other swarms are not. [ABSTRACT FROM AUTHOR]

This paper develops a tsunami inundation model, filling the current void between industry applied simplified methods (bathtub and attenuation) and comprehensive numerical modeling. The proposed model utilizes two‐dimensional equations established on hydraulic principles (energy conservation and friction loss) to produce the finite‐difference, two‐dimensional model. While the sophistication of depth‐averaged numerical modeling has not been entirely replicated, the incorporation of hydraulic roughness and gravitational effects (slope) through the Bernoulli energy equation, accompanied by suitable assumptions, significantly improves performance over simplified bathtub and attenuation methods. This improvement not only retains excellent efficiency (completing case studies in under 100 s) but also yields inundation results comparable to traditional numerical modeling, which typically takes multiple hours to days. This is the first application of such equations to a two‐dimensional tsunami inundation model, leading to simulations at Gisborne and Christchurch, New Zealand, for validation against the numerical model, COMCOT. F1 scores produced from inundation extent comparisons were upwards of 84%. Inundation depth discrepancies recorded 77% within a ±$\pm$1 m range, while over 93% within a ±$\pm$2 m range. [ABSTRACT FROM AUTHOR]

The term NaTech was coined to describe events where natural hazards trigger technological accidents in industrial facilities. Structural damage to the installations, caused by natural events such as earthquakes or tsunami, may cause loss of containment, which may in turn lead to fires, blasts, or dispersion of toxic gases. Thus, NaTech quantitative risk assessment (QRA) requires a measure of structural risk to provide estimates of future losses and a detailed assessment of the consequences arising from such losses. This paper presents an industrial risk analysis for anchored atmospheric storage tanks subjected to tsunami hazard, by means of a multidisciplinary approach integrating structural analysis and consequence assessment. This is performed for a case study consisting of a waterfront tank farm located at a coastal Italian site. The first part of the analysis requires calculation of the structural failure rate of storage tanks that suffer content release due to damage induced by tsunami inundation, via models of probabilistic hazard for the site of interest and the vulnerability (fragility) of the examined structures. Structural failure rates are evaluated for various numbers of simultaneous waterfront storage tank failures, using tsunami fragility curves for variable tank geometry and filling level. The failure rates and consequence analysis for the tank farm are then used as input parameters for the NaTech QRA, leading to the calculation of risk figures for tsunami hazard. [ABSTRACT FROM AUTHOR]

The 1771 Meiwa tsunami which struck the southern Ryukyu Islands (Sakishima Islands) had greater than 22 m run-up height, leaving about 12,000 casualties in its wake. At many places, the tsunami inundation or lack of inundation is well recorded in historical documents. Several tsunami source models have been proposed for this event using historical records as constraints of tsunami calculations. Nevertheless, the source model remains under discussion. This study re-evaluated the tsunami wave source model of the 1771 Meiwa tsunami using high-resolution (10 m mesh) bathymetric and topographical data for tsunami calculation, the latest historical record dataset, and seismological knowledge. Results demonstrated that a tsunami earthquake along the southern Ryukyu Trench was the likely cause of the 1771 event. However, it is noteworthy that assumption of a large slip with 30 m is necessary for a shallow and narrow region (fault depth = 5 km, fault width = 30 km, Mw = 8.49) of the plate boundary in the Ryukyu Trench, which is far larger than previously thought. This requirement of very large initial water level change at the source might involve not only the fault rupture along the plate boundary but also deformation by splay faults, inelastic deformation of unconsolidated sediments near the trench axis, and/or giant submarine landslides. Results also show that the effects of fault parameters on the run-up were quite different depending on the offshore coral reef width. This phenomenon strongly constrained the fault width to 30 km. Our tsunami ray tracing analysis further revealed the effects of bathymetry on tsunami propagation. It is noteworthy that meter-long huge tsunami boulders tend to be distributed along the specific coasts at which the tsunami was concentrated by bathymetric effects. This finding suggests that past tsunamis, including the 1771 event, might have affected the specific coral reefs on Sakishima Islands repeatedly, which is crucially important for understanding the heterogeneous distribution of tsunami boulders. This feature might also be useful to elucidate the effects of large tsunamis on the corals and reefs because a direct comparison of coral reefs that are damaged and not damaged by tsunami waves is testable in narrow areas in the case of the Sakishima Islands. [ABSTRACT FROM AUTHOR]

In mining areas with high groundwater tables, mining subsidence can lead to the inundation of cropland by water, causing damage to cropland and posing a threat to national food security. The implementation of concurrent mining and reclamation techniques can effectively enhance the reclamation rate of cropland. This technique requires engineers to initiate reclamation measures before cropland waterlogging occurs. Therefore, when mining a panel underground, an accurate calculation of the time when cropland becomes waterlogged, known as the theoretical reclamation timing, is crucial. To address this issue, this study proposes a computational method for the theoretical reclamation timing of cropland under the conditions of single-panel mining based on intelligent optimization algorithms. In addition, this paper also proposes an optimization method for the theoretical reclamation timing of cropland within a district based on an intelligent optimization algorithm. Utilizing this method makes optimizing the layout of multiple panels possible, thereby delaying the theoretical reclamation timing for cropland within a district. This approach aims to shorten the duration of reclamation projects and minimize their interference with agricultural activities. Through experimental validation, this paper demonstrates the reliability of these two methods. This study is beneficial for the rational planning of reclamation projects. [ABSTRACT FROM AUTHOR]

The widespread use of rubble-mound (RM) breakwaters along coasts across the world highlights the importance of understanding their behavior during natural disasters such as tsunamis. The failure of these breakwaters during tsunamis can have far-reaching consequences, potentially causing damage to coastal infrastructure and loss of life. Many breakwaters failed during past tsunamis. Despite this, studies on the behavior of RM breakwaters during tsunamis are minimal. The present study thus attempts to elucidate the behavior of RM breakwater subjected to a tsunami. Furthermore, efforts were made to develop effective countermeasures that can safeguard the breakwater against tsunamis. To the end, a novel technique of using geogrids for reinforcing the RM is proposed. This study could be a pioneering application of geogrids as reinforcing elements in RM breakwaters to mitigate damages from tsunamis. Geogrid layers are provided on both the seaside and harborside to mitigate tsunami-induced damage to the breakwater. In addition, a crown wall (with shear keys) is also introduced to prevent the scouring of the crest and sheet piles from preventing excess seepage through the seabed. Physical model tests, analytical studies and numerical simulations were carried out to assess the performance of the proposed countermeasures by comparing it with the behavior of conventional RM breakwater during the tsunami. The tsunamis can overflow the breakwater, potentially exceeding its design limits. Hence, provision was made in the study for overflow, where the breakwater may overflow by the tsunami. It was observed that excess seepage through the body of the breakwater and the scouring of the crest were significant factors that led to the failure of RM breakwaters under tsunami overflow. A novel reinforced model was proposed to address these issues. This model effectively withstood tsunami-induced damages without significant deformations, demonstrating its potential as a reliable solution. In the past, tsunamis have caused significant damage to several rubble-mound breakwaters, leading to devastating impacts on coastal communities. The 2004 Indian Ocean tsunami and the 2011 Great East Japan tsunami are two well-known examples of the destructive power of tsunamis. A significant number of breakwaters across the globe are of the rubble-mound type, and finding a practical solution to make them resilient against tsunamis could protect many coasts against future tsunamis. This study proposes novel reinforcing techniques to make the rubble-mound breakwater tsunami-resilient. These techniques include adding geogrid layers on either side, providing a crown wall (with shear key) at the top, and inserting two sheet piles into the seabed at either end of the rubble-mound breakwater. Perhaps, this is the first-time geogrids were used on rubble-mound breakwaters to mitigate tsunami-induced damages. The reinforcing elements were chosen for their practicality in the real world. These elements can be practically applied to make existing and future breakwaters tsunami resilient. The study found that the proposed reinforced model, particularly Reinforced model III, remained intact without significant deformation even under a 15-m high tsunami. [ABSTRACT FROM AUTHOR]

This paper studies the damage spectra of single-degree-of-freedom (SDOF) systems for tsunami loading. The 2011 Tohoku tsunami wave traces are computed and obtained by adopting the Cornell Multi-grid Coupled Tsunami (COMCOT) model and are further verified by the Tohoku Tsunami Joint Survey (TTJS) data. The tsunami response analyses of SDOF systems are conducted taking into account the dynamic analysis method. The classical ductility damage is considered as the damage performance. The damage spectra are computed for five force reduction factors and 791 tsunami loadings. The effects of inundation depths, hysteretic model, post-yield stiffness ratio, α , viscous damping ratio, ξ , are explored and interpreted scientifically and statistically. The results demonstrate that the effect of the hysteretic model, force reduction factor, R, post-yield stiffness ratio, α , viscous damping ratio, ξ , on the damage of the structure is evident. Comparison with the static method and influence analysis of structural damping indicate the necessity for the application of the dynamic method. A simplified predictive formulation is developed for the evaluation of structural damage for tsunami loadings. [ABSTRACT FROM AUTHOR]

The alarming increase in extreme weather events, such as severe storms with torrential rain and strong winds, is a direct result of climate change. These events have led to discernible shifts in forest structure and the carbon cycle, primarily driven by a surge in tree mortality. However, the impacts caused by these severe storms on the production and carbon increment from coarse woody debris (CWD) are still poorly understood, especially in the Brazilian Atlantic Forest. Thus, the goal proposed by the study was to quantify the CWD volume, necromass, and carbon stock before and after the occurrence of a severe storm and to determine the importance of spatial, structural, and qualitative variables of trees in the CWD carbon increment. The increase in carbon by the storm was 2.01 MgC ha−1, with a higher concentration in the CWD less decomposed and smaller diameter class. The forest fragment plots showed distinct increments (0.05–0.35 MgC), being influenced by spatial (elevation, declivity, and slope angle) structural (basal area) and qualitative factors (trunk quality and tree health), intrinsic to the forest. Thus, it is concluded that severe storms cause a large increase in carbon in CWD, making it essential to understand the susceptibility of forests to the action of intense rains and strong winds to model and monitor the future impacts of these extreme weather events on Atlantic Forest and other tropical forests in the world. [ABSTRACT FROM AUTHOR]

Predicting earthquakes through reasonable methods can significantly reduce the damage caused by secondary disasters such as tsunamis. Recently, machine learning (ML) approaches have been employed to predict laboratory earthquakes using stick-slip dynamics data obtained from sheared granular fault experiments. Here, we adopt the combined finite-discrete element method (FDEM) to simulate a two-dimensional sheared granular fault system, from which abundant fault dynamics data (i.e., displacement and velocity) during stick-slip cycles are collected at 2203 "sensor" points densely placed along and inside the gouge. We use the simulated data to train LightGBM (Light Gradient Boosting Machine) models and predict the gouge-plate friction coefficient (an indicator of stick-slips and the friction state of the fault). To optimize the data, we build the importance ranking of input features and select those with top feature importance for prediction. We then use the optimized data and their statistics for training and finally reach a LightGBM model with an acceptable prediction accuracy (R2 = 0.94). The SHAP (SHapley Additive exPlanations) values of input features are also calculated to quantify their contributions to the prediction. We show that when sufficient fault dynamics data are available, LightGBM, together with the SHAP value approach, is capable of accurately predicting the friction state of laboratory faults and can also help pinpoint the most critical input features for laboratory earthquake prediction. This work may shed light on natural earthquake prediction and open new possibilities to explore useful earthquake precursors using artificial intelligence. [ABSTRACT FROM AUTHOR]

This study was conducted to elaborate on the factors contributing to indirect deaths due to earthquakes between 1995 and 2016 in Japan and to identify their prevalence by focusing on life and health changes. A content analysis was conducted to determine the factors using documents provided by the local government. From the 472 indirect death cases, 12 categories and 137 detailed factors were identified. From the 13 cases related to suicide, six categories and 15 detailed factors were extracted. Among the categories, intense disaster-related work was ranked highest, followed by damage to jobs and property and family changes. For the other 459 non-suicide related causes of death, 12 categories and 122 detailed factors were extracted. The most prevalent categories were related to delay or interruption of treatment due to hospital shutdowns, followed by changes in living conditions. In detailed factor of living conditions, cold or hot environments—which are due to being washed away by tsunamis, weather, drafty shelters, the number of evacuees, damaged infrastructure, and a lack of clothes—were found in 60 cases. In conclusion, maintenance of medical services, promotion of a safe environment, and identification and intervention of high-risk people based on these factors are imperative. Developing assessment tools based on these factors for future research is essential to estimate the size of high-risk populations, assist in the distribution of limited resources, and respond quickly to survivors in disasters. [ABSTRACT FROM AUTHOR]

Non‐inertial afterslip has been inferred to occur following large earthquakes. An explanation for this slow slip phenomenon is that coseismically generated stresses induce sliding on parts of a fault surface with velocity‐strengthening frictional properties. Here we develop an alternative mesoscale heuristic explanation for afterslip based on the idea that afterslip may occur on any portion of a fault that exhibits positive residual geometric moment following an earthquake, including sections that ruptured coseismically. Following a large earthquake, this model exhibits exponential time decay of afterslip and allows for variable sensitivity to coseismic event magnitude and residual geometric moment. This model provides a partial explanation for the spatial relationship of co‐ and post‐seismic slip associated with the 2011 MW = 9 Tohoku‐oki earthquake. Plain Language Summary: Afterslip is slow slip that occurs after large earthquakes. Some geodetic inferences of afterslip suggest that regions experiencing afterslip may have also slipped coeismically. This spatially coincident behavior is poorly explained by classical stress‐driven afterslip models. Here, we develop a motion‐based model to explain this possible spatial relationship. The model predicts faster afterslip rates in regions that have an excess of accumulated slip to be released following a large earthquake. This model may be used to describe the spatial relationship of co‐ and post‐seismic slip associated with the 2011 Great Japan earthquake. Key Points: We develop a geometric moment based model for time‐dependent afterslipThe model exhibits and exponential time decay of afterslip ratesThis model provides a kinematic explanation for overlapping co‐ and post‐seismic slip proximal to the 2011 great Japan earthquake [ABSTRACT FROM AUTHOR]

The structural styles and magnitudes of Alpine tectonic inversion are reviewed for the Atlantic margin of southwestern (SW) Iberia, a region known for its historical earthquakes, tsunamis and associated geohazards. Reprocessed, high-quality 2D seismic data provide new images of tectonic faults, which were mapped to a depth exceeding 10 km for the first time. A total of 26 of these faults comprise syn-rift structures accommodating vertical uplift and horizontal advection (shortening) during Alpine tectonics. At the regional scale, tectonic reactivation has been marked by (a) the exhumation of parts of the present-day continental shelf, (b) local folding and thrusting of strata at the foot of the continental slope, and (c) oversteepening of syn- and post-rift sequences near reactivated faults (e.g. "passive uplift"). This work proves, for the first time, that geometric coherence dominated the growth and linkage of the 26 offshore faults mapped in SW Iberia; therefore, they are prone to reactivate as a kinematically coherent fault network. They form 100–250 km long structures, the longest of which may generate earthquakes with a momentum magnitude (Mw) of 8.0. Tectonic inversion started in the Late Cretaceous, and its magnitude is greater close to where magmatic intrusions are identified. In contrast to previous models, this work postulates that regions in which Late Mesozoic magmatism was more intense comprise thickened, harder crust and form lateral buttresses to northwest–southeast compression. It shows these structural buttresses to have promoted the development of early stage fold-and-thrust belts – typical of convergent margins – in two distinct sectors. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) fully-coupled fluid-structure model has been developed in this study to calculate the impact force of tsunamis on a flexible structure considering fluid-structure interactions. The propagation of a tsunami is simulated by solving the 3D Navier–Stokes equations using a finite volume method with the volume-of-fluid technique. The structure motion under the tsunami impact force is simulated by solving the motion equation using the generalized alpha method. The structure motion is fed back into the fluid solver via a technique that combines a sharp-interface immersed boundary method with the cut-cell method. The flow model predicts accurate impact forces of dam-break flows on rigid blocks in three experimental cases. The fully coupled 3D flow-structure model is tested with experiments on a large-scale (1:5) model bridge under nonbreaking and breaking solitary waves. The simulated wave propagation and structure restoring forces generally agree well with the measured data. Then, the fully-coupled fluid-structure model is compared with an uncoupled model and applied to assess the effect of flexibility on structure responses to tsunami loading, showing that the restoring force highly depends on the dynamic characteristics of the structure and the feedback coupling between fluid and structure. The maximum hydrodynamic and restoring forces decrease with increasing structure flexibility. [ABSTRACT FROM AUTHOR]

In tsunami inundations or slope disasters of heavy rain, a lot of floating debris or driftwood logs are included in the flows. The damage to structures from solid body impacts is more severe than the damage from the water pressure. In order to study free-surface flows that include floating debris, developing a high-accurate simulation code of free-surface flows with high performance for large-scale computations is desired. We propose the single-phase free-surface flow model based on the cumulant lattice Boltzmann method coupled with a particle-based rigid body simulation. The discrete element method calculates the contact interaction between solids. An octree-based AMR (Adaptive Mesh Refinement) method is introduced to improve computational accuracy and time-to-solution. High-resolution grids are assigned near the free surfaces and solid boundaries. We conducted two kinds of tsunami flow experiments in the 15 and 70m water tanks at Hachinohe Institute of Technology and Kobe University to validate the accuracy of the proposed model. The simulation results have shown good agreement with the experiments for the drifting speed, the number of trapped wood pieces, and the stacked angles. [ABSTRACT FROM AUTHOR]

Cilacap is one of several areas that experienced significant damage due to the Pangandaran tsunami in 2007. Currently, tsunamis are one of the most serious threats to coastal areas as they can cause devastation to the function of coastal areas. The physical environment can extensively affect the probability of damage caused by tsunamis. In addition, it is critical to maintain building stability as a substantial component in the integrated management efforts of coastal areas. The aim of this research is to assess the physical susceptibility and the vulnerability of school buildings to tsunami, particularly senior high school buildings (known as SMA/MA) located in the coastal area of the Cilacap region. This research is essential for the continuity of learning and teaching activities in the coastal area. Therefore, mapping the physical environment and school buildings in the coastal area of the Cilacap region is necessary. In this study, the physical approach method and Papathoma Vulnerability Tsunami Assessment (PVTA) model were optimally applied to assess coastal vulnerabilities to tsunami. Ultimately, the results were further evaluated by using cross-tabulation. The results confirm that specific coastal areas were categorised as having "moderate to high" susceptibility. Simultaneously, owing to the field survey, we determined that school buildings at this location were made of simple reinforced concrete materials. Notwithstanding that the vulnerability of the school buildings were low, the conditions were deemed to be reasonably harmful given that the schools were located in a "moderate to high" susceptibility. The results of this study have implications for the level of potential physical susceptibility of the coastal areas and the vulnerability of school buildings to tsunamis in the Cilacap region. [ABSTRACT FROM AUTHOR]

Despite significant research on the effects of stress on the hypothalamic-pituitary-adrenal (HPA) axis, questions remain regarding long-term impacts of large-scale stressors. Leveraging data on exposure to an unanticipated major natural disaster, the 2004 Indian Ocean tsunami, we provide causal evidence of its imprint on hair cortisol levels fourteen years later. Data are drawn from the Study of the Tsunami Aftermath and Recovery, a population-representative longitudinal study of tsunami survivors who were living along the coast of Aceh, Indonesia, when the tsunami hit. Annual rounds of data, collected before, the year after and 2 y after the disaster provide detailed information about tsunami exposures and self-reported symptoms of post-traumatic stress. Hair samples collected 14 y after the tsunami from a sample of adult participants provide measures of cortisol levels, integrated over several months. Hair cortisol concentrations are substantially and significantly lower among females who were living, at the time of the tsunami, in communities directly damaged by the tsunami, in comparison with similar females living in other, nearby communities. Differences among males are small and not significant. Cortisol concentrations are lowest among those females living in damaged communities who reported elevated post-traumatic stress symptoms persistently for two years after the tsunami, indicating that the negative effects of exposure were largest for them. Low cortisol is also associated with contemporaneous reports of poor self-rated general and psychosocial health. Taken together, the evidence points to dysregulation in the HPA axis and "burnout" among these females fourteen years after exposure to the disaster. [ABSTRACT FROM AUTHOR]

Coastal dikes are an essential social infrastructure to mitigate tsunami damage. However, there are no clear guidelines on effective dike shapes for reducing tsunami overflow. To examine effective dike shapes, numerical simulations of the amount of tsunami overflow at coastal dikes are conducted with reference to tsunami waveforms caused by the Great East Japan Earthquake. Results reveal the relationship between the dike shape and the amount of the overflow; the mechanism of overflow reduction based on the velocity and water level distribution is also verified. The comparison of the seaward and landward slopes of coastal dikes reveals that the seaward slope has a greater impact on the overflow, and the seaward slope with a vertical wall or a wave return structure reduces the overflow by 5%–30% compared to the 1:2 (26.6°) seaward slope. The landward slope should be determined based on the tsunami scale and the scour related to the dike stability. Since tsunami inflow damages human life and social infrastructure, achieving the overflow reduction without increasing dike height is vital. Our work contributes to rational design guidelines for coastal dikes. [ABSTRACT FROM AUTHOR]

The "blue economy" idea promotes the responsible and sustainable use of coastal and marine resources. The need to balance the exploitation and economic use of these resources has moved to the top of the research agenda and management priorities for small island developing states (SIDS). SIDS face unique challenges due to their geographic, economic, and environmental characteristics. While the specific challenges can vary based on the individual SIDS, some common future challenges include (i) climate change and sea-level rise resulting from the increased frequency and intensity of storms and coastal erosion; (ii) natural disasters such as hurricanes, cyclones, tsunamis, and earthquakes, resulting in extensive damage, disruption of essential services, and lead to loss of lives and livelihoods; (iii) lack of sustainable development and economic diversification leading to reliance on few key sectors, such as tourism and agriculture, which are vulnerable to market fluctuations; (iv) energy security and renewable energy transition; as there is dependency on imported fossil fuels for their energy needs, price fluctuations and supply disruptions occurs; (v) biodiversity conservation and marine resource management; they host unique ecosystems and rich biodiversity, including coral reefs, mangroves, and marine species; and (vi) access to finance and technology; there are direct opportunities, for accessing funds to support technology development under sustainable finance projects. This themed article set attracted 14 submissions, 7 of which were accepted for publication. The topics covered fisheries, climate change effects, marine litter, and development of new technologies and finance mechanisms to support the SIDS. Overall, these contributions have emphasized the remarkable role that SIDS play in the protection and management of coastal and marine ecosystems, but also highlighted several needs and key priorities. [ABSTRACT FROM AUTHOR]

Despite the importance of critical infrastructure for the effective functioning of communities, their vulnerability to tsunamis remains unstudied. This study addresses this issue by developing empirical fragility curves for infrastructure components currently absent from tsunami vulnerability research. This research applies post-event damage data from the 2015 Illapel tsunami in a cumulative link model (CLM) to form fragility curves for three-waters (manholes, culverts, and drain inlets) and railway infrastructure components. The synthesized fragility curves reveal that in response to the flow depth, culverts exhibit the highest vulnerability of all the infrastructures studied. The curves also suggest that culverts, drain inlets, and railways have higher vulnerability when compared to infrastructure such as roads or utility poles. [ABSTRACT FROM AUTHOR]

Reliable forecasts of building damage due to debris flows may provide situational awareness and guide land and emergency management decisions. Application of debris-flow runout models to generate such forecasts requires combining hazard intensity predictions with fragility functions that link hazard intensity with building damage. In this study, we evaluated the performance of building damage forecasts for the 9 January 2018 Montecito postfire debris-flow runout event, in which over 500 buildings were damaged. We constructed forecasts using either peak debris-flow depth or volume flux as the hazard intensity measure and applied each approach using three debris-flow runout models (RAMMS, FLO-2D, and D-Claw). Generated forecasts were based on combining multiple simulations that sampled a range of debris-flow volume and mobility, reflecting typical sources and magnitude of pre-event uncertainty. We found that only forecasts made with volume flux and the D-Claw model could correctly forecast the observed number of damaged buildings and the spatial patterns of building damage. However, the best forecast only predicted 50% of the observed damaged buildings correctly and had coherent spatial patterns of incorrectly forecast building damage (i.e., false positives and false negatives). These results indicate that forecasts made at the building level reliably reflect the spatial pattern of damage, but do not support interpretation at the individual building level. We found the event size strongly influences the number of damaged buildings and the spatial pattern of debrisflow depth and velocity. Consequently, future research on the link between precipitation and the volume of sediment mobilized may have the greatest effect on reducing uncertainty in building damage forecasts. Finally, because we found that both depth and velocity are needed to forecast building damage, comparing debris flow models against spatially distributed observations of building damage is a more stringent test for model fidelity than comparison against the extent of debris-flow runout. [ABSTRACT FROM AUTHOR]

Vehicles are one of the most common objects that are usually washed away by the water flow during flood events resulting in several damages and casualties. Regardless of the vehicle type and flow condition, vehicle orientations in relation to the incoming flow play a significant role on the vehicles stability limits. Therefore, studying the hydrodynamic forces on a vehicle placed at different angles with respect to the incoming flow can help to understand the most unstable orientation. As a result, parking lots design may improve by rearranging the vehicles in a way that the critical vehicle orientation will not face the expected incoming flow. Herein, 3-dimensional numerical modelling was conducted to assess the critical orientation of a parked full-scale passenger vehicle exposed to water flow at three different angles, namely 0°, 45°, and 90°. The highest drag force and displacement were observed for the vehicle at 90° orientation making it the critical one. While the highest torque on the vehicle centre of mass was reported for the vehicle at 45° orientation, making it more rotatable when compared with other orientations. Obtained results were compared with previously published experimental studies and good agreements were observed. [ABSTRACT FROM AUTHOR]

In recent years, large-scale heavy rainfall disasters have occurred frequently in several parts of the world. Therefore, a quantitative approach to understanding how buildings are damaged during floods is necessary to develop appropriate flood-resistant technologies. In flood inundation simulations for the quantitative evaluation of a building's resistance to flooding, a subgrid model is necessary to appropriately evaluate the resistance of buildings smaller than the grid size at a medium grid resolution. In this study, a new subgrid (SG) 3D inundation model is constructed to evaluate the fluid force acting on buildings and assess the damage to individual buildings during flood inundation. The proposed method does not increase the computational load. The model is incorporated into a 2D and 3D hybrid model with high computational efficiency to construct a 3D river and inundation flow model. Its validity and effectiveness are evaluated through comparisons with field observations and the conventional equivalent roughness model. Considering horizontal and vertical velocity distributions, the proposed model showed statistically significant improvements in performance in terms of building loss indices such as velocity and fluid force. These results suggest that the SG model can effectively evaluate the fluid force acting on buildings, including the vertical distribution of flow velocities. [ABSTRACT FROM AUTHOR]

Currently available performance-based methodologies for assessing the fragility of structures subjected to tsunami neglect the effects of tsunami-induced vertical loads due to internal buoyancy. This paper adopts a generalized methodology for the performance assessment of structures that integrates the effects of buoyancy loads on interior slabs during a tsunami inundation. The methodology is applied in the fragility assessment of three case-study frames (low, mid and high-rise), representative of existing masonry-infilled reinforced concrete (RC) buildings typical of Mediterranean region. The paper shows the effect of modelling buoyancy loads on damage evolution and fragility curves associated with different structural damage mechanisms for existing RC frames with breakaway infill walls including consideration of blow-out slabs. The outcomes attest that buoyancy loads affect the damage assessment of buildings during a tsunami, especially in the case of mid and high-rise structures with blow-out slabs. The rate of occurrence of slabs uplift failure increases with the number of stories of the building, indicating the need to account for such damage mechanism when assessing the performance of structures. It is also found that buoyancy loads slightly affect the fragility curves associated to other structural damage mechanisms for existing RC buildings commonly monitored for fragility assessment. [ABSTRACT FROM AUTHOR]

Multi-hazard risk assessments for building portfolios exposed to earthquake shaking followed by a tsunami are usually based on empirical vulnerability models calibrated on post-event surveys of damaged buildings. The applicability of these models cannot easily be extrapolated to other regions of larger/smaller events. Moreover, the quantitative evaluation of the damages related to each of the hazard types (disaggregation) is impossible. To investigate cumulative damage on extended building portfolios, this study proposes an alternative and modular method to probabilistically integrate sets of single-hazard vulnerability models that are constantly being developed and calibrated by experts from various research fields to be used within a multi-risk context. This method is based on the proposal of state-dependent fragility functions for the triggered hazard to account for the pre-existing damage and the harmonisation of building classes and damage states through their taxonomic characterisation, which is transversal to any hazard-dependent vulnerability. This modular assemblage also allows us to separate the economic losses expected for each scenario on building portfolios subjected to cascading hazards. We demonstrate its application by assessing the economic losses expected for the residential building stock of Lima, Peru, a megacity commonly exposed to consecutive earthquake and tsunami scenarios. We show the importance of accounting for damage accumulation on extended building portfolios while observing a dependency between the earthquake magnitude and the direct economic losses derived for each hazard scenario. For the commonly exposed residential building stock of Lima exposed to both perils, we find that classical tsunami empirical fragility functions lead to underestimations of predicted losses for lower magnitudes (Mw) and large overestimations for larger Mw events in comparison to our state-dependent models and cumulative-damage method. [ABSTRACT FROM AUTHOR]

Strike-slip fault ruptures have a limited capacity to generate vertical deformation, and for this reason they are usually dismissed as potential destructive tsunami sources. At the western tip of the western Mediterranean, in the Alboran Sea, tectonics is characterized by the presence of large transcurrent fault systems and minor reverse and normal faults in a zone of diffuse deformation. The strike-slip Carboneras fault is one of the largest sources in the Alboran Sea and therefore with the greatest seismogenic capacity. It is also one of the active structures with higher slip rates in the eastern Betic fault zone and has been proposed as the source of the damaging 1522 (M 6.5; Int. VIII–IX) Almeria earthquake. The dimensions and location of the Carboneras fault imply a high seismic and tsunami threat. In this paper we present tsunami simulations from seismic sources generated with physics-based earthquake simulators. We have generated a 1 Myr synthetic seismic catalogue consistent on 773 893 events, with magnitudes ranging between Mw 3.3 and 7.6. From these events we have selected those sources producing a potential energy capable of generating a noticeable tsunami, those sources being earthquakes with magnitudes ranging from 6.71 to 7.62. The Carboneras fault has the capacity to generate locally damaging tsunamis; however, on a regional scale its tsunami threat is limited. The frequency–magnitude distribution of the generated seismic catalogue reflects the variability of magnitudes associated with the rupture of the entire fault, departing the upper limit from the classical Gutenberg–Richter potential relation. The inter-event time for the maximum earthquake magnitudes is usually between 2000 and 6000 years. The use of physics-based earthquake simulations for tsunamigenic sources allows an in-depth characterization of the scenarios, allowing a qualitative leap in their parametrization. [ABSTRACT FROM AUTHOR]

Atmospherically generated coastal waves labelled as meteotsunami are known to cause destruction, injury and fatality due to their rapid onset and unexpected nature. Unlike other coastal hazards such as tsunami, there exists no standardised means of quantifying this phenomenon which is crucial for understanding shoreline impacts and to enable researchers to establish a shared language and framework for meteotsunami analysis and comparison. In this study, we present a new 5-level Lewis Meteotsunami Intensity Index (LMTI) trialled in the United Kingdom (UK) but designed for global applicability. A comprehensive dataset of meteotsunami events recorded in the UK was utilised and the index's effectiveness was evaluated, with intensity level and spatial distribution of meteotsunami occurrence derived. Results revealed a predominant occurrence of Level 2 moderate intensity meteotsunamis (69%) in the UK, with distinct hotspots identified in Southwest England and Scotland. Further trial implementation of the LMTI in a global capacity revealed its potential adaptability to other meteotsunami prone regions facilitating the comparison of events and promoting standardisation of assessment methodologies. [ABSTRACT FROM AUTHOR]

Many coastal bridges have been destroyed or damaged by tsunami waves. Some studies have been conducted to investigate wave impact on bridge decks, but there is little concerning the effect of bridge superelevation. A three-dimensional (3D) dam break wave model based on OpenFOAM was developed to study tsunami-like wave impacts on bridge decks with superelevation. The Reynolds-averaged Navier–Stokes equations and the k-ɛ turbulence model were used. The numerical model was satisfactorily checked against Stoker's analytical solution and the published hydrodynamic experiment. The validated model was employed to carry out parametric analyses to investigate the effects of upstream and downstream water depths and the bridge deck's superelevation. The results show that the tsunami force is proportional to the relative wave height. The dam break wave impact on the bridge deck can be identified as two distinct scenarios according to whether the wave height is higher than the bridge deck top. The trend of the tsunami force is also different in different scenarios. The superelevation will significantly influence the tsunami forces acting on the box girder, with some exceptions. [ABSTRACT FROM AUTHOR]

A megathurst magnitude 9.0-9.1 (Mw), undersea earthquake on 11 March 2011 off Japan's Tohoku region on the Pacific coast, generated massive tsunami waves. Extremely high waves and the resultant debris flow overtopped and destroyed the existing seawalls which offered little or no protection, thus resulting in thousands of deaths and causing extensive destruction of coastal facilities, including the Fukushima Daiichi nuclear plant. The tsunami destroyed easily the tidal gates on the roads connecting the port to the town, and since there was no seawall protection on the tsunami's path on rivers, there was also extensive inland damage upstream, as the waves striking over river banks reverted river flows, thus causing the water to rise and form even higher waves with greater inland inundation. Even weak tsunamis striking a river outlet on a coast can generate a highvolume river water flow reversal and potentially cause substantial damage upstream. The present government tsunami countermeasures in Japan for such river areas are unable to prevent such enhancement of tsunami damage and to provide adequate protection for inland areas. [ABSTRACT FROM AUTHOR]

A tsunami is a natural disaster that destroys structures and kills many lives in many countries in the world. A risk assessment of the building under a tsunami loading is thus essential to evaluate the damage and minimize potential loss. A crucial tool in risk assessment is the fragility curve. Most building fragility curves for tsunami force were developed using survey building damaged data. This research proposed a method for developing fragility curves under tsunami loading based on the analytical building model data. In the development, the generic building was a one-story reinforced-concrete building with masonry-infilled walls constructed from the structural index, popularly built as residential buildings along the west coast of southern Thailand. Three damage levels were investigated: damage in masonry infill walls, damage in primary structures, and collapses. The masonry infill wall was modeled using multisprings to represent the load-bearing behavior due to tsunami with a hydrodynamic pattern. The fragility curves were developed using the maximum likelihood method and considering the uncertainty due to masonry infill wall type, tsunami flow direction, and tsunami flow velocity. The developed fragility curve agrees well with the empirical tsunami fragility curve of a one-story reinforced-concrete building damage data in Thailand from the 2004 Tsunami. The developed fragility functions could be adopted for assessing tsunami risk assessment and disaster mitigation for similar structures against different tsunami scenarios in the future. [ABSTRACT FROM AUTHOR]

The present work proposes a simulation-based Bayesian method for parameter estimation and fragility model selection for mutually exclusive and collectively exhaustive (MECE) damage states. This method uses an adaptive Markov chain Monte Carlo simulation (MCMC) based on likelihood estimation using point-wise intensity values. It identifies the simplest model that fits the data best, among the set of viable fragility models considered. The proposed methodology is demonstrated for empirical fragility assessments for two different tsunami events and different classes of buildings with varying numbers of observed damage and flow depth data pairs. As case studies, observed pairs of data for flow depth and the corresponding damage level from the South Pacific tsunami on 29 September 2009 and the Sulawesi–Palu tsunami on 28 September 2018 are used. Damage data related to a total of five different building classes are analysed. It is shown that the proposed methodology is stable and efficient for data sets with a very low number of damage versus intensity data pairs and cases in which observed data are missing for some of the damage levels. [ABSTRACT FROM AUTHOR]

Baek, D.; Lee, B.W.; Ha, T.; Jang, S.-W., and Yoon, J.-S., 2023. Experimental study of tsunami force coefficients for Imwon Port on the east coast of Korea. Journal of Coastal Research, 39(1), 175–180. Charlotte (North Carolina), ISSN 0749-0208. A tsunami can cause severe damage to people and infrastructure in coastal areas through inundation caused by strong wave forces. In this study, three-dimensional hydraulic experiments were conducted to estimate tsunami force coefficients at Imwon Port, which is located on the eastern coast of the Korean peninsula. For hydraulic experiments, the offshore topography around the target area and the onshore structures in the port hinterland were modeled by applying the Froude similitude. Solitary waves were adopted as incident tsunami waves. The inundation water depths and tsunami forces were mainly measured in the onshore region to estimate the tsunami force coefficients. The tsunami force coefficients obtained at Imwon Port ranged from 0.85 to 5.27. The maximum wave forces and inundation depth were observed at the forefront structures closest to the shoreline among the measuring points. The tsunami force coefficients estimated for Imwon Port in this study can help to establish the design criteria for preventing tsunami disasters. [ABSTRACT FROM AUTHOR]

SMPN 25 building in Padang City is a junior high school building located in the high seismic zone and prone to tsunamis. Based on the initial analysis of the existing building using the current Indonesian building codes, this building has not been able to withstand the working earthquake and tsunami loads. In this study, the retrofitting of the building was designed using concrete jacketing that is with additional dimensions and reinforcement, aimed at making the building function as a vertical evacuation structure. The structural fragility curve of the building is determined before and after retrofitting for both earthquake and tsunami loads. The fragility curve is determined from the ductility of the building for each variation of earthquake acceleration based on the Hazus standard. The first yield displacement was determined from the pushover analysis, and the ultimate displacement was determined from the time history analysis. The earthquake acceleration records used were the El-Centro earthquake, the Northridge earthquake, the Kobe earthquake, and the Padang earthquake. The results of the analysis show that the retrofit of the building structure using concrete jacketing reduces the probability of damage to the building structure due to earthquake loads by 42.06% at the level of extensive damage and by 4.42% at the level of complete damage at PGA 0.6g, while, it reduces the probability of building damage due to tsunami loads by 45.53% at the level of extensive damage and by 26.32% at the level of complete damage at a tsunami inundation depth of 4.5m. [ABSTRACT FROM AUTHOR]

The increasing exposure of Mediterranean coastal regions to tsunami risk, also due to climate changes, leads to the need of tools to support disaster risk management and loss assessment. This study presents a tsunami structural vulnerability model for Italian residential buildings based on numerical analysis and Monte Carlo simulation. Starting from national building census repositories, typical building typological classes and main attributes are defined. Monte Carlo simulation is performed to simulate building stocks statistically representative of existing Italian residential buildings, and analytical models are adopted for the structural damage assessment of such buildings under tsunami inundation. The structural damage is classified according to a unified damage scale adapted for different structural typologies, and a damage index is computed to describe the structural vulnerability to tsunami hazard. Based on the analytical vulnerability curves, tsunami vulnerability classes for Italian residential buildings are finally proposed to be used for an informed definition and prioritisation of risk mitigation strategies. Results from this study can be also applicable to other Mediterranean regions with a similar construction practice. [ABSTRACT FROM AUTHOR]

Following the Great East Japan Earthquake, vertical evacuation shelters (VES) were constructed to reduce tsunami risk. Childcare centers (CCs) in the inundation area are required to evacuate to the nearest VES in the event of a tsunami. The study aim was to identify CCs and VES predicted to be inundated by a Nankai Trough earthquake-generated tsunami, and to clarify CC inundation risk. We identified 52 (45.6%) CCs in the tsunami inundation area and found that 14 (25.9%) would evacuate toward the tsunami. If the walking speed was 2.24 km/h and a 0.3 m tsunami arrived in 10 min, nine (17.3%) CCs would be late to safe evacuation. If the tsunami arrival time was 20 min, four (7.7%) CCs would have late evacuation. At a walking speed of 1.00 km/h, 38 (73.1%) and 20 (38.5%) CCs would have late evacuation, with tsunami arrival times of 10 min and 20 min, respectively. Evacuation direction is important in avoiding tsunami damage. An evacuation strategy is needed that evacuates people away from the tsunami, and takes into account children's age, walking speed, and evacuation method. The evaluation of tsunami risk in this study may support the development of tsunami countermeasures in other coastal areas with latent tsunami risks. [ABSTRACT FROM AUTHOR]

• The failure mechanism of tanks in earthquake-tsunami coupling scenarios is investigated; • The influence of seismic damage on the resistance of tank to tsunami impact is discussed; • The damage amplification phenomena between earthquake and tsunami of tanks is quantified. In coastal areas, earthquakes are very likely to cause deformation of the seafloor crust, which in turn triggers large-scale water displacement and forms tsunamis. Structural damage caused by an earthquake may diminish the resistance of steel cylindrical tanks to tsunami impact, resulting in more pronounced failure behavior. In this study, a sequential loading experimental program and corresponding Coupled Eulerian Lagrangian-based numerical model are developed to investigate the failure mechanism of steel cylindrical tanks subjected to earthquake-tsunami sequence. To be specific, failure characteristics of tank models under isolated tsunami loading are examined through experiments with different solitary wave heights and water velocities. The damage amplification effect of seismic pre-damage on subsequent tsunami impact is compared by subjecting earthquake-damaged tanks to tsunami loading. Results indicate that seismic-damaged tanks exhibit more significant failure behavior due to factors such as geometric deformation, residual stress, and wave breaking. Specifically, the protruding edges caused by seismic pre-damage induce concentrated stress, leading to higher maximum stresses and more pronounced displacement changes in the tank walls. Compared with considering the individual tsunami hazard only, peak displacement failure amplification exhibits fluctuations ranging from 17.1% to 94.5%, while peak stress amplification factors varied between 4.5% and 158.3%. This work lays the groundwork for overcoming the limitations of traditional single-hazard fragility analyses. [ABSTRACT FROM AUTHOR]

Tsunamis can cause extensive damages and loss of lives in coastal communities. Early warning for tsunami can help save lives and mitigate damages from tsunamis. This study aimed to develop an early warning for tsunamis using an artificial neural network (ANN) that can predict maximum tsunami heights and arrival time. Imwon Port, located on the eastern coast of Korea was selected as the target area. A weighted logic tree approach that assigns weights to fault parameters of earthquake based on their importance was proposed to establish tsunami scenarios and generate tsunami big data. Nine offshore observations in the East Sea were used as standard observations for predicting maximum tsunami height and arrival time at Imwon Port. ANN was developed to predict maximum tsunami heights and arrival time. The Kriging method was adopted to investigate the spatial distribution of the maximum tsunami height in the port, and the root mean square error, and coefficient of determination were used to evaluate the model's performance. The estimates of maximum tsunami heights and arrival times generated by the proposed model agreed with the results of the numerical model. Furthermore, the ANN can generate these estimation quickly, enhancing the effectiveness of early tsunami warnings. • This study aims to develop an early warning system for maximum tsunami heights and arrival times using an artificial neural network (ANN). • A weighted logic tree approach is proposed to establish tsunami scenarios and generate tsunami big data. • Offshore observations are used for predicting maximum tsunami heights and arrival time at target area. • The estimates by ANN shows excellent agreement with the numerical model results. • ANN could produce the results in short-time making it effective for early warning of tsunami. [ABSTRACT FROM AUTHOR]

Indium is a rare metal that is an essential raw material for indium tin oxide (ITO) essential for transparent electrodes for displays. However, its supply is unstable as it is a by-product of zinc. In this research, we investigated the domestic substance flow of indium used for liquid crystal applications in Japan. Accordingly, we quantitatively evaluated the amount of indium contained in the process loss and the content of indium in end-of-life products. Through this quantification, we examined the visualization of loss in the entire flow and the usability of end-of-life products as secondary production. Consequently, it was found that the amount of indium used in the production of end-use-products in Japan has increased significantly due to the growth of liquid crystal display TVs, particularly in preparation for the transition to terrestrial digital broadcasting in 2011, and has drastically decreased after 2012. Meanwhile, some manufacturing bases have been relocated from Japan to other countries, and a certain proportion of end-use-products are imported, by which we infer the domestic input amount of end-use-products in recent years is estimated to have remained at approximately 4 t. Based on the result, after having continued to increase to the maximum value of approximately 70 t in 2014, the in-use stock has exhibited a gradually decreasing trend. Moreover, the indium content in end-of-life products has continued to increase, and in 2015, it exceeded the amount of the end-use-products input into society. Furthermore, compared with the process loss at the time of processing from ITO to a display, the gap has been narrowed from 100 times or more, and the indium content in end-of-life products in 2008 to about 15 times in 2017. These results suggest that the recycling potential of end-of-life products has increased with the spread of indium-based products. [ABSTRACT FROM AUTHOR]

In this research, we investigate how submarine landslides are able to produce extremely damaging tsunami waves and estimate the maximum height of the waves in question using a mathematical model. The model is based on the non-linear shallow water equations, which are solved numerically using the finite volume method on a staggered grid. We also derive a new analytical solution in order to obtain a description of surface waves generated by a submarine landslide. To validate the numerical model, several benchmark tests are conducted by comparing the results from the numerical scheme to those obtained from the analytical solution, experimental data, or other numerical results. After validation, the scheme is implemented on the real topography of Palu Bay to simulate the generation of tsunami waves by submarine landslides. The simulations provide excellent results. Accurate estimates of the maximum tsunami wave amplitude are produced by the numerical scheme, confirmed by data from records of the 2018 Palu tsunami. [ABSTRACT FROM AUTHOR]

Japan has the sixth-largest Exclusive Economic Zone in the world, covering approximately 4.47 million square kilometers. Methane hydrate is known to exist under the seafloor, with approximately 100 times the amount of Japan's annual natural gas consumption. To minimize the cost from extraction to the processing of such seabed resources, the installation of facilities that can generate electricity directly above the sea area where the resources are located is considered the most efficient strategy for the extraction and conversion to energy. Furthermore, methane gas can be converted to hydrogen gas through a steam reforming process, thereby minimizing greenhouse gas emissions. By arranging various factories around the facility as floating structures, it will be possible to reduce the costs from product processing to the manufacturing of finished products. Further, floating factories can minimize tsunami damage when compared with factories on reclaimed land in the coastal areas. To effectively utilize energy resources and reduce greenhouse gas emissions, we propose a floating structure that can consolidate the respective movements of people, products, and logistics from the seafloor to the sea and its surroundings. [ABSTRACT FROM AUTHOR]

The explosive eruption/collapse of the submarine portion of the volcano Hunga-Tonga- Hunga-Ha'apai (HT-HH) on the Tonga Kermadec volcanic arc in the southwest Pacific on 15 January 2022 occurred at the end of many weeks of activity. It was a truly global event, as was the 1883 explosive eruption/collapse of the volcano of Krakatau in Indonesia and the 1490 BC explosion, caldera and flanc collapses of the Santorin volcano in the Aegean Sea, both generating destructive tsunamis. The eruption of HT-HH was a combination of a major submarine Surtsean (phreatomagmatic) and of a subsequent ultra-Plinian atmospheric explosion which generated a very damaging local tsunami by the crustal displacements of the volcano's caldera and flanc collapses, but also an atmospheric paroxysmal explosion similar to that of the Krakatau event. In recent years, the development of new instrumentation and of an expanded array of terrestrial and space instruments - including atmospheric pressure sensors, seismometers and a fleet of satellites monitoring the Earth across the entire spectrum of light -- provided better global monitoring of the effects of this particular and unusual 2022 Hunga-Tonga volcanic event. Specifically detected were concentric atmospheric gravity waves, which also resulted in unusually-traveling ionospheric disturbances (CTIDs) -- mapped on both of the earth's northern and southern hemispheres along conductive magnetic field lines, and which circled the earth three or four times many hours after the eruption/explosion. In addition to local destructive tsunami generation in the immediate area and elsewhere in the Paciific, the violent eruption created an impulsive Lamb wave propagation on the surface air pressure which, moving near the speed of sound at ~340 m., traveled faster than sea surface tsunami wave(s) and was observed globally - reaching Japan, Australia, Central and South America and elsewhere. Tsunami-like waves were observed or recorded, particularly along coastal areas of Central and South America. The present study provides an overview, an analysis and a brief comparison with past volcanic events and of their different tsunami generation mechanisms, as well as a brief description of the recorded atmospherically-generated waves and disturbances following the eruption/collapse of the HT-HH volcano. [ABSTRACT FROM AUTHOR]

Strike-slip fault ruptures have a limited capacity to generate vertical deformation, and for this reason they are usually dismissed as potential destructive tsunami sources. At the western tip of the western Mediterranean, in the Alboran Sea, tectonics is characterized by the presence of large transcurrent fault systems and minor reverse and normal faults in a zone of diffuse deformation. The strike-slip Carboneras fault is one of the largest sources in the Alboran Sea, and therefore, with the greatest seismogenic capacity. It is also one of the active structures with higher slip rates in the Eastern Betic Fault Zone and has been proposed as source of the damaging 1522 (M6.5; Int. VIII-IX) Almeria earthquake. The dimensions and location of the Carboneras fault imply a high seismic and tsunami threat. In this paper we present tsunami simulations from seismic sources generated with physics-based earthquake simulators. We have generated a 1 Myr synthetic seismic catalogue consistent on 773,893 events with magnitudes ranging between M[sub W] 3.3 and 7.6. From these events we have selected those sources producing a potential energy capable of generating a noticeable tsunami, being earthquakes with magnitudes ranging from 6.71 to 7.62. The Carboneras Fault has the capacity to generate locally damaging tsunamis, however, on a regional scale its tsunami threat is limited. The frequency -- magnitude distribution of the generated seismic catalogue reflects the variability of magnitudes associated to the rupture of the entire fault, departing the upper limit from the classical Gutenberg-Richter potential relation showing a bell-shaped distribution. The inter-event time for the maximum earthquake magnitudes is usually j between 2000 and 6000 years. The use of physics-based earthquake simulations for tsunamigenic sources allows a robust characterization of the scenarios, allowing a qualitative leap in their parametrization. [ABSTRACT FROM AUTHOR]