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New Makran simulations imply two generalized zones of mid-field tsunami hazard in greater Karachi. The simulations presuppose seven megathrust ruptures that strike east-west, range in area from 100 × 150 km to 355 × 800 km, and lie west of the city by no less than 100 km. The assumed seismic slip is uniform across each rupture area. The smallest rupture approximates the 1945 Makran earthquake of magnitude 8.1, while the largest corresponds to a previously conjectured giant Makran earthquake of magnitude 9.2. None of the sources include a complication in 1945: late-arriving waves from submarine slides or splay faulting. Consequently, the first simulated wave is the largest in each of the seven scenarios. And because the sources are to the west, the simulated waves are higher, and arrive sooner, at Karachi Port (1.5 hr) than 30 km farther east at Port Qasim (nearly 3 hr). These combinations of height and arrival time can be generalized as properties of two hazard zones: a western one that includes Karachi Port, and an eastern one that includes Port Qasim. The simulated flooding extends farthest inland into low-lying residential areas of the western zone. Neither hazard zone is near-field or far-field. That is, neither is near enough to the fault ruptures for felt seismic shaking to dependably warn of a fast-arriving tsunami, yet neither is distant enough to receive more than three hours of advance notice through tsunami warning systems. Our simulations are intended to support emergency management in this mid-field setting. [ABSTRACT FROM AUTHOR]

The tsunami disaster in Palu, Indonesia, on September 28, 2018, caused many casualties and damage along Palu Bay, Indonesia. Prior to the tsunami, an earthquake was recorded 25 km northeast of Donggala. The analysis suggests that the tsunami was triggered by a landslide beneath the waters of Palu Bay. The investigation then focused on the earthquake’s impact on the tsunami. This study conducts simulations to discern the dominant causes of tsunamis, comparing the effects of landslides with earthquakes. Three distinct tsunami sources were identified: earthquake-only (T-E), earthquake and submarine landslide (T-EL), and submarine landslide-only (TL). Interpretation of tsunami source parameters for underwater landslides is carried out accurately. A nesting grid numerical method was employed to increase resolution and accuracy in the simulations. This study accurately interprets tsunami source parameters using data from the Bathymetry National Data-Geospatial Information Agency (185 m resolution) and the field survey data from Baruna Jaya IV-BPPT Research Vessel Indonesia (25 m resolution), thereby contributing to the creation of a tsunami inundation model map. This map serves to inform preparedness efforts and guide recommendations for infrastructure development in the Palu Bay area. The tsunami inundation model map is verified with field data and estimated using tide gauge monitoring data. The characteristics of the tsunami waves on September 28, 2018, reflect a T-EL-type tsunami source, while the T-L type source produces tsunami waves with longer periods compared to earthquake-generated tsunamis (T-EL). The T-E type, located on land, had minimal influence in causing the tsunami, despite the destructive potential of the shallow-depth M7.5 earthquake. [ABSTRACT FROM AUTHOR]

The Guangdong-Hong Kong-Macao Greater Bay Area (GBA) is threatened by potential tsunami hazards from the Littoral Fault Zone (LFZ) and the Manila subduction zone (MSZ), and may suffer huge damage because of its dense population, concentrated infrastructure, and low-lying coasts. Previous tsunami studies for the GBA made simple assumptions on the mechanisms of LFZ earthquakes, and used coarse bathymetry data in tsunami simulation, which limited the prediction of detailed tsunami hazard characteristics. In this paper, we develop a parallel dispersive tsunami model PCOMCOT to efficiently simulate dispersive, nonlinear, and breaking tsunami waves. We also construct large-scale and high-resolution bathymetry models for the GBA by correcting and integrating various data sources. Dynamic rupture simulation is performed for the LFZ to obtain a more reliable earthquake source model. We propose several representative earthquake scenarios for the LFZ and MSZ, and use PCOMCOT to calculate the resulting tsunami waves, currents, and inundation in the GBA. Our results indicate that if an Mw7.5 oblique-slip earthquake occurs in the LFZ off the Pearl River Estuary (PRE), the subsequent tsunami will primarily impact Hong Kong, causing maximum positive and negative waves of around 1 m and −2 m, respectively, along with slightly destructive currents (⩾1.5 m/s). An Mw9.0 MSZ megathrust earthquake can lead to widespread inundation with >1 m depth on the outlying islands of Macao and in the urban areas of Hong Kong around the Victoria Harbour. Besides, it will also cause catastrophic tsunami currents along the narrow waterways in Hong Kong and Macao, and the spatial distribution of strong currents (⩾3 m/s) shows a considerable discrepancy from the areas of serious inundation. Thus, more attention should be paid to the potential impacts of tsunami currents on the GBA. [ABSTRACT FROM AUTHOR]

Chinese humanitarian actors have worked frequently with the Chinese diaspora in disaster‐affected areas, but little, if any, research has been conducted into the important role of the diaspora in disaster response and humanitarian assistance. This paper investigates what local knowledge the Chinese diaspora has offered to humanitarian actors from the People's Republic of China (PRC), and how this has contributed to their effectiveness. Based on a case study of the semi‐autonomous Indonesian province of Aceh in the aftermath of the Indian Ocean tsunami of 2004, this paper argues that the diaspora can serve as a linchpin in local and international humanitarian action. It can do so by strengthening networks and bringing together local ethnic communities, local governments, and the PRC's humanitarian actors, while also offering local knowledge in the form of contextual memory. Such local knowledge may have to be fully utilised to address any underlying ethnic tensions in disaster‐affected areas. [ABSTRACT FROM AUTHOR]

In the maritime environment, multipath interference exhibits a significantly pronounced influence, resulting in GNSS system performance degradation. Enhancing system performance involves the identification and elimination of NLOS signals. This study focuses on the analysis of multipath data induced by sea waves, collected off the coast of Kakinada Sea (16.98° N, 82.29° E), to categorize signals as Line-of-Sight (LOS), Non-Line-of-Sight (NLOS) and Multipath (MP). A machine learning (ML) approach is employed to identify the presence of LOS, NLOS and MP signals in a coastal environment, both before and after the advancement of tidal waves. In the proposed approach, ML algorithms are trained using 3 key parameters namely elevation angle, signal strength and pseudorange residuals. This study involves the implementation of 14 prominent supervised classification algorithms and their accuracies and computational times are compared. The results due to GPS (L1) and IRNSS (L5 and S1) are considered. Decision Tree and its ensemble function AdaBoost, exhibited exceptional performance of accuracy (99.99 %) and computational time (0.45 s). [ABSTRACT FROM AUTHOR]

Estimating coastal tsunami impact for early-warning or long-term hazard analysis requires the calculation of inundation metrics such as flow-depth or momentum flux. Both applications require the simulation of large numbers of scenarios to capture both the aleatory variability and the epistemic tsunami uncertainty. A computationally demanding step in simulating inundation is solving the non-linear shallow water (NLSW) equations on meshes with sufficiently high resolution to represent the local elevation accurately enough to capture the physics governing the flow. This computational expense is particularly challenging in the context of Tsunami Early Warning where strict time constraints apply. A machine learning (ML) model that predicts inundation maps from offshore simulation results with acceptable accuracy, trained on an acceptably small training set of full simulations, could replace the computationally expensive NLSW part of the simulations for vast numbers of scenarios and predict inundation rapidly and with reduced computational demands. We consider the application of an encoder–decoder based neural network to predict high-resolution inundation maps based only on more cheaply calculated simulated time-series at a limited number of offshore locations. The network needs to be trained using input offshore time-series and the corresponding inundation maps from previously calculated full simulations. We develop and evaluate the ML model on a comprehensive set of inundation simulations for the coast of eastern Sicily for tens of thousands of subduction earthquake sources in the Mediterranean Sea. We find good performance for this case study even using relatively small training sets (order of hundreds) provided that appropriate choices are made in the specification of model parameters, the specification of the loss function and the selection of training events. The uncertainty in the prediction for any given location decreases with the number of training events that inundate that location, with a good range of flow depths needed for accurate predictions. This means that care is needed to ensure that rarer high-inundation scenarios are well-represented in the training sets. The importance of applying regularization techniques increases as the size of the training sets decreases. The computational gain of the proposed methodology depends on the number of complete simulations needed to train the neural network, ranging between 164 and 4196 scenarios in this study. The cost of training the network is small in comparison with the cost of the numerical simulations and, for an ensemble of around 28 000 scenarios, this represents a 6- to 170-fold reduction in computing costs. [ABSTRACT FROM AUTHOR]

Impulse waves result from submarine or subaerial landslides colliding with water. To model this multiphase disaster, it is imperative to gain a comprehensive understanding of the complex processes and interactions involved. Achieving accurate simulations over a wide area is computationally demanding and presents a significant challenge. In this paper, we analyze the 1946 Aleutian tsunami to assess the effectiveness of various models: SNAKE (rigid landslide model), Ls-Rapid (progressive landslide model advocated by the International Consortium on Landslides), and the Cornell Multi-grid Coupled Tsunami model. We integrate these models using Fortran, presenting two approaches: RL-SWE (rigid landslide-shallow water equations) and PL-SWE (progressive landslide-shallow water equations). The RL-SWE model assumes a rigid semi-ellipsoid sliding mass, while the PL-SWE model considers progressive failure. We conducted computational simulations and validated the results using observed data. Significantly, the PL-SWE model outperformed LS-Tsunami (linked to Ls-Rapid) in simulating submarine landslide-generated waves. This demonstrates the practicality of using the PL-SWE model for large-scale landslide-generated impulse wave simulations. [ABSTRACT FROM AUTHOR]

On July 9th, 551 AD, a strong earthquake followed by a noticeable tsunami and another destructive shock hit the littoral zone of Phoenicia, currently Lebanon. The sequence of events was associated with active faults in the region, but the source able to explain both seismic and tsunami effects is still a matter of open debate. This article contributes to unlocking this enigma by providing a modern analysis of the historical accounts of macroseismic effects, earthquake environmental and tsunami effects, and archaeoseismic findings. Here, we conduct seismotectonic research, evaluate the intensities of all the associated effects, and perform coseismic deformation and numerical tsunami modeling to infer the most likely source. Our results suggest that either the thrust system noted as Mount Lebanon Thrust underlying Lebanon and crops out at the seabed offshore of the coast or the intermittent transpressive Tripoli-Batroun-Jounieh-Damour fault zone along the Lebanese coast are the best candidate sources for the 551 AD earthquakes and tsunami. Both of these sources allow us to better explain the macroseismic, morphological and tsunamigenic effects. Remarkably, the notable uplift of the coastal, marine-cut terraces along the Lebanese littoral zone is well reproduced by the coseismic uplift associated with these sources, thus also clarifying the considerable drawback of the sea and limited inundation reported by the historical accounts. [ABSTRACT FROM AUTHOR]

The rapid growth of cities worldwide is a phenomenon that has generated numerous debates about the effects it could have on the environment and society. An issue that has not been well addressed in the literature is the relationship between expected urban growth and risks to natural hazards. The relationship is an important aspect for planning because urban expansion is uncertain. In this sense, land change simulation models can be useful tools to address this uncertainty, because simulation models can produce growth scenarios, which allow anticipation of exposure to natural threats. This article compares two land change simulation models: the CA_Markov model in the Selva version of IDRISI and the DINAMICA EGO model. We apply both models to extrapolate areas of future urban gain in the coastal cities of Antofagasta and Mejillones, where there is high exposure to tsunamis, mudslides, and steep slopes. The models can extrapolate differently in terms of both quantity and spatial allocation of urban gain depending on the parameter settings. CA_Markov projected urban growth adjacent to existing urban patches, while best fits to Markov equation, and the urban form was achieved with DINAMICA EGO, according to our parameter settings. We conclude that if modelers understand the models' behaviors, then applying these spatially explicit models to natural risks opens great prospects for urban planning and risk management, especially in countries highly exposed to dangerous natural events, such as in the case of Chile. [ABSTRACT FROM AUTHOR]

This paper reports exploratory research that considers two challenges recognised in the disaster risk reduction (DRR) community in recent years: one is the reinforcement of community-based DRR and the other is experts' prioritising high-impact/low-frequency hazards. Inquiries into stakeholders'—community members' in particular—understandings of disaster risks have been scarce. The research aimed to address these gaps by investigating communities' perceptions around community-based DRR and disaster risks. The research focused on natural water hazards, such as floods and typhoons generated due to atmospheric forcing factors, as well as tsunamis in four communities in Japan and England. A field survey of major structural mitigation solutions, non-structural measures, and community interviews revealed that community members did not necessarily find the often-used impact/frequency description of hazards helpful in developing and implementing community-based DRR activities. Such hazard-based scientific language does not necessarily correspond with the general public. The paper attempted 'the number of affected people', which was recognised by the research participants, to be applied as a tool for understanding disaster risks. [ABSTRACT FROM AUTHOR]

We discovered several imbricate beachrock deposits (IBD), one of which was observed to have formed during the tsunami caused by the 1994 7.8 Mw earthquake in East Java, Indonesia. Similar IBD were also found along the southern coastlines of central Java, Bali, Lombok, Sumba, Kisar, Leti and Nailaka Islands. Most IBD are composed of thin, rectangular (2.5 × 1.7 × 0.4 m) slabs of in situ calcareous beachrock dislodged from the intertidal platform during powerful wave impacts. The largest imbricated beachrock slabs are around 3 m3. Ages of coral boulders incorporated into the IBD generally match with historical records of known tsunamigenic earthquakes and candidate paleotsunami sand deposit ages. To test for the influence of storms on the IBD, we measured the positions of boulders over a 3-year period at one site by overlaying digital surface models created from small uncrewed aerial system surveys. During the 3 years there were multiple uncommonly high wave events including two tropical cyclones, which are rare in Indonesia. Of the approximately 1220 slabs in the IBD around 113 moved slightly or flipped within the deposit, but no beachrock slabs were added or removed. The combination of data from various sources (eyewitnesses, consistent boulder characteristics, lack of storms or their effects on boulders, and age analyses) favors the hypothesis that the IBD are emplaced by recurring large wave events. The most probable causes of these events are tsunamis generated by the Java Trench and other submarine faults and landslides. If this is the case, then the IBD may provide durable records of previous mega-thrust earthquakes and tsunamis that should be incorporated into tsunami risk assessments for the highly populated coastlines of the eastern Sunda and Banda Arcs. We include two tsunami models that estimate > 6 million people inhabit likely inundation zones of a worst-case scenario tsunami generated by a Java Trench mega-thrust earthquake. [ABSTRACT FROM AUTHOR]

The shallowest regions of subduction megathrusts mainly deform aseismically, but they can sporadically host slow-slip events (SSEs) and tsunami earthquakes, thus representing a severe hazard. However, the mechanisms behind these remain enigmatic because the frictional properties of shallow subduction zones, usually rich in clay, do not allow earthquake slip according to standard friction theory. We present experimental data showing that clay-rich faults with bulk rate-strengthening behavior and null healing rate, typically associated with aseismic creep, can contemporaneously creep and nucleate SSE. Our experiments document slow ruptures occurring within thin shear zones, driven by structural and stress heterogeneities of the experimental faults. We propose that bulk rate-strengthening frictional behavior promotes long-term aseismic creep, whereas localized frictional shear allows slow rupture nucleation and quasi-dynamic propagation typical of rate-weakening behavior. Our results provide additional understanding of fault friction and illustrate the complex behavior of clay-rich faults, providing an alternative paradigm for interpretation of the spectrum of fault slip including SSEs and tsunami earthquakes. [ABSTRACT FROM AUTHOR]

On 8 October 2023 UTC, significant tsunamis were observed around Japan without any major tsunamigenic earthquake, associated with a series of 14 successive minor earthquakes (mb = 4.5–5.4) near Sofugan in the Izu‐Bonin Islands. To examine the cause of this tsunami, we estimated the horizontal locations of the tsunami source and temporal history of the seafloor displacement, using the tsunami data recorded by the ocean‐bottom pressure gauges >∼600 km away. Our results showed the main tsunami source was an uplift located at a caldera‐like bathymetric feature near Sofugan, suggesting the involvement of caldera activity in the tsunami generation. The total seafloor uplift was estimated as ∼4 m, and the uplift amount of each event gradually increased over time, reflecting an accelerating occurrence of volcanic unrest of the submarine caldera within only a few hours. Plain Language Summary: On 8 October 2023, a tsunami was widely observed along the Japanese coast without any major tsunamigenic earthquake, while a series of 14 small earthquakes occurred near Sofugan, located in the Izu‐Bonin Islands. Two possible candidates for this tsunami have been proposed, involving submarine volcanic processes or submarine landslides, but the exact cause remains unclarified. Using the tsunami data observed by the seafloor pressure gauges located more than 600 km from the tsunami source region, we analyzed sea height movements to obtain insights into the origin of this enigmatic tsunami. Our analysis showed that the tsunami source consisted of the seafloor uplift that repetitively occurred at a submarine volcanic caldera. Our results also showed an accelerating tsunami excitation, such that the amount of the seafloor uplift movement increased over time and the time intervals of the earthquakes gradually shortened. These results are consistent with the acceleration process of volcanic activity, suggesting the tsunami originated from the multiple sudden uplifts of the submarine caldera. Key Points: We revealed the source kinematics of enigmatic tsunamis excited near Torishima on 8 October 2023 with remote (>∼600 km) tsunami dataIts tsunami source was identified as repetitive seafloor uplift at the same location with gradually increasing amounts for later eventsThis unique feature of the accelerating caldera uplift within a few hours was brought about by the volcanic unrest of a submarine caldera [ABSTRACT FROM AUTHOR]

An often-overlooked question of the biodiversity crisis is how natural hazards contribute to species extinction risk. To address this issue, we explored how four natural hazards, earthquakes, hurricanes, tsunamis, and volcanoes, overlapped with the distribution ranges of amphibians, birds, mammals, and reptiles that have either narrow distributions or populations with few mature individuals. To assess which species are at risk from these natural hazards, we combined the frequency and magnitude of each natural hazard to estimate their impact. We considered species at risk if they overlapped with regions where any of the four natural hazards historically occurred (n = 3,722). Those species with at least a quarter of their range subjected to a high relative impact were considered at high risk (n = 2,001) of extinction due to natural hazards. In total, 834 reptiles, 617 amphibians, 302 birds, and 248 mammals were at high risk and they were mainly distributed on islands and in the tropics. Hurricanes (n = 983) and earthquakes (n = 868) affected most species, while tsunamis (n = 272), and volcanoes (n = 171) affected considerably fewer. The region with the highest number of species at high risk was the Pacific Ring of Fire, especially due to volcanoes, earthquakes, and tsunamis, while hurricane-related high-risk species were concentrated in the Caribbean Sea, Gulf of Mexico, and northwestern Pacific Ocean. Our study provides important information regarding the species at risk due to natural hazards and can help guide conservation attention and efforts to safeguard their survival. [ABSTRACT FROM AUTHOR]

Real-time detection of tsunami waves is a fundamental part of tsunami early warning and alert systems. Several algorithms have been proposed in the literature for that. Three of them and a newly developed one, based on the Fast Iterative Filtering technique, are applied here to a large number of records from the DART monitoring network in the Pacific Ocean. The techniques are compared in terms of earthquake and tsunami event-detection capabilities and statistical properties of the detection curves. The classical Mofjeld's algorithm is very efficient in detecting seismic waves and tsunamis, but it does not always characterize the tsunami waveform correctly. Other techniques, based on Empirical Orthogonal Functions and cascade of filters respectively, show better results in wave characterization but they usually have larger residual than Mofjeld's. The FIF-based detection method shows promising results in terms of detection rates of tsunami events, filtering of seismic waves and characterization of wave amplitude and period. The technique is a good candidate for monitoring networks and in data assimilation applications for realtime tsunami forecasts. [ABSTRACT FROM AUTHOR]

Dense and broad‐coverage ocean‐bottom observation networks enable us to obtain near‐fault displacement records associated with an offshore earthquake. However, simple integration of ocean‐bottom strong‐motion acceleration records leads to physically unrealistic displacement records. Here we propose a new method using a Kalman filter to estimate coseismic displacement waveforms using the collocated ocean‐bottom seismometers and pressure gauges. First, we evaluate our method using synthetic records and then apply it to an offshore Mw 6.0 event that generated a small tsunami. In both the synthetic and real cases, our method successfully estimates reasonable displacement waveforms. Additionally, we show that the computed waveforms improve the results of the finite fault modeling process. In other words, the proposed method will be useful for estimating the details of the rupture mechanism of offshore earthquakes as a complement to onshore observations. Plain Language Summary: Ocean‐bottom observations enable us to obtain near‐fault displacement records associated with an offshore earthquake. However, simple integration of ocean‐bottom acceleration records leads to physically unrealistic displacement records. Here we propose a new method to estimate offshore coseismic displacement waveforms. First, we evaluate our method using synthetic records and then apply it to an offshore earthquake that generated a small tsunami. In both cases, our method successfully estimates reasonable displacements. Additionally, we show that the computed waveforms improve the results of the earthquake source modeling process. In other words, the proposed method will be useful for estimating the details of the rupture mechanism of offshore earthquakes as a complement to onshore observations. Key Points: Propose a new method to estimate the near‐fault displacement waveform associated with an offshore earthquakeOur method adopts the Kalman filter approach to combine the collocated strong‐motion seismometer and ocean‐bottom pressure gaugeSince the obtained displacement waveforms have fault rupture information, it can improve the finite fault model [ABSTRACT FROM AUTHOR]

Recent distributed acoustic sensing (DAS) experiments in ocean areas throughout the world have accumulated records for various wavefields. However, there are few tsunami records because tsunami observation depends on the DAS experimental period and its location. From continuous DAS records, we found tsunami signals at a frequency band of 5–30 mHz, which correspond to high‐frequency components of tsunamis and their propagation velocities differ from low‐frequency tsunamis. We estimated time series of the tsunami excitations at the source using the DAS records, which are consistent with those using records of ocean‐bottom absolute pressure gauges. Our study suggests that DAS records can be used for detecting tsunami propagations in the regions where other geophysical instruments are not available, and contribute to elucidating their excitation mechanisms. Plain Language Summary: Using distributed acoustic sensing (DAS) techniques, various types of wavefields, such as earthquake and ocean waves, have been captured by submarine fiber optic cables. However, the recording of tsunamis has been limited, as their observation depends on the timing and location of the DAS experiments. On 8 October 2023, in southern Japan, changes in sea level attributable to tsunamis were detected by tide gauges. Continuous DAS records in southern Japan have enabled the capture of signals associated with these tsunamis. The observed signals exhibit frequency‐dependent propagation velocities, which correspond to infragravity waves. These are essentially deep water waves or ocean surface gravity waves, representing the high‐frequency components of tsunamis. Using the DAS records alone, we were able to estimate the time‐series of the tsunami generation at the source location. The features obtained from the time‐series were consistent with those from records of absolute pressure gauges on the seafloor deployed in southwestern Japan. Our findings demonstrate the utility of DAS records in detecting tsunami propagations and also elucidating excitation mechanisms of tsunamis. Key Points: The countinuous records of our distributed acoustic sensing measuresment capture tsunami‐related signalsThe phase velocity dispersion of the obtained signals matches that of infragravity waves (high‐frequency tsunamis)The time‐series of the tsunami generation obtained by the cable data are consistent with those from nearby absolute pressure gauges [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]

A moment magnitude (Mw) 7.5 earthquake occurred on January 1, 2024, at the northern tip of the Noto Peninsula, Central Japan, triggering a large tsunami. Seismological and geodetic observations revealed the rupture of mapped submarine active faults. While proximal segment ruptures have been well resolved by previous research, far offshore segments have posed challenges for onshore-based inversions. This emphasizes the necessity for a comprehensive study on the fault through tsunami modeling. Here, we aimed to examine tsunami propagation and inundation using four different fault models to identify the general characteristics of the tsunami source and evaluate the complexities of earthquake- and submarine landslide-induced tsunamis. We identified the simultaneous rupture of two active fault systems as the most suitable model for explaining observed tsunami height and inundation; however, some inconsistencies with observations remained. The propagation process did not follow a concentric pattern but aligned with bathymetric heterogeneity. The findings also suggested potential amplification effects responsible for the devastation of the coast of Iida Bay and indicated a possible submarine landslide in southern Toyama Bay. The findings of the present work could benefit the exploration of a more realistic tsunami source model, considering the differences between observations and simulations. Such efforts, in collaboration with paleotsunami research, can contribute to the improved assessment of hazards from submarine active faults. [ABSTRACT FROM AUTHOR]

This study explored closed-circuit television (CCTV) networks in northeastern Toyama Prefecture, Japan, as a new data source for tsunami detection following the 2024 Noto Peninsula earthquake. We analyzed CCTV footage and extracted time-series water level fluctuations at Yokoyama, Shimoiino, and Ekko. Spectral analysis of these waveforms revealed several long-period peaks (more than 100 s) in power spectral density (PSD), suggesting the presence of tsunami components. Notably, relatively large PSD peaks at approximately 5–10 min were observed at all CCTV locations in this study and at offshore wave observation points (Tanaka and Toyama). At Yokoyama, a maximum run-up of approximately 3 m was confirmed around 16:28. Although water level fluctuations at Shimoiino and Ekko were detected, identifying tsunami components proved challenging due to their small magnitude compared to other wave components. Despite these challenges, this study demonstrates the potential of CCTV networks for tsunami detection, and further research is needed to achieve real-time detection. [ABSTRACT FROM AUTHOR]

Tsunamis generated by volcanic eruptions have risen to prominence since the December 2018 tsunami generated by the flank collapse of Anak Krakatau during a moderate eruption and then the global tsunami generated by the explosive eruption of the Hunga volcano in the Tongan Archipelago in January 2022. Both events cause fatalities and highlight the lack in tsunami warning systems to detect and warn for tsunamis induced by volcanic mechanisms. Following the Hunga Tonga—Hunga Ha'apai eruption and tsunami, an ad hoc working group on Tsunamis Generated by Volcanoes was formed by the Intergovernmental Oceanographic Commission of UNESCO. Volcanic tsunamis differ from seismic tsunamis in that there are a wide range of source mechanisms that can generate the tsunamis waves and this makes understanding, modelling and monitoring volcanic tsunamis much more difficult than seismic tsunamis. This paper provides a review of both the mechanisms behind volcanic tsunamis and the variety of modelling techniques that can be used to simulate their effects for tsunami hazard assessment and forecasting. It gives an example of a volcanic tsunami risk assessment undertaken for Stromboli, outlines the requirement of volcanic monitoring to warn for tsunami hazard and provides examples of volcanic tsunami warning systems in Italy, the Hawaiian Island (USA), Tonga and Indonesia. The paper finishes by highlighting the need for implementing monitoring and warning systems for volcanic tsunamis for locations with submarine volcanoes or near-shore volcanoes which could potentially generate tsunamis. [ABSTRACT FROM AUTHOR]

Tsunamis generated by the Hunga Tonga–Hunga Ha'apai volcanic eruption on January 15, 2022 were recorded on ocean bottom pressure and tide gauges around the Pacific Ocean, earlier than the expected arrival times calculated by tsunami propagation speed. Atmospheric waves from the eruption were also recorded globally with propagation speeds of ~ 310 m/s (Lamb wave) and 200–250 m/s (Pekeris wave). Previous studies have suggested that these propagating atmospheric waves caused at least the initial part of the observed tsunami. We simulated the tsunamis generated by the propagation of the Lamb and Pekeris waves by adding concentric atmospheric pressure changes. The concentric sources are parameterized by their propagation speeds, initial atmospheric wave amplitudes that decay with the distance, and a rise time. For the Lamb wave, inversions of the observed tsunami waveforms at 14 U.S. and nine New Zealand DART stations indicate the start of the positive rise at 4:16 UTC, the peak amplitude of 383 hPa, and the propagation speed of 310 m/s, assuming a rise time of 10 min. The later phases of the observed tsunami waveforms can be better reproduced by adding another propagating concentric wave (Pekeris wave) with a negative amplitude (− 50 hPa) and propagation speeds of 200–250 m/s. The DART records around the Pacific indicate that the Pekeris wave speed is faster toward the northwest and slightly slower toward the northeast. The synthetic waveforms roughly reproduced the far-field tsunami waveforms recorded at tide gauge stations, including the later phases, suggesting that the large amplitude in the later phase may be due to the coupling of the Pekeris wave and the tsunami, as well as resonance around tide gauge stations. [ABSTRACT FROM AUTHOR]

Accurate earthquake source parameters are crucial for understanding plate tectonics, yet, it is difficult to determine these parameters precisely for offshore events, especially for outer‐rise earthquakes, as the limited availability of direct P or S wave data sets from land‐based seismic networks and the unsuitability of simplified 1D methods for the complex 3D structures of subducting systems. To overcome these challenges, we employ an efficient hybrid numerical simulation method to model these 3D structural effects on teleseismic P/SH and P‐coda waves and determine the reliable centroid locations and focal mechanisms of outer‐rise normal‐faulting earthquakes in northeastern Japan. Two M6+ events with reliable locations from ocean bottom seismic observations are utilized to calibrate the 3D velocity structure. Our findings indicate that 3D synthetic waveforms are sensitive to both event location, thanks to bathymetry and water reverberation effects, and the shallow portion of the lithospheric structure. With our preferred velocity model, which has Versus ∼16% lower than the global average, event locations are determined with uncertainties of <5 km for horizontal position and <1 km for depth. The refined event locations in a good match between one of the nodal strikes and the high‐resolution bathymetry, enabling the determination of the causative fault plane. Our results reveal that trench‐ward dipping normal faults are more active, with three parallel to the trench as expected, while five are associated with the abyssal hills. The significant velocity reduction in the uppermost lithosphere suggests abundant water migrating through active normal faults, enhancing both mineral alteration and pore density. Plain Language Summary: The subduction of oceanic plates plays a crucial role in recycling earth materials and generating the largest earthquakes and tsunamis. This process causes significant bending of the oceanic plate near the trench, where forces from frictional coupling on the plate interface and far‐field subduction loading act in opposite directions, forming a gentle bulge on the seafloor termed the outer‐rise region. This region is rich in shallow bending‐related earthquakes at shallow depths and is characterized by rough bathymetry bounded by faults. Identifying the relationship between these earthquakes and their hosting faults is critical for understanding the seismic and tsunami hazards and fault development in the outer rise. However, building up this link is impeded by large uncertainties of earthquake source parameters. Here, we employ an advanced numerical wavefield simulation approach to precisely handle the structural complexity near 8 ∼ M6 outer‐rise earthquakes, which allows use of far‐field seismic waveform data to constrain source parameters. Reliable earthquake locations and focal mechanisms, along with high‐resolution bathymetry, enable us to identify the causative faults. Dramatically low velocity structure of the subducting oceanic plate is also revealed through this process, which suggests a fluid‐rich outer rise region that efficiently recycles water into the deeper earth. Key Points: Centroid location and focal mechanism of outer‐rise earthquakes were reliably determined through 3D modeling of teleseismic body wavesAlong with high‐resolution bathymetry, reliable source parameters allow us to identify the ruptured faults hosting these normal events3D waveform modeling required a Versus ∼16% lower than the global average, suggesting a fluid‐rich oceanic lithosphere at the outer rise [ABSTRACT FROM AUTHOR]

Tsunamis propagate over long distances and can cause widespread damage even after crossing ocean basins. Prediction of tsunamis in distant areas based on observations near their sources is critical to mitigating damage. In recent years, the accuracy of numerical models of trans‐oceanic tsunami propagation has improved significantly due to the incorporation of effects such as the solid earth response to tsunami loading and wave dispersion. However, these models are computationally expensive and have not been fully utilized for real‐time prediction. Here, we derive the adjoint operator for the linear set of equations describing deep‐ocean tsunami propagation and show how a pre‐computed database of adjoint states can achieve rapid synthesis of tsunami waveforms at target sites from nonpoint arbitrary tsunami sources. The adjoint synthesis method allows for an exhaustive parameter search for tsunami source estimation. A method for simultaneous inversion of fault geometry and slip distribution using adjoint synthesis with Sequential Monte Carlo method was proposed and applied to the 2012 Haida Gwaii earthquake tsunami. The influence of model accuracy and the amount of observed data on the estimation of tsunami sources and waveforms was examined. It was found that with a highly accurate propagation model, using only a limited amount of observed data produced source and waveform estimates very similar to the final models obtained with much larger data sets. The final inferred fault model involved megathrust slip distributed between the Haida Gwaii trench and the Queen Charlotte fault. The proposed method can also quantify the uncertainty of the waveform forecasts. Plain Language Summary: Tsunamis can propagate across the ocean for more than 10,000 km and cause damage even areas far from the source. By observing with new instruments and testing theories over the past decade, far‐reaching tsunamis can now be predicted with high accuracy with the consideration of the effects on the seawater compressibility, seafloor deformation due to tsunami loading, gravitational potential change, and Boussinesq dispersion. Reproducing these effects in numerical simulation has been shown to accurately predict tsunami waveforms at distant locations. However, this type of simulation is time‐consuming and has not been used for real‐time tsunami warnings. In this study, we propose a new waveform calculation method named adjoint synthesis. This method can compute waveforms at target points from an arbitrary tsunami source in short time by synthesizing a pre‐computed database. The database can be efficiently computed by adjoint equations. We also propose a method to simultaneously invert fault geometry and slip distribution for earthquake‐generated tsunamis using adjoint synthesis. A case study of the 2012 Haida Gwaii earthquake tsunami showed that source estimation by exhaustive parameter search can provide highly accurate waveform predictions and uncertainty ranges at distant locations from waveform data observed within 1 hr of the source origin time. Key Points: An exact reciprocity approach for linear deep ocean tsunami waveforms is established by defining a tsunami adjoint operatorA method for simultaneous estimation of fault geometry and slip distribution using a sequential Monte Carlo method is proposedExhaustive parameter search enabled by adjoint synthesis improves waveform prediction accuracy for trans‐oceanic tsunami [ABSTRACT FROM AUTHOR]

This study examined the relationship between risk perception and evacuation behavior, and the sociospatial contexts that affect evacuation. It is argued that risk perception and contextual conditions have a joint effect on evacuation. Data were collected from 3,756 evacuees in sixteen cities and towns affected by the 2011 Tohoku earthquake off the Pacific coast. Using geographic information systems (GIS), data from questionnaires on risk perception and activity diary surveys on behavioral response were combined with geospatial data. The main finding was that high risk perception leads to evacuation behavior, but that the difference between immediate and delayed evacuation depends on the sociospatial context. Delayed evacuation, compared with immediate evacuation, tends to occur in the following contexts: (1) the physical context (e.g., being inland at the time of the disaster impact); (2) the household context (e.g., the need to confirm the safety of household members); and (3) the social context (e.g., the need for assistance with mobility). This study extends the literature on disaster science and cognitive-behavioral geography by considering the relationship between perception and behavior in urban spaces in emergencies. The findings are relevant to the development of disaster preparedness planning to minimize human losses. [ABSTRACT FROM AUTHOR]

The Makran Subduction Zone (MSZ) in the northwestern Indian Ocean can generate large tsunamigenic thrust earthquakes affecting the coastal regions of Pakistan, Iran, Oman, and western India. In this paper, a probabilistic tsunami hazard assessment is conducted for the MSZ using stochastic tsunami simulations of moment magnitude (Mw) of 7.7–9.1 earthquake scenarios. This study investigates uncertainties associated with earthquake occurrence rate, single-segment (eastern and western MSZ) or two-segment (full MSZ) rupture scenarios, source geometry, and slip heterogeneity. The total number of simulated source models is 15,000. This study presents two major categories of results: stochastic source models and ranges of 475, 975, and 2475-year tsunami heights. For instance, tsunami heights generated by Mw 8.5‒8.7 stochastic sources of western MSZ vary between 1 m and 10 m with a mean of ~ 4.5 m in the affected areas. The tsunami heights are sensitive to the source models' characteristics, such as location of the large slip areas, bathymetry of the nearshore area, and the location of bays. Considering different occurrence rates results in significant variability in the estimated 475, 975, and 2475-year tsunami heights. For example, 2475-year tsunami height in Chabahar is in the range of 3‒7.4 m at 10 m water depth. [ABSTRACT FROM AUTHOR]

Tsunami inundation maps are crucial for understanding the impact of tsunamis and planning mitigation measures. Our research focuses on creating a database of stochastic tsunami scenarios along the Chilean subduction zone and probabilistic inundation maps for 11 coastal cities. We divided the Chile-Perú subduction zone into four seismic segments based on historical seismicity. Stochastic rupture scenarios, ranging from 8.0 to 9.6 magnitudes, were generated using the Karhunen-Loeve expansion. The Stochastic Reduced Order Model (SROM) helped select representative tsunami scenarios for each segment and magnitude bin. We then used the NEOWAVE model to simulate these scenarios to an inundation level, creating probabilistic tsunami maps for various return periods. Our findings reveal that local geography significantly influences tsunami inundation, with some areas facing high inundation risks while others experience minimal impacts. As a result, a uniform planning and design criterion across the entire country is not advisable; site-specific studies are necessary. These probabilistic scenarios can provide tailored solutions for different Chilean coastal cities, enhancing their resilience. Additionally, this research marks the first comprehensive probabilistic tsunami hazard analysis for the Chilean coast, considering multiple seismic sources, marking a crucial step toward full tsunami risk assessment for coastal communities. [ABSTRACT FROM AUTHOR]

We studied the earthquake detection capacity of DONET (Dense Oceanfloor Network system for Earthquakes and Tsunamis) operating in the Nankai Trough, a target region monitored for future megathrust earthquakes. The focus of this paper was to evaluate the impact on this capacity from the malfunction of parts of the network. For this purpose, the completeness magnitude, above which all earthquakes are considered to be detected by a seismic network, was used. Then, a catalog that includes events observed by DONET was used. We found spatiotemporal variability of completeness magnitude, ranging from values below 1 in one of the areas where stations are densely deployed to values above 2 at the periphery and outside of the DONET area. We conducted a simulation computation for cases of malfunction of densely distributed stations. The results showed that completeness estimates in the area near the malfunctioning stations were about 1 magnitude larger. This implies that malfunction repair and/or replacement with new stations would be desirable because they pronouncedly affect earthquake monitoring. We then demonstrated an example of how to use the information of completeness magnitude as prior knowledge to compute the b value of the Gutenberg-Richter distribution. The result indicates the b value as a proxy that can help to image stress heterogeneity when there is a magnitude-6 class slow slip event on the Nankai Trough plate boundary. [ABSTRACT FROM AUTHOR]

A submarine landslide on the edge of the Norwegian shelf that occurred around 8150 ± 30 cal. years BP triggered a major ocean-wide tsunami, the deposits of which are recorded around the North Atlantic, including Scotland. Ground-penetrating radar (GPR) was used here to investigate tsunami sediments within estuaries on the coast of northeastern Scotland where the tsunami waves were funnelled inland. Around the Dornoch Firth, the tsunami deposits are up to 1.6 m thickness, which is exceptionally thick for tsunami deposits and about twice the thickness of the 2004 IOT or 2011 Tohoku-oki tsunami deposits. The exceptional thickness is attributed to a high sediment supply within the Dornoch Firth. At Ardmore, the tsunami appears to have overtopped a beach ridge with a thick sand layer deposited inland at Dounie and partly infilled a valley. Later, fluvial activity eroded the tsunami sediments locally, removing the sand layer. At Creich, on the north side of the Dornoch Firth, the sand layer varies in thickness; mapping of the sand layer with GPR shows lateral thickness changes of over 1 m attributed to a combination of infilling an underlying topography, differential compaction, and later reworking by tidal inlets. Interpretation of the GPR profiles at Wick suggests that there has been a miscorrelation of Holocene stratigraphy based on boreholes. Changes in the stratigraphy of spits at Ardmore are attributed to the balance between sediment supply and sea-level change with washovers dominating a spit formed during the early Holocene transgression, while spits formed during the subsequent mid-Holocene high-stand are dominated by progradation. [ABSTRACT FROM AUTHOR]

The Makran subduction zone has historically experienced major earthquakes and tsunamis. Here, we integrate fault morphology, InSAR measurements, and high‐resolution bathymetry to quantitively evaluate potential future tsunami sources and tsunami wave characteristics. We systematically investigate how earthquake rupture speed and direction could affect tsunami hazards for the Makran region. Our analyses reveal the following new understanding: (1) The estimated maximum slip deficit in the Makran region southeast of the Gwadar port is >4 m since the last significant 1851 rupture; (2) Earthquakes with finite rupture speed investigated in the range of 300–1,000 m/s are calculated to generate higher tsunami waves than the static rupture model; (3) For an east‐to‐west rupture direction, the tsunami waves are calculated to arrive at the Gwadar port 3–5 mins later but with higher waves than the static rupture model. Together, our results highlight the importance of the source earthquake rupture speed and directivity in controlling tsunamigenic effects. [ABSTRACT FROM AUTHOR]

The spatial distribution and size structure of two infaunal filter‐feeding bivalves, that is, Sakhalin surf clam Spisula sachalinensis (Schrenck, 1862) and dwarf sunray surf clam Mactra crossei (Dunker, 1877), and an epibenthic deposit feeder, namely the sand dollar Scaphechinus mirabilis (A. Agassiz, 1864), were investigated on an open sandy beach in northern Japan after the tsunami caused by the 2011 Tohoku earthquake. Settlement of S. sachalinensis was relatively abundant in the 2011‐ and 2012‐year classes, but then substantially decreased until the early months of 2013. The 0+‐year‐old distribution was associated mainly with a depth gradient and weakly with the median grain size of the sediment. Mactra crossei had (1) an inverse trend in long‐shore variation in abundance at 2+ years of age and (2) later‐post‐settlement processes that regulated its population dynamics, compared to those of S. sachalinensis. The 2010‐year classes for both Mactridae species survived until 2+ years of age, although their abundance showed a high level of spatial variation. Scaphechinus mirabilis showed fine‐scale spatial variation in their recruitment dynamics. The cross‐shore distribution of S. mirabilis showed a clear ontogenetic shift from shallow to deep water. The cross‐shore distribution of small S. mirabilis (<40 mm in test diameter) overlapped that of the juvenile S. sachalinensis, but their interaction was unclear. Overall, the level of spatial and temporal recruitment variation was relatively high in each species. However, the tsunami has scarcely influenced the cross‐shore distribution and population structure of each species. [ABSTRACT FROM AUTHOR]

In ancient records, discrimination of specific triggering events from sediment gravity flow deposits is very difficult, due to multiple interactions between triggering events and similar sedimentary characteristics. For this study, we introduce the Hakcheon-Chogok Megaturbidite (HCM) in the Miocene Pohang-Youngduk Basin (PYB), providing an opportunity to differentiate the triggering events. This megaturbidite is over 70 m thick in the proximal part and less than 4 m thick in the distal part. The diachronous stratigraphic position and distinct coarser sediments than those of the underlying and overlying successions suggest a large-scale slope failure of the fine-grained foreset (more than 2 km3). The occurrence of exotic granitic boulders, originating from the basement rock, more than 1 km west of the present fan-apex, is indicative of extreme sea-level run-up. The dispersal pattern and paleocurrent direction suggest that the HCM flowed to the northeast, irrespective of the local depositional slope which show a radial distribution from the fan-apex. The distribution pattern almost perpendicular to the strike of the NW-SE trending transfer fault suggests that the HCM was triggered by a reflection flow of giant tsunami wave, resulting in a large-scale failure of high-gradient (> 15° in slope angle) fandelta slope. [ABSTRACT FROM AUTHOR]

On 18 March 2021 an earthquake of magnitude M w = 6.0 occurred offshore the Algerian coasts and generated a tsunami with offshore amplitudes smaller than a few millimetres crossing the western Mediterranean Sea. The objective of this study is threefold: first, to determine whether seismic sources calculated in the context of tsunami early warning are relevant; secondly, to determine whether tsunami simulations are able to reproduce tide-gauge observations and thirdly, to define the sensitivity of simulations to the grid resolutions and tsunami parameters. In the Mediterranean Sea, a very small number of available coastal tide gauges recorded the tsunami. Among them, a few French tide gauge stations recorded water waves with amplitudes smaller than a few centimetres and with periods ranging from 5 to 20 min associated to harbour or bay resonances. Numerical simulations of the tsunami are performed by the operational code Taitoko for seven different source fault models. Three of them allow for a rapid source detection and characterization in the framework of tsunami warning at CENALT (Centre National d'Alerte aux Tsunamis, France). The integrated code Taitoko uses a system of multiple nested grids. Standard Boussinesq equations are solved in the Mediterranean grid, whereas non-linear shallow water equations are solved in coastal and harbour grids with 25 and 5 m resolutions, respectively. Whatever the fault model, the observed time-series of water heights are reproduced satisfactorily both in phase and amplitude by the model at Nice and Monaco but poorly at Port Mahon (Minorca) and Toulon. [ABSTRACT FROM AUTHOR]

We present a kinematic slip model and a simulation of the ensuing tsunami for the 2020 M w 7.0 Néon Karlovásion (Samos, Eastern Aegean Sea) earthquake, generated from a joint inversion of high-rate GNSS, strong ground motion and InSAR data. From the inversion, we find that the source time function has a total duration of ∼20 s with three peaks at ∼4, 7.5 and 15 s corresponding to the development of three asperities. Most of the slip occurs at the west of the hypocentre and ends at the northwest downdip edge. The peak slip is ∼3.3 m, and the inverted rake angles indicate predominantly normal faulting motion. Compared with previous studies, these slip patterns have essentially similar asperity location, rupture dimension and anticorrelation with aftershocks. Consistent with our study, most published papers show the source duration of ∼20 s with three episodes of increased moment releases. For the ensuing tsunami, the eight available gauge records indicate that the tsunami waves last ∼18–30 hr depending on location, and the response period of tsunami is ∼10–35 min. The initial waves in the observed records and synthetic simulations show good agreement, which indirectly validates the performance of the inverted slip model. However, the synthetic waveforms struggle to generate long-duration tsunami behaviour in simulations. Our tests suggest that the resolution of the bathymetry may be a potential factor affecting the simulated tsunami duration and amplitude. It should be noted that the maximum wave height in the records may occur after the decay of synthetic wave amplitudes. This implies that the inability to model long-duration tsunamis could result in underestimation in future tsunami hazard assessments. [ABSTRACT FROM AUTHOR]

In this study, the double-difference tomography (tomoDD) method is applied to jointly invert the three-dimensional (3-D) crustal velocity structure and earthquake locations in the Maduo area based on automatically and manually picked seismic phase data. The results show that: (1) We speculated that the seismogenic fault is the Kunlun Pass–Jiangcuo Fault based on the spatial distributions of the aftershocks and surface rupture and the strike slip nature of the fault and the mainshock. In addition, a continuous northwest-trending branch fault may exist on the north side of the western section of the Maduo aftershocks. (2) We speculated that the Maduo earthquake was a bilateral rupture based on the media strength of the upper crust and near the surface and the seismic distribution. The findings also provide evidence for the large-scale rupture of the Maduo earthquake. In addition, the high-velocity body to the upper right of the mainshock satisfactorily explains the unobvious rupture above the mainshock. The late weak seismicity indicates that the energy released during the earthquake rupture was sufficient, and it is concluded that the short-term seismic hazard is insignificant. (3) The low S-wave velocity and high wave ratio reflect the existence of crustal fluids in the Maduo area based on the results of previous studies. The Maduo earthquake occurred on the side of the biased high-velocity body in the high-low velocity transition zone, where the stress easily accumulates and is easily released. Therefore, we conclude that the Maduo earthquake accumulated significant stress in the source area. The crustal fluids encountered a hard slope-type high-velocity body and flowed upward into the seismogenic fault, weakening the seismogenic fault. The combined effect of both processes finally triggered the Maduo MS7.4 earthquake. [ABSTRACT FROM AUTHOR]

In the context of climate change, height and frequency variations in extreme sea levels (ESLs) are studied using deterministic and probabilistic approaches. However, this type of approach does not highlight the dynamic effects (waves, currents) generated by metocean events (storms, cyclones, long swells, and tsunamis) beyond their effects on sea levels. In particular, ESL estimates are calculated by considering the main determining physical factors but cannot include all the effects of these factors. Ultimately, this can lead to confusion between ESL and hazard. This article proposes a systemic assessment method to analyze coastal hazard changes at regional scales, integrating parameters influencing sea levels, as well as factors describing the geomorphological context (length and shape of the coast, width of the continental shelf), metocean events, and the marine environment (e.g., coral reef state and sea ice extent). French mainland and overseas territories were selected to apply the method. The present study highlights the need to consider not only the sea level variability, but also the current and future characteristics of metocean events. The long, concave coasts bordered by a wide continental shelf appear particularly sensitive to variations in the intensity or trajectory of metocean events. Coral reef degradation in the tropics and the decrease in seasonal sea ice extent in the polar regions can also significantly change the nearshore hydrodynamics and impacts on the shoreline. These results help us to predict the types of hazard (shoreline erosion, rapid submersion, and/or permanent flooding) that will increase the most in different coastal zones. [ABSTRACT FROM AUTHOR]

Retail companies are greatly interested in performing continuous monitoring of purchase traces of customers, to identify weak customers and take the necessary actions to improve customer satisfaction and ensure their revenues remain unaffected. In this paper, we formulate the customer churn prediction problem as a Predictive Process Monitoring (PPM) problem to be addressed under possible dynamic conditions of evolving retail data environments. To this aim, we propose TSUNAMI as a PPM approach to monitor the customer loyalty in the retail sector. It processes online the sale receipt stream produced by customers of a retail business company and learns a deep neural model to early detect possible purchase customer traces that will outcome in future churners. In addition, the proposed approach integrates a mechanism to detect concept drifts in customer purchase traces and adapts the deep neural model to concept drifts. Finally, to make decisions of customer purchase monitoring explainable to potential stakeholders, we analyse Shapley values of decisions, to explain which characteristics of the customer purchase traces are the most relevant for disentangling churners from non-churners and how these characteristics have possibly changed over time. Experiments with two benchmark retail data sets explore the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]

Coastal erosion caused by continuous sea wave action is destructive. One potential solution to reduce the impact of waves and coastal erosion is the utilization of mangrove forests as natural barriers. The Banyuglugur Coastal Area has a thriving mangrove forest that grows along 5.1 km of coastline. The objective of this research is to determine the percentage reduction of the mangrove forest as an energy buffer and the wave height along the Banyuglugur Coast. The method employed to achieve this goal involves numerical simulation using Delft3D, considering the influence of mangrove forest length, tides, wind, and wavelength. The Delft3D-Coupling model is used, combining two modules, FLOW for tidal simulation and WAVE for wind-wave simulation. Mangroves with a width of 70 m in Zone A are high-density mangrove locations that can reduce wave energy by 62.14%, while low-density mangroves in Zone D with a width of 30 m can reduce wave energy by 44.28%. The simulation results indicate that mangrove forests on Banyuglugur Beach, with an average width of 50 m, can dampen waves by an average of 52.8% and reduce the average wave height by 39% compared to incoming waves. [ABSTRACT FROM AUTHOR]

On January 15, 2023, a major earthquake with Mw 6.2 occurred in the northern part of Sumatra, Indonesia, and generated widespread ground shaking around III - V MMI without any damages. The hypocenter was located at a shallower depth than the common slab contour, which may address another blind tectonic system called backthrust. An extended waveform inversion and hypocenter relocation analysis is demonstrated to identify the responsible system. A total of 1,750 earthquakes were compiled from the 10-year catalog (2010 - 2022) and recorded by 72 stations associated with 1,2536 P-phase and 5,604 S-phase. Up to 85% (1211) of the total earthquakes were successfully relocated, while 15% (103) were not relocated because they did not meet the predetermined criteria. Furthermore, the mainshock was resolved with a thrusting fault with NW - SE orientation, steeply dipping to the SW direction, and a moment magnitude estimation of Mw 6.2 ± 0.03 at a depth of 35.50 ± 2 Km. The focal parameters include two nodal planes, i.e., the 1st nodal plane with strike 319°, dip 15.5°, and rake 101° while the 2nd nodal plane with strike 127°, dip 74.8° and rake 86.8°. The results successfully show the existence of the blind back thrust in the Sumatra subduction zone, which will provide new insight and contribute to the recent tectonic system in the northern part of Sumatra and its surroundings. [ABSTRACT FROM AUTHOR]

This article explains the theme "Kh. Abdul Karim Jamak: His Tiological Perspective on Qada' and Qadar of the Digital Era in Kerinci Regency - Jambi". It is known that indeed Qadar is the secret of Allah towards His creatures. About what God explains to man, man can know and believe it. And what he does not know, then man accepts and trusts him. Without anyone arguing against Allah regarding His perfect Work and wisdom. Accepting and believing in qada and qadar in the digital information era which is full of modern and sophisticated knowledge, Muslims should have intelligence in mastering digital technology, to answer challenges and challenges that want to damage the pure values of Islamic teachings. Through the way and approach of Kh. Abdul Karim Jamak expounding the Islamic principles of qada and qadar can help instill confidence that no matter how intelligent humans are assisted by science and technology, the qadar and qadar of Allah Almighty will still happen. Among examples are when earthquakes, floods and tsunamis occur, lightning and so on that cannot be detected by existing technological tools. To answer the question that arises for the current generation, it is necessary to refer to the thoughts of one of the scholars which in this case is the thought of Kh. Abdul Karim Jamak, adapted to the Quran and Sunnah. [ABSTRACT FROM AUTHOR]

The virtual water flow behind product trade provides researchers with ideas to alleviate water problems in China's coastal areas, with accompanying resource and economic implications. This paper adopts a multi-region input–output model to calculate virtual water flows in coastal areas and analyses resource benefits and economic benefits, by combining the water stress index and shadow price, to measure gains and losses of virtual water flow. This study shows that (1) China's coastal areas depends on external water supplies; (2) virtual water flows between coastal and inland areas generated 38.26 billion m3 of net scarce water savings and CNY 31,751 billion of net economic benefits, indicating that coastal areas benefited from virtual water flows from both resource and economic perspectives; (3) virtual water flows among coastal provinces and cities caused 11.10 billion m3 of net scarce water losses, but generated CNY 9784 billion of net economic gains, indicating that a further intensification of water stress in coastal areas, but such a virtual water flow pattern was beneficial from an economic perspective. This paper reveals the resource and economic impacts of virtual water flow at the national scale and among coastal provinces and cities and further proposes suggestions for promoting the beneficial flow of virtual water in coastal areas. [ABSTRACT FROM AUTHOR]

Between 2 and 3 April 2024, two strong earthquakes occurred in Taiwan, resulting in a significant number of deaths and millions of euros in damage. The primary event also resulted in a tsunami that overwhelmed the population and infrastructure. In this study, the natural electromagnetic spectrum is analyzed a few days before these earthquakes occurred, with the aim of investigating any electromagnetic signals as possible candidates for physical phenomena in the preparatory phases of earthquakes. The signals detected are characterized by very low frequencies, already noted during other potentially destructive earthquakes, and by RDF signals attributable to candidate pre-seismic signals. [ABSTRACT FROM AUTHOR]

Coastal wetlands are transitional ecosystems between land and sea. Participants of citizen science programs have detected frequent floods in wetlands, as well as small pools that appear and then disappear. Considering that it is not clear whether their main hydrologic drivers are of marine or continental origin, we studied the El Culebrón wetland located in the Chilean semi-arid zone. El Culebrón is strongly influenced by extreme rain events. This wetland also experiences seasonal changes in its water stage (WS). A high mean sea level agreed with 41% of the WS rises. High intensity storm surges coincided with 53% of WS peaks. A small tsunami in 2022 impacted the WS, and another very intense tsunami flooded it in 2015. An apparent diurnal cycle in the WS was discarded due to an instrumental artifact. The combination of the aforementioned factors provided an explanation for 91% of the WS rises. The probable and novel mechanism for sea level and storm surge influence on WS is the formation of a sand barrier between the coastal lagoon and the sea. As a whole, El Culebrón receives varied influences from both the sea and the mainland, but it seems to be more dependent on freshwater sources. [ABSTRACT FROM AUTHOR]

Volcanic flank collapses, especially those in island settings, have generated some of the most voluminous mass transport deposits on Earth and can trigger devastating tsunamis. Reliable tsunami hazard assessments for flank collapse‐driven tsunamis require an understanding of the complex emplacement processes involved. The seafloor sequence southeast of Montserrat (Lesser Antilles) is a key site for the study of volcanic flank collapse emplacement processes that span subaerial to submarine environments. Here, we present new 2D and 3D seismic data as well as MeBo drill core data from one of the most extensive mass transport deposits offshore Montserrat, which exemplifies multi‐phase landslide deposition from volcanic islands. The deposits reveal emplacement in multiple stages including two blocky volcanic debris avalanches, secondary seafloor failure and a late‐stage erosive density current that carved channel‐like incisions into the hummocky surface of the deposit about 15 km from the source region. The highly erosive density current potentially originated from downslope‐acceleration of fine‐grained material that was suspended in the water column earlier during the slide. Late‐stage erosive turbidity currents may be a more common process following volcanic sector collapse than has been previously recognized, exerting a potentially important control on the observed deposit morphology as well as on the runout and the overall shape of the deposit. Plain Language Summary: Disintegration of volcanic islands can cause very large landslides and destructive tsunamis. To assess the tsunami hazard of such events, it is crucial to understand the processes that are involved in their formation. We present new insights from seismic data and drill cores from a landslide deposit offshore Montserrat, a volcanic island in the Lesser Antilles Arc in the Caribbean. Our analysis reveals the emplacement of landslide material in several stages, including multiple volcanic flank collapses, incorporation of seafloor sediments and an erosive flow that carved channels into the top of the deposit right after its emplacement. We suggest that highly erosive flows are a common process during volcanic flank collapse deposition and that they play a significant role in the shaping of the deposit's appearance. Key Points: Landslide emplacement offshore Montserrat included volcanic flank collapses, sediment incorporation, and a late‐stage erosive flowHighly erosive flows are likely to be common processes during volcanic flank collapse depositionPre‐existing topography plays a major role in shaping flank collapse‐associated mass transport deposits [ABSTRACT FROM AUTHOR]

The nonlinear interactions between river discharge, astronomical tidal wave, and local geomorphology during storm passage or water release from upstream dams can produce severe floods in the Río Negro lower basin (Argentina). For this reason, this paper aims to detect and study nonlinear processes in this area. The watercourse hydrodynamics was described using hourly water level data from three limnigraphs during 2003 – 2021 and flow time series. The tide gauge dataset was employed to describe the influence of tidal cycles on the hydrological regimen. Nonlinear processes' impact on the astronomical tidal cycle and river discharge was analyzed using Harmonic Analysis, and Fourier higher-order spectra, also it was complemented with the selection of two study cases. Harmonic Analysis results showed that the tidal wave entry upstream of the Río Negro modulates its hydrological regime, presenting the water column semidiurnal variations. Also, high-order spectral analysis detected nonlinear interactions in the signal in storm conditions with an energetic redistribution among the linear tidal constituents toward shallow water harmonics. Additionally, nonlinear interactions provoked a delay in the tidal ebb phase with a consequential extension of flooding duration time. This type of study contributes to the knowledge of the flood mechanisms activated during a storm. [ABSTRACT FROM AUTHOR]

Historically, Andaman Teal Anas albogularis have been primarily found in South Andaman. However, the land uplifts and subsidence resulting from the 2004 tsunami and the earthquake have created new wetlands across the island. These wetlands became suitable habitats for the Andaman Teal, leading to population expansion within South Andaman and a range shift to North Andaman. [ABSTRACT FROM AUTHOR]

Probabilistic tsunami hazard and risk assessment (PTHA and PTRA) are vital methodologies for computing tsunami risk and prompt measures to mitigate impacts. At large regional scales, their use and scope are currently limited by the computational costs of numerically intensive simulations behind them, which may be feasible only with advanced computational resources like high-performance computing (HPC) and may still require reductions in resolution, number of scenarios modelled, or use of simpler approximation schemes. To conduct PTHA and PTRA for large proportions of the coast, we therefore need to develop concepts and algorithms for reducing the number of events simulated and for more efficiently approximating the needed simulation results. This case study for a coastal region of Tohoku, Japan, utilises a limited number of tsunami simulations from submarine earthquakes along the subduction interface to build a wave propagation and inundation database and fits these simulation results through a machine learning-based variational encoder-decoder model. This is used as a surrogate to predict the tsunami waveform at the coast and the maximum inundation depths onshore at the different test sites. The performance of the surrogate models was assessed using a 5-fold cross validation assessment across the simulation events. Further to understand its real world performance and test the generalisability of the model, we used 5 very different tsunami source models from literature for historic events to further benchmark the model and understand its current deficiencies. [ABSTRACT FROM AUTHOR]