Search Results (171)

Granular collapse-induced wave generation is a critical process in coastal engineering and natural hazards, yet its rapid and complex fluid–solid coupling mechanism poses significant challenges for numerical modeling. This paper presents a comprehensive validations and performance benchmarking study of non-spherical granular collapse-induced wave generation using a GPU-accelerated resolved SPH-DEM coupling framework. Through three benchmark cases with increasing complexity, the numerical accuracy and robustness of the model are thoroughly verified with respect to free-surface flows, multi-body collisions, and intense fluid–solid interactions. Subsequently, the influence of SPH resolution and particle shape on computational efficiency is quantitatively assessed. It is found that the total runtime is dominated by the number of SPH particles, while the GPU acceleration advantage becomes more pronounced as the number of DEM faces increases. Furthermore, in the granular collapse-induced wave case, the temporal evolution of the leading wave amplitude and the difference in granular runout distance under dry and wet conditions are analyzed, revealing from the particle scale how fluid resistance modulates the coupling between wave generation and granular motion. This study not only validates the capability of the model to capture complex particle–wave interactions, but also provides quantifiable performance benchmarks and physical insights for its engineering applications. Full article

Coastal flood exposure indicators are increasingly needed to support climate adaptation and sustainable coastal planning in small island regions, yet regional-scale assessments that translate hydrodynamic simulations into spatially explicit exposure indicators remain limited across the Caribbean. This study develops a spatially explicit coastal flood exposure framework by integrating LISFLOOD-FP simulations with settlement dynamics, land-cover change, and population distribution data. Coastal inundation was simulated under baseline (1985–2014) and SSP5-8.5 (2015–2050) 100-year extreme sea-level conditions and overlaid with land-cover, settlement, and WorldPop data to assess land-cover, settlement, and population exposure across Caribbean island systems. The results show that SSP5-8.5 generally increases coastal inundation extent relative to the baseline, although the broad regional pattern remains similar. Large islands with extensive low-lying coastal plains show greater absolute inundation, whereas several smaller islands exhibit higher proportional exposure because of limited land area and concentrated coastal settlements. Wetlands constitute the largest share of exposed terrestrial land cover, while built-up land shows increasing exposure. These findings suggest that future coastal flood exposure in the Caribbean is shaped by both increasing hazard intensity and persistent human concentration in flood-prone coastal zones. Because the modelling framework does not explicitly represent wave setup/runup, compound flooding, or coastal defences, the results are interpreted as regional-scale screening indicators rather than locally calibrated flood-risk estimates. Full article

With the growing interest in Maritime Autonomous Surface Ships (MASS), numerous risk-assessment models have been proposed for route planning and hazard avoidance during navigation. Existing models, however, generally share two limitations. First, many assess risk from information such as vessel traffic and therefore do not adequately reflect the marine weather and sea state itself. Second, they often consider only one or two factors, such as wave height or wind, and even when several factors are merged into a single value, it is difficult to trace back why the result is dangerous. To overcome these limitations, this study proposes a Meteo-Hydrological Fusion Index (MHFI) that combines five environmental factors—wave height, swell period, current, wind, and visibility—into a single risk value. Each factor is first mapped to a 0–4 risk score, and the three highest scores at a given location are then combined by a weighted sum. This summarizes composite risk in a single value while preserving the ranking of the factors that produced it, so the result remains traceable. Applying the index to the coastal waters of Mokpo, we confirmed that the dominant factor behind a given risk grade varies with time and location, and that a rapid, area-wide rise in risk over a short period can be captured by a single indicator. We further show how risk varies along the main fairway and how the index can be overlaid on a display panel. These results indicate that the MHFI could serve as a decision-support layer in an S-100-based digital navigation environment. Full article

Coastal defenses under tsunami-like long waves are judged not only by wave attenuation but by their own stability and the hazard left landward, so a porous structure is assessed through several responses at once. OpenFOAM (porousWaveFoam) and FLOW-3D HYDRO are the two models most widely used for such problems, representing the open-source and the commercial approach, and each has an extensive record for solitary waves and for porous structures separately. Which to adopt for a given response is not established, since the two have not been compared where both occur together. Five hydraulic benchmarks were, therefore, reproduced with both, taken as configured in practice, since the differing elements cannot be exchanged by the user. Agreement was decomposed into error components and into the scalars that enter a design check, and each difference was weighed against a combined uncertainty. Neither model is superior across the responses. Across 57 signals, the more accurate one changes with the metric in 81% of cases, and six of thirteen governing comparisons exceed the uncertainty. Some of the largest errors are shared, so changing the model does not remove them, and the cost ordering reverses with the problem size. Model selection should, therefore, follow the target design response, together with a statement of whether the difference exceeds the uncertainty. These findings hold within the configurations tested; extension to random waves remains for future work. Full article

The southern coast of Java, Indonesia, is situated along the active Sunda subduction margin where raised coastal landforms may record the combined influence of relative sea-level change, wave processes, sedimentation, and vertical land motion. This study presents field-based RTK-GNSS topographic profiles from four coastal sites: Pantai Ajah, Kalijali, Kulon Progo, and Wingko. Profiles were used to locate terrace treads, risers, slope breaks, residual topographic highs, and possible raised coastal surfaces. The results show spatially varying coastal morphology. Pantai Ajah has a marked riser and probable terrace tread at about 7–8.5 m elevation. Kalijali shows a lower terrace-like surface at about 4–5 m, an upper surface at about 7–9 m, and a higher local topographic high at about 12–13 m. Kulon Progo is characterized by a low-elevation coastal surface that is only weakly expressed in the topography, whereas Wingko contains a distinct slope break and a broad landward surface at approximately 5–6.5 m elevation. Across the four profiles, broad low-gradient surfaces recur within two elevation ranges, approximately 4–6.5 m and 7–9 m. These ranges are treated as provisional morphometric groupings rather than correlated or coeval terrace levels. Higher isolated elevations are described as ridge-like or residual topographic highs whose origin and age remain unresolved. No direct chronological or sedimentological constraints are currently available, so correlations with Holocene or older sea-level highstands are only tentative. The results show the usefulness of RTK-GNSS profiling for the documentation of local coastal terrace morphology and for the identification of priority sites for future dating, sedimentological analysis, and coastal-hazard assessment. Full article

Mediterranean coastal regions are increasingly affected by hydrometeorological hazards associated with high-impact weather events, including cyclones. Between 18 and 21 January 2026, the intense extratropical cyclone Harry affected Sicily, Sardinia, and Calabria, producing severe weather conditions including heavy precipitation, strong winds, and extreme wave activity. This study investigates both the meteo-marine characteristics of the event and its associated damage in Calabria, where the cyclone triggered multiple hazards (wave storms, landslides, flooding, and strong winds). Meteo-marine forcing was characterized using integrated rainfall data, wave parameters, and wind data. In situ observations, radar-derived precipitation estimates, satellite measurements, and model-based reanalysis products were combined to provide a comprehensive evaluation of the event. A georeferenced database of 195 damage records was compiled and classified according to the EU Floods Directive (2007/60/EC), allowing spatial analyses within a GIS framework. Although the cyclone produced exceptional rainfall totals, locally exceeding 580 mm in 90 h, the distribution of impacts reveals the predominance of coastal processes. Wave storm-related damage accounted for 68% of all recorded impacts, mainly affecting transportation and communication infrastructures, tourism facilities, and population. The prevalence of coastal damage appears to be linked not only to the intensity of marine forcing but also to its persistence which locally exceeded the maximum climatological persistence, suggesting that event duration plays a critical role in determining impact severity. Geomorphological analyses indicate that short-term coastal vulnerability is influenced not only by long-term shoreline evolution but also by local topographic characteristics and exposure to marine forcing. These findings contribute to improving risk assessment and mitigation strategies for Mediterranean coastal regions under a changing climate. Full article

This study experimentally investigated the wave transmission and setup characteristics of biomimetic submerged structures as Nature-based Solutions (NbSs) for coastal protection. A non-porous monolithic pillar and a highly porous, multi-branched staghorn coral replica were tested in a 2D flume featuring a 1:20 foreshore slope representative of Kuta Beach, Bali. The results revealed a highly divergent, period-dependent hydrodynamic response. Under short-period waves ($T=0.8 \mathrm{s}$), attenuation was density dependent; the porous replica gradually dissipates energy through canopy micro-turbulence, yielding transmission coefficients ($K_t$) ranging from 0.25 to 1.18. Conversely, under long-period waves ($T=1.6 \mathrm{s}$), the attenuation mechanism shifted to density-independent, depth-induced breaking. This establishes a critical hydrodynamic trade-off: higher wave attenuation (lower $K_t$) inherently generates a higher coastal wave setup due to momentum transfer. Crucially, while both structures reduced transmission, the internal porosity of the multi-branched replica facilitated sub-surface return flow, effectively capping the maximum normalized wave setup at 0.09. This represents an 18% reduction in setup-induced coastal hazards compared to the monolithic baseline. To facilitate practical engineering design, new empirical equations ($R^2\approx 0.80$) for predicting $K_t$ were derived, integrating the frontal area index (${\lambda }_f$). Ultimately, these findings demonstrate that multi-branched biomimetic structures provide an optimal NbS design, balancing effective wave energy attenuation with the mitigation of secondary setup hazards for vulnerable coastal regions. Full article

Extreme precipitation and waves both drive coastal hazards along the American Mediterranean Sea, yet whether the two have changed in coordinated ways over recent decades remains unclear. We analyzed 43 years (1981–2023) of coastal precipitation and wave climate across five sub-regions, using CHIRPS v2.0 daily rainfall at 2656 coastal land pixels and ERA5 wave reanalysis at 1159 nearshore ocean pixels. Five ETCCDI precipitation indices and five wave metrics were computed; their trends were estimated with the Mann–Kendall test and Sen’s slope, and their uncertainty was quantified by bootstrap resampling. Coastal precipitation shows a “fewer but more intense” pattern in parts of the basin: along the Mexican Gulf and Central American coasts, heavy-precipitation frequency (R10mm) declines by about 1.4 to 2.6 days/decade while the most extreme events intensify, with one-day maxima rising by about 6 mm/decade and five-day maxima by 7 to 10 mm/decade; trends in annual total precipitation are comparatively uncertain. Wave trends are generally positive, with significant wave height rising most rapidly off Central America (about 0.021 to 0.027 m/decade) and peak wave period lengthening most along the South American Caribbean coast. To test whether these changes are spatially linked, we paired neighboring land and ocean pixels and applied pairwise trend correlations, sub-regional time-series analysis, and joint clustering. Across the basin, coastal segments with stronger increases in extreme rainfall tend to coincide with segments of rising wave height. Among the examined index pairs, the largest positive correlation was observed between the trends in short-duration precipitation extremes (Rx1day and Rx5day) and the 90th-percentile wave height, although the association was modest ($\rho \approx 0.28$). Joint clustering suggests that concurrent positive trends are more frequently represented along the southwestern Gulf of Mexico and the Caribbean coast of Central America. These results indicate that the principal drivers of compound coastal flooding may not be evolving independently across this basin, and they support considering precipitation and wave climate change jointly in regional coastal hazard assessment. Full article

Coastal zones are facing rising exposure to climate-related hazards alongside intensifying human pressures, which highlights the need for robust tools to assess vulnerability. This study uses a GIS-based Coastal Vulnerability Index (CVI) to quantify and map relative vulnerability along ~13 km of shoreline in Al Hoceima Bay (northern Morocco). The proposed CVI integrates eight geological and physical indicators, including geomorphology, shoreline erosion and accretion rates, coastal slope, elevation, natural habitats, relative sea-level rise, significant wave height, and tidal range. Spatial analyses were performed using remote sensing data, historical records, field measurements, and Geographic Information Systems (GIS). The analysis reveals that 37% of the shoreline is categorized as high vulnerability, 44% is moderate, and 19% is low. Highly vulnerable sectors are primarily associated with low elevations, gentle coastal slopes, sandy beach systems, limited natural habitat protection, and proximity to river mouths. These findings demonstrate that the applied CVI provides a rapid and cost-effective framework for identifying priority areas for coastal management and climate adaptation. The proposed approach offers valuable decision-support insights for sustainable coastal planning in Al Hoceima Bay and other Mediterranean coastal environments characterized by limited data availability. Full article

In the context of global climate warming, sea surface temperature (SST) rise and sea level (SL) rise are projected to amplify typhoon-related marine dynamic disaster risks. These are idealized sensitivity experiments designed to isolate the individual effects of SST warming and SL rise, not full climate projections. This study investigates Super Typhoon Doksuri (2023) using the WRF-SWAN-ROMS coupled model, with sensitivity experiments designed for SST (+0.8 °C, +2.0 °C, +3.5 °C) and SL rise (+0.4 m, +0.6 m, +0.8 m) scenarios referenced to IPCC AR6 projections. Results indicate that SST rise enhances typhoon intensity by approximately 16% at +3.5 °C, elevates mean wave height by 25.0%, and increases extreme significant wave height by 24.0%, with the extreme wave height sensitivity approximately 2.75 times that of the mean. Storm surge exhibits a nonlinear response, with the extreme surge sensitivity approximately 13.2 times that of the mean. SL rise has relatively minor effects on open sea areas but affects coastal regions notably, expanding the inundation area by approximately 47% under the 0.8 m scenario. The Taiwan Strait channeling effect amplifies wave heights and surges on the right side of the track. Comparative analysis suggests that SST indirectly amplifies disasters by enhancing typhoon intensity, while SL rise directly constrains nearshore dynamics through static water level elevation. These findings offer process-based insights into the contrasting physical mechanisms through which SST rise and SL rise affect coastal hazards in semi-enclosed regions and may inform future ensemble-based climate impact assessments. Full article

Wave overtopping is one of the most complex coastal hazards to characterize in field conditions due to its high non-linearity and the interaction between unsteady hydrodynamics and wave–structure processes. To get insights into the underlying occurrence and persistence of overtopping, this study proposes an integration of numerical and data-driven models. Multi-month field observations made at a breakwater are used to investigate the hydro-meteorological parameters causing overtopping initiation and persistence. High-frequency video-derived overtopping detections are combined with coupled ADCIRC–UnSWAN (ADvanced CIRCulation–Unstructured Simulating WAves Nearshore) hindcasts to construct near-structure hydro-meteorological conditions. The results reveal a clear dynamical asymmetry showing that overtopping initiation corresponds to exceedance of crest elevation at individual wave-scale associated with elevated wave height, water level, wave steepness, and wind characteristics, whereas overtopping persistence depends on short-term temporal effects associated with wave energy, direction, and sustained water levels. Gradient-boosted decision trees, temporal convolutional networks, and Transformer models are employed, demonstrating that persistence cannot be inferred from instantaneous sea-states alone, indicating a separation of timescales between triggering and sustained overtopping dynamics. These findings provide field-scale evidence of distinct hydrodynamic regimes governing overtopping processes, highlighting the importance of temporal characteristics for understanding overtopping dynamics and developing predictive coastal hazard frameworks. Full article

Wave height is a critical parameter for marine hazard warning systems and the structural safety of offshore engineering. The Bohai Sea and its surrounding region is an important economic hub in northern China and serves as the maritime route for the coastal provinces of North, Northwest, and Northeast China. Therefore, the sea state in the Circum-Bohai Sea has a significant impact on the Bohai economic circle. This study analyzes and summarizes the medium-term variation trends of waves in the Circum-Bohai Sea based on multi-source satellite data (AVISO/Copernicus dataset) from 2009 to 2025. The results indicate that the Significant wave height (SWH) in the Circum-Bohai Sea is mainly dominated by wind waves, exhibiting significant seasonal variation characteristics. The significant wave height in winter exhibited a consecutive decline from 2014 to 2018, with a reduction of approximately 14%. Spectral analysis reveals the existence of one-year, half-year, and two-year cyclical variation signals in the SWH of the Circum-Bohai Sea. This study provides a scientific foundation for marine hazard early warning systems, offshore engineering safety assessments, and climate change adaptation strategies in the Bohai Economic Rim. Full article

The initial seconds after an earthquake are critical for rapid magnitude estimation to support real-time early warning. This study evaluates the determination of P-wave moment magnitude (M_wp) using strong-motion records from the 23 April 2025 Marmara Sea earthquake. High-quality accelerometric data from the Turkish National Strong Motion Network were analysed to extract early P-wave features within the first 3 s after P-wave onset. Results show significant rupture-directivity effects, whereby stations located approximately along the fault strike and rupture-propagation direction recorded larger ground-motion amplitudes and higher station-based Mwp estimates than stations located near nodal directions. The mean M_wp was 6.5 ± 0.2, consistent with the Global Centroid Moment Tensor (GCMT) moment magnitude estimate. Magnitude estimation was achievable within 8–20 s of P-wave arrival, confirming the method’s real-time applicability. Our findings demonstrate that strong-motion P-wave analysis can provide rapid and reliable magnitude estimates suitable for earthquake early warning, tsunami warning, and rapid-response applications. In the Marmara Sea region, where tsunami arrival times may be on the order of 20–30 min and critical infrastructure is concentrated in densely populated coastal areas, rapid determination of magnitude within seconds of earthquake initiation can provide valuable information for emergency management and hazard mitigation decisions. Full article

As they are home to numerous significant ecosystems, natural resources, and a growing population, coastal regions are among the most vital locations on Earth. This study, pertaining to the east coast of the UAE, integrates nine distinct characteristics to provide a thorough methodology for assessing integrated coastal vulnerability. Land use and land cover (LULC), nearshore bathymetry, coastal geomorphology, coastal slope, shoreline erosion and deposition, population density, wave and tide, and nearshore benthic features are important parameters that are examined. For the first time, coastal benthic features are included to assess coastal vulnerability in this region. By combining the variably weighted rank values of the nine variables, an Integrated Coastal Vulnerability Index was created, which divides the coastline into low-, moderate-, and high-risk categories. The methodology improves the precision of regional risk assessments by combining these factors with data from real-time coastal surveillance. Approximately 26.4% of the UAE’s 178 km east coast (or 47.1 km) is at high risk, followed by 17.3% (or 30.9 km) at moderate risk and 56.3% (or 100.2 km) at low risk. The offshore areas of the east coast of the UAE are prone to shoaling and tunneling effects from incoming high waves at certain areas due to the concave-shaped bathymetry and medium-range canyons present, which exacerbate storm surges or tsunamis due to the shoaling effect. For a 3 m rise in sea level, most significantly, 5.58 km² of plantation and 14.39 km² of residential areas will be damaged in the Kalba and Fujairah regions. Additional commercial spaces totaling 1.07 km² will also have an impact, adding to the existing 2.59 km² of oil bunkers in Fujairah. More than 40,000 people who live within 3.0 m of the UAE’s east coast in six separate districts—Kalba, Fujairah City, Mirbah and Qidfa, Khorfakkan, Dadna and Bidya, and Dibba—will be impacted if a tsunami wave or storm surge of three meters strikes the east coast. Our results are intended to assist government agencies, coastal planners, and policymakers in the Northeast Emirates (Fujairah and Sharjah) in creating sustainable and successful adaptation and mitigation plans for areas most vulnerable to coastal hazards. In addition to enhancing scientific knowledge of coastal vulnerabilities, this integrative method is a useful tool for making well-informed decisions in the face of shifting socio-economic and climatic situations. Full article

Submarine landslides pose severe marine geological hazards. Their movement and deposition behaviors can seriously threaten marine engineering stability and coastal safety. The propagation characteristics of landslide-generated tsunamis are therefore critical for hazard assessment. Physical model experiments provide an effective approach for investigating the underlying mechanisms of tsunami generation and propagation. To investigate the complete process from landslide motion to wave generation and propagation, this study developed an underwater soil-movement physical model test system. The system integrates controllable landslide initiation, real-time monitoring of landslide motion, wave height measurements, and full-field image acquisition, enabling synchronous observation of landslide movement and water body response. By controlling the main variables influencing submarine landslide dynamics, a series of physical model experiments were conducted to investigate water surface waves generated under different test conditions. The study examines the complete process from the initial water disturbance caused by submerged landslide motion to tsunami generation and propagation. The effects of landslide volume, particle size, initial submergence depth, and slope angle on tsunami parameters, including wave height, wave velocity, and wave period, were evaluated. Using 21 experimental datasets for each landslide type, namely, cohesionless sandy slides and muddy debris flows, empirical formulas for maximum surge height were established through dimensional analysis, SPSS (v25)-based multiple nonlinear regression, and validation against experimental results. The validation results show strong agreement between the empirical predictions and the physical model test data. Full article