Wave Hazard Research Articles

Characterizing Spatiotemporal Patterns of Disasters and Climates to Evaluate Hazards to Crop Production in Taiwan

Climate change causes frequent and severe disasters. A comprehensive assessment of disaster hazards is thus crucial to understanding variations in disaster patterns and planning mitigation and adaptation strategies. This study obtained information from a crop disaster dataset of Taiwan covering the period from 2003 to 2022. Additionally, principal component analysis and K-means clustering were used to create climate clusters to evaluate the effect of climate patterns on disaster hazards. The results revealed that tropical storm frequency substantially decreased, whereas rain disasters exhibited an increasing trend. The four regions of Taiwan exhibited variations in terms of hazards of various disasters. The cold wave hazard showed a significant upward trend in the central region. An upward trend of rain disaster hazards was only detected in the southern region. However, a downward trend in tropical storm hazards was detected across all regions. A distinct climate pattern was identified over the study period. After 2012, high temperature and dry climate were the primary climate patterns. These patterns exhibited a high hazard value for cold waves, droughts, and rain disasters. Hence, the present study’s findings indicate that managing cold waves and rain disasters is crucial to protecting crop production in Taiwan.

Unveiling the global influence of tropical cyclones on extreme waves approaching coastal areas

Tropical and extra-tropical storms generate extreme waves, impacting both nearby and remote regions through swell propagation. Despite their devastating effects in tropical areas, the contribution of tropical cyclones (TCs) to global wave-induced coastal risk remains unknown. Here, we enable a quantitative assessment of TC’s role in extreme waves approaching global coastlines, by designing twin oceanic wave simulations with and without realistic TC wind forcing. We find that TCs substantially contribute to extreme breaking heights in tropical regions (35-50% on average), reaching 100% in high-density TC areas like the North Pacific. TCs also impact remote TC-free regions, such as the equatorial Pacific experiencing in average 30% of its extreme wave events due to TCs. Interannual variability amplifies TC-induced wave hazards, notably during El Niño in the Central Pacific, and La Niña in the South China Sea, Caribbean Arc, and South Indian Ocean coastlines. This research offers critical insights for global risk management and preparedness.

Hazard assessment of dynamic marine processes during two extreme weather systems near the Shandong Peninsula

Typhoons and extratropical cyclones both occurred frequently on the Shandong Peninsula and have induced severe dynamic marine disasters. In this study, the typhoons and extratropical cyclones that occurred from 1979 to 2018 were counted and classified according to their tracks. We simulated the storm surge and disastrous waves using a coupled ocean-wave model and assessed the hazard distribution under different types of typhoons and extratropical cyclones. Through comparison, it was found that the southern Yellow Sea steering type typhoons and Yangtze-Huai cyclones occurred most frequently and were most likely to cause disasters. Regarding the hazard posed by the storm surge, there was a clear demarcation between the northern and southern coasts of the peninsula, as well as between the eastern and western coasts. The western coast of the peninsula was more exposed to storm surges induced by typhoons, while the northern coast of the peninsula was more exposed to storm surges induced by extratropical cyclones. The hazard posed by waves exhibited a localized characteristic. The wave hazard was the greatest near the peninsula cape and the lowest surrounding the Laizhou Bay, which was contrary to the distribution of the storm surge hazard. The identification of key management areas for disasters provides basic data and a technical reference for coastal development planning and can play a positive role in disaster prevention.

Evolving Arctic maritime hazards: Declining sea ice and rising waves in the Northwest Passage

The ongoing and projected retreat of Arctic sea ice has garnered international interest toward the utilization of Arctic maritime corridors for shipping, tourism, and development. Yet, with potential for increasing traffic in Arctic regions, it's important to consider additional environmental variables affected by climate change which may threaten maritime operations. Here, we use four climate model projections to produce ocean wave simulations and investigate the future magnitude and seasonality of sea ice risk coupled with wave hazards. Analyzing the potential 5 mo shipping season spanning July to November along the Northwest Passage maritime route between 2020 and 2070, our results show a substantial decline in sea ice risk over the analysis time period, resulting in near open-water conditions along the route for a 5 mo period by 2070. However, as seasonal ice coverage retreats, there is a significant upward trend in wave heights along the route during July and November, with the timing of the greatest wave height shifting away from September toward later in the season. This result is pertinent as the possibility of seasonally unprecedented extreme waves coupled with subfreezing late fall temperatures makes for an especially hazardous environment, thus emphasizing the importance of considering the interaction between evolving sea ice and interdependent hazards when predicting the risks and challenges faced by Arctic maritime operations.

Computer model for detecting tsunami wave hazard on built-up land using machine learning and sentinel 2A satellite imagery

<p>The aim of this research is to compile a tsunami wave hazard scale based on built-up land density extracted and classified by machine learning from Sentinel 2A satellite and digital elevation model (DEM) imageries. This research was carried out in 5 stages, namely: (i) pre-processing of Sentinel 2A and DEM images, (ii) Classification of VI data using the machine learning algorithms, (iii) Spatial prediction using the ordinary kriging method, (iv) Field testing using the confusion matrix method, (v) Preparation of decision matrix for tsunami wave hazard. The results of the study show that the most accurate classification algorithm for classifying built-up indices data is the k-nearest neighbor (k-NN) algorithm. The results of the statistical accuracy test show that the most accurate is normalized difference built-up index (NDBI) with a mean of square error (MSE) value of 0.073 and a mean of absolute error (MAE) of 0.003. DEM analysis shows that the research area is at an altitude of 0–15 meters above sea level so it is in the high vulnerability to medium vulnerability category. Field testing showed user accuracy of 91.11%, manufacturer accuracy of 92.16%, and overall average accuracy of 91%.</p>

Analysis of extreme wave probabilistic return value based on the 20-year spectral and empirical wave modeling approach in the Coastal Area of Pangandaran

Abstract The coastal area of Pangandaran is located on the southern coast of Java Island, Indonesia. It offers stunning beach panoramas, and tempting waves for surfers, while also providing livelihoods for people who depend on the marine biodiversity and abundance of fish caught in the surrounding waters. However, its exposure to the Indian Ocean makes it susceptible to extreme waves, posing risks to tourism, fishing, and safety. This study aims to conduct an extreme wave hazard analysis based on the Probabilistic Return Value (PRV) using Significant Wave Height (SWH) data for over 20 years of data to obtain a wave climate value in the Batukaras area. The SWH values are obtained from two methods, numerical spectral wave modeling using Simulating Waves Nearshore (SWAN) and calculations using an empirical formula from the Joint North Sea Wave Project (JONSWAP), both using wind data from the ERA-5 Satellite. Based on these calculations, the Gumbel distribution was analysed to determine the PRV value on the coast. By estimating the return value of extreme waves based on the spectral SWAN method, for a return period of 300 years, extreme wave events occur at a height of 2.01 m to 2.64 m at a depth of 5-21 m. Meanwhile, the empirical JONSWAP method generates the same probability for wave heights of 7.19 m to 12.81 m based on statistical predictions based on modeling data. Based on these results, community and tourist preparedness on the coast of Batukaras Village is expected to increase, particularly during bad weather.

Increasing coastal exposure to extreme wave events in the Alaskan Arctic as the open water season expands

Declining Arctic sea ice over recent decades has been linked to growth in coastal hazards affecting the Alaskan Arctic. In this study, climate model projections of sea ice are utilized in the simulation of an extratropical cyclone to quantify how future changes in seasonal ice coverage could affect coastal waves caused by this extreme event. All future scenarios and decades show an increase in coastal wave heights, demonstrating how an extended season of open water in the Chukchi and Beaufort Seas could expose Alaskan Arctic shorelines to wave hazards resulting from such a storm event for an additional winter month by 2050 and up to three additional months by 2070 depending on climate pathway. Additionally, for the Beaufort coastal region, future scenarios agree that a coastal wave saturation limit is reached during the sea ice minimum, where historically sea ice would provide a degree of protection throughout the year.

Risk assessment of wave hazard in Guangdong Province

In order to improve the prediction ability of wave hazard levels in the ocean under the jurisdiction of Guangdong Province, this paper uses the wave simulation data to evaluate the wave hazard index of the ocean under the jurisdiction of Guangdong Province, and analyses the risk assessment analysis of wave hazards in the Guangdong Province, which provides data support for future wave disaster prevention and mitigation, coastal development, and spatial planning in Guangdong Province. The significant wave height of the 50-year return period in the coastal areas of Guangdong Province is generally distributed within 9 meters of the territorial sea baseline. The intensity of the return period gradually increases with the distance from the mainland and decreases with the decrease of water depth. In the past 30 years, the sea areas under the jurisdiction of the Guangdong Province are mainly dominated by class III and IV wave heights, with class IV being higher than class III. The frequency of Class IV wave heights in the mainly marine area is more than 90%. The risk level of wave disasters in the coastal waters of Guangdong Province is mainly level IV. However, the risk level of wave disasters in the waters under the jurisdiction of Guangdong Province is mainly Level I.

Numerical simulation on potential landslide–induced wave hazards by a novel hybrid method

Landslide-induced waves pose significant risks to human lives, property, and infrastructure. The multifaceted nature of landslide movements combined with solid-fluid interactions makes hazard assessment of these waves particularly challenging. This study proposes a novel hybrid numerical method for simulating potential landslide–induced wave. The Material Point Method (MPM) is employed to evaluate landslide movement, taking into account residual slope strength and examining a potential landslide's displacement and velocity. Concurrently, the Smoothed Particle Hydrodynamics (SPH) method is used to model the propagation characteristics of impulse waves. This novel method's validity is established through two physical tests. Subsequently, it is employed to assess the impulse wave risk arising from a potential landslide in China. The findings indicate a maximum wave amplitude of 5.661 m, which reaches a proximate residential zone 75 s post-landslide, traveling at an approximate speed of 2.5 m/s. The influence of a landslide's residual strength on the amplitude of an impulse wave is also explored. Notably, a 20% increase in residual strength results in a 62% reduction in peak wave amplitude. Hence, comprehensive geotechnical investigations and tests are indispensable for gauging the risks associated with landslide-induced waves. This research offers a potent numerical simulation technique for such waves and furnishes valuable insights into risk assessment.

Global increase in tropical cyclone ocean surface waves

The long-term changes of ocean surface waves associated with tropical cyclones (TCs) are poorly observed and understood. Here, we present the global trend analysis of TC waves for 1979–2022 based on the ERA5 wave reanalysis. The maximum height and the area of the TC wave footprint in the six h reanalysis have increased globally by about 3%/decade and 6%/decade, respectively. The TC wave energy transferred at the interface from the atmosphere to the ocean has increased globally by about 9%/decade, which is three times larger than that reported for all waves. The global energy changes are mostly driven by the growing area of the wave footprint. Our study shows that the TC-associated wave hazard has increased significantly and these changes are larger than those of the TC maximum wind speed. This suggests that the wave hazard should be a concern in the future.

An optimized DEM‐SPH model for surge waves induced by riverside landslides

AbstractRiverside landslides can induce surge waves during the process of entering water. The landslide‐induced surge wave is often regarded as a significant secondary disaster, as its impact region is likely to be even more remarkable than the landslide itself. Due to the large deformation of the soil landslide and water body during the evolution of surge waves, commonly adopted multi‐phase flow models and mesh‐based methods coupled with discrete element models have some limitations, such as weak accuracy, and simulation distortion with immature coupling algorithms. As a result, the pure meshless method of smoothed particle hydrodynamics (SPH) coupling discrete element methods (DEM) become promising. Modified from the traditional empirical formulae‐based coupling algorithm, this study proposes a semi‐resolved algorithm that effectively eliminates the particle distortion at the fluid‐solid coupling interface. The proposed model demonstrates its superiority through a comparison of the pressure and porosity near the coupling interface. Furthermore, the optimized DEM‐SPH model is applied to simulate landslide‐induced surge waves, and the simulation results have also validated the accuracy of the model. This model is capable of accurately simulating the entire propagation process from landslide entry into water to the wave reaching the opposite shore, and therefore provides an effective tool for the prediction and mitigation of wave hazards caused by landslides.

Estimation of breaking wave region based on coupled wave and storm surge simulations of historical typhoons: A case study of Hangzhou Bay

Breaking waves pose a serious threat to offshore structures. Estimating the breaking wave region is hence important for structural design and construction. This paper developed a numerical approach for estimating the breaking wave region based on the coupled wave and storm surge simulations of typhoons. The SWAN + ADCIRC coupling model was employed to hindcast the wave height, wave period, and storm surge under historical typhoons. The values of two breaking prediction variables at different mean return periods (MRPs) were calculated by probability models. The breaking wave region can then be estimated by either a univariate or bivariate probability model of the breaking prediction variables. The developed approach was illustrated using Hangzhou Bay as a case study. Hindcast simulations of 40 typhoons in the past 25 years were conducted. The effects of breaking criteria, probability model, and breaking threshold on the breaking wave region were investigated and discussed as a function of MRP. The main findings include that 1) the waves on the north shore of Hangzhou Bay break more easily; 2) the distribution and area of the estimated breaking wave region depend on the selection of breaking criteria and thresholds; and 3) neglecting the correlation between variables results in an underestimation of breaking wave hazards. This study provides engineers with an efficient tool to estimate the breaking wave hazards for projects located in tropical cyclone-prone sea areas.

Whitewater Sound Dependence on Discharge and Wave Configuration at an Adjustable Wave Feature

AbstractStream acoustics has been proposed as a means of monitoring discharge and wave hazards from outside the stream channel. To better understand the dependence of sound on discharge and wave characteristics, this study analyzes discharge and infrasound data from an artificial wave feature which is adjusted to accommodate daily changes in recreational use and seasonal changes in irrigation demand. Monitorable sound is only observed when discharge exceeds ∼35 m3/s, and even above that threshold the sound‐discharge relationship is non‐linear and inconsistent. When sound is observed, it shows consistent dependence on wave type within a given year, but the direction of this dependence varies among the 3 years studied (2016, 2021, and 2022). These findings support previous research that establishes discharge and stream morphology as relevant controls on stream acoustics and highlights the complex, combined effects of these variables.

Physics-based modeling of climate change impact on hurricane-induced coastal erosion hazards

Coastal erosion is an adverse impact of extreme water levels during major hurricanes. A warmer climate is expected to increase storm surge and wave hazards due to hurricane climatology change (HCC) and sea level rise (SLR). We conduct physics-based morphodynamic modeling to quantify the regional impacts of HCC and SLR on erosion hazards to sandy beaches and dunes along the barrier islands of New Jersey in the United States. Under the RCP8.5 scenario, we find a substantial increase in erosion hazards from the late-20th-century to late-21st-century. The regionally averaged 100-year eroded volume of beach-dune systems would increase by 58 and 84%, respectively, under the HCC and HCC + SLR scenarios. Our projections show a large spatial variability in future changes to erosion hazards, suggesting that, in addition to HCC and SLR, the morphological characteristics of beach-dune systems play an important role in the impacts of climate change on coastal erosion.

A comprehensive performance evaluation methodology for sea-crossing cable-stayed bridges under wind and wave loads

This study proposes a probabilistic performance evaluation framework for sea-crossing cable-stayed bridges (SCBs) subjected to wind and wave excitations with the incorporation of wind speed and direction, bridge orientation, wind-wave correlation and parameter uncertainties. Both the bridge serviceability and safety are taken into account in the performance assessment. The fragility analysis of the SCB under wind and wave loads is conducted using the wind-wave correlation model constructed based on field data. The actual damage probability of a local SCB is computed by combining the fragilities of bridge under different wind incidence angles with the copula-based joint probability distribution (JPD) of wind speed and direction, which is developed using the wind field data recorded in Lianyungang city of China from 1971 to 2020. The results show that under the defined wind incidence angle of 0°, the exemplar SCB suffers the highest fragility. Moreover, with the data-based occurrence probability model of wind and wave hazards, the damage probabilities under all possible wind speeds and directions are computed; then the optimal and most unfavorable orientations of the SCB are obtained. This investigation provides a comprehensive and practical method for the performance evaluation and design optimization of SCBs under wind and wave loads with long-term recorded hazard data at the local site.

Analysis of the 20-Year Variability of Ocean Wave Hazards in the Northwest Pacific

In the Northwest Pacific (NWP), where a unique monsoon climate exists and where both typhoons and extratropical storms occur frequently, hazardous waves pose a significant risk to maritime safety. To analyze the 20-year variability of hazardous waves in this region, this study utilized hourly reanalysis data from the ECMWF ERA5 dataset covering the period from 2001–2020, alongside the wave risk assessment method. The ERA5 data exhibits better consistency, in both the temporal and spatial dimensions, than satellite data. Although hazardous wind seas occur more frequently than hazardous swells, swells make hazardous waves travel further. Notably, the extreme wave height (EWH) shows an increasing trend in high- and low-latitude areas of the NWP. The change in meridional wind speeds is the primary reason for the change in the total wind speed in the NWP. Notably, the maximum annual increase rate of 0.013 m/year for EWH exists in the region of the Japanese Archipelago. This study elucidated the distributions of wave height intensity and wave risk levels, noting that the EWHs of the 50-year and 100-year return periods can reach 20.92 m and 23.07 m, respectively.

Radio Direction Finding Method to Mitigate Tsunami Risk in Sierra Leone

In this study, the Radio Direction Finding method is proposed for the detection of electromagnetic signals, in the VLF band, to try to anticipate the occurrence of potentially destructive geophysical events. The experimentation concerns the interception of electromagnetic anomalies in Sierra Leone, in the five-day time window, associated with seismic events that could potentially generate tsunamis. The area of investigation is Sierra Leone, whose coastline is subjected to tidal wave hazards triggered by earthquakes generated in the Mid-Atlantic Ridge. Although Sierra Leone is not affected by recurrent earthquakes, there is nevertheless a low probability, estimated at 2 percent, of the occurrence of destructive earthquakes in the next 50 years. Also in estimates, the risk of rogue and potentially damaging waves is estimated to strike the Sierra Leone coast at least once in the next 10 years. The Radio Direction Finding experiment carried out continuously 24/7, has shown a close relationship between increased radio-anomalies, in the frequencies of 6,000 Hz, a time window between electromagnetic anomaly detection and the imminence of an earthquake, and higher frequency times for the risk of earthquake occurrence in the Mid-Atlantic Ridge.

Assessment of Dams’ Failure and Flood Wave Hazards on the Downstream Countries: A Case Study of the Grand Ethiopian Renaissance Dam (GERD)

Dams are built for different purposes, but failure of a dam could result in extreme disasters such as floods. The Grand Ethiopian Renaissance Dam (GERD) was mainly built for power generation, but concerns about its safety, location and site conditions have led the downstream countries to investigate the GERD’s stability. This paper aims to investigate the impact of the failure of the dam on the downstream countries using the Hydrologic Engineering Center River Analysis System (HEC-RAS). Outflow hydrographs and flood inundation maps were provided through a hypothetical dam break scenario. An unsteady flow hydrodynamic routing with a 2D model was used to simulate the failure of the dam. A sensitivity analysis study of the output’s findings against breach parameters was also performed. The breach outflow discharge increases as the breach dimension increases. However, the peak discharge decreases with increasing breach formation time. Moreover, to prepare emergency action plans, it is important to predict the inundation depth, levels, arrival of flood waves, flood coverage area and water velocity. Furthermore, the results showed that Khartoum would turn into lakes within about 10 days and flood water depth would exceed 11 m at some locations in residential areas. Moreover, the flood waves overtopped the Roseires, Sennar and Merowe dams by 11, 7 and 20 m, respectively. In addition, the level of Lake Nasser would reach 188 m above sea level and the Aswan High Dam might be in great danger.

A multi-proxy approach to assess tsunami hazard with a preliminary risk assessment: A case study of the Makran Coast, Pakistan

Tsunamis and cyclones are sea-borne hazards capable of inundating vast coastal areas. This study aims at an extreme wave hazard assessment with a preliminary inundation analysis along the Makran Coast, Pakistan. The coastal hazard, particularly tsunamis, is evaluated by integrating five approaches: (i) probabilistic tsunami hazard assessment (PTHA); (ii) deterministic tsunami hazard assessment (DTHA); (iii) geophysical-seismic (2-D thermal modelling), (iv) sedimentary tsunami deposits (tsunamis); and (v) the historical record. The recurrence interval for a mega-tsunami event (≥12 m) is between 500 and 1000 years in the Arabian Sea. Of these mega-tsunamis, about 60% are generated by seismic sources, while the remaining 40% are attributed to secondary (co-seismic submarine landslides) and other non-seismic sources. Based on the above five approaches, the hazard analysis helped to shortlist four wave scenarios (3, 7, 10, and 15 m). Which were further used to demarcate risk areas through static inundation analysis. The results indicated that the damage potential at the coast is minor to negligible with 3 m waves and moderate with 7 m waves. Whereas the 10 m and 15 m waves will severely disrupt the study area. In addition to tsunami risk, cyclone risk is assessed by interpolating storm tracks dating back to 1842 CE. In the last 64 years, cyclone frequency has jumped from 1 cyclone per 10 years to 20 cyclones per 10 years, and the intensity has increased by two levels from Tropical Storm (TS) to Category-3.

Scenario-based modelling of waves generated by sublacustrine explosive eruptions at Lake Taupō, New Zealand

Abstract. Volcanogenic tsunami and wave hazard remains less understood than that of other tsunami sources. Volcanoes can generate waves in a multitude of ways, including subaqueous explosions. Recent events, including a highly explosive eruption at Hunga Tonga-Hunga Ha'apai and subsequent tsunami in January 2022, have reinforced the necessity to explore and quantify volcanic tsunami sources. We utilise a non-hydrostatic multilayer numerical method to simulate 20 scenarios of sublacustrine explosive eruptions under Lake Taupō, New Zealand, across five locations and four eruption sizes. Waves propagate around the entire lake within 15 min, and there is a minimum explosive size required to generate significant waves (positive amplitudes incident on foreshore of > 1 m) from the impulsive displacement of water from the eruption itself. This minimum size corresponds to a mass eruption rate of 5.8×107 kg s−1, or VEI 5 equivalent. Inundation is mapped across five built areas and becomes significant near shore when considering only the two largest sizes, above VEI 5, which preferentially impact areas of low-gradient slope. In addition, novel hydrographic output is produced showing the impact of incident waves on the Waikato River inlet draining the lake and is potentially useful for future structural impact analysis. Waves generated from these explosive source types are highly dispersive, resulting in hazard rapidly diminishing with distance from the source. With improved computational efficiency, a probabilistic study could be formulated and other, potentially more significant, volcanic source mechanisms should be investigated.