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Many bridges that lie within possible tsunami inundation zones are critical links in transport networks. Some efforts have been made to determine the effects of tsunamis on bridges, but only a limited range of published design guidelines are available. Therefore, it is necessary to further investigate the effects of tsunamis on bridges. In the current study, physical modeling experiments were carried out to measure bore impact forces and pressures for various tsunami bore strengths on a bridge deck with different abutment types (wing wall and spill-through) and different opening and submergence ratios. The experiments were conducted in a wave flume with dimensions of 14 × 1.2 × 0.8 m (length × width × height), equipped with an automatic gate designed to generate a tsunami bore. The horizontal and vertical forces showed an increasing trend with increasing submergence ratio for both types of abutment. However, the horizontal force showed a decreasing trend as the opening ratio decreased, while the vertical force initially increased as the opening ratio decreased, until it reached a peak value, and then it started to decrease. The overall shapes of the results for both types of abutment are similar, with higher values for spill-through abutments due to their lower energy dissipation rates. Based on the experimental data, empirical equations are proposed for estimation of tsunami loads as a function of opening and submergence ratios. [ABSTRACT FROM AUTHOR]

• This study advances the in-practice traditional CRA frameworks through the incorporation of CNHs into risk assessment. • Empirical evidence on the influence of CNHs on risk level and its spatial patterns is provided. • The results show significant difference in risk level and its geographical distribution under the two scenarios. • The CNHs exclusive CRA overestimates the population in the highest risk category by 10 % and number of counties by 40 %. • The findings highlight the importance of CNHs and the need of incorporating CNHs into CRA. The coastal risk assessment (CRA) has important implications for policy development, resilience enhancement, and risk reduction to reduce the magnitude and likelihood of future losses to coastal hazards. However, few if any existing in-practice CRA approaches account for the effects of coastal natural habitats (CNHs), which shield communities from natural hazards and support resilience enhancement in coastal regions. Here, we use a coupled human-nature system-based CRA framework to provide evidence on the influence of CNHs on coastal storm-risk levels and spatial distributions. We calculate a risk index for each coastal county along the U.S. Atlantic coast and employ different spatial assessment approaches to systematically analyse the risk. This index incorporates several bio-geo-physical variables (e.g., geomorphology, natural habitats, coastal relief, and historical data on sea level trends, wind, and wave) and data on socio-ecological systems. The index is calculated under two CNH scenarios (i.e., without- and with-habitat) and is further used for mapping the at-risk population. We find that the without-habitat scenario overestimates the population in the highest risk category by 10 % and the number of counties by as much as 40 % as compared to the with-habitat scenario—mostly in the Gulf region. Also, the without-habitat scenario miscalculates the spatial distribution of the risk (e.g., over/under-estimate the relative risk for Florida/New York). These findings highlight the role of CNHs to provide defensive services and the importance of incorporating CNHs into the risk assessment process. While the CNHs inclusive risk results are important for coastal risk-reduction through prioritization and smart resource allocation, the well evident influence of CNHs on risk level and its distribution is also supportive for conservationists to stress the policies relevant to the protection and restoration of coastal natural systems owing to their multiple services. [ABSTRACT FROM AUTHOR]

• Impacts of the 2004 Indian Ocean Tsunami to Malaysia were diverse and significant. • Majority of Malaysia's at-risk coastline are still highly vulnerable. • Tourism, fishing and aquaculture industries were heavily affected. • Impacts of the tsunami towards local ecosystem need better understanding. • Research on tsunami have gained interest in Malaysia. Situated in the middle of the Sunda Plate and close to the Ring of Fire, Malaysia is surrounded by seismically active zones that pose risks of natural hazards, among which is tsunami. The 2004 Indian Ocean Tsunami caused by a magnitude 9.3 earthquake off Sumatran coastline was the first tsunami to have reached Malaysia in the country's own recorded history, though there are brief records of other tsunami reaching Malaysian coastline in the past. This paper reviewed relevant literature sources to highlight the intensity and diversity of damages caused by the tsunami towards Malaysia. These damages ranged from loss of lives, physical damage to structures and infrastructures, environmental changes, socioeconomic setbacks, and health issues among the victims. Subsequent measures taken by the Malaysian government and agencies in managing disaster risk in the country are also reviewed. These measures include the identification of tsunami hazard zones, development of tsunami emergency response plans, and the formation of the National Disaster Management Agency (NADMA). In addition, the shift in disaster management approaches from being heavily top-down towards community-based was examined. Understanding of the wide spectrum of impacts caused by the tsunami disaster, the contributing factors as well as mitigation efforts reviewed in this paper can be particularly useful in making informed decisions regarding future risk reduction strategies in the context of a developing country like Malaysia. [ABSTRACT FROM AUTHOR]

• We propose a robust evacuation framework that integrates the hydrodynamic model into a traffic simulation model. • We quantify the risk of flooding on evacuation routes in a GIS framework. • Results enhance the emergency evacuation planning during extreme storm events. Developing an effective real-time evacuation strategy during extreme storm events such as hurricanes has been a topic of critical significance to the emergency planning and response community. The spatial and temporal variabilities of inland flooding during hurricanes present significant challenges for robust evacuation planning. In this study, a framework for real-time evacuation planning was developed that combines the results obtained from hydrodynamic modeling and traffic microsimulation. First, a fine-scale hydrodynamic model was developed based on depth-averaged 2D shallow-water equations (SWE) to obtain information pertaining to flood depth and velocity for planning evacuation routes during a storm event. Next, a traffic microsimulation was conducted using time-dependent information from the hydrodynamic model regarding the traffic velocities along evacuation routes during an event. An optimization technique was also implemented to reduce the overall travel time by about 6% from that of the base model. The last component of the framework involves combining the results from both models to generate a time-lapse animation of emergency evacuation based on a geographic information system (GIS). The results obtained using this framework could be easily accessed by the general public and decision-makers to enable efficient evacuation planning during extreme storm events. [ABSTRACT FROM AUTHOR]

• A simulation based bi-level model minimizes network delays due to inundations. • Budget constraints, hydrodynamic and traffic interactions are considered. • Findings are applied to a real world network in California for 0.5 m sea level rise. • The optimal strategies vary according to the available budget. • There exist critical shorelines to protect, to reduce the traffic disruptions. Sea level rise predictions have motivated research towards the protection of shoreline infrastructures, including transportation systems. Transportation network interactions in cases of inundation can lead to severe disruptions that cause capacity and accessibility reduction and thus considerable delays, especially due to congestion feedback, because congestion occurring due to an inundated link or a link that becomes isolated through inundation of one of its nodes can lead to delays in other parts of the network, due to queue spillback or traffic rerouting. This paper describes a decision tool to support infrastructure protection planning against sea level rise. A simulation-based optimization model is designed to minimize delays occurring in a transportation system under inundation. The model considers budget constraints, hydrodynamic interactions within the shoreline, as well as traffic assignment in the network. The case study focuses on San Francisco Bay area, for a 0.5 m sea level rise that is expected in 2054 and may increase highway users' travel time by 37%. The results show that the optimal strategies vary according to the available budget, and that there exist relatively critical shorelines to protect in order to reduce the traffic disruptions. We anticipate our research to provide a general framework for transportation infrastructure protection planning against sea level rises. [ABSTRACT FROM AUTHOR]

Due to the richness of its coastal environments, particularly lagoons and mangrove, the low-lying areas of the Omani coastline attracted settlements very early. However, the low-lying coasts are highly mobile landscapes, whose evolution is controlled by multiple factors acting at different timescales, from episodic (extreme events) to millennial timescales (gradual shoreline changes). From a geoarchaeological analysis (geomorphological mapping, archaeological survey, core drilling, and sedimentological, faunic and microfaunic analyses), this study proposes for the first time to reconstruct the landscape evolution of the Quriyat coastal plain landscape during the Mid-Late Holocene. Results indicate a coastal landscape dominated by large lagoons and mangroves during the mid-Holocene (5th millennium). Between 6712 -6501 cal. BP and 6183−5992 cal. BP, an extreme wave event identified as a tsunami, is registered in the southern part of the coast. Between 4223−3984 cal. BP and 4150−3981 cal. BP, lagoons were quickly clogging over more than 3.5 km in favour of the development of sebkhas or dune fields. We suggest this rapid evolution is related to erosional crises linked to the setting up of arid conditions in this part of the Omani coast. The production of several sea-level index points shows a great stability of the relative sea-level over the last 6.000 yearscal. BP and point out the predominant role of sedimentary infilling in the coastline evolution of Quriyat. The high sedimentation rates, added to the exposure of coastal hazards, partially explains the relatively low density of archaeological sites found in the Quriyat coastal plain, despite the presence of major shell-midden (Khor Milk I and II), which attest the old attractiveness of this sector. From geoarchaeological and taphonomic points of view, the Quriyat area is considered as having non-favourable conditions for the preservation of archaeological remains. [ABSTRACT FROM AUTHOR]

• A method is proposed for mapping coral reef inundation from time-series OLI images. • The reef-water reflectance contrast varying with bands and water level was adopted. • An inventory of 137 coral reefs in the Spratly Islands is established. • The extent, inundation frequency, and geomorphic zones of coral reefs are derived. Coral reefs are crucial for the maintenance of the marine ecological environment and for the sustainability of local societies and economies. The use of remote sensing methods with the support of field data has been proposed for mapping coral reef habitats and bathymetry. However, the geomorphology of coral reefs over substantial areas is poorly documented, because of the absence of field data, especially in disputed areas where in situ investigation is difficult. In this study, we developed a simple method for mapping the inundation frequency (within the penetration range of optical remote sensing) of coral reefs using time-series Landsat-8 OLI images. The method uses the reef-water reflectance contrast (which varies with bathymetry, bands, and water level) in time-series optical multi-band images in order to derive the inundation frequency and geomorphic zonation of coral reefs. The method was applied to the Spratly Islands—the largest coral reef system in the South China Sea (SCS) using more than 1,100 Landsat-8 OLI images. We established an inventory which comprises 137 reefs/sandbanks/islands, including their spatial extent, inundation frequency, and geomorphic zonation. We also interestingly found that the inundation frequency of reef flats around reclaimed areas has decreased since island construction, which probably reflects the influence of anthropogenic activity on the coral reef ecosystem. Our approach was validated by a study of the Great Barrier Reef in Australia, which demonstrated that the inundation frequency of coral reefs can serve as an indirect representation of their bathymetry. [ABSTRACT FROM AUTHOR]

• A coherent three-step framework is introduced to Quantify Climate change-driven Environmental Losses (QuantiCEL) in coastal areas in developing countries. • The QuantiCEL framework is applied to quantify environmental losses due to different relative sea level rise and storm induced inundation and erosion scenarios in Indonesia, Bangladesh, and Sri Lanka. • Food provision and tourism are the Coastal Ecosystem Services (CES) with estimated high absolute loss values by the end of the 21st century. • Art, amenity, and tourism are the highly affected CES by the end of the 21st century with considerable percentage of loss value compared to the present-day value. Climate change impacts threaten the coastal environment and affect Coastal Ecosystem Services (CES) that are vital to human wellbeing. Quantifying the monetary value of climate change driven environmental losses is scarce, especially in coastal areas of developing countries that have low adaptive capacity to climate change impacts. To address this knowledge gap, we present a practical framework to Quantify Climate change driven Environmental Losses (QuantiCEL) that coherently assesses the likely physical impacts of climate change on CES, and pursues the valuation of their losses with primary data collection. The framework is applied to coastal areas in three developing countries, and may serve as a useful guide for practitioners. We quantify potential environmental losses due to relative sea level rise-induced coastal inundation in Indonesia and Bangladesh, and losses due to sea level rise and storm-induced coastline recession in Sri Lanka in the next 100 years. This study illustrates the applicability of the framework in different contexts in the data-scarce developing countries. Our findings suggest that the three case studies will experience the absolute loss value of CES by the end of the 21 st century, with food provision and tourism suffering the highest losses. Moreover, art, amenity, and tourism services are highly affected CES with respect to the percentage loss relative to the present-day value of these CES. The QuantiCEL framework and its application presented in this study could help researchers, policy makers, and coastal zone managers to get better insights into likely climate change driven environmental losses in coastal areas, contributing to the development of much needed environmental risk quantification methods, and sustainable management of coastal wetlands. [ABSTRACT FROM AUTHOR]

• Stochastic tsunami hazard assessment of western Makran subduction zone was improved. • Stochastic rupture modeling with incorporation of slip heterogeneity was modified. • New comprehensive scaling relationships of the fault geometry was applied. • Uniform-slip source models need to be revised in future tsunami risk assessment. • The proposed scaling relationships creates a large variation in maximum wave heights. The Makran Subduction Zone (MSZ) is one of the world's most tsunami-prone regions. In the present study, tsunami hazards associated with potential MSZ earthquakes are evaluated using stochastic earthquake rupture modeling, which allows for the incorporation of uncertainties related to slip heterogeneity. Along the western segment of the MSZ, where tsunami hazard studies have received less attention, megathrust earthquakes with moment magnitudes of M w 8.5, 8.7, and 8.9 are considered. The source parameters of 600 stochastic earthquake scenarios are calculated using the scaling relationships of Goda et al. (2016), which represent significant improvements over previous scaling relationships by taking into account the uncertainty of multiple source parameters and the coverage of a wide range of earthquake magnitudes. In order to simulate tsunami propagation and inundation, the nonlinear shallow water equations are used in four-level nested grid model domains.According to the calculated slip fields, the seismic source characteristics provided by stochastic source models significantly change within the earthquakes scenarios with identical magnitudes and may completely differ from the results of traditional uniform-slip source models. The results of the 600 Monte Carlo tsunami simulations demonstrate that even extremely large earthquakes in the west MSZ do not lead to significant tsunamis along the eastern coastal regions of Makran. The average maximum wave heights of 8, 10, and 17 m along the western Makran coasts, which correspond to the M w 8.5, 8.7, and 8.9 scenarios, respectively, emphasize the severe potential threat of a possible tsunamigenic event in the west of the MSZ to the Iranian coasts. In addition, the significant difference between the maximum wave heights of the 10th and 90th percentiles for each scenario demonstrates the large variability of tsunami heights resulting from uncertainties associated with stochastic seismic source modeling. Thus, it can be concluded that the tsunami hazard parameters estimated by simple uniform-slip source models need to be revised in future tsunami risk assessment studies. [ABSTRACT FROM AUTHOR]

The coastal Atacama Desert is exposed to strong earthquakes and giant tsunamis associated with the subduction of the Nazca plate beneath the South American plate. Nevertheless, historical and geological records of tsunamis and paleotsunamis in this region are scarce. Taltal (25.4°S) is located at the southern edge of the hyperarid Atacama Desert within a major historical ∼1000 km-long megathrust seismic gap in northern Chile where the most recent large tsunamigenic earthquakes occurred in 1877 CE and 1922 CE, rupturing its northern and southern segments, respectively. By multiproxy geological and archaeological analyses from pits and trenches, we report distinctive strata of reworked archaeological material as well as sedimentary layers that we interpret as being produced by tsunami run-up and/or backwash deposition. We identified two large Holocene paleotsunamis dated close to ∼4000 cal yrs BP and younger than 863 ± 199 CE (∼1087 cal years BP). By comparing the run-ups of the last historical tsunamis with our minimum run-up estimates from the geo-archaeological record, we conclude that the impact of these Holocene paleotsunamis was larger than any known historical event, suggesting the need to re-evaluate local, regional and Pacific basin-scale tsunami hazard assessments. • First report of Holocene paleotsunami deposits in the hyperarid Atacama Desert. • We document two large Holocene paleotsunamis in the northern Chile seismic gap. • We reanalyzed the last large historical tsunamis in northern Chile. • We suggest a re-assessment of the Pacific-wide tsunami hazard. [ABSTRACT FROM AUTHOR]

Understanding plant traits in response to physical stress has been an important issue in the study of coastal saltmarshes. For plants that reproduce both sexually and asexually, whether and how seedlings (sexual reproduction) and clonal ramets (asexual reproduction) may differentially respond to tidal inundation is still unclear. We investigated the growth and morphology of sexual and asexual propagules of an exotic saltmarsh plant (Spartina alterniflora) along a gradient of tidal submergence in the Yellow River Delta. Our results showed that the density, height and basal diameter of clonal ramets or sexual seedlings increased with tidal inundation. The patch amplification edge clonal ramets are superior than patch center plants. The differences response of plants to tidal inundation highlight the sensitivity of S. alterniflora to future tidal regime shifts and can help predict and evaluate the impacts of changes in inundation conditions due to sea level rise, coastal erosion and human activities. • The positively relationship between trait and density of plants and tidal height • Advantages in trait of offspring propagules versus maternal plants • There is inundation height adaptation threshold for sexual propagules. [ABSTRACT FROM AUTHOR]

• Simulation of Chennai flood in 2015. • Construction of urban sprawl scenarios for Chennai city using ANN model. • Impact of urban sprawl and increased rainfall on flooding for the Chennai city. The 2015 Chennai (India) flood event claimed many lives and incurred an economic loss of $2.2 billion. Simulation of such a destructive flood event in an ever growing urban sprawl and changing climate is of great importance for better flood preparedness and management of the city. In that light, this study aims to (a) study the 2015 Chennai flood event and (b) simulate the occurrence of a similar event in future, considering both urban sprawl and increased rainfall resulting from climate change effects. The baseline scenario is generated using freely available hydrologic (HEC-HMS)-hydraulic (HEC-RAS) models and the results are validated with observed flood-mark data. Historical land use and land cover maps of the study area are used to train an Artificial Neural Network model for constructing spatially varying urban sprawl scenarios. The hydrologic model is run for the increased rainfall and urban sprawl scenarios to generate flood hydrographs, which are then used as inputs to the hydraulic model for simulating possible flood inundation patterns. The simulations indicate that the average increase in inundation extent considering the worst possible urban sprawl solely, and that taken together with extreme rainfall, are 20 and 33 percent, respectively. Furthermore, the analysis shows that on an average 1.7 times more number of buildings are exposed to flood hazard under the worst case combined scenario in comparison to the baseline scenario. This study, therefore, demonstrates the importance of considering urban sprawl, in addition to changes in rainfall, for evaluating the worst possible consequences of flooding of a city. Considering the uncertainties involved in the study, the presented results may be considered as "what-if" scenarios for planning suitable flood mitigation measures for the city of Chennai. [ABSTRACT FROM AUTHOR]

The Prairie Pothole Region of North America is characterized by millions of depressional wetlands, which provide critical habitats for globally significant populations of migratory waterfowl and other wildlife species. Due to their relatively small size and shallow depth, these wetlands are highly sensitive to climate variability and anthropogenic changes, exhibiting inter- and intra-annual inundation dynamics. Moderate-resolution satellite imagery (e.g., Landsat, Sentinel) alone cannot be used to effectively delineate these small depressional wetlands. By integrating fine spatial resolution Light Detection and Ranging (LiDAR) data and multi-temporal (2009–2017) aerial images, we developed a fully automated approach to delineate wetland inundation extent at watershed scales using Google Earth Engine. Machine learning algorithms were used to classify aerial imagery with additional spectral indices to extract potential wetland inundation areas, which were further refined using LiDAR-derived landform depressions. The wetland delineation results were then compared to the U.S. Fish and Wildlife Service National Wetlands Inventory (NWI) geospatial dataset and existing global-scale surface water products to evaluate the performance of the proposed method. We tested the workflow on 26 watersheds with a total area of 16,576 km2 in the Prairie Pothole Region. The results showed that the proposed method can not only delineate current wetland inundation status but also demonstrate wetland hydrological dynamics, such as wetland coalescence through fill-spill hydrological processes. Our automated algorithm provides a practical, reproducible, and scalable framework, which can be easily adapted to delineate wetland inundation dynamics at broad geographic scales. • A fully automated algorithm was developed to map wetland inundation dynamics. • Multiple wetland inundation maps (1-m) were produced for the Prairie Pothole Region. • Mapped wetlands show high accuracy when compared to existing surface water products. • The algorithm is scalable for mapping wetland inundation at large geographic scales. [ABSTRACT FROM AUTHOR]

The frequent occurrence of landslide tsunami has aroused great social concern, hence an efficient approach for modeling the phenomena is required urgently. Herein, we present and supplement a meshless numerical model named 'Tsunami Squares' (TS). TS simulates both the landslide and its generated wave using an updated numerical scheme that has enhanced computational efficiency. TS also provides an artful way of approximating linear dispersive wave propagation and non-linear wave inundation that makes it quite capable of simulating real-scale events. A well-designed test that compares TS output with an analytical formula for a tsunami propagation calculation provides firm validation of the approach. We then applied the 'Tsunami Squares' to simulate the 1792 Unzen-Mayuyama mega slide and generated tsunami. This event remains the largest volcanic disaster in the history of Japan. Landslide dynamics simulated by TS coincide with historical reports and the known geometry of landslide deposits. The model output of tsunami runup heights well match the observed values recorded by the locations of historical 'Tsunami Stones'. This well documented and data-rich case further validates the 'Tsunami Squares' model and the excellent reproduction of the 1792 event provides new insights for better understanding of landslide tsunami hazards. • Development of a new model for linear and non-linear wave propagation and inundation • Model validation with an analytical formula of a Gaussian water pile propagation • Model application to the data-rich 1792 Unzen-Mayuyama landslide tsunami • Features of energy dissipation in landslide and its generated tsunami dynamics [ABSTRACT FROM AUTHOR]

The scope of this study is to investigate the effect of the kinematic rupture process on tsunami propagation and corresponding tsunami hazards in coastal regions. It is significant for the tsunageneric earthquakes of long fault length and subsequent long duration of the fault rupture in the strike direction. Most previous studies on the tsunami hazard assessments of the Manila Trench did not consider the effect of the rupture process of huge plates. The movements of the seabed near the earthquake source are calculated by Okada model. The free surface elevation triggered by the seafloor motion is modeled by the nonlinear shallow water equations. The 2004 Indian Ocean tsunami and the 2011 Japan Tohoku tsunami are used to validate the numerical model by comparing with measurement data. The numerical experiments of the tsunami propagation for the cases of different source rupture velocities in uniform depth and continental shelf are carried out to understand the mechanism of the changes of the tsunami arrival time and the tsunami amplitude due to the kinematic rupture process. Stimulated by the long duration of plate motion of 2004 Indian Ocean tsunami, we propose several typical patterns of the rupture process of the long fault of the Manila Trench and analyze quantitatively on the role of the uncertain rupture process of tectonics source in tsunami propagation in the South China Sea. Our results have highlighted that the slow rupture velocity will remarkable affect the tsunami arrival time and maximum amplitude in the South China Sea, comparing to the instantaneous rupture. It is suggested that the rupture process is essential for assessments of the tsunami hazards generated by submarine mass failure with extreme long earthquake rupture source. • The 2004 Indian Ocean tsunami and 2011 Japan Tohoku tsunami are simulated by using the dynamic source model. • Numerical experiments depict the changes of the tsunami amplitude and the arrival time due to different rupture velocities. • The kinematic effect of the rupture process on the propagation of a virtual extreme tsunami in the Souh China Sea is investigated. [ABSTRACT FROM AUTHOR]

Abstract Flood-inundation modelling is essential for understanding flood dynamics and implementing flood risk management. Despite its increasing demands, it remains computationally expensive to perform 2-D flood-inundation simulations at large scales or fine spatial resolutions. This study presents a simple and novel algorithm for 2-D flood-inundation modelling, called the Automatic Domain Updating method, which dynamically updates the simulation domain of a 2-D flood-inundation model. The method limits the simulation domain where governing equations are solved to flooded areas in each time step by tracking the location of wet and dry interfaces. The proposed algorithm was tested in an actual river basin for different types of flooding. The results show that the ADU method regulates the simulation domain to flooded areas and slashes the computational time for grid-based 2-D flood-inundation simulations typically by 5%–20%, with correspond to the ratio of flooded area to the whole simulation domain. [ABSTRACT FROM AUTHOR]

• Dryland wetland vegetation responds to inundation depth, duration and frequency. • Hydrodynamic modelling identifies if inundation requirements of vegetation are met. • Satellite/field data help detect inundation thresholds for vegetation transition. • Terrestrial vegetation invades wetlands after 4 years of inundation below threshold. Dryland wetlands receiving periodical floods are of key importance for ecological resilience. The inundation regime (i.e., frequency, duration, depth, and timing of inundation), is one of the major factors that determine the suitability of local conditions for specific wetland species. During droughts, inundation conditions can reach a threshold after which wetland vegetation could transition to dryland vegetation. This study analyses the response of vegetation to hydrologic variability in an arid wetland in Australia over a period of 22 years (including the Millennium drought) in order to identify inundation thresholds for transitions. We use numerical modelling, field observations and remote sensing data to relate continuous detailed simulations of the inundation regime with the response of patches of Common reed, Water couch and River red gum, three key vegetation associations in the study site. We focus in patches that were affected by the drought and presented dryland vegetation invasion as well as reference patches that remained healthy throughout the drought. On each patch, we compare annual and inter-annual simulated inundation regimes to the minimum inundation conditions that can support the specific vegetation, and we compute the percentage area of the patch that verifies minimum inundation for each year. We define this area percentage as minimum inundation index. This index is analysed in conjunction with Landsat derived information on green vegetation coverage (green Seasonal Fractional Cover) for the selected patches. We found that the minimum inundation index and inter annual frequency are able to describe the vegetation dynamics of the patches, which can be characterised by two distinct response modes that depend on a threshold value of the minimum inundation index. Inundation below the threshold noticeably leads to degraded vegetation, but the vegetation can recover quickly if this threshold is later maintained for one or two years. Values below the threshold for more extended periods (drought) result in a gradual decrease of wetland vegetation to almost complete disappearance after four years and subsequent dryland vegetation invasion. [ABSTRACT FROM AUTHOR]

• Presents a typology of emergent risk that highlights the iterative and inter-related nature of climate change risk, and propensity for impacts, such as legal action and reduced debt access, to emerge subsequent to, yet far removed from, initial physical impacts. • Highlights current practice and gaps in local government risk management concerning emergent risk. • Highlights the potential and need for local government to consider, the application of risk transfer mechanisms such as catastrophe bonds in the face of historical and conceivable climate change-perpetuated reduced access to, and increased cost of, traditional mechanisms such as insurance. • Provides insight into barriers and enablers to local government agencies gaining an appreciation of the potential application of alternative risk transfer mechanisms. Insurance represents an integral part of local government risk management strategy. As climate change progresses, increased loss and risk related to extreme weather events such as tropical cyclones, could motivate insurers to withdraw from certain markets. In some regions, such a withdrawal represents an emergent risk that, when coupled with increasing populations and other climate change impacts, could leave local governments and ratepayers particularly vulnerable. This paper investigates such a scenario and its ramifications in the context of a region particularly vulnerable to climate change, through an exploration of the degree that consideration of emergent risks, such as loss of insurance, and the potential application of insurance alternatives influence Queensland local government risk management. The study finds little appreciation amongst government officials of emergent risk implicit in extreme weather events such as cyclones, little understanding of the nuances of risk transfer mechanisms beyond familiar traditional insurance and disaster funding mechanisms, and by default, a lack of appreciation of the relationship between the two. A lack of resource and leadership with respect to emergent risk, and an absence of dialogue between insurance brokers and local government concerning climate change risk arise as the main reasons for this result. This research is significant because it challenges current local government risk management practice through an exploration of the risks inherent in the process itself. This has potential social, economic and ecological ramifications in drawing attention to aspects of possible "uninsurability" and prospects of alleviation thereto. Further research is recommended to consider the insurance industry's part in this study's findings in order to inform current industry practice and thinking and further enlighten the causes of local government disengagement in this critical area. [ABSTRACT FROM AUTHOR]

Abstract The potential tsunami hazard for atoll islands inside the South China Sea (SCS) has not been investigated previously. In this study, we assess the tsunami hazard for the Xisha Archipelago using a deterministic approach. The tsunami source considered in this study is hypothesized earthquakes in the Manila subduction zone. We employ COMCOT (COrnell Multi-grid Coupled Tsunami model) for tsunami simulations. Different with previous deterministic assessments, our study investigates the uncertainties caused by bathymetric resolution and rupture complexities (here refers to rupture speed and direction variations related to fault geometry complexity). Comparison between results of different resolution suggests that coarser grids may over/underestimate tsunami hazards around mid-ocean atoll islands and this depends on the surrounding bathymetry. But results of different datasets show that GEBCO may lead to a lower result than the multibeam data. We also investigate the uncertainties caused by different rupture speed and direction, which are highly affected by subducting seamounts/ridge. Different rupture direction will shift the hardest hit locations to areas, which are possibly underestimated in cases of instantaneous ruptures. Also, the distribution of slip and location of the rupture zone can affect the local tsunami wave height significantly. We suggest that near-island high-resolution bathymetric data and dynamic rupture process should be considered in future tsunami hazard assessment in locations with similar geological structures. Highlights • Tsunami hazard evaluation inside the SCS is taken for the first time, mainly focusing on the small scattered reef islands. • Tsunami hazard on atoll islands may be over/underestimated when using low-resolution bathymetry data. • Rupture complexity related to seamounts/ridge subduction along the Manila trench should be taken into consideration. [ABSTRACT FROM AUTHOR]

Digital elevation models (DEMs) derived from remote sensing data provide a valuable and consistent data source for mapping coastal flooding at local and global scales. Mapping of flood risk requires quantification of the error in DEM elevations and its effect on delineation of flood zones. The ASTER, SRTM, ALOS, and TanDEM-X (TDX) DEMs for the island of Hispaniola were examined by comparing them with GPS and LiDAR measurements. The comparisons were based on a series of error measures including root mean square error (RMSE) and absolute error at 90% quantile (LE90). When compared with >2000 GPS measurements with elevations below 7 m, RMSE and LE90 values for ASTER, SRTM, ALOS, TDX DEMs were 8.44 and 14.29, 3.82 and 5.85, 2.08 and 3.64, and 1.74 and 3.20 m, respectively. In contrast, RMSE and LE90 values for the same DEMs were 4.24 and 6.70, 4.81 and 7.16, 4.91 and 6.82, and 2.27 and 3.66 m when compared to DEMs from 150 km2 LiDAR data, which included elevations as high as 20 m. The expanded area with LiDAR coverage included additional types of land surface, resulting in differences in error measures. Comparison of RMSEs indicated that the filtering of TDX DEMs using four methods improved the accuracy of the estimates of ground elevation by 20–43%. DTMs generated by interpolating the ground pixels from a progressive morphological filter, using an empirical Bayesian kriging method, produced an RMSE of 1.06 m and LE90 of 1.73 m when compared to GPS measurements, and an RMSE of 1.30 m and LE90 of 2.02 m when compared to LiDAR data. Differences in inundation areas based on TDX and LiDAR DTMs were between −13% and −4% for scenarios of 3, 5, 10, and 15 m water level rise, a much narrower range than inundation differences between ASTER, SRTM, ALOS and LiDAR. The TDX DEMs deliver high resolution global DEMs with unprecedented elevation accuracy, hence, it is recommended for mapping coastal flood risk zones on a global scale, as well as at a local scale in developing countries where data with higher accuracy are unavailable. • Elevation accuracy of ASTER, SRTM, ALOS, and TDX DEMs for Hispaniola was assessed. • RTK GPS and LiDAR measurements were used as reference data for accuracy analysis. • TDX DEMs were filtered to remove building and tree pixels for generating DTMs. • The potential coastal inundation areas depicted by LiDAR and TDX DTMs were compared. • TDX DEMs provides the best global data source for mapping coastal flooding. [ABSTRACT FROM AUTHOR]

Highlights • EIM was proposed for urban flood hazard mapping at the large catchment scale. • SWMM model was introduced in floodwater generation process. • Floodwater spreading was based on topological relation of depression outlets. • Floodwater from lower depression elements was considered in EIM. • The performance of EIM was validated in terms of inundation locations and depths. Abstract Urban flooding occurs frequently in the world and urban hydrological models are widely applied in urban flood management and disaster mitigation. In this study, an enhanced inundation method (EIM) for urban flood hazard mapping at the large catchment scale is proposed. EIM can be easily coupled with urban hydrological models and the coupled framework can consider both source flooding and non-source flooding in floodwater generation. In EIM, the floodwater spreading order in the positive process is based on the topological relationship between depression outlets; the floodwater from lower depression elements is considered as a feedback process. These improvements make this proposed method suitable for inundation estimation in large urban catchments. Dahongmen (DHM) catchment in Beijing, China was selected as the case study area to illustrate the applicability of the proposed method. Historical inundation records during one heavy storm were applied to test the performance of the method. EIM is compared with USISM (urban storm-inundation simulation method) on the flood hazard map in the DHM catchment, which reveals the effectiveness of the improvements. The results show that all inundation locations are successfully identified by EIM and are distributed in flooding areas (water depth greater than 0.15 m) in the catchment. The average relative error of simulated inundation depths is 15%, which indicates that EIM can successfully simulate flooding scopes and depths in the study area. The results revealed that EIM can be a valuable tool for mapping urban flood hazards at the large catchment scale based on GIS techniques. [ABSTRACT FROM AUTHOR]

Highlights • A multi-level framework for stress testing port infrastructures is presented. • Regulatory requirements do not exist, and risk objectives are based on judgments. • Critical components are identified, and recommendations are provided. • The results depend on the stress test level, analysis approach, and risk metrics. • The systemic risk for the tsunami hazard is very low compared to seismic risk. Abstract An engineering risk-based methodology for stress testing critical infrastructures is introduced and applied to the port of Thessaloniki in Greece exposed to seismic, geotechnical and tsunami hazards. The methodology workflow consists of four phases: Pre-Assessment, Assessment, Decision and Report phase. In the pre-assessment phase, all the necessary information is collected and archived. For the pilot study, the inventory includes the main port components namely buildings, waterfronts, cranes and the electric power system. Generic or site-specific fragility models are used for all exposed elements and considered hazards. Risk metrics and objectives are defined related to the functionality of the system and the structural losses. In the first level of the assessment phase, the performance of each component is evaluated using a risk-based approach. Then, a system level probabilistic risk analysis is conducted separately for earthquake and tsunami hazards. A complementary scenario-based risk analysis is carried out aiming to investigate the impact of site-specific response and extreme seismic events to the performance of the port. In the Decision phase, the results are compared with predefined objectives to decide whether the infrastructure passes, partly passes or fails the test. Guidelines and strategies to improve the performance and resilience of the port are summarized. [ABSTRACT FROM AUTHOR]

This study develops a dynamic traffic microsimulation model for testing a mass evacuation of the Halifax Peninsula, Canada. The model is developed utilizing multiple data sources and calibrated using a Latin Hypercube (LH) sampling technique. The proposed microsimulation modeling framework adopts a Dynamic Traffic Assignment process to capture temporal variations in travel time and traffic congestion propagation during evacuation in the Halifax transport network. The study demonstrates the efficacy of the model in predicting traffic flows for evacuation due to floods of water level 2.9m, 3.9m, and 7.9m. Network level impacts as well as individuals' evacuation experiences are examined utilizing the developed model. The results suggest that it takes 22 hours to evacuate the Peninsula in the case of a flood of water level 2.9m. In case of all scenarios, it takes 6-8 hours to complete 50% evacuation, whereas the rest is evacuated in 14-16 hours depending on the extent of the road damages caused by the floods. Individuals departing early experience higher network and local level traffic congestion during evacuation. The model results will be useful for policy makers to develop evacuation plans and countermeasures. [ABSTRACT FROM AUTHOR]

Abstract Holocene sea level change in the northern Indian Ocean was studied using geochemical and geophysical approaches. Molluscs were sub-sampled for radiocarbon dating from sediment cores retrieved from a south Sri Lankan coastal lagoon. They were then combined with previously published sediment core radiocarbon ages from the same lagoon. We observe a ∼20-fold reduction in sedimentation rates at around 4 ka, attributed to a decrease in the rate of sea level rise. Previously reported radiocarbon ages based on total organic matter in the lagoon show remarkable agreement with our new dates suggesting stable and homogeneous sedimentation during the last 8 ka. Comparison of down core age trends of both data sets reveal that sediments are older than coeval molluscs, except for the horizons adjacent to the paleo Tsunami layers, indicating fresh and younger sediments are provided during Tsunami events, which could become a new proxy for identifying paleo Tsunamis. Compilation of previously reported sea level indicators from Sri Lanka, Southeastern India and the Maldives, together with predicted sea level obtained from a glacio-hydro-isostatic adjustment model (GIA), suggest that 3–4 m of global sea level equivalent ice sheet melting occurred during the Mid Holocene due to the retreat of the Antarctic and/or Greenland ice sheets. Previous works suggests late Holocene (ca. 4 ka) climate anomalies in both the low and high latitudes. We suggest the low latitude climate anomaly, transmitted via atmosphere to the high latitude during the late Holocene, seems to have induced changes in polar ice sheets. Highlights • Indian Ocean Holocene Sea level was studied at Sri Lanka, Southern India and Maldives. • GIA and relative sea level indicators revealed the melting history of Antarctic ice. • Antarctic ice sheet had been melted by 4000 years. • New identification method of past Tsunami layers are proposed. • Low latitude and high latitude climate connection via Atmosphere is considered. [ABSTRACT FROM AUTHOR]

Abstract To complement historical written records of tsunamis in the Nankai Trough and reconstruct prehistoric tsunami records, we conducted a coring survey at a coastal lowland in Mie Prefecture, central Japan. We found 10 sand layers deposited from about 4500 to 500 years ago. The layers are interpreted as tsunami deposits because of the presence of abundant bioclasts of marine organisms and sedimentary structures such as alternating sub-layers of sand and silt, rip-up clasts, and upward-fining structures, all of which are common in modern tsunami deposits. At the study site, no substantial seawater inundations and sand depositions have been recorded even for the largest typhoons to ever hit the region. There are historical accounts of earthquake and tsunami damage along the Nankai Trough in 1498, 1361, 1096, 887, and 684 CE. Estimated ages of the youngest three sand layers overlap well with tsunamis in 1498, 1096, and 684 CE. Our results support the hypothesis suggested by archaeological studies that the 684 CE rupture extended farther eastward than the historical record indicates or that another tsunami occurred at some time close to 684 CE. We did not find any sand layers that were definitely correlated with the tsunamis of 1361 and 887 CE, which are thought to have occurred by multi-segment ruptures of the Nankai Trough that includes the segment directly offshore from the study site. If the sand layers found at the study site were deposited by the tsunamis of 1498, 1096, and 684 CE, and if the tsunamis of 1361 and 887 CE did not inundate the study site, the tsunami recurrence interval during the relevant time period was about 400 years. This finding does not support the widely believed hypothesis that earthquakes and tsunamis occur at regular intervals of approximately 100 years in this area. In addition, similar to the historical tsunamis, intervals of geologically recorded prehistoric tsunamis at the study site vary from about 100 to 600 years. The hypothesis of variable recurrence of earthquakes and tsunamis along the Nankai Trough should be tested by future geological and historical studies in unbiased way. Highlights • Ten tsunami sand layers were observed on the Pacific coast of central Japan. • Two tsunami deposits were correlated with the tsunamis of 1498 and 1096 CE. • The age range of one tsunami deposit overlapped with the tsunami of 684 CE. • We did not find deposits definitely correlated to the 1361 and 887 CE tsunamis. • Intervals between geologically recorded tsunamis are not constant. [ABSTRACT FROM AUTHOR]

Harbours are crucial assets for the sustainment and development of human activities. The recent devastating tsunami events as well as the increasing number of people, structures and economic activities being exposed to tsunami hazards revealed the need for the estimation of the effects of tsunami wave on seaport structures. However, only a limited number of tools to estimate the potential impacts of tsunami are available until now. This study aims at developing analytical tsunami fragility functions for some representative typologies of seaport structures in Greece. In particular, low-code moment resisting frame (MRF) and dual reinforced concrete (RC) buildings of various heights, and a typical warehouse are considered in the analysis. A numerical investigation is performed considering different combinations of tsunami loads based on FEMA P646 (2008) [1] recommendations for gradually increasing tsunami inundation depths and for the various structure typologies. To minimize the uncertainties related to the definition of damage limit states, tsunami nonlinear static analyses are performed and appropriate tsunami capacity curves are derived for the considered structures. Structural limit states are defined on tsunami capacity curves in terms of threshold values of material strain. For the complete damage state, shear failure is also considered, since the collapse of structures may be caused by the occurrence of either a flexural or shear failure in structural components. Fragility curves are numerically calculated for the different damage states using nonlinear regression analysis. They could be used within a probabilistic risk assessment framework to assess the vulnerability of low-code RC buildings and typical warehouses exposed to tsunami hazard along European-Mediterranean and other regions of similar facilities worldwide. [ABSTRACT FROM AUTHOR]

The processes of tsunami inundation, sediment transport, and deposition on coastal lowlands are investigated experimentally. We conducted large-scale experiments with land slopes of 0.00 and 0.01 and compared them with experiments conducted previously with a slope of 0.02. The ratio of marine-originated sediment in the inland deposits decreased as the land slope decreased, reflecting the strong inundation flow and weak return flow. The sediment concentration near the bed increased remarkably and supplied a greater quantity of coarse sand inland when the land slope decreased, indicating the strong influence of land slope on bed load. The extent of sandy deposits and the inundation limit nearly corresponded with the sloping topographies. However, the inundation flow reached much farther inland than the sandy deposits on the flat (i.e., level) topography. This was because the extent of sandy deposits was determined by the flow speed, which depended in turn on the wave speed, whereas the inundation limit was determined by the inland water mass, which depended in turn on the waveform. The floating load reached the inundation limit and formed very thin and sparse muddy deposits. Considering the uncertainty of the waveform and the difficulty of detecting muddy deposits, it is more feasible to estimate the wave speed from the extent of sandy deposits. The spatial distributions of sandy deposits for various waves, land slopes, and topographies were characterized by the nondimensional area density and inundation distance. This result suggested the possibility of quantitative comparison among field investigations of tsunami deposits under various conditions. The formation of an inverse grading layer, experimentally observed in a wide range of inland deposits, was attributed to kinetic sieving. The bed load under slow deposition was speculated to thicken the inverse grading layer by reworking the coarse sand. Additionally, the sediment behind dunes became liquefied and showed shear deformation during the erosion. The shear deformation of liquefied sediment below the erosional surface might leave sedimentary characteristics specific to earthquake tsunamis. [ABSTRACT FROM AUTHOR]

The numerical investigation of tsunami evacuation is becoming a major way to assess the potential evacuation risks and consider countermeasures, but it has been mostly limited to GIS-based static analysis or macroscopic agent-based modelling due to the costs of large-scale simulations. In this paper, we propose a simplified force-based evacuation simulation model and an easy-to-implement parallelization strategy for a large-scale microscopic tsunami evacuation simulation and demonstrate its applications in an actual urban environment. First, the simulation performance was verified and validated against experimental and observational results regarding basic pedestrian movement. The test results qualitatively and quantitatively showed good agreement with real pedestrian movements. The model was then applied to a case of tsunami evacuations in Kesennuma City, where the 2011 Tohoku tsunami caused devastating damage. The model was successfully scaled up to provide urban-scale characterization. In this application, the developed simulator was implemented by a hybrid MPI/OpenMP parallelized computing technique. By utilizing the proposed model with parallel computing, we achieved an urban-scale microscopic evacuation simulation five times faster than real-time and a stochastic simulation to evaluate the uncertainty in the evacuation simulation. [ABSTRACT FROM AUTHOR]

This study investigates the impact of model complexity in source characterization and digital elevation model (DEM) resolution on the accuracy of tsunami hazard assessment and fatality estimation through a case study in Padang, Indonesia. Two types of earthquake source models, i.e. complex and uniform slip models, are adopted by considering three resolutions of DEMs, i.e. 150 m, 50 m, and 10 m. For each of the three grid resolutions, 300 complex source models are generated using new statistical prediction models of earthquake source parameters developed from extensive finite-fault models of past subduction earthquakes, whilst 100 uniform slip models are constructed with variable fault geometry without slip heterogeneity. The results highlight that significant changes to tsunami hazard and fatality estimates are observed with regard to earthquake source complexity and grid resolution. Coarse resolution (i.e. 150 m) leads to inaccurate tsunami hazard prediction and fatality estimation, whilst 50-m and 10-m resolutions produce similar results. However, velocity and momentum flux are sensitive to the grid resolution and hence, at least 10-m grid resolution needs to be implemented when considering flow-based parameters for tsunami hazard and risk assessments. In addition, the results indicate that the tsunami hazard parameters and fatality number are more sensitive to the complexity of earthquake source characterization than the grid resolution. Thus, the uniform models are not recommended for probabilistic tsunami hazard and risk assessments. Finally, the findings confirm that uncertainties of tsunami hazard level and fatality in terms of depth, velocity and momentum flux can be captured and visualized through the complex source modeling approach. From tsunami risk management perspectives, this indeed creates big data, which are useful for making effective and robust decisions. [ABSTRACT FROM AUTHOR]

The eroding coastal sections of Ashkelon, Israel contain exposed sequences of natural and anthropogenic sedimentological deposits; some of unknown origin. Ashkelon, an important and long-occupied ancient coastal city, is directly referred to within written records of past tsunami events yet field studies and archaeological descriptions have not yet corroborated these claims. This is not unusual, nor unexpected, given the amount of anthropogenic and natural disturbance that can erase the sedimentary remains, as well as the relatively recent advancements in identifying such deposits. A sequence of sediments at the base of an eroding coastal archaeological section shows clear waterborne transport characteristics and was previously interpreted as alluvial; however, no alluvial sources could be associated to the deposit. In this study, the sedimentological characteristics of this section were described and analyzed in greater detail to determine their nearest similarity to possible transport mechanism such as storms, rivers, and tsunamis. The deposits contain fining-upward sequences, rip-up clasts, imbricated inclusions, fine mud layers, microfauna (foraminifera), and broken diagnostic pottery from the 4–5th c. BC Reconstructions of the coastline at the time of the event place the sampled profile at least 100 m inland from the shoreline, at an elevation + 2.0 to 2.4 m above sea level. River-channel features were not identified in the section. For this area, modern observations of major storms show inundations of < 75 m which are not coupled with depositional deposits (erosional only), suggesting that these deposits are not storm-related. Rather, it is possible that the deposits support the arrival of an undocumented tsunami at Ashkelon some time following the 4–5th century BCE. These results reinforce the importance of the reassessment of many coastal sedimentological studies in light of improved capabilities of recognizing possible tsunamigenic sediments, as well as increased field efforts for the purpose of producing more complete tsunami catalogues; and also highlights the need to better record and document eroding coastlines that may contain valuable information regarding both anthropogenic and natural history. [ABSTRACT FROM AUTHOR]

An uncommon coastal sedimentary record combines evidence for seismic shaking and coincident tsunami inundation since AD 1000 in the region of the largest earthquake recorded instrumentally: the giant 1960 southern Chile earthquake (Mw 9.5). The record reveals significant variability in the size and recurrence of megathrust earthquakes and ensuing tsunamis along this part of the Nazca-South American plate boundary. A 500-m long coastal outcrop on Isla Chiloé, midway along the 1960 rupture, provides continuous exposure of soil horizons buried locally by debris-flow diamicts and extensively by tsunami sand sheets. The diamicts flattened plants that yield geologically precise ages to correlate with well-dated evidence elsewhere. The 1960 event was preceded by three earthquakes that probably resembled it in their effects, in AD 898–1128, 1300–1398 and 1575, and by five relatively smaller intervening earthquakes. Earthquakes and tsunamis recurred exceptionally often between AD 1300 and 1575. Their average recurrence interval of 85 years only slightly exceeds the time already elapsed since 1960. This inference is of serious concern because no earthquake has been anticipated in the region so soon after the 1960 event, and current plate locking suggests that some segments of the boundary are already capable of producing large earthquakes. This long-term earthquake and tsunami history of one of the world's most seismically active subduction zones provides an example of variable rupture mode, in which earthquake size and recurrence interval vary from one earthquake to the next. [ABSTRACT FROM AUTHOR]

After the 2004 Indian Ocean tsunami, the effectiveness of fringing reefs in protecting coastlines from tsunami-induced inundation has aroused great attention in the post-tsunami surveys. To better understand the role of fringing reefs in the mitigation of a tsunami hazard, laboratory experiments were conducted in a wave flume to study the transformation and run-up of tsunami-like solitary waves over various fringing reef profiles. The effects of incident wave height, reef-flat submergence, lagoon width and reef surface roughness were examined. Cylinder arrays were employed to create artificial roughness elements on the reef surface. Empirical formulas based on the experimental data were also proposed for the wave run-up. The ratio of the reef flat submergence to the incident wave height was always found to be the dominant parameter to characterize the wave run-ups over various tested reef profiles. Subsequently, a numerical model based on the improved Boussinesq equations including the drag effect of roughness elements was validated by the experimental data. The validated model was then applied to investigate the impacts of variations of reef morphologies (fore-reef slope, back-reef slope, reef-flat width, reef-crest width) on the solitary wave run-up. [ABSTRACT FROM AUTHOR]

In the present paper an appropriate model for Sri Lanka to build Disaster resilience nation, by participatory approach introducing evacuation zones through Eco-technological integration is discussed. The study was conducted in Gandara and Devinuwara area which underwent the Tsunami tragedy in 2004. A field survey was conducted through a structured questioner to collect the data on Tsunami impact and elevation in the area of four bays in Gandara which were affected due to the tsunami. Locational data were collected using GPS techniques. Evacuation sites were demarcated in the outer skirt of the Tsunami hazard zone, considering the factors of elevation, road accessibility, availability of common places, such as temples, schools in coordination with the disaster management center and other stake holder institutions. This helped to develop simulation maps for the planning processes of tsunami evacuation programs to build community resilience. Levels of inundation due to 2004 tsunami in the affected areas were demarcated through a Digital Elevation Model and appropriate evacuation sites and routes were identified to fix sign boards to follow in case of a tsunami warning. An eco-touristic approach is strictly followed to maintain the sustainability of the site. People mobilization and training programs were initiated by cataloging the historical and cultural heritages, Natural resources, Local wisdom and knowledge of the people, etc. to convert the sites in to an eco-touristic zone. In the investigated areas, the flooded area was demarcated as 172,380 square meters and the average distance covered by the wave inside the land as 90 meters with a maximum of 530 meters. The sustainable evacuation shelters for the future Tsunami evacuation programs in Gandara and Devinuwara areas were identified in Purana Viharaya and Jayabhodhi Viharaya in Gandara, and Wawwa temple in Devinuwara. [ABSTRACT FROM AUTHOR]

With the experience of storm surges along Persian Gulf of Iran it is needed to simulate storms in coastal areas and study the protection techniques in order to protect communities and industrial facilities in coastal areas. Mangrove forests play a unique role in attenuating storm surge during tropical cyclones. MIKE21 FM is an applicable software for simulating cyclones within coastal environments. A hydrodynamic model is used to analyze the attenuating role of the protected area of mangroves between Gheshm Island and Khamir Port mangroves under a realistic conditions by updating the calibrated Manning's coefficient based on the land cover data to incorporate the mangrove effect with modifying bottom friction and characteristics of cyclone Gonu 2007 which is the strongest cyclone recorded in the Arabian Sea and Persian Gulf. In this research we measured the maximum surge levels in both scenarios (in situ conditions and the condition which mangrove forest is neglected); maximum storm tide reduction by mangroves (MSTRM) by mangroves and maximum storm tide reduction rate by mangroves (MSTRRM). Also inundation maps are presented aiming to measure the areas rescued from inundation and the areas inundated caused by mangroves. The simulations shows that the minimum and maximum storm tide reduction rate by mangroves are 5.32% and 34.88% respectively. [ABSTRACT FROM AUTHOR]

A wall-flap-gate is automatic watertight door, and it works by buoyancy without powered machineries and human operations. In the Tohoku Earthquake tsunamis, serious damages were caused by inundation from ventilators of outer walls in power plants. The wall-flap-gate is estimated to be effective in keeping sustainability of nuclear plants against extreme tsunamis. The present study examines the hydrodynamic characteristics of the wall-flap-gate by hydraulic model experiments and verifies its capability of flood prevention for nuclear plants through various prototype tests. The experimental results proved that the wall-flap-gate had sufficient strength, watertightness, and durability against tsunamis and that its motion was not disturbed by debris. The viability of the wall-flap-gate as an inundation defence structure for nuclear plants was confirmed through this study. As a result, practical wall-flap-gates are installing on Hamaoka nuclear power station in Shizuoka prefecture, Japan. [ABSTRACT FROM AUTHOR]

The Arauco Peninsula (37°-38°S) in south-central Chile has been proposed as a possible barrier to the along-strike propagation of megathrust ruptures, separating historical earthquakes to the south (1960 AD 1837, 1737, and 1575) and north (2010 AD, 1835, 1751, 1657, and 1570) of the peninsula. However, the 2010 (M w 8.8) earthquake propagated into the Arauco Peninsula, re-rupturing part of the megathrust that had ruptured only 50 years earlier during the largest subduction zone earthquake in the instrumental record (M w 9.5). To better understand long-term slip variability in the Arauco Peninsula region, we analyzed four coastal sedimentary sections from two sites (Tirúa, 38.3°S and Quidico, 38.1°S) located within the overlap of the 2010 and 1960 ruptures to reconstruct a ∼600-year record of coseismic land-level change and tsunami inundation. Stratigraphic, lithologic, and diatom results show variable coseismic land-level change coincident with tsunami inundation of the Tirúa and Quidico marshes that is consistent with regional historical accounts of coseismic subsidence during earthquakes along the Valdivia portion of the subduction zone (1960 AD and 1575) and coseismic uplift during earthquakes along the Maule portion of the subduction zone (2010 AD, 1835, 1751). In addition, we document variable coseismic land-level change associated with three new prehistoric earthquakes and accompanying tsunamis in 1470–1570 AD, 1425–1455, and 270–410. The mixed record of coseismic subsidence and uplift that we document illustrates the variability of down-dip and lateral slip distribution at the overlap of the 2010 and 1960 ruptures, showing that ruptures have repeatedly propagated into, but not through the Arauco Peninsula and suggesting the area has persisted as a long-term impediment to slip through at least seven of the last megathrust earthquakes (∼600 years). [ABSTRACT FROM AUTHOR]

Research on disaster response frequently uses volunteered geographic information (VGI), due to its capability to provide near real-time information during and after a disaster. It is much less commonly used in spatial planning related to disaster management. However, VGI appears to have considerable potential for use in spatial planning and offers some advantages over traditional methods. For example, VGI can capture residents' preferences in a much faster, more timely, and more comprehensive fashion than is possible with, for example, questionnaires and surveys. This research investigates the usefulness of VGI for planning flood evacuation shelters. Using Jakarta, Indonesia, as a case study, we use VGI to capture the locations of flood evacuation shelters based on residents' preferences during flood periods in 2013–2014 and 2014–2015 and compare these with the locations of official shelters. Floods frequently affect Jakarta and the city administration uses VGI in flood emergency responses. Moreover, Jakarta has been identified as having the largest number of active Twitter users among cities worldwide. Thus, Jakarta is an appropriate place to study the use of VGI for planning evacuation shelters. VGI generated by Twitter users was used to identify the shelter locations preferred by Jakarta residents, and more precisely the flood evacuees. Of 171,046 tweets using keywords relating to flood evacuation, the content of 306 tweets indicated that they had been sent from inside or near evacuation shelters. The spatial pattern showed that those tweets were sent from 215 locations, mostly located near flooded areas. The analysis further showed that 35.6% of these shelter locations preferred by residents intersected with the locations of official evacuation shelters. As a general conclusion, our study demonstrates the advantages of using VGI for spatial planning, which mainly relates to the ease of capturing community preferences over a large area. [ABSTRACT FROM AUTHOR]

As more population migrates to coastal regions worldwide, earthquake-triggered tsunamis pose a greater threat than ever before. Stakeholders, decision makers, and emergency managers face an urgent need for operational decision-support tools that provide robust and accurate hazard assessments, when human lives and built environment are at risk. To meet this need, this study presents a new probabilistic procedure for estimating the likelihood that seismic intensity and tsunami inundation will exceed given respective hazard levels. The novelty of the procedure is that a common physical rupture process for shaking and tsunami is explicitly taken into account. The procedure consists of generating numerous stochastic slip distributions of earthquakes with different magnitudes using scaling relationships of source parameters for subduction zones and then using a stochastic synthesis method of earthquake slip distribution. Coupled estimation of earthquake and tsunami intensity parameters is carried out by evaluating spatially correlated strong motion intensity through the adoption of ground motion prediction equations and by solving nonlinear shallow water equations for tsunami wave propagation and inundation. The main output of the proposed procedure is the earthquake-tsunami hazard curves, representing the one-to-one mapping between mean annual rate of occurrence and seismic and inundation tsunami intensity measures. Results are particularly useful for coupled multi-hazard mapping purposes. The developed framework can be further extended to probabilistic seismic and tsunami risk assessment. [ABSTRACT FROM AUTHOR]

Earthquakes, tsunamis and gravity flows are common processes offshore Eastern Sicily and pose a significant hazard to coastal communities and infrastructure. The 1908 Messina earthquake and tsunami resulted in >60,000 casualties. It caused a large turbidity current, which broke the Malta-Zante telegraph cable. Yet, this gravity flow remains poorly characterised in terms of its route and flow behaviour. A comprehensive analysis of multibeam echosounder data, sub-bottom profiles, and sediment cores has been carried out to improve our understanding about gravity flow activity within conduit systems of the western Ionian Basin to reconstruct the characteristics of the 1908 sediment flow (e.g., erosion, velocity, source region). Three main canyon-channel systems can be distinguished within the study area. The easternmost system (C3) appears to be the most active in terms of sediment transport. There are numerous erosional and depositional bedforms, including large-scale scours (>100 m-long), turbidite sediment waves and channel wall collapses that are not overprinted by younger events. The other two canyon-channel systems (C1, C2) do not show many bedforms indicative of repeated and recent gravity flow activity. Indeed, the transport of the majority of sediment discharged into the western system (C1) is limited to <25 km downslope from the continental slope, while the central system (C2) facilitates sediment deposition from gravity flows. C3 is, thus, suggested to have been the main passageway of the 1908 sediment flow. It also leads directly to two of three cable break locations. The most likely source areas for the gravity flow are north-eastern Sicily and southern Calabria. Bedforms indicate a flow thickness of >170 m along the upper channel portion of C3 and > 140 m along its lower portion close to the cable breaks. An average flow velocity of 5.6 to 6.3 ms−1 is reconstructed, given the timing of the breaks and length of the canyon-channel system. The flow may have locally decelerated and accelerated while bypassing morphologic highs and knickpoints. These new findings significantly improve our understanding of the 1908 gravity flow (e.g., passageways, depositional/erosional behaviour, thickness, velocity) and provide important insights into gravity flow events in general, especially those with a large run-out. This knowledge is needed to assess potential hazards associated with these events. • the western Ionian Basin shows three distinct canyon-channel systems. • >140 m-thick gravity flow along main passageway in the east; velocity 5–6 m s−2. • numerous erosional and depositional bedforms (e.g., scours, sediment waves). • north-eastern Sicily and southern Calabria are potential source areas. • main failure likely offshore between San Leo and Bocale (southern Calabria). [ABSTRACT FROM AUTHOR]

We develop a framework for assessing the sensitivity and variability of tsunami inundation characteristics for stochastic physics-based scenarios of mega-thrust subduction earthquakes. The method is applied to the 2011 Tohoku, Japan earthquake, and tested against observed inundation maps at several locations along the Tohoku coast, using 11 different, previously published, rupture models for this devastating tsunamgenic earthquake. The earthquake rupture models differ in fault dimension (length and width), geometry (dip, strike and top-edge depth), as well as asperity characteristics (slip heterogeneity on the fault plane). The resulting source variability allows exploring a wide range of tsunami scenarios for an M w 9 mega-thrust subduction earthquake in the Tohoku region to conduct thorough sensitivity analyses and to quantify the inundation variability. The numerical results indicate a strong influence of the reference source models on inundation variability, and demonstrate significant sensitivity of inundation to the details of the rupture realization. Therefore, relying on a single particular earthquake rupture model as a representative case when varying earthquake source characteristics may lead to under-representation of the variability of potential scenarios. Moreover, the proposed framework facilitates the rigorous development of critical scenarios for tsunami hazard and risk assessments, which are particularly useful for tsunami hazard mapping and disaster preparedness planning. [ABSTRACT FROM AUTHOR]

In the study of palaeotsunamis it is crucial to decipher the sedimentological record, to derive intensity of past events and to infer different inundation phases. To achieve this goal, it is important to apply high-resolution techniques that allow magnifying intra-deposit details (at a sub-centimetric scale) that otherwise would not be perceived; consequently, valuable information could be overlooked. In this work, we applied successfully high-resolution geochemical and grain-size analyses – XRF core-scanning and image analysis, respectively – to the AD 1755 tsunami deposit. This quartz sand enriched in bioclast deposit (exhibiting high Si/Al and Ca/Ti) was recognized in the coastal stratigraphic sequence of Salgados lagoon due to its contrasting composition when compared with the under and overlying mud layers with scarce bioclasts (exhibiting low Si/Al and Ca/Ti). In the absence of textural evidence, the identification of peaking concentrations of Cl, S and Br (all major constituents of sea salt) in a continuous muddy sequence allowed slightly extending farther inland the limit of inundation. In addition, grain-size analysis data attested the fining inland of the deposit. Furthermore, despite the macroscopic massive structure of the tsunami deposit, throughout the lagoon, grain-size results revealed more complexity and allowed inferring up to four depositional sequences directly associated with the AD 1755 tsunami inundation. [ABSTRACT FROM AUTHOR]

Washover fans typically form due to barrier overwash or breaching and coastal inundation and generally represent geomorphological and depositional evidence of intense storms. Few studies have investigated the chronostratigraphy of washover fans in order to infer magnitude/frequency patterns of extreme-wave events over longer time scales. Here we present new data on the chronostratigraphy of late Holocene washover fans in the Exmouth Gulf (Western Australia) by using ground penetrating radar and unmanned aerial vehicle (UAV) survey techniques, as well as geomorphological, sedimentological and chronological investigations. This study aims to (i) provide a detailed characterization of the washover fans' geomorphology and stratigraphical architecture; (ii) document depositional processes involved in their formation; (iii) establish a chronostratigraphy based on optically stimulated luminescence (OSL); and (iv) understand the significance of the washover fans for recording past tropical cyclone (TC) activity. The fans consist of multiple sequences of sand, shell debris and coral rubble comprising depositional units related to TC-induced inundation. The units are separated by palaeosurfaces with incipient soil formation, formed during periods of reduced depositional activity. In combination with the interpretation of a UAV-based high-resolution digital surface model, multiple phases of reactivation are inferred. OSL results allow the establishment of a local long-term TC record and suggest storm-induced deposition at ∼170, ∼360, ∼850 and ∼1300 years ago. Further units were dated to ∼1950, ∼2300, and ∼2850 years ago. The chronology of TC events is consistent with other work relating TC activity with El Niño Southern Oscillation (ENSO) and sea surface temperature (SST) patterns, corroborating the regional palaeotempestological relevance of this unique geomorphological record. [ABSTRACT FROM AUTHOR]

The recent M w = 7.8 Kaikoura (New Zealand) earthquake involved a remarkably complex rupture propagating in an intricate network of faults at the transition between the Alpine fault in the South Island and the Kermadec-Tonga subduction zone. We investigate the main features of this complicated rupture process using long-period seismological observations. Apparent Rayleigh-wave moment-rate functions reveal a clear northeastward directivity with an unusually weak rupture initiation during 60 s followed by a major 20 s burst of moment rate. To further explore the rupture process, we perform a Bayesian exploration of multiple point-source parameters in a 3-D Earth model. The results show that the rupture initiated as a small strike-slip rupture and propagated to the northeast, triggering large slip on both strike-slip and thrust faults. The Kaikoura earthquake is thus a rare instance in which slip on intraplate faults trigger extensive interplate thrust faulting. This clearly outlines the importance of accounting for secondary faults when assessing seismic and tsunami hazard in subduction zones. [ABSTRACT FROM AUTHOR]

The influence of flow velocity on structural damage induced by tsunami inundation is investigated to improve empirical fragility models considering flow velocity as explanatory hazard variable in addition to inundation depth. The analysis is based on extensive tsunami damage data for the 2011 Tohoku earthquake collected by the Ministry of Land, Infrastructure, and Transportation of the Japanese Government. Multivariate tsunami fragility curves are developed through multinomial logistic regression of un-binned data. This approach facilitates the flexible development of various nested models considering inundation depth alone or inundation depth and velocity altogether. Statistical diagnostic metrics, such as the Bayesian Information Criterion, the Akaike Information Criterion, and the residual deviance, are used to determine which model improves the predictability of tsunami damage. The significance and importance of including flow velocity in the vulnerability models are assessed quantitatively by examining the influence of different spatial resolutions in elevation model and different source models. Then, the effects of coastal topography have been investigated. Numerical results show that flow velocity generally improves the fragility models, particularly for severer structural damage states, and that it is important for sites along the coast where the inundation depth is not extremely high. Coarse digital elevation model and inaccurate source models have influence on the calculated values of flow velocity and thus they affect the accuracy of fragility modeling. Finally, two different fragility models are calibrated for plain-type and ria-type coasts by reflecting differences in hydrodynamic behavior and recorded damage on the structures. [ABSTRACT FROM AUTHOR]

Much progress has been made since the first published studies of tsunami deposits nearly 30 years ago. Geochemistry is now a much more widely used proxy in tsunami research, mainly due to its increasingly recognised value in the identification of historical and/or prehistorical deposits, at times even providing the conclusive proof when other proxies are missing or equivocal, but also its significance in environmental impact assessments following recent tsunamis. The rapid advance in analytical techniques has also made it a more approachable and popular method, as it is now often faster and cheaper. Here we provide a review of the applications of geochemistry, including the techniques used, as well as a database of studies that used chemical proxies in their investigation of recent and old events, including onshore and offshore tsunami deposits. Chemical signatures are often used as markers of marine inundation, either as salinity indicators, where they can also allow the identification of the limit of tsunami inundation, or tracers of the incorporation of marine-sourced carbonates. Their applications as indicators of source material are nevertheless expanding, thereby potentially providing additional information on the hydrodynamic processes associated with tsunami inundation, although they are largely site-specific. The effects of post-depositional changes in different climatic regimes are examined, with a particular emphasis on water-leachable components and implications for post-event recovery of coastal ecosystems. We demonstrate the usefulness of chemical proxies in studies of the geological record of tsunamis extending back thousands of years, suggest new approaches and discuss limitations and existing knowledge gaps. [ABSTRACT FROM AUTHOR]

Banda Aceh was struck by the 2004 tsunami and submerged by seawater almost half a day and covered by mud monthly. The effect of the tsunami inundation for reinforce concrete (RC) buildings was the buildings become more susceptible to corrosion due to ion chloride intrusion. Hence, early failure might happen to the buildings because of rebar corrosion. It can be worsening by the earthquakes that frequently occur in the region. Thus, the corrosion monitoring for the buildings become important. The previous monitoring was taken on 2009 and 2012 and found that the corrosion level of the buildings already at intermediate to high risk. The objective of this study is to conduct corrosion risk monitoring for RC building after ten year the 2004 tsunami in Banda Aceh city, Indonesia. The monitoring was conducted using half-cell potential mapping technique that refers to ASTM C876 and performed in 2015. Three building in tsunami-affected area were chosen for the monitoring. The monitoring results show that the corrosion levels for the buildings located in the 2004 tsunami-affected area were at intermediate to high risk. Comparing the results with those on 2009 and 2012 indicated that the corrosion risk level tend to increase. Therefore, the regular monitoring and repairing are important to be carried out in order to hinder sudden failure of the buildings. [ABSTRACT FROM AUTHOR]

Managed Realignment (MR) schemes are considered by many coastal managers and engineers to be a preferable method of coastal flood defence and compensating for habitat loss, by creating new areas of intertidal saltmarsh and mudflat habitat. Monitoring of MR sites has tended to focus on short term ecological factors, resulting in a shortage of high frequency, high resolution long term measurements of the evolution of the sediment erosion, transportation, deposition and consolidation cycle (ETDC) in newly breached sites. This is particularly true of analysis of the formation and preservation of sedimentary rhythmites and evaluations of sedimentation rates (and their variability) in newly inundated intertidal environments. This study provides an evaluation of sedimentation rhythms and hydrodynamics from two contrasting sites within the Medmerry Managed Realignment scheme, the largest open coast realignment in Europe (at the time of site inundation). Bed sediment altimeter data highlighted different sedimentation patterns at the two sites; near constant deposition of sediment occurred near the breach resulting in 15.2 cm of sediment being accreted over the one year monitoring period, whereas periodic accretion and erosion of sediment occurred inland leading to 2.7 cm of net accretion. Differences in the relationship between suspended sediment concentrations and site hydrodynamics were observed on a semi-diurnal to annual scale. This study highlights the need for further consideration of the sedimentation processes in MR schemes in order to enhance the design and construction of these sites. Advancements in the understanding of these processes will increase the success of MR schemes in terms of the evolution of the sediment regime and the ecosystem services provided, particularly as they are more widely accepted as a form of coastal flood defence and intertidal habitat creation method. [ABSTRACT FROM AUTHOR]

Subduction mega-thrust earthquakes in the SW Ryukyu trench pose a seismic and tsunami hazard. One of the objectives of this study is to estimate the downdip width of the seismogenic zone using numerical modeling to determine the temperature distribution along the plate interface. However, this approach depends strongly on the thermal parameters of the subducting slab. While the Philippine Sea plate (PSP) subducting beneath the central and eastern Ryukyu arc is of Eocene age (35–50 Ma), its age west of the Gagua Ridge is uncertain, with proposed ages ranging from Lower Cretaceous (140 Ma) to Upper Eocene (35 Ma). Since the sparse available heat flow data are insufficient to resolve this debate, both end-member hypotheses are tested as input parameters. We examined two transects at 122.5°E and 123.5°E on either side of the N-S trending, 4-km high, Gagua Ridge. The shallow forearc geometry is obtained from wide-angle seismic data. The deep slab geometry was obtained from hypocenter distribution and tomography. For an Eocene slab age, we obtain a 100 km and 110 km wide seismogenic zone (between the 150 °C and 350 °C isotherms) west and east of Gagua Ridge, respectively. This is in good agreement with the observed distribution of hypocenters. Using a Cretaceous slab west of Gagua Ridge predicts a deep seismogenic zone (25 km–60 km depth), inconsistent with observed thrust earthquakes. Tomographic images at 122.5°E and 123.5°E show a similar slab thickness of 70–80 km suggesting that the oceanic lithosphere has a young (Eocene) thermal age. The westernmost PSP (Huatung Basin) may have been thermally rejuvenated by mantle convection near the slab corner. The tectonic history since 6 Ma (transition from subduction to collision beneath Taiwan) may have also perturbed the thermal structure. [ABSTRACT FROM AUTHOR]

The generation, propagation and inundation for a probabilistic near-field tsunami hazards assessment (PTHA) at the Cascadia Subduction Zone (CSZ) are analyzed numerically. For the tsunami hazard assessment, a new method is presented to characterize the randomness of the fault slip in terms of the moment magnitude, peak slip location, and a fault slip shape distribution parameterized as a Gaussian distribution. For the tsunami inundation resulting from the seismic event, five tsunami intensity measures (IMs) are estimated: (1) the maximum inundation depth, h Max , (2) the maximum velocity, V Max , (3) the maximum momentum flux, M Max , (4) the initial arrival time exceeding a 1 m inundation depth, T A , and (5) the duration exceeding a 1 m inundation depth, T h , and presented in the form of annual exceedance probabilities conditioned on a full-rupture CSZ event. The IMs are generally observed to increase as the moment magnitude increases, as the proximity of the peak slip becomes closer to the study area, and as the distribution of fault shape narrows. Among the IMs, the arrival time ( T A ) shows a relatively weak sensitivity to the aleatory uncertainty while the other IMs show significant sensitivity, especially M Max . It is observed at the shoreline that M Max increases by an order of magnitude from the 500-year to the 1000-year event, while h Max increases by a factor of 3, and T A decreases by only factor of 0.05. The intensity of IMs generally decreases inland, but there are also varying dependencies on bathymetry. For example, a shorter inundation duration, T h (< 10 min) is observed at the higher ground level (z > 3 m) while a longer T h (~ 100 min) is observed near the river and creek. [ABSTRACT FROM AUTHOR]

Recent studies suggest that the tsunami speed can be slowed down by around 1% due to Earth elasticity, water compressibility and density stratification. Analytical solutions of wave dispersion relationship, accounting for such effects, were found in previous studies. In this paper, we investigate the additional effects of water viscosity, ocean stratification due to temperature/salinity and numerical dispersion. Theoretical solutions are derived and checked with known solutions. All the formulas are then simplified for long tsunamis waves so that the propagation speed can be calculated explicitly. The simplified solutions are evaluated using realistic geophysical parameters. For a typical tsunami wavelength of ∼200km, the viscous effect is found to be negligible; ocean stratification due to temperature/salinity causes significant speed reduction because of the high density change rate, which has been ignored before. We also evaluate the numerical dispersion of tsunami simulations, which is shown to be potentially comparable to physical dispersion. [ABSTRACT FROM AUTHOR]