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The occurrence of large earthquakes followed by tsunamis west off Saint Vincent Cape before the 1755 Lisbon earthquakes is the subject of a historical review. There are historical evidences of the occurrence of such earthquakes. Among the possible earthquakes with some historical records in this area, those with better information are those at years 241 B.C., 216 B.C., 881, 1356 and 1531. Although not a subduction zone very large earthquakes have happened in this area. [ABSTRACT FROM AUTHOR]

Flooding is a recurrent hazard in east Gangetic plains, largely on account of natural factors that pose risks to life and property. Bagmati and Burhi Gandak rivers draining parts of North Bihar causes substantial flooding owing to higher rainfall. This comprehensive study was carried out to map near real-time flood inundation using multi-temporal Sentinel-1A (SAR) and Moderate-resolution Imaging Spectroradiometer Near Real-Time (MODIS NRT) flood data (Optical and 3-day composite) over Darbhanga district of North Bihar during August and September 2017. Floodwater pixels were extracted using the binarization technique, wherein the threshold was applied as −22.5, −23.4, −23.8 and − 22.7 over VH polarization image. The key results revealed that during peak flooding stage (23rd August), 13% of areas were submerged based on SAR data, whereas overestimation by >20% was estimated using MODIS data. As shown in the composite flood inundated map, the inundated patches are quite similar in both the optical and SAR based data. Notably, there were higher flood patches observed in the central, northern, and western parts of the district due to the presence of more water channels in those regions. Our findings suggested that agriculture patches of ~392 sq.km area were inundated due to flood followed by vegetation clutters (16.07 sq.km) and urban (8.46 sq.km). These results indicated the impact of floodwater on agriculture and urban patches. These findings are crucial for policymakers to assess flood impacts. It can be inferred that flood prognosis using SAR data will lead to spatial accuracy and can be improved when coupling with various hydro-meteorological parameters and hydrological models. [ABSTRACT FROM AUTHOR]

A tsunami caused by a flank collapse of the southwest part of the Anak Krakatau volcano occurred on 22 December 2018. The tsunami affected the coastal areas located at the edge of the Sunda Strait, Indonesia. To gain an understanding of the tsunami event, field surveys were conducted a month after the incident. The surveys included measurements of run-up height, inundation distance, tsunami direction, and sediment characteristics at 20 selected sites. The survey results revealed that the run-up height reached 9.2 m in Tanjungjaya and an inundation distance of 286.8 m was found at Cagar Alam, part of Ujung Kulon National Park. The tsunami propagated radially from Anak Krakatau and reached the coastal zone with a direction between 25 and 350 ∘ from the north. Sediment samples were collected at 27 points in tsunami deposits with a sediment thickness of 1.5–12.7 cm. The average distance from the coast of the area with significant sediment deposits and the deposit limit are 45 % and 73 % of the inundation distance, respectively. Sand sheets were sporadic, highly variable, and highly influenced by topography. Grain sizes in the deposit area were finer than those at their sources. The sizes ranged from fine sand to boulders, with medium sand and coarse sand being dominant. All sediment samples had a well-sorted distribution. An assessment of the boulder movements indicates that the tsunami run-up had minimum velocities of 4.0–4.5 m s -1. [ABSTRACT FROM AUTHOR]

Recent events in Aotearoa New Zealand, such as the Canterbury earthquakes in 2010 and 2011 and the Kaikōura earthquake in 2016, highlight the need for comprehensive and inclusive disaster education programs that are geographically and contextually relevant. Disaster risk reduction activities in Aotearoa New Zealand have historically adopted a top-down, expert-driven approach. They have also employed relatively homogenous methods for how communities in New Zealand can prepare for and respond to disasters. As a result, the inclusion of Māori communities and voices within traditional disaster risk reduction planning has been sparse. In addition, there is a lack of preparedness materials for tsunami designed specifically by Māori with Māori community needs front and centre. This paper documents a pilot education project taking an inclusive approach to increasing the knowledge and preparedness of tamariki (children) and rangatahi (youth) in coastal areas of Aotearoa New Zealand that are vulnerable to tsunami. Research was undertaken to develop a toolkit with kura kaupapa Māori (Māori-language immersion schools) and schools located in tsunami evacuation zones in Hawke’s Bay, on the east coast of the North Island. A Māori-led, bi-cultural approach to developing and running the activities was taken. The aim was to create culturally and locally relevant materials for ākonga (students) and kura kaupapa Māori as well as giving ākonga a proactive role in making their communities better prepared for a tsunami event. [ABSTRACT FROM AUTHOR]

In this paper, a set of models responsible for hydrodynamics, sediment transport, and morphological evolution are introduced with their theoretical backgrounds, and it is explained how they are fully connected through a two‐way coupling to yield an integrated sediment transport model applicable to tsunami cases. In particular, a fully nonlinear Boussinesq model with bottom shear‐induced rotational terms is chosen for the hydrodynamic model in order to provide a better physical approximation of tsunami‐related, near‐bed hydrodynamics in the nearshore. A finite‐volume scheme, stable and suitable for phase‐resolving model runs longer than 10 simulated hours, is adopted in the numerical discretization. The accuracy and applicability of the developed model are investigated through numerical tests on various sediment problems in the shallow region. Calculated results agree well with existing experimental records. Finally, an ocean‐wide, field‐scale simulation of the 2011 Tohoku‐oki tsunami is attempted, with a focus on the localized effects of tsunami‐induced morphological changes at Crescent City Harbor and Santa Cruz Harbor (USA). Consistent with the reported observations, strong and vortical velocity fields are generated through the model and result in significant changes in morphological configurations. Depth variations and areas of scouring and deposition are compared between modelled and observed records, and the results are discussed. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

One of the most essential inputs in flood inundation mapping is the geometric description of the floodplains and river channel that often derives from the digital elevation models (DEMs). By increasing the satellite-based technologies during the past 30 years, several DEM sources ranging from fine-resolution and accurate, but costly, to low-cost and low-resolution have been developed. In most parts of the world, especially developing countries and data sparse regions, the coarse resolution DEMs is the only available data set for hydraulic modelling and flood inundation mapping. This research addressed the usefulness and efficiency of the recently released Advanced Land Observing Satellite (ALOS) DEM in flood inundation mapping using 1D Hydrologic Engineering Centre- River Analysis System (HEC-RAS) model. In addition, other DEM sources such as Shuttle Radar Topography Mission (SRTM-90 m), SRTM-30 m, and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER-30 m) are used to carry out a comprehensive evaluation of remotely sensed DEMs for flood inundation mapping. Findings indicate that using ALOS-30m for hydraulic simulation approximately leads to the similar results as well as ground-based DEM (GDEM). For example, the Mean Absolute Percentage Error (MAPE) in simulating mean Water Surface Elevation (WSE) and mean inundated extents based on this dataset, within the cross-sections, is lower than 8% and 13% for SojasRood river, respectively, while for Sarbaz river these values are 9% and 2%. Moreover, in both rivers, SRTM-30 m relative to ASTER-30 m and SRTM-90 m DEMs presents better results in deriving the geometric model and hydraulic simulation. Also, Hydraulic modelling based on ASTER-30 m, even relative to SRTM-90 m as a coarser resolution DEM, shows a significant discrepancy compared to GDEM. Moreover, in both rivers, the MAPE in predicting inundated extents, within the reaches, is higher than 38%. [ABSTRACT FROM AUTHOR]

In 2011, after the Fukushima Dai-ichi Nuclear Power Plant accident, the initial decrease in the ambient dose equivalent rate (dH*(10) dt−1), an alternative quantity to the effective dose, was studied using monitoring data obtained from March 16, 2011. The dH*(10) dt−1 was normalized by the 137Cs activity per unit area (norm-dH*(10) dt−1) to analyze the data across monitoring sites with different deposition levels. The norm-dH*(10) dt−1 showed a rapid decrease during the first 60 days, followed by slow decrease and was modeled using two exponential functions. The norm-dH*(10) dt−1 obtained in areas dominated by paved surfaces and buildings showed a faster decrease than the unpaved-dominant field, and this decrease was facilitated in residential areas compared with the evacuation zone. The decrease in norm-dH*(10) dt−1 was compared with simulation results using parameters obtained in Europe after the Chernobyl Nuclear Power Plant accident that represent a decrease due to radionuclide migration (e.g., soil penetration and horizontal wash-off). The simulation results showed a faster decrease than our results, implying that there was less radiocesium migration in Fukushima than in Europe. The results also suggested that the regional variation in the decrease rate led to uncertainty regarding the external dose estimation. [ABSTRACT FROM AUTHOR]

Kim, D.-S.; Jeong, Y.-H.; Lee, H.-Y.; Kim, D.-H., and Hong, S.-J., 2020. Using hypothetical tsunami scenarios to analyze tsunami inundation characteristics in the coastal city of Ulsan, South Korea. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 1140–1145. Coconut Creek (Florida), ISSN 0749-0208. To establish a tsunami disaster prevention plan, including prior risk assessment and damage reduction for Ulsan in South Korea, a hypothetical scenario-based tsunami inundation simulation for 12 emergency evacuation areas was designed, and the inundation characteristics of the tsunami were analyzed. A hypothetical source 01 tsunami combined with a magnitude 9.0 earthquake affected the evacuation areas most significantly, while a hypothetical source 11 tsunami with a magnitude 7.5 earthquake had a relatively minor impact on the areas. In the Ilsan area of Ulsan, the hypothetical scenarios exhibited minimum and maximum inundation depths of 0.5 m and 6 m, respectively, and a maximum inundation area of about 206 km2. The tsunami inundation characteristics of the Ulsan area analyzed in this study will be useful for establishing an emergency action plan and countermeasures for tsunami situations. [ABSTRACT FROM AUTHOR]

Tropical cyclones (TCs) of the Bay of Bengal (BoB) cause catastrophic loss over the coasts at the time of landfall in India, Bangladesh, Myanmar and Sri Lanka. To strengthen TCs' disaster risk management works, it is obligatory to estimate their return periods and probability of occurrence. Therefore, in this study, extreme value theory has been employed for probabilistic assessment of BoB TCs' extreme wind speed. For TCs' extreme wind speed, Joint Typhoon Warning Centre data have been used for 44 years (1972–2015). The analyses exhibit that the cumulative probability of exceedance decreases from the cyclonic storms (CSs) to greater than supercyclonic storms (SupCSs) intensity. The exceedance probability of occurrence of CSs is about 99%, while it is about 15% for SupCSs and of greater intensity in the BoB. The most probable annual maxima show that at least one TC of hurricane category I (wind speed ≥ 64 knots) can occur every year. The return period exhibits that on an average one CS can occur once in about 0.27-years, whereas one SupCS can occur once in about 6 years in the BoB. Spatial plots of return period and probability with respect to TCs' extreme wind speed exhibit that coasts of West Bengal, Orissa, Andhra Pradesh and Tamil Nadu in India and entire Bangladesh and adjacent Myanmar coast are at high risk. This study provides a unique insight into BoB coastal countries TCs' extreme wind risk. It is assumed that estimated TCs' wind speed will be useful for government officials, scientists, disaster managers, engineers, public interest groups and private sectors. [ABSTRACT FROM AUTHOR]

Coastal inundation due to storm tides is computed using ADvanced CIRCulation (ADCIRC) model along the east coast of India. Inland inundation due to storm tides is calculated every 10 km along the coast by using synthetic tracks as described in Rao et al. (Nat Hazards, 2019. 10.1007/s11069-019-03804-z). The cyclonic winds are computed using a maximum pressure drop of the cyclone based on a 100-year return period. The coast is mapped for the maximum possible extent of inland inundation with water levels at the district level. The influence of climate change impact as a result of global warming on the coastal inundation is evaluated by enhancing the intensity of the cyclones. Peak water levels of about 10–12 m are found along the north of Odisha coast. The most vulnerable region in terms of coastal inundation in the present scenario is found in the districts of West Bengal; however, they are the least affected by about 5–6% due to climate change scenario (CCS). The most affected inundated districts by more than 50% due to CCS are observed in the Godavari deltaic region in Andhra Pradesh. Though the water levels in the Ramanathapuram District in Tamil Nadu reach more than 8 m in any scenario, the region is unaffected by the coastal inundation due to high local topography. By examining the inundated area of different water levels, it is revealed that more than 75% of the total area is inundated with greater than 2 m water levels in the northern districts of Odisha and Ramanathapuram District in Tamil Nadu. [ABSTRACT FROM AUTHOR]

The major (Mw 7.9) earthquake that struck the Gulf of Alaska near Kodiak Island on 23 January 2018 was a rare, mid-plate strike-slip event that triggered a minor trans-Pacific tsunami. An analysis of the simultaneous measurements of tsunami waveforms at 21 open-ocean sites (including three independent arrays of stations) and 27 coastal tide gauges in the Gulf of Alaska and along the coast of North America has enabled us to examine properties of the 2018 tsunami, its transformation over the continental slope and shelf, and its amplification as the waves approached the coast. Results show that the tsunami wave variance decreased monotonically along the west coast from northern British Columbia to southern Oregon. Based on the variance structure, the mean amplification factor for Tofino on the west coast of Vancouver Island (a "beacon" site with a long time series), was A RMS Tof = 5.3, in good agreement with corresponding estimates for four major past events; 4.5 (2009 Samoa), 4.3 (2010 Chile), 6.3 (2011 Tohoku) and 5.2 (2012 Haida Gwaii). This variance-derived amplification for Tofino was greater than the amplification factor based on the amplitude ratio ( A Tof = 3.2). Spectral analysis of the records showed that the tsunami had a relatively large high-frequency content (i.e., was "blueish"), with nearly 90% of the total energy in the open ocean at frequencies > 1.7 cph (periods < 35 min) and with an "integral frequency scale" of 4 cph (period 15 min). Wavelet analysis revealed strong dispersion of the propagating tsunami waves, in agreement with theoretical estimates. The abrupt jump in water depth of about 4 cm detected at DART 46409, located mid-plate about 85 km from the epicenter of the 2018 Kodiak earthquake, appears to have been due to an earthquake-induced seafloor subsidence. [ABSTRACT FROM AUTHOR]

Following the first volume (PAGEOPH, 2019, 176, No. 7), twenty-four papers on tsunamis are included in the PAGEOPH topical issue "Twenty five years of modern tsunami science following the 1992 Nicaragua and Flores Island tsunamis: Volume II," reporting on the frontiers of tsunami science and research. The first two papers overview meteorological tsunamis, discussing progress since the 1992 Daytona event, and examining the March 2017 Persian Gulf destructive event. The next four papers review historical tsunami events, starting with a paper providing statistics for the last 120 years. The 2018 Kodiak event is investigated in the following two papers. A set of five papers discusses tsunami-warning methodologies specifically for the Australia and Nankai (Japan) regions, and general tsunami warning approaches. Probabilistic tsunami hazard assessment including case studies for two Australian coasts and the Pacific Coast of Central America, as well as discussion regarding the effect of shallow slip amplification uncertainty, and tsunami hazard assessment for the Port of Ensenada, Baja California, are presented in the next five papers. Two papers discuss tsunami tide interaction, and the following two investigate landslide-generated tsunamis, specifically a tsunami landslide scenario study for the Maltese Islands, and the 1694 Ambon, Indonesia tsunami. Tsunami hydrodynamics studies investigating shoaling on steep continental slopes and transmission of long surface, and tsunami-like waves are presented in the last two papers. [ABSTRACT FROM AUTHOR]

Tsunami modelling is widely used to estimate the potential impacts of tsunamis. Models require a tide input, which can be either static, representing a specific tide level, such as Highest Astronomic Tide or dynamic, which represents a moving tide level. Although commonly used, static tide inputs do not account for tsunami–tide interactions, which are known to be non-linear and more significant in estuaries when compared to the open coast. To demonstrate the differences between tsunami models using static or dynamic tide inputs, a series of models were carried out for two New South Wales estuaries, Sydney harbour and port hacking. Model boundary conditions phased a MW 9.0 Puysegur source tsunami with multiple tide scenarios. Fourteen distinct scenarios with dynamic tides were created by phasing the largest tsunami wave peak at regular intervals across the tidal range. For comparison, static tide models were run using equivalent tide levels. The situations where static tide models provide results comparable or more conservative than dynamic tide models are for the first 1–2 h after tsunami arrival, at high tides, and when compared to dynamic falling tides at the same tide level. Differences are most apparent upriver of geomorphological constrictions. The effects of geomorphological constrictions were further examined using idealised model setups with a constriction variable. Results show that constrictions affect downriver maximum water levels, tsunami wave heights, upriver water accumulation and inundation maxima and distributions. These results have implications for estuaries vulnerable to erosion at constriction sites during a tsunami event. [ABSTRACT FROM AUTHOR]

We present an analysis of the oldest detailed account of tsunami run-up in Indonesia, that of the 1674 Ambon tsunami (Rumphius in Waerachtigh Verhael van de Schuckelijcke Aerdbebinge, BATAVIA, Dutch East Indies, 1675). At 100 m this is the largest run-up height ever documented in Indonesia, and with over 2300 fatalities even in 1674, it ranks as one of Indonesia's most deadly tsunami disasters. We consider the plausible sources of earthquakes near Ambon that could generate a large, destructive tsunami, including the Seram Megathrust, the South Seram Thrust, and faults local to Ambon. We conclude that the only explanation for the extreme run-up observed on the north coast of Amon is a tsunami generated by an earthquake-triggered coastal landslide. We use a two-layer tsunami model to show that a submarine landslide, with an approximate volume of 1 km3, offshore the area on Ambon's northern coast, between Seith and Hila, where dramatic changes in coastal landscape were observed can explain the observed tsunami run-up along the coast. Thus, the 1674 Ambon tsunami adds weight to the evidence from recent tsunamis, including the 1992 Flores, 2018 Palu and Sunda Strait tsunamis, that landslides are an important source of tsunami hazard in Indonesia. [ABSTRACT FROM AUTHOR]

The tsunami hazard for the Maltese Islands is poorly defined, and historic records are available for only two recent events. Most of the population and touristic infrastructure of the archipelago is concentrated along the eastern low-lying coastline, which is exposed to tsunamis from near-field and far-field sources. In this study we present a scenario-based tsunami inundation study to assess the impact of potential significant cases. We simulated four scenarios—two submarine landslide sources (outer Malta Plateau slide and Gela Basin slide) and two earthquake sources mimicking events comparable to the 365 A.D. western Hellenic Arc event and the 1693 south-east of Sicily event. We find that all scenarios cause inundation in densely populated low-lying bays or rias of Mellieha Bay, Xemxija, Salini, Gzira, Msida, Marsaskala, St Thomas Bay, Marsaxlokk and Birzebbuga. The largest inundation extents and flow depths (> 10 m) are produced by the two landslide sources and the western Hellenic Arc earthquake. Of interest is the role of the Malta Escarpment and Sicily in amplifying and reflecting tsunami waves, and in generating consistent hot spots along the eastern coastline of Malta. [ABSTRACT FROM AUTHOR]

The east coast of Tasmania is directly exposed to tsunamis originating from the Puysegur subduction zone, off New Zealand's southwest coast. However, the potential impacts of tsunami inundation for coastal communities and Hobart Airport, and risks to maritime operations in Hobart Port, are poorly understood. The purpose of this project is to simulate a maximum credible earthquake/tsunami/high tide scenario (a Mw 8.7 rupture of the Puysegur subduction zone) across a 17,000 km2 model area and provide outputs that can inform local hazard management plans. Modelling was performed using the ANUGA hydrodynamic library, along with a detailed elevation model constructed from LiDAR, photogrammetric contours and bathymetric datasets. The modelling strategy comprised three primary scenarios: a 13 h simulation of tsunami activity focusing on maritime hazard from waves and currents, with two further 4 h simulations focusing on coastal inundation for 71 coastal communities and Hobart Airport. The models were run on a variable triangulated mesh with a detailed Manning's n surface roughness model. Tsunami erosion of sand dunes was accounted for through the development of an erosion operator. Results predict severe inundation (> 4 m flow depth) in exposed east-facing areas and the maritime hazard assessment advises that water disturbance would pose a significant threat to marine craft. The assessment suggests that the feasibility of shipping evacuation from Hobart port is questionable, given the timeframes involved and the nature of simulated water disturbance. Modelling results suggest that the dune line in front of Hobart Airport would not be breached in this instance and so inundation would not occur. [ABSTRACT FROM AUTHOR]

Tsunami warnings issued by the Joint Australian Tsunami Warning Centre (JATWC) are derived from a database (T2) consisting of more than two thousand pre-computed tsunami scenarios. Following any potentially tsunamigenic earthquake, warnings are issued for individual coastal zones with three different levels of threat: Land Threat, Marine Threat or No Threat. The decision is based on the 95th percentile (P95) of the maximum wave amplitudes (over time) of the relevant T2 scenario within each coastal zone. Threshold values for P95 have previously been derived through analysis of observed impacts for recent events. Given that historical records are available for only a short time period and no observations exist for which a Land Threat would have been issued for Australia, it has been difficult to determine the appropriate threshold for a Land Threat. Several recent tsunami hazard assessment studies have used inundation models nested within T2 scenarios. These modelling results are used to evaluate the threshold values for JATWC tsunami warnings and provide guidance on a possible further warning tier—Major Land Threat. The optimal Land Threat threshold for P95 is found to be 48.5 cm, however, it is not recommended that any changes are made from the existing operational threshold of 55 cm. The optimal threshold for P95 a Major Land Threat is found to be 150.5 cm. [ABSTRACT FROM AUTHOR]

Historical data indicate that the Middle America subduction zone represents the primary tsunamigenic source that affects the Central American coastal areas. In recent years, the tsunami potential in the region has mainly been assessed using maximum credible earthquakes or historical events showing moderate tsunami potential. However, such deterministic scenarios are not provided with their adequate probability of occurrence. In this study, earthquake rates have been combined with tsunami numerical modeling in order to assess probabilistic tsunami hazard posed by local and regional seismic sources. The common conceptual framework for the probabilistic seismic hazard assessment has been adapted to estimate the probabilities of exceeding certain tsunami amplitudes along the Central American Pacific coast. The study area encompasses seismic sources related to the Central America, Colombia and Ecuador subduction zones. In addition to the classical subduction inter-plate events, this study also incorporates sources at the outer rise, within the Caribbean crust as well as intra-slab sources. The study yields conclusive remarks showing that the highest hazard is posed to northwestern Costa Rica, El Salvador and the Nicaraguan coast, southern Colombia and northern Ecuador. In most of the region it is 50 to 80% likely that the tsunami heights will exceed 2 m for the 500 year time exposure (T). The lowest hazard appears to be in the inner part of the Fonseca Gulf, Honduras. We also show the large dependence of PTHA on model assumptions. While the approach taken in this study represents a thorough step forward in tsunami hazard assessment in the region, we also highlight that the integration of all possible uncertainties will be necessary to generate rigorous hazard models required for risk planning. [ABSTRACT FROM AUTHOR]

Probabilistic Tsunami Hazard Assessment (PTHA) often proceeds by constructing a suite of hypothetical earthquake scenarios, and modelling their tsunamis and occurrence-rates. Both tsunami and occurrence-rate models are affected by the representation of earthquake slip and rigidity, but the overall importance of these factors for far-field PTHA is unclear. We study the sensitivity of an Australia-wide PTHA to six different far-field earthquake scenario representations, including two rigidity models (constant and depth-varying) combined with three slip models: fixed-area-uniform-slip (with rupture area deterministically related to magnitude); variable-area-uniform-slip; and spatially heterogeneous-slip. Earthquake-tsunami scenarios are tested by comparison with DART-buoy tsunami observations, demonstrating biases in some slip models. Scenario occurrence-rates are modelled using Bayesian techniques to account for uncertainties in seismic coupling, maximum-magnitudes and Gutenberg-Richter b-values. The approach maintains reasonable consistency with the historical earthquake record and spatially variable plate convergence rates for all slip/rigidity model combinations, and facilitates partial correction of model-specific biases (identified via DART-buoy testing). The modelled magnitude exceedance-rates are tested by comparison with rates derived from long-term historical and paleoseismic data and alternative moment-conservation techniques, demonstrating the robustness of our approach. The tsunami hazard offshore of Australia is found to be insensitive to the choice of rigidity model, but significantly affected by the choice of slip model. The fixed-area-uniform-slip model produces lower hazard than the other slip models. Bias adjustment of the variable-area-uniform-slip model produces a strong preference for 'compact' scenarios, which compensates for a lack of slip heterogeneity. Thus, both heterogeneous-slip and variable-area-uniform-slip models induce similar far-field tsunami hazard. [ABSTRACT FROM AUTHOR]

The most acceptable method to estimate tsunami inundation caused by a submarine earthquake is by conducting a nonlinear tsunami simulation. However, this method has the disadvantages of a relatively high computational cost and the necessity for immediate warning announcements when a tsunami is imminent. In this study, to overcome this problem, we apply two machine learning models, a convolutional neural network and a multilayer perceptron, to estimate tsunami inundation in real time. We run multiple fault scenarios and store the result of the maximum tsunami amplitude in a low-resolution grid and the associated tsunami inundation in a high-resolution grid in the database. The convolutional neural network selects tsunami inundation in the high-resolution grid as the forecast based on pattern similarity between the input, which is the results of linear forward modeling in the low-resolution grid, and the precomputed patterns in the database. Slightly different from the convolutional neural network, instead of selecting the best-fit scenario in the database, the multilayer perceptron directly generates the inundation forecast based on knowledge acquired during the training process. We conduct an experiment using the hypothetical future Nankai megathrust earthquake with Atashika and Owase Bays in Japan as the study cases. The results show that our proposed methods are extremely fast (less than 1 s) and comparable with nonlinear forward modeling. Therefore, the proposed methods can be used as a deterministic model for real-time simulation. [ABSTRACT FROM AUTHOR]

The complexity of coseismic slip distributions influences the tsunami hazard posed by local and, to a certain extent, distant tsunami sources. Large slip concentrated in shallow patches was observed in recent tsunamigenic earthquakes, possibly due to dynamic amplification near the free surface, variable frictional conditions or other factors. We propose a method for incorporating enhanced shallow slip for subduction earthquakes while preventing systematic slip excess at shallow depths over one or more seismic cycles. The method uses the classic k−2 stochastic slip distributions, augmented by shallow slip amplification. It is necessary for deep events with lower slip to occur more often than shallow ones with amplified slip to balance the long-term cumulative slip. We evaluate the impact of this approach on tsunami hazard in the central and eastern Mediterranean Sea adopting a realistic 3D geometry for three subduction zones, by using it to model ~ 150,000 earthquakes with M w from 6.0 to 9.0. We combine earthquake rates, depth-dependent slip distributions, tsunami modeling, and epistemic uncertainty through an ensemble modeling technique. We found that the mean hazard curves obtained with our method show enhanced probabilities for larger inundation heights as compared to the curves derived from depth-independent slip distributions. Our approach is completely general and can be applied to any subduction zone in the world. [ABSTRACT FROM AUTHOR]

On 19 March 2017, destructive tsunami-like waves impacted the northeast shore of the Persian Gulf (PG). The maximum surveyed runup of about 3 m was observed at Dayyer in southern Iran, where damaging waves inundated the land for a distance of ~ 1 km and resulted in the deaths of five people. Because the PG has always been considered safe from extreme oceanic waves, the event was totally unexpected. In this study, we examined sea level data from 12 stations across the PG and a variety of meteorological information, including satellite imagery, high-altitude isohypse maps and high-resolution air pressure records from 47 instruments along the PG. Our results show that the event was very local, with recorded maximum trough-to-crest wave heights of 197 cm at Dayyer and 234 cm at Asaluyeh, near-field cities in Iran located ~ 80 km apart. The dominant wave periods were in the range of 15–20 min. At all distant tide gauges, the observed wave heights were < 35 cm. No earthquakes or landslides were evident at the time of the event. On the other hand, atmospheric processes during 18–22 March were very active and 10 distinctive tsunamigenic air pressure disturbances were observed propagating over the PG, suggesting that the event of 19 March 2017 was a "meteorological tsunami". Atmospheric conditions over the PG were highly favourable for the generation of meteotsunamis and very similar to those that caused a chain of strong meteotsunamis in the Mediterranean and Black Sea regions during 23–27 June 2014. Based on the 500 hPa wind, we evaluated that the disturbances had propagation speeds of 21–38 m/s, with the disturbance at Dayyer having a speed of ~ 26 m/s toward 77° True. The Froude number, Fr (estimated as the ratio of the air disturbance speed to the long wave speed), on 19 March 2017 in the Dayyer/Asaluyeh region was close to resonance, Fr ~ 0.9 to 1.1, which is highly favourable for meteotsunami generation. Our findings indicate that the Dayyer/Asaluyeh area is a "hot spot" that is highly vulnerable to extreme, weather-induced tsunami-like waves. [ABSTRACT FROM AUTHOR]

On July 1, 2009, a Mw 6.45 earthquake ruptured south of Crete Island (Greece) along the Hellenic Arc triggering a local tsunami. Eyewitness reported the tsunami from Myrtos and Arvi (south-eastern Crete) and from the north of Chrisi Islet, located to the southeast of Crete. The earthquake occurred offshore, about 80 km south of Crete, where routine earthquake locations are poor. The hypocentre is relocated using a 2-D velocity model and several local 1-D velocity models. Epicentral locations obtained by using the different velocity models show very minor variations. Instead, relocated hypocentres can be grouped into two sets of solutions: (1) those with a shallower depth (depth < 12 km) obtained with the 2-D velocity model and the 1-D velocity models having a shallower Moho at less than 30 km, and (2) those with a larger depth (depth of 28 and 40 km) obtained with the velocity models having a Moho at about 40 km. Shallower hypocentres are more consistent with the tsunamigenic nature of the earthquake as also supported by tsunami numerical simulations. In fact, shallow sources (depths < 12 km) are capable of generating tsunami waves, while it is not the case for deeper sources (depth > 25 km) either in the upper-plate or along the plate interface. Models accounting for either homogeneous or heterogeneous slip on the causative fault are tested, with the heterogeneous one better reproducing the observations in terms of number of tsunami waves reaching the shoreline and duration of the sea disturbance. The short travel time, about 10 min, of the first tsunami arrival at the southern coast of Crete represents a big challenge for tsunami early warning systems operating in the area. [ABSTRACT FROM AUTHOR]

The characteristics of urban pluvial flooding are altering all over the world due to environmental change. In this paper, generalized additive models for location, scale and shape (GAMLSS) was employed to analyze nonstationary frequency of extreme precipitation at subdaily scale. Nonstationary precipitation return periods were estimated using the expected waiting time (EWT) interpretation. A model coupling SWMM and MIKE21 was established, and calibrated and verified by three historical urban floods. Then, it was utilized to simulate urban floods under stationary and nonstationary rainfall conditions with different return periods. The simulated results illustrated that rainfall depth under nonstationarity was greater than that of stationarity when return period was less than 10 years, but the results reversed when the return period was over 20 years. The main variation of rainfall depth occurred within 6 h. The deviation of the maximum water depth was less than 10% for five return levels, and the difference in the longest inundation lengths was 1.2 h for 50-year return period under two assumptions. It may indicate that slight differences of urban flooding were detected between stationary and nonstationary conditions in the study region, which suggested a further study about urban flood under nonstationarity. [ABSTRACT FROM AUTHOR]

Although tsunamis generated by submarine mass failure are not as common as those induced by submarine earthquakes, sometimes the generated tsunamis are higher than a seismic tsunami in the area close to the tsunami source, and the forecast is much more difficult. In the present study, reciprocal Green's functions (RGFs) are proposed as a useful tool in the forecast of submarine landslide tsunamis. The forcing in the continuity equation due to depth change in a landslide is represented by the temporal derivative of the water depth. After a convolution with reciprocal Green's function, the tsunami waveform can be obtained promptly. Thus, various tsunami scenarios can be considered once a submarine landslide happens, and a useful forecast can be formulated. When a submarine landslide occurs, the various possibilities for tsunami generation can be analyzed and a useful forecast can be devised. [ABSTRACT FROM AUTHOR]

A set of complex processes contribute to generate river runoff, which in the hydrological sciences are typically divided into two major categories: surface runoff, sometimes called Hortonian flow, and baseflow-driven runoff or Dunne flow. In this study, we examine the covariance of global satellite-based surface water inundation (SWI) observations with two remotely sensed hydrological variables, precipitation, and terrestrial water storage, to better understand how apparent runoff generation responds to these two dominant forcing mechanisms in different regions of the world. Terrestrial water storage observations come from NASA's Gravity Recovery and Climate Experiment (GRACE) mission, while precipitation comes from the Global Precipitation Climatology Project (GPCP) combined product, and surface inundation levels from the NASA Surface WAter Microwave Product Series (SWAMPS) product. We evaluate the statistical relationship between surface water inundation, total water storage anomalies (TWS; TWSAs), and precipitation values under different time lag and quality control adjustments between the data products. We find that the global estimation of surface inundation improves when considering a quality control threshold of 50 % reliability for the SWAMPS data and after applying time lags ranging from 1 to 5 months. Precipitation and total water storage equally control the majority of surface inundation developments across the globe. The model tends to underestimate and overestimate at locations with high interannual variability and with low inundation measurements, respectively. [ABSTRACT FROM AUTHOR]

China is one of the countries that are most seriously affected by storm surges. In recent years, storm surges in coastal areas of China have caused huge economic losses and a large number of human casualties. Knowledge of the inundation range and water depth of storm surges under different typhoon intensities could assist pre-disaster risk assessment and making evacuation plans, as well as provide decision support for responding to storm surges. Based on historical typhoon-induced storm surges in the study area of Pingyang County in Zhejiang Province, China, key parameters including typhoon tracks, radius of maximum wind speed, astronomical tide, and upstream flood runoff were determined for different typhoon intensities. Numerical simulations were conducted using these parameters to investigate the inundation range and water depth distribution of storm surges in Pingyang County under five different intensity scenarios (915, 925, 935, 945, and 965 hPa) with consideration of the impact of seawall collapse. The simulation results show that the range of storm surge inundation expands with increasing typhoon intensity. The scenario with the most intense typhoon (915 hPa) had the most adverse track, with an associated area of inundation of 233 km² that included most areas of the town of Aojiang, eastern areas of Wanquan, northern areas of Songbu, as well as parts of Kunyang and Shuitou. [ABSTRACT FROM AUTHOR]

Coastal flooding is increasingly common in many areas. However, the degree of inundation and associated disruption depend on local topography as well as the distribution of people, infrastructure and economic activity along the coast. Local measures of flooding that are comparable over large areas are difficult to obtain. Here we use the remarkability of flood events, measured by flood-related posts on social media, to estimate county-specific flood thresholds for shoreline counties along the east coast of the United States. While thresholds in most counties are statistically-indistinguishable from minor flood thresholds of nearby tide gauges, we find evidence that several areas experience noticeable flooding at tide heights lower than existing flood thresholds. These 22 counties include several major cities such as Miami, New York, and Boston, with a total population over 13 million. Our analysis implies that large populations might currently be exposed to nuisance flooding not identified via standard measures. The degree of flooding in a particular location depends sensitively on local topography and bathymetry. Here the authors used the remarkability of flood events to estimate county-specific flood thresholds for shoreline counties along the Atlantic and Gulf coasts of the United States and found that several areas experience noticeable flooding at a height lower than existing thresholds. [ABSTRACT FROM AUTHOR]

Natural hazards are naturally occurring physical events that can impact human welfare both directly and indirectly, via shocks to ecosystems and the services they provide. Animal‐mediated pollination is critical for sustaining agricultural economies and biodiversity, yet stands to lose both from present exposure to natural hazards, and future climate‐driven shifts in their distribution, frequency, and intensity. In contrast to the depth of knowledge available for anthropogenic‐related threats, our understanding of how naturally occurring extreme events impact pollinators and pollination has not yet been synthesized. We performed a systematic review and meta‐analysis to examine the potential impacts of natural hazards on pollinators and pollination in natural and cultivated systems. From a total of 117 studies (74% of which were observational), we found evidence of community and population‐level impacts to plants and pollinators from seven hazard types, including climatological (extreme heat, fire, drought), hydrological (flooding), meteorological (hurricanes), and geophysical (volcanic activity, tsunamis). Plant and pollinator response depended on the type of natural hazard and level of biological organization observed; 19% of cases reported no significant impact, whereas the majority of hazards held consistent negative impacts. However, the effects of fire were mixed, but taxa specific; meta‐analysis revealed that bee abundance and species richness tended to increase in response to fire, differing significantly from the mainly negative response of Lepidoptera. Building from this synthesis, we highlight important future directions for pollination‐focused natural hazard research, including the need to: (a) advance climate change research beyond static "mean‐level" changes by better incorporating "shock" events; (b) identify impacts at higher levels of organization, including ecological networks and co‐evolutionary history; and (c) address the notable gap in crop pollination services research—particularly in developing regions of the world. We conclude by discussing implications for safeguarding pollination services in the face of global climate change. [ABSTRACT FROM AUTHOR]

In this research, we have conducted a numerical simulation to obtain the seismic source, coseismic deformation field, and the tsunami propagation of the great Lima-Peru 1940 earthquake and tsunami, based on macroseismic information and focal mechanism from the literature. The seismic dimensions of our preferred model were set at 162 km×71 km according to VIII isoseismal intensity. The slip distribution is homogeneous with a mean value of 2.7 m. The fault plane orientation was set at strike = 330∘, dip = 20∘, and rake = 90∘. The maximum simulated uplift was 1.27 m and the maximum subsidence was 0.36 m. Due to the proximity of the seismic source to the coast, the city of Huacho was uplifted around 11 cm. The fault plane of the 1940 earthquake was located in the updip near the coast. The maximum tsunami height simulated in Huacho was 1.80 m. We suggest that there is a high tsunamigenic potential near the trench to generate a shallow earthquake. [ABSTRACT FROM AUTHOR]

We relocated the seismicity in SE Aegean that was recorded by both permanent and temporary seismic networks during 2004–2018 in order to investigate its correlation with the active faults in this area. P and S-phase travel times of best quality events were used to estimate a minimum 1D velocity model with station delays by utilizing VELEST. This velocity model and station delays were then used to obtain absolute locations of 3055 events, utilizing the probabilistic nonlinear algorithm NLLOC. The double-difference algorithm was used along with catalog and cross-correlation differential times to relocate all the events, resulting in 2200 precise relative locations with horizontal and vertical uncertainties of less than 1.0 km. The precise locations delineated faults along the Gulf of Gökova, SW of Nisyros, and Karpathos area. Based on the comparison of the resulting seismicity distribution with the regional stress field, it can be concluded that seismicity only occurred along faults with ENE-WSW strike in the area north of Tilos and N-S strike in the area south of Tilos. Seismogenic layer thickness estimated from the hypocentral depth distribution was found to vary between 12.1 and 15.4 km. Expected moment magnitudes of faults in this area were calculated by using their geometrical properties and the seismogenic layer thickness, yielding magnitudes in the range of 5.9–6.9. The fact that most of the seismically active faults in SE Aegean lie offshore increases the probability that a major earthquake will be followed by a tsunami and calls for the close monitoring of seismicity in this area. [ABSTRACT FROM AUTHOR]

Wetlands are permanently or seasonally flooded areas which support countless species of plants and animals. The Pantanal, in central‐west Brazil is one of the largest freshwater wetlands in the world covering an area of ~150 000 km2. The relationships between geomorphology, hydrology, sedimentation, and vegetation cover are critical for understanding how the landscape constrains the dynamics of wetlands. We provide a detailed study of the geomorphology and surface hydrology of the Negro River Interfan System (NRIS), in the southern Pantanal, by applying multiple approaches (i.e. remote sensing analysis, geomorphological zonation and hydrosedimentological surveys). A multitemporal analysis of Landsat imagery produced an inundation frequency map (2000–2011 period) that revealed a permanently flooded area in the central portion of the NRIS. A hidden fluvial lake was previously undetected due to the accumulation of floating mats and floating meadows of macrophytes. The Negro and Aquidauana feeder rivers exhibit remarkable differences in channel planform, water discharge, and sediment load. The Negro River presents a distributary pattern with marginal levees with decreasing elevation as it progrades into the lake and remains as a subaqueous landform conditioning the water flow downstream. The lake outflow to the Paraguay River occurs mainly by sheet flow during flood seasons and through small tributary channels during dry months. The lake's geometry is outlined by east–northeast and west–northwest straight borders, suggesting that the area is tectonically controlled. A cloud‐based worldwide water surface database (1984–2015) revealed frequent channel changes within the NRIS. Recent channel avulsions in the lower course of the Negro River are noteworthy mainly because the former river channel at the confluence with the Paraguay River is no longer connected with the Negro River channel. © 2019 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A methodology for a comprehensive probabilistic tsunami hazard analysis is presented for the major sources of tsunamis (seismic events, landslides, and volcanic activity) and preliminarily applied in the Gulf of Naples (Italy). The methodology uses both a modular procedure to evaluate the tsunami hazard and a Bayesian analysis to include the historical information of the past tsunami events. In the SourceModule the submarine earthquakes and the submarine mass failures are initially identified in a gridded domain and defined by a set of parameters, producing the sea floor deformations and the corresponding initial tsunami waves. Differently volcanic tsunamis generate sea surface waves caused by pyroclastic density currents from Somma‐Vesuvius. In the PropagationModule the tsunami waves are simulated and propagated in the deep sea by a numerical model that solves the shallow water equations. In the ImpactModule the tsunami wave heights are estimated at the coast using the Green's amplification law. The selected tsunami intensity is the wave height. In the BayesianModule the probabilistic tsunami analysis computes the long‐term comprehensive Bayesian probabilistic tsunami hazard analysis. In the prior analysis the probabilities from the scenarios in which the tsunami parameter overcomes the selected threshold levels are combined with the spatial, temporal, and frequency‐size probabilities of occurrence of the tsunamigenic sources. The prior probability density functions are integrated with the likelihood derived from the historical information based on past tsunami data. The posterior probability density functions are evaluated to produce the hazard curves in selected sites of the Gulf of Naples. Plain Language Summary: Probabilistic analyses are essential to estimate the natural hazards caused by infrequent and devastating events and to elaborate risk assessments aiming to mitigate and reduce the impact of the natural disasters on society. Probabilistic tsunami hazard analyses use procedures that trace and weight the different tsunami sources (submarine earthquakes, aerial/submarine slides, volcanic activity, meteorological events, and asteroid impacts) with varying probability of occurrence. The scope of the present methodology is the reduction of possible biases and underestimations that arise by focusing on a single tunamigenic source. The multisource probabilistic tsunami hazard analysis is applied to a real case study, the Gulf of Naples (Italy), where relevant threats due to natural events exist in a high densely populated district. The probabilistic hazard procedure takes into account multiple tsunamigenic sources in the region and provides a first‐order prioritization of the different sources in a long‐term comprehensive analysis. The methodology is based on a Bayesian approach that merges computational hazard quantification (based on source‐tsunami simulations) and past data, appropriately including in the quantification the epistemic uncertainty. For the first time a probabilistic analysis of the tsunami hazard in the region is presented taking into consideration multiple tsunamigenic sources. Key Points: A comprehensive methodology is proposed to evaluate the probabilistic hazard posed by different tsunamigenic sourcesA modular Bayesian methodology is used to treat different levels of epistemic uncertainty in a case studyThree major tsunamigenic sources (earthquakes, submarine landslides, and volcanic pyroclastic flows) are analyzed in the Gulf of Naples, Italy [ABSTRACT FROM AUTHOR]

On the evening of December 22, 2018, the coasts of the Sunda Strait, Indonesia, were hit by a tsunami generated by the collapse of a part of the Anak Krakatau volcano. Hundreds of people were killed, thousands were injured and displaced. This paper presents a preliminary modeling of the volcano flank collapse and the tsunami generated based on the results of a 2D depth-averaged coupled model involving a granular rheology and a Coulomb friction for the slide description and dispersive effects for the water flow part. With a reconstructed total volume (subaerial and submarine) of the landslide of 150 million m 3 inferred from pre and post-collapse satellite and aerial images, the comparison of the simulated water waves with the observations (tide gauges located all around the strait, photographs and field surveys) is satisfactory. Due to the lack of information for the submarine part of the landslide, the reconstructed submarine slope is assumed to be approximately constant. A significant time delay on the results and particularly in the Bandar Lampung Bay could be attributed to imprecisions of bathymetric data. The sensitivity to the basal friction and to dispersive effects is analyzed through numerical tests. Results show that the influence of the basal friction angle on the simulated wave heights decreases with distance and that a value of 2 ∘ gives consistent results with the observations. The dispersive effects are assessed by comparing water waves simulated by a shallow water model and a Boussinesq model. Simulations with frequency dispersion produce longer wave periods and smaller wave amplitudes in the Sunda Strait and particularly in deep waters. [ABSTRACT FROM AUTHOR]

This article presents improvements and the development of a postprocessing module for the regional-scale flood mapping tool, AutoRoute. The accuracy of this model to simulate low-, medium-, and high-flow-rate scenarios is demonstrated at seven test sites within the US. AutoRoute is one of the tools used to create high-resolution flood inundation maps at regional to continental scales, but it has previously only been tested using extreme flood events. Modifications to the AutoRoute model and postprocessing scripts are shown to improve accuracy (e.g., average F value increase of 17.5 % for low-flow events) and computational efficiency (simulation time reduced by over 40 %) when compared to previous versions. Although flood inundation results for low-flow events are shown to be comparable with published values (average F value of 63.3 %), the model results tend to be overestimated, especially in flatter terrain. Higher-flow scenarios tend to be more accurately simulated (average F value of 77.5 %). With improved computational efficiency and the enhanced ability to simulate both low- and high-flow scenarios, the AutoRoute model may be well suited to provide first-order estimates of flooding within an operational, regional- to continental-scale hydrologic modeling framework. [ABSTRACT FROM AUTHOR]

An urban flood in the Sadang area located in South Korea was reproduced using a rainfall simulator. The rainfall simulator was developed to be able to demonstrate the rainfall intensity in range of 80–200 mm/h, and the artificial rainfall was created using 42 full cone type nozzles in the urban model. The uniformity coefficient of the rainfall distribution was 89.5%, which indicates the rainfall simulator achieved the high requirements for spatial uniformity. The flood experiments in the 1/200 scale model of the Sadang area were conducted using the rainfall simulator, and the flood patterns were investigated by changing the rainfall intensity. The rainwater mainly accumulated in the lowland of the crossroad where the entrances to the subway station are located. The flow velocity and the inundation depth were sharply increased until the rainfall intensity became 160 mm/h. Furthermore, the unstable human activities based on the moment and the friction instabilities also occurred from 160 mm/h. These results suggest that the study area requires flood damage mitigation facilities considering a rainfall intensity exceeding 160 mm/h. [ABSTRACT FROM AUTHOR]

In the present study, the local tsunami amplification observed in Ryori Bay, located on the Sanriku coast of Japan, was investigated using numerical simulations. Large-scale tsunami propagation simulations and tsunami inundation simulations for the bay were systematically conducted to estimate and model the 2011, 1933, and 1896 tsunamis that occurred off the Sanriku coast and which resulted in large run-ups. The simulation results, which are moderately consistent with observations, presented larger run-up heights and inundations for the 1933 and 1896 tsunamis (which followed relatively small earthquakes) compared to those of the 2011 tsunami (which followed a larger earthquake). Furthermore, the frequency analysis indicated that the former two tsunamis comprised higher predominant components. A tsunami inundation simulation using parametrized synthetic waveforms was conducted to identify the contributing factors associated with the large amplification and run-ups. The results indicated that the predominant components are significantly amplified in the bay and the initial decrease in the water surface elevation prior to the primary waves of the two tsunamis leads to an increase in their run-up heights. Furthermore, the simulated waveforms of the tsunamis revealed that the 1933 and 1896 tsunamis had their wavefronts changed into a steep wavefront, i.e., a bore-like wave, during their wave developments in the bay, attributed to shoaling, narrowing bay width, and the nonlinear effect of the wave. These results, therefore, indicate that bores which are known to generate large run-up heights were generated in the bay during the two tsunamis. [ABSTRACT FROM AUTHOR]

The lack of offshore seismic data caused uncertainties associated with understating the behavior of future tsunamigenic earthquakes in the Makran subduction zone (MSZ). Future tsunamigenic events in the MSZ may trigger significant near-field tsunamis. Tsunami wave heights in the near field are controlled by the heterogeneity of slip over the rupture area. Considering a non-planar geometry for the Makran subduction zone, a range of random k - 2 slip models were generated to hypothesize rupturing on the fault zone. We model tsunamis numerically and assess probabilistic tsunami hazard in the near field for all synthetic scenarios. The main affected areas by tsunami waves are the area between Jask and Ormara along the shorelines of Iran and Pakistan and the area between Muscat and Sur along the Oman coastline. The maximum peak-wave height along the shores of Iran and Pakistan is about 16 m and about 12 m for the Oman shoreline. The slip distributions control the wave height along the Makran coastlines. The dependency of tsunami height on the heterogeneity of slip is higher in the most impacted areas. Those areas are more vulnerable to tsunami hazard than other areas. [ABSTRACT FROM AUTHOR]

Urban planning can serve to minimise the effects of a tsunami and enhance community resilience. This study explores to what extent urban planning has addressed tsunami resilience in four villages on Chile's South Pacific coast, each of which was struck by tsunamis in 1960, 2010, and 2015. Through a detailed policy review and semi‐structured interviews with residents, this paper analyses whether tsunami mitigation policies were incorporated into regional and local planning tools. It finds that although the government proposed relocation to tsunami‐safe areas after the tsunami of 1960, urban development continued mainly in tsunami inundation zones—in the context of weak local planning frameworks and in the absence of community participation. In only one of the four case studies did participatory planning bring about the relocation of an entire village to a safe location. This paper concludes that incorporating participatory risk zone planning into urban planning enhances tsunami resilience. [ABSTRACT FROM AUTHOR]

Riparian depressional wetlands (haors) in the Upper Meghna River Basin of Bangladesh are invaluable agricultural resources. They are completely flooded between June and November and planted with Boro rice when floodwater recedes in December. However, early harvest period (April/May) floods frequently damage ripening rice. A calibrated/validated Soil and Water Assessment Tool for riparian wetland (SWATrw) model is perturbed with bias free (using an improved quantile mapping approach) climate projections from 17 general circulation models (GCMs) for the period 2031–2050. Projected mean annual rainfall increases (200–500 mm or 7–10%). However, during the harvest period lower rainfall (21–75%) and higher evapotranspiration (1–8%) reduces river discharge (5–18%) and wetland inundation (inundation fraction declines of 0.005–0.14). Flooding risk for Boro rice consequently declines (rationalized flood risk reductions of 0.02–0.12). However, the loss of cultivable land (15.3%) to increases in permanent haor inundation represents a major threat to regional food security. [ABSTRACT FROM AUTHOR]

After recent large earthquakes, field investigations confirmed that several bridges were severely damaged and collapsed not only due to the earthquake, as an independent hazard, but also to the subsequent tsunami, landslide or fault displacement. In addition, long-term material deterioration might have an important impact on seismic damage to bridges. Therefore, it is important to study both independent and interacting hazards and their effects on the reliability and risk of bridges and bridge networks. Although earthquake is still a dominant hazard to bridges in many earthquake-prone countries, a life-cycle reliability and risk approach has to consider both independent and interrelated hazards causing bridge failure. Such an approach is presented in this paper. In addition, issues related to life-cycle analysis, design, risk, resilience and management of bridges under earthquake and other hazards are discussed. Finally, the concepts and methods presented are illustrated on both single bridges and bridge networks. [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]

A field survey team went to Palu City, Indonesia in the aftermath of the September 28th, 2018 earthquake and tsunami to investigate its effects on local infrastructure and buildings. The study focused on the coast of Palu Bay, where a tsunami wave between approximately 2 and 7 m high impacted the local community as a result of several complex tsunami source mechanisms. The following study outlines the results, focused on loading caused by debris entrained within the inundating flow. Damage to timber buildings along the coast was widespread, though reinforced concrete structures for the most part survived, providing valuable insights into the type of debris loads and their effects on structures. The results of this survey are placed within the context of Canadian tsunami engineering challenges and are compared to the recently-released ASCE 7 Chapter 6 – Tsunami Loads and Effects, detailing potential research gaps and needs. [ABSTRACT FROM AUTHOR]

The southern Peru and northern Chile coastal region is an active subduction zone that contains one of the most significant seismic gaps in the eastern Pacific basin (~ 17°S–~ 24°S). Although the gap was partially filled by the 2014 Mw 8.1 Iquique earthquake, there is still a high seismogenic potential to release a Mw ~ 9 earthquake in the near future; therefore, all the near-field coastal cities in the region face a latent tsunami threat. In this article, we propose a hybrid deterministic–stochastic multi-scenario approach to assess the current tsunami hazard level in the city of Iquique, an important commercial and industrial center of northern Chile that is home to 184,000 inhabitants. In our approach, we defined 400 stochastic, 10 deterministic and 10 homogeneous tsunamigenic earthquake scenarios, covering the entire area of the seismic gap. Based on the regional distribution of gravity anomalies and published interseismic coupling distributions, we interpreted the occurrence of four major asperities in the subduction interface of the seismic gap. The asperity pattern was used to construct a group of deterministic slip-deficit earthquake sources with seismic magnitudes ranging between Mw 8.4 and Mw 8.9. Additionally, we constructed 10 homogeneous slip scenarios to generate an inundation baseline for the tsunami hazard. Subsequently, following a stochastic scheme, we implemented a Karhunen–Loève expansion to generate 400 stochastic earthquake scenarios within the same magnitude range as the deterministic slip-deficit sources. All sources were used as earthquake scenarios to simulate the tsunami propagation and inundation by means of a non-hydrostatic model (Neowave 2D) with a classical nesting scheme for the city of Iquique. We obtained high-resolution data for flow depth, coastal surface currents and sea level elevation. The results suggest that the peak slip location and shelf resonance play an important role in the calculated coastal flow depths. The analysis of the entire set of simulated stochastic earthquake scenarios indicates that the worst-case scenario for Iquique is a Mw 8.9 earthquake. This scenario presented a tsunami arrival time of ~ 12 min, which is critical for the evacuation process. In addition, the maximum wave height and tsunami flow depth were found to be ~ 10 m and ~ 24 m, respectively. The observed coastal resonance processes exhibit at least three destructive tsunami wave trains. Based on historical and instrumental catalog statistics, the recurrence time of the credible worst-case earthquake scenario for Iquique (Mw 8.9) is 395 years, with a probability of occurrence of ~ 11.86% in the next 50 years. [ABSTRACT FROM AUTHOR]

To evaluate urban flood risk while considering spatial and temporal characteristics, this paper establishes an assessment method based on a coupled hydrodynamic model and a fuzzy comprehensive evaluation method. An assessment system is developed using hydrologic, social and economic factors. In addition, hydrology factors are obtained by the coupled hydrodynamic model. The hydrodynamic model is solved using the three-cascade method of the Saint–Venant equations for a river system, and the surface runoff is solved using a modified Roe-type approximate Riemann solver. The hydrology results are used as hydrologic factors and directly reflect the inundation of the subsequent assessment. Afterward, an analytic hierarchy process is used to calculate the weights of the assessment indices. Then, the urban flood risk is analyzed using the fuzzy comprehensive evaluation method. Five different rainfall events in Quzhou City are simulated and evaluated. The numerically computed results compare well with the statistical data and indicate an extreme inundation depth of more than 3 m. In addition, the assessment risk of Quzhou City is at level IV (high). This study shows that combining the assessment method with the coupled hydrodynamic model efficiently reflects the urban flood risk by considering flood, social and economic data. [ABSTRACT FROM AUTHOR]

Nowcasting refers to the use of proxy data to estimate the current dynamic state of driven complex systems such as earthquakes, neural networks, or the financial markets. In previous papers, methods to nowcast earthquakes have been presented based on the natural time count of small earthquakes after the last large earthquake in a defined, seismically active geographic region. In this method, a large geographic region is identified in which a local region of interest is embedded. The primary assumption in the method is that the frequency-magnitude statistics of the local region are the same as the frequency-magnitude relation of the large region. The nowcasting technique relies on seismic catalogs that are complete in the sense that all events whose magnitude is larger than a completeness threshold have been detected. For this reason, the previous papers have been limited to nowcasting large earthquakes with magnitudes of approximately M7.5. In this article, we extend the nowcasting method to great global earthquakes of magnitudes as large as M9 by defining the surrounding large region as the entire earth. We then analyze the current hazard of a number of selected "local" regions and rank the regions in terms of current risk of great earthquakes. These great events also present significant hazards for generating mega-tsunamis as well as local damage due to intense shaking. We also perform a sensitivity analysis to establish the reliability of the nowcasts. One of our main results is that the eastern Aleutian Islands, site of the M8.6 earthquake of 1 April 1946, is currently the region most at current risk of a great earthquake larger than M8.0. We finish by presenting comments on the applicability of our methods for anticipating the occurrence of great destructive earthquakes and tsunamis. [ABSTRACT FROM AUTHOR]

Emergency medical service (EMS) response is extremely critical for pre-hospital lifesaving when disaster events occur. However, disasters increase the difficulty of rescue and may significantly increase the total travel time between dispatch and arrival, thereby increasing the pressure on emergency facilities. Hence, facility location decisions play a crucial role in improving the efficiency of rescue and service capacity. In order to avoid the failure of EMS facilities during disasters and meet the multiple requirements of demand points, we propose a multi-coverage optimal location model for EMS facilities based on the results of disaster impact simulation and prediction. To verify this model, we explicitly simulated the impacts of fluvial flooding events using the 1-D–2-D coupled flood inundation model FloodMap. The simulation results suggested that even low-magnitude fluvial flood events resulted in a decrease in the EMS response area. The integration of the model results with a geographical-information-system (GIS) analysis indicated that the optimization of the EMS locations reduced the delay in emergency responses caused by disasters and significantly increased the number of rescued people and the coverage of demand points. [ABSTRACT FROM AUTHOR]

One of the greatest concerns for the Omani coastal infrastructure and developmental planning is the impacts of sea level rise (SLR) flooding in association with the extreme storm events. This paper argues that if coastal infrastructure in Oman is to be resilient, it is necessary to measure the extent of storm surge inundation effects to provide a better understanding for future coastal infrastructural development and planning. A hydrodynamic model, 3Di, developed by TU-Delft, the Netherlands, is used to simulate the May 9–11, 2002 storm surge inundation of Dhofar's coast in Oman. The model simulation is based on 60-min-interval water-level data for a 72-h, extreme storm event, coupled with 0.5, 1.0, and 1.41 m SLR for different inundation scenarios. 3Di's results included a series of inundated areas with 1-h-interval time steps that provided spatial inundation extents and water depth at every hour of an event. The study reveals that with SLR at 1.0 m and at 1.41 m, in terms of coastal development and infrastructure, it is largely roads that are vulnerable. This study provides a database to allow planners and decision makers to make informed decisions regarding the location of future infrastructure as a path toward resiliency in future coastal developmental and infrastructural planning in Oman. [ABSTRACT FROM AUTHOR]

On the 17th of June 2017, a massive landslide which mobilized ca. 35-58 million m³ of material entered the Karrat Fjord in western Greenland. It triggered a tsunami wave with a runup height exceeding 90 m close to the landslide, ca. 50 m on the opposite shore of the fjord. The tsunami travelled ca. 32 km across the fjord and reached the settlement of Nuugaatsiaq with ca. 1-1.5 m high waves, which were powerful enough to destroy the community infrastructure, impact fragile coastal tundra landscape, and unfortunately, injure several inhabitants and cause 4 deaths. Here we report the results of the field survey of the surroundings of the settlement focused on the perseverance of infrastructure and landscape damages caused by the tsunami, carried out 25 months after the event. [ABSTRACT FROM AUTHOR]

As one of the main natural disasters, flood disaster poses a great threat to township development and property security. Numerous hydrological models and hydrodynamic models have been developed and implemented for flood simulation, risk prediction and inundation assessment. In this study, a dynamic and bidirectional coupled hydrodynamic-hydrologic-hydrodynamic model (DBCM) is developed to predict and evaluate inundation impact in a catchment in mountain area. Based on characteristic theory, the proposed method is able to dynamically adapt and alternate the simulation domain of hydrologic model, and/or hydrodynamic model according to the local flow condition, and a key feature of the proposed model is the dynamic coupling splitting the hydrologic and hydrodynamic simulation domains. The proposed model shows good prediction accuracy and overcomes the shortage existing in previous unidirectional coupling model (UCM). Existing numerical examples and physical experiments were both used to validate the performance of DBCM. Compared to UCM, results from DBCM show good agreements with analytical and measured data which indicates that the proposed model effectively reproduces flood propagation process and accounts for surface flow interaction between non-inundation region and inundation region. Finally, DBCM is applied to predict the flood in the Longxi river basin, and the simulation results show the capability of DBCM in conducting flood event simulation in interested catchment which can support flood risk early warning and future management. [ABSTRACT FROM AUTHOR]