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The amount of disaster waste is one of the most important performance indicators in quantifying the resilience of a community. In fact, disaster waste can have significant negative impacts on the environment in affected regions and hinder the postdisaster recovery process. Appropriate disaster waste management should be developed in Japan before the occurrence of the Nankai Trough earthquake. It is expected that the seismic and tsunami intensities caused by the anticipated Nankai Trough earthquake will be substantially larger than those caused by the 2011 Great East Japan earthquake. In this paper, a risk‐based methodology is presented for estimating the amount of disaster waste generated by both the ground motions and the tsunami due to the anticipated Nankai Trough earthquake. First, Monte Carlo simulation‐based probabilistic hazard analyses are performed to obtain seismic and tsunami hazard curves considering the uncertainty associated with fault movement along the Nankai Trough. Structural damage data associated with past earthquakes are used to develop seismic and tsunami fragility curves. The amount of disaster waste generated from a single structure is defined as the generation unit and is determined based on past disasters. Finally, with the aid of a geographic information system, the risk of disaster waste can be estimated using the hazard and fragility curves and the generation units. As an illustrative example, the risk curves and expected values associated with disaster waste in Mie Prefecture, Japan, are estimated based on the proposed framework. [ABSTRACT FROM AUTHOR]

The Indian Tsunami Early Warning System (ITEWS) was established at the Indian National Centre for Ocean Information Services, Hyderabad in October 2007 following the devastating tsunami on 26 December 2004. The Intergovernmental Oceanographic Commission of United Nations Educational, Scientific and Cultural Organization (IOC/UNESCO) coordinated with the National Tsunami Warning Centers in the Indian Ocean region and promoted the establishment of a well-knit tsunami early warning system called Indian Ocean Tsunami Warning and Mitigation System (IOTWMS) so that all countries on the Indian Ocean can get benefitted. The end-to-end capabilities of this warning system have been well-proven during the tsunamigenic earthquakes that occurred since September 2007. The capability of the system is examined, with special reference to Indian Tsunami Early Warning System (ITEWS), to ascertain the readiness of the Indian Ocean region to face a major tsunami. [ABSTRACT FROM AUTHOR]

The Nankai-Tonankai megathrust earthquake and tsunami pose significant risks to coastal communities in western and central Japan. Historically, this seismic region hosted many major earthquakes, and the current national tsunami hazard assessments in Japan consider megathrust events having moment magnitudes between 9.0 and 9.1. In responding to the lack of rigorous uncertainty analysis, this study presents an extensive tsunami hazard assessment for the Nankai-Tonankai Trough events, focusing upon the southwestern Pacific region of Japan. A set of 1,000 kinematic earthquake rupture models is generated via stochastic source modelling approaches, and Monte Carlo tsunami simulations are carried out by considering high-resolution grid data of 10-m and coastal defense structures. Significant advantages of the stochastic tsunami simulation methods include the enhanced capabilities to quantify the uncertainty associated with tsunami hazard assessments and to effectively visualize the results in an integrated manner. The results from the stochastic tsunami simulations can inform regional and local tsunami risk reduction actions in light of inevitable uncertainty associated with such probabilistic tsunami hazard assessments, and complement conventional deterministic tsunami scenarios and their hazard predictions, such as those developed by the Central Disaster Management Council of the Japanese Cabinet Office. [ABSTRACT FROM AUTHOR]

This paper examines the effects of the 2012 revisions to the damage predictions of an anticipated Nankai Trough megathrust earthquake on subsequent inter-municipality migration in Japan's coastal areas. We find that an increase in predicted tsunami height—rather than anticipated seismic movements—after the 2012 revision is associated with a subsequent reduction in net migration. While the reducing effect of tsunami predictions on in-migration persisted throughout the study period, the effect on out-migration was only temporary. Moreover, working-age people are more likely to respond to tsunami risk and avoid moving to municipalities with a high tsunami risk after the revisions. [ABSTRACT FROM AUTHOR]

This article reviews tsunami modeling and its relation to recent developments of deep-ocean observations. Unlike near-coast observations, deep-ocean observations have enabled the capture of short-wavelength dispersive tsunamis and reflected waves from the coast. By analyzing these waves, researchers can estimate tsunami sources and earthquake slip distributions more reliably with higher spatial resolution. In addition, fractional tsunami speed reduction due to the elasticity of the Earth medium is now clearly detected. Densely and widely distributed tsunami sensors make it possible to observe tsunamis inside the earthquake focal area, and understanding tsunami generation mechanisms is increasingly important. In order to describe the generation field, we should consider seismic waves overlapping tsunami signals in addition to vertical and horizontal displacements at the sea bottom. The importance of elastic dynamics, in addition to fluid dynamics, is increasing in order for researchers to fully understand tsunami phenomena using the new offshore and inside focal area observations. ▪ Deep-ocean observations have advanced tsunami propagation modeling. ▪ New deep-ocean observations in earthquake focal areas are expected to detect in situ tsunami generation caused by megathrust earthquakes. ▪ The importance of elastic dynamics, in addition to fluid dynamics, is increasing to help researchers fully understand mechanics in tsunami generation and propagation. ▪ Tsunami modeling including earthquake rupture and seismic waves contributes to mega-thrust earthquake investigation and disaster mitigation. [ABSTRACT FROM AUTHOR]

In the last two decades, the vulnerability of coastal populations to the occurrence of natural phenomena such as tsunamis has increased, among other hazards that have existed throughout the development of civilizations and have constantly kept at risk the resources that a population needs for its development. The current study presents a representative sample of the perception of the population regarding the possibility of the occurrence of a natural phenomenon such as the tsunami on the Panamanian coasts. Although Panama is not at the top of the list of countries with high risk of current tsunamis, it does maintain an index that must be considered for the development of prevention strategies, so it is necessary to determine the perception of the population in order to execute contingency plans. The performed survey clearly demonstrates the poor preparation of the Panamanian population and the need for a drastic increase in the carrying out of all kinds of preventive activities towards tsunamis and their respective hazards. [ABSTRACT FROM AUTHOR]

This study aims to simulate tsunami wave heights and their travel time toward the West Kalimantan coastal area. A Nuclear Power Plant (NPP) will be developed in a coastal area in the West Kalimantan Province, Indonesia. The two scenarios of events that may trigger the tsunami waves are volcanic events caused by Mount Krakatau located in the Sunda Strait and tectonic subduction located at the Indian Ocean on the west side of the Sunda Strait. Modeling the tsunami propagation using a finite-element-based hydrodynamic model developed by the US Army Corps of Engineer, namely the Surface-water Modeling System (SMS), is carried out. The model simulates tsunami wave propagation for six alternative locations at the proposed site of NPP. The model domains consist of Sunda Strait and Karimata Strait domains. The Sunda Strait domain model is validated by the observed historical tsunami heights reaching the 12 locations in Lampung, Banten, West Java, and Jakarta of Indonesia. The model validations show a good agreement. The validated hydrodynamic model results of the Sunda Strait model are used as the boundary conditions for the Karimata Strait domain model. The Karimata Strait model results show that the peaks of tsunami wave heights that reach the western Kalimantan coast are between 12 cm and 116 cm. The minimum wave height peak that reaches the six prospective locations is 12 cm, which is located in Sambas Regency. [ABSTRACT FROM AUTHOR]

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]

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]

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]

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]

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]

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]

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]

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]

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]

The estimate of an individual wave run-up is especially important for tsunami warning and risk assessment, as it allows for evaluating the inundation area. Here, as a model of tsunamis, we use the long single wave of positive polarity. The period of such a wave is rather long, which makes it different from the famous Korteweg–de Vries soliton. This wave nonlinearly deforms during its propagation in the ocean, which results in a steep wave front formation. Situations in which waves approach the coast with a steep front are often observed during large tsunamis, e.g. the 2004 Indian Ocean and 2011 Tohoku tsunamis. Here we study the nonlinear deformation and run-up of long single waves of positive polarity in the conjoined water basin, which consists of the constant depth section and a plane beach. The work is performed numerically and analytically in the framework of the nonlinear shallow-water theory. Analytically, wave propagation along the constant depth section and its run up on a beach are considered independently without taking into account wave interaction with the toe of the bottom slope. The propagation along the bottom of constant depth is described by the Riemann wave, while the wave run-up on a plane beach is calculated using rigorous analytical solutions of the nonlinear shallow-water theory following the Carrier–Greenspan approach. Numerically, we use the finite-volume method with the second-order UNO2 reconstruction in space and the third-order Runge–Kutta scheme with locally adaptive time steps. During wave propagation along the constant depth section, the wave becomes asymmetric with a steep wave front. It is shown that the maximum run-up height depends on the front steepness of the incoming wave approaching the toe of the bottom slope. The corresponding formula for maximum run-up height, which takes into account the wave front steepness, is proposed. [ABSTRACT FROM AUTHOR]

The Italian Tsunami Alert Centre of the Istituto Nazionale di Geofisica e Vulcanologia (Centro di Allerta Tsunami, hereinafter CAT-INGV) supported a computer-assisted telephone interview (CATI) survey to investigate tsunami risk perception in two pilot regions of southern Italy. The survey was carried out on a stratified sample of 1021 interviewees representing about 3.2 million people living in 183 coastal municipalities of the two regions, namely Calabria and Apulia. The main goal of this research is to verify whether and how people's perception of tsunami hazard compares to the results of (PTHA) – probabilistic tsunami hazard assessment (TSUMAPS-NEAM project; Basili et al., 2018). As shown by the results of this project, both investigated regions are characterised by high tsunami hazard. Nonetheless, the long return time of such events could lead people to consider the occurrence of a tsunami in the Mediterranean Sea to be very unlikely. The survey results reveal that people's risk perception is low: for almost half of the whole sample the occurrence of a tsunami in the Mediterranean Sea is considered quite unlikely, with a clear difference between Apulia and Calabria. In the latter region the risk perception is much higher than in the former, probably due to the shorter time elapsed since the last event. Also, belonging to different coastal areas For the purposes of this paper, the term "coastal area" refers to the part of the coastline defined by both seas and regions' limits, according to current geographical conventions. Tyrrhenian Calabria indicates the coastal region between the municipalities of Tortora and Scilla, Ionian Calabria spans from Reggio Calabria to Rocca Imperiale; Ionian Apulia from Ginosa to Castrignano del Capo, and Adriatic Apulia from Gagliano del Capo to Chieuti. appears to have a significant influence on the way tsunami hazard is conceived, having a stronger effect on risk characterisation: the interviewees of Tyrrhenian Calabria are indeed more likely to associate tsunami risk with volcanoes than the Ionian citizens. This is coherent considering the presence of active volcanoes and related tsunami precedents in the Tyrrhenian. Television emerged as the most relevant source of knowledge for almost 90 % of the sample, and the influence of media also results in the way tsunami risk is characterised. In particular, the survey showed that people's perception and understanding of tsunamis are affected by media accounts of large events, such as the 2004 Sumatra and the 2011 Japan tsunamis. At the same time, it is evident that the risk posed by smaller events is underrated. Furthermore, the survey's results show that the word "tsunami" occupies a different semantic space in comparison to the Italian traditional headword maremoto , with differences among sample strata. In other words, the same physical phenomenon would be understood in two different ways by younger, educated people and elders with a low education level. The results of this study, although limited to two regions, provide a first assessment of tsunami risk perception in Italy, also entailing important consequences for both risk communication practice and mitigation policies. [ABSTRACT FROM AUTHOR]

On September 28, 2018, a large earthquake and its accompanying tsunami waves caused severe damage to the coastal area of Palu Bay, in the central western part of Sulawesi Island, Indonesia. To clarify the distribution of tsunami inundation and run-up heights, and damage to coastal communities due to the tsunami, the authors conducted a field survey 1 month after the event. In the inner part of Palu Bay tsunami inundation and run-up heights of more than 4 m were measured at many locations, and severe damage by the tsunami to coastal low-lying settlements was observed. In the areas to the north of the bay and around its entrance the tsunami inundation and run-up heights were lower than in the inner part of the bay. The tsunami inundation distance depended on the topographical features of coastal areas. The southern shore of the bay experienced a longer inundation distance than other shores, though generally severe damage to houses was limited to within around 200 m from the shoreline. The main lessons that can be learnt from the present event are also discussed. [ABSTRACT FROM AUTHOR]

The 2018 Sulawesi earthquake (Mw 7.5) and tsunami destroyed many buildings and caused more than 3300 fatalities in Sulawesi, Indonesia. Damage reports and satellite images from Palu City indicated severe tsunami impacts to buildings and lifelines infrastructure within 300 m from the coastline. Seven-weeks after the earthquake a field survey was carried out in Palu City to measure tsunami flow depths and record damage levels for buildings, roads and electricity infrastructure. Above ground level tsunami flow depths measured at 371 building sites ranged from 0.1 to 3.65 m, with a 1.05 m mean and 0.55 m standard deviation. The survey team also recorded attributes and damage levels for 463 buildings, 7.9 km of road and 455 utility poles. We observed that non-engineered 'light timber' and 'lightly reinforced concrete' construction frame buildings were highly susceptible to 'non-structural' component damage when tsunami flow depths respectively exceed 0.4 m and 1 m above the first finished floor level, while unrepairable or complete building damage was regularly observed when flow depths exceeded 1.2 m. Only non-structural component damage was observed for engineered 'reinforced concrete' buildings. While tsunami flow depth traces could not be measured for affected road and utility pole components, hazard intensity parameters can be obtained from tsunami inundation maps to estimate the conditions contributing to observed damage levels. The information presented herein forms an important evidence base to support future tsunami hazard and risk research in Indonesia. [ABSTRACT FROM AUTHOR]

A numerical model that simulates the propagation of tsunamis produced by submarine earthquakes was applied to the Caspian Sea. The model was first applied to the June 1990 (Rudbar) earthquake and our results proved to be coherent with previous simulations. It was also applied to the Krasnovodsk earthquake (1895), which had not been simulated before, and it was found that the coastal area was flooded by a tsunami, as reported in literature. Nevertheless, it was a rather local effect since the tsunami was generated in very shallow waters. Some worst-case hypothetical earthquakes were simulated in the most seismically active regions of the Caspian. In general, both the east and west coasts of the central Caspian Sea would be the most affected by these earthquake-induced tsunamis, with potential significant effects in some cases in cities such as Baku. [ABSTRACT FROM AUTHOR]

This study presents the first tsunami scenario database in Marmara Sea, Turkey referring to 30 different earthquake scenarios obtained with the combinations of 32 possible fault segments. The fault mechanisms in Marmara Sea have been studied in detail within FP-7 MARSite project, which were derived from various databases and literature review. Tsunami simulations have been performed according to these defined 30 earthquake scenarios by tsunami numerical code NAMI DANCE (NAMIDANCE, 2011) which solves Nonlinear Shallow Water Equations (NLSWE) using leap-frog scheme. For each earthquake scenario, tsunami hydrodynamic parameters, mainly maximum water surface elevations, arrival time of first wave and maximum wave, and water level fluctuations were calculated at 1333 synthetic gauge points meticulously selected along the coasts of Marmara Sea. The overall simulation results indicate that maximum expected wave heights due to these earthquake scenarios are between 1 m and 2 m and even more than 2 m at some locations along Marmara coasts, such as Kadikoy, Halic and Silivri coasts in Istanbul and Bayramdere and Kursunlu districts along the coasts of Bursa province. The estimated maximum water levels at Bostanci, Pendik and Buyukada coasts in Istanbul, Cinarcik and Bandirma towns and at the entrance of Izmit Bay would reach up to 2 m. Tekirdag coasts and Buyuk Cekmece and Bakirkoy coasts in Istanbul and Yalova coasts would experience maximum tsunami wave amplitudes around 1.5 m. The waves reach up to 1 m at Izmit and Gemlik Bays, Erdek Peninsula and Marmara Island. The overwiew of the results reveal that higher historical tsunami wave heights observed in Marmara Sea cannot be explained by only earthquake-generated tsunamis. Therefore, there is strong agreement on considering submarine landslides as the primary tsunami hazard component in the Marmara Sea as experienced during history and expected in the future. [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]

On March 11, 2011, a magnitude MW 9.0 thrust earthquake ruptured the Japan Trench along the northwest coast of Honshu and generated a tsunami that killed 15,894 people, left 2585 missing (as of March 2017) and destroyed more than 130,000 houses. The purpose of this paper is to review the current status and scope of tsunami recovery in the Tohoku region, focusing on investments in structural protection measures as well as extensive implementation of non-structural "managed retreat." Japan's response to the 2011 tsunami contrasts with approaches to disaster management in the USA and elsewhere in the world. New structural protections built in Japan since 2011 include a massive concrete-lined tsunami barrier system, stretching > 400 km of coast, at a cost of at least $8 billion. Managed retreat is a relatively new area of research and risk management focusing on withdrawal of infrastructure and population from at-risk areas. Japan's post-tsunami disaster response may represent the single largest case of disaster-related managed retreat in recent world history. Approximately 145,000 homes, including whole new towns, are being built outside the tsunami hazard zone. Disaster managers worldwide should look to Japan for lessons learned from the investment and efforts since 2011. [ABSTRACT FROM AUTHOR]

Offshore sensor networks like DONET and S‐NET, providing real‐time estimates of wave height through measurements of pressure changes along the seafloor, are revolutionizing local tsunami early warning. Data assimilation techniques, in particular, optimal interpolation (OI), provide real‐time wavefield reconstructions and forecasts. Here we explore an alternative assimilation method, the ensemble Kalman filter (EnKF), and compare it to OI. The methods are tested on a scenario tsunami in the Cascadia subduction zone, obtained from a 2‐D coupled dynamic earthquake and tsunami simulation. Data assimilation uses a 1‐D linear long‐wave model. We find that EnKF achieves more accurate and stable forecasts than OI, both at the coast and across the entire domain, especially for large station spacing. Although EnKF is more computationally expensive than OI, with development in high‐performance computing, it is a promising candidate for real‐time local tsunami early warning. Plain Language Summary: Recent years have seen more research on tsunami early warning using data from seafloor pressure sensors. Forecasts of the tsunami wave height can be computed by incorporating the pressure observations into the physical model of wave propagation. The current approach uses a simple, constant linear interpolator to blend the data with the model forecast. To improve the accuracy and stability of the forecast, we propose a more mathematically sophisticated approach that dynamically updates this interpolator, as the physical model evolves and as more data become available. This will incorporate more information into the forecast and optimize it. Using a scenario tsunami from our earthquake‐tsunami coupled simulation in the Cascadia subduction zone, we run our proposed data assimilation approach. The predicted wave heights across the ocean and at the coast are more accurate and consistent over time. More reliable forecasts can therefore be issued to coastal residents earlier in the event of a destructive tsunami. Although our method takes longer to run, with greater computing power and more efficient implementation, it is a promising candidate for real‐time tsunami early warning. Key Points: We propose an alternative tsunami wavefield assimilation method, the ensemble Kalman filterThe methods are tested on scenario tsunami in Cascadia from fully coupled dynamic earthquake and tsunami simulationEnsemble Kalman filter achieved more accurate and stable forecasts compared to optimal interpolation [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]

This study investigates the relationship among peacetime human relations, that is, formation of networks, social capital accumulated as a result of human relations, and group evacuation (in units of neighborhood groups, Tonari-gumi) in Numanouchi ward. Located in Iwaki City, in Fukushima Prefecture, Japan, Numanouchi ward was partially destroyed by the Great East Japan Earthquake. The study found that there are differences in the formation of networks, social capital, and group evacuation between the Numanouchi and Suwahara areas. The study also found that there is a (slight) difference in the processes followed in group evacuation and the factors influencing the choice of processes in both areas. [ABSTRACT FROM AUTHOR]

Maps do not correspond to a neutral or scientifically objective process. They are instruments historically linked to relations of power as they represent certain visions of territory, generally imposed by a dominant Western society. Risk maps are an empirical example since they represent nature from a technical-scientific point of view, usually not considering ancestral and local knowledge. From a political ecology perspective and through an alternative mapping exercise this article analyses the official tsunami inundation map that currently exists in Saavedra (Araucanía Region, Chile), revealing the importance of considering both the ancestral and local knowledge of the lafkenche people in order to decolonize natural risks. [ABSTRACT FROM AUTHOR]

To evaluate tsunami hazards with strong locality in urban areas, this study developed a novel tsunami inundation model based on nonlinear shallow water wave equations and a porous body model (PBM). By applying a kinematic boundary condition that includes both porosity and surface permeability of the porous medium, the proposed model could accurately incorporate geometric effects such as the flow anisotropy caused by the distributions of buildings. The proposed PBM demonstrated as good accuracy for the inundation heights around buildings near the coastline as with a conventional three-dimensional simulation with high resolution. In addition, the model showed its capability to reproduce a tsunami's essential behaviors in urban areas. In particular, the amplification effect of flow velocity along straight roads surrounded by buildings was reasonably reproduced. It can be expected that the present model can become a useful tool to accurately evaluate the tsunami risks in urban areas. [ABSTRACT FROM AUTHOR]

A powerful tsunami triggered by the Mw 9.0 Tohoku earthquake struck the northern Pacific coast of Japan in 2011, destroying several coastal communities in Iwate Prefecture, Miyagi Prefecture, and Fukushima Prefecture. Here, we investigate a new spatio-temporal slip model (model B) developed by the Cabinet Office of the Government of Japan. This slip model was compared against the non-uniform slip model estimated using tsunami waveform data (model A). We focused our analysis on two areas that were destroyed by the tsunami. The town of Onagawa and the coastal Sendai Plain area were selected because they were located in front of the epicentre, where the most significant slips were registered. Our simulation results revealed that the spatio-temporal slip distribution better replicated the observed data. Regarding the tsunami waveforms from the coastal tide gauge station and offshore stations, the Cabinet Office's slip model showed an approximately 30% better accuracy relative to the non-uniform slip model. Furthermore, by comparing the local inundation features at two locations with unique topographic and coastal morphological characteristics, we also found that model B better replicated the measured inundation depths. Finally, considering that tsunami-induced damage is a direct function of various inundation features such as the flow depth and flow velocity, this new slip model can generate more realistic damage scenarios for future tsunami assessments. [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]

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]

The 2011 Tohoku earthquake and tsunami motivated an analysis of the potential for great tsunamis in Hawai'i that significantly exceed the historical record. The largest potential tsunamis that may impact the state from distant, Mw 9 earthquakes-as forecast by two independent tsunami models-originate in the Eastern Aleutian Islands. This analysis is the basis for creating an extreme tsunami evacuation zone, updating prior zones based only on historical tsunami inundation. We first validate the methodology by corroborating that the largest historical tsunami in 1946 is consistent with the seismologically determined earthquake source and observed historical tsunami amplitudes in Hawai'i. Using prior source characteristics of Mw 9 earthquakes (fault area, slip, and distribution), we analyze parametrically the range of Aleutian-Alaska earthquake sources that produce the most extreme tsunami events in Hawai'i. Key findings include: (1) An Mw 8.6 ± 0.1 1946 Aleutian earthquake source fits Hawai'i tsunami run-up/inundation observations, (2) for the 40 scenarios considered here, maximal tsunami inundations everywhere in the Hawaiian Islands cannot be generated by a single large earthquake, (3) depending on location, the largest inundations may occur for either earthquakes with the largest slip at the trench, or those with broad faulting over an extended area, (4) these extremes are shown to correlate with the frequency content (wavelength) of the tsunami, (5) highly variable slip along the fault strike has only a minor influence on inundation at these tele-tsunami distances, and (6) for a given maximum average fault slip, increasing the fault area does not generally produce greater run-up, as the additional wave energy enhances longer wavelengths, with a modest effect on inundation. [ABSTRACT FROM AUTHOR]

The evacuation behavior observed in Kesennuma City, Tohoku, Japan during the Great East Japan Earthquake and Tsunami and a corresponding evacuation simulation are presented. We first organized the damage and evacuation behaviors observed in the target area using the results of previous studies and official surveys. In addition, we compiled all available multimedia sources recording evacuation behavior during the 2011 event to identify the precise temporal and spatial details of the evacuation behavior. Then, a tsunami evacuation simulation was developed based on all compiled evacuation data, considering the tendencies regarding the use of main roads for evacuation, residents' shelter preferences, and pedestrian-car interactions. The developed simulation was validated against the compiled evacuation behaviors by inputting the estimated initial conditions of the 2011 event. The traffic scenarios calculated in the simulation closely reproduced the actual traffic flow as observed from the evacuation data. The evacuee populations at several shelters in the simulation also quantitatively reproduced the trend of the real numbers of evacuees reported by Kesennuma City. The results of the simulation exhibited a better capability to estimate the actual evacuation behavior during the 2011 event than that achieved in previous studies. [ABSTRACT FROM AUTHOR]

The Great East Japan Earthquake of 11 March 2011 unleashed a powerful tsunami that struck the coastal region and left death and extensive destruction in its wake. This event prompted many investigations to assess the damage and the extent to which the tsunami affected areas along and adjacent to the coast. In this paper, we use aerial photography and a digital elevation model to assess the inundation extent and run-up height of the tsunami along the coast of Iwate prefecture. First, the size of the area affected by the tsunami was calculated by using the observed borderline trace of its farthest reach inland. Then, elevations above sea level were determined for various points along the trace. This required a variety of approaches because of the variation in the topography and gradient of the slope along the coastline from flat to very steep. The results of our investigation showed that aerial photography can be used successfully to obtain a broad approximate assessment of the reach of a tsunami and associated damage, thereby avoiding the need for immediate on-site inspections. Furthermore, our results suggested that the tsunami run-up height in 2011 could have reached more than 40 m at places scattered along the Iwate coast. [ABSTRACT FROM AUTHOR]

Kaoru, T. and Udo, K., 2016. Analysis of beach erosion because of the 2011 Tohoku earthquake and tsunami. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1252 - 1256. Coconut Creek (Florida), ISSN 0749-0208. The 2011 Tohoku earthquake and tsunami caused the disappearance of beaches over a wide area because of inundation accompanying the land subsidence caused by the earthquake and because of tsunami erosion. This study aims to investigate the general characteristics of the 2011 earthquake and tsunami and identify the factors that caused beach damage. The study focuses on 74 beaches from Aomori Prefecture to Chiba Prefecture, including those where the damage was insignificant. Satellite and aerial image analyses demonstrated that the main factor in beach disappearance was not inundation following land subsidence caused by the earthquake but erosion because of sediment transport by the tsunami. There were many cases where a significant increase in the amount of beach retreat occurred when the tsunami overflowed a seawall, leading to the collapse of the seawall. It was also quantitatively confirmed that beach erosion could have been significantly reduced by the survival of the seawall. Three years after the 2011 tsunami and earthquake, the recovery rates differed between beaches on the Sanriku coast and those in other areas. The rate was ≤25% for many beaches on the Sanriku coast of the Rias terrain and ≥75% throughout the south of the Sendai plain. [ABSTRACT FROM AUTHOR]

In this paper, we deal with evacuation decision making of people in the disaster area. By threshold model, we discuss whether all agents decide to evacuate or not. It is reported that not all people in the affected area evacuated during the Great East Japan Earthquake. But, many evacuation simulations treat that all people evacuate. In the previous work, on the assumption that all people decide to evacuate, we dealt with the needed time to make all people evacuate if psychological conditions exist at the time of disaster. In this paper, we deal with the condition that not all people decide to evacuate and focus on contagion of evacuation decision making on real map. We found that for contagion of evacuation decision making, local neighborhood and connection of sub network is necessary. [ABSTRACT FROM AUTHOR]

The coastal areas of Japan were hard hit by a magnitude 9.0 earthquake on 11 March 2011. The earthquake triggered a disastrous tsunami over the area which led to massive destruction. In this paper, tsunami-induced changes in Soma, Watari, Natori and Iwanuma areas using Landsat 7 ETM+ and EO-1 ALI images are identified. The proposed method is based on image classification using radial basis function neural network and generalized improved fuzzy partition FCM algorithm. The pre- and post-tsunami images of the area are first classified using a radial basis function neural network. The pre- and post-tsunami images are classified into three classes including water, vegetation and urban and bare land class. The classified images are compared with other to obtain a set of four change classes. These change classes are labelled to obtain a classified change map. The change map reveals that large areas of vegetations and urban land are washed away by the tsunami in all the four cities, Soma, Watari, Natori and Iwanuma. The accuracy assessment of the method shows that the results obtained are quite satisfactory. The method has high overall accuracy and kappa coefficient value. [ABSTRACT FROM AUTHOR]

Correctly characterizing tsunami source generation is the most critical component of modern tsunami forecasting. Although difficult to quantify directly, a tsunami source can be modeled via different methods using a variety of measurements from deep-ocean tsunameters, seismometers, GPS, and other advanced instruments, some of which in or near real time. Here we assess the performance of different source models for the destructive 11 March 2011 Japan tsunami using model-data comparison for the generation, propagation, and inundation in the near field of Japan. This comparative study of tsunami source models addresses the advantages and limitations of different real-time measurements with potential use in early tsunami warning in the near and far field. The study highlights the critical role of deep-ocean tsunami measurements and rapid validation of the approximate tsunami source for high-quality forecasting. We show that these tsunami measurements are compatible with other real-time geodetic data, and may provide more insightful understanding of tsunami generation from earthquakes, as well as from nonseismic processes such as submarine landslide failures. [ABSTRACT FROM AUTHOR]

We investigate the currents produced by recent tsunamis in Humboldt Bay and Crescent City, California. The region is susceptible to both near-field and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 kms north of Humboldt Bay, suffered US $28 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US $26 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600 kHz 2D acoustic Doppler current profiler (ADCP) with a 1-min sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the M 8.8 Chile earthquake on February 27, 2010 and the M 9.0 Japan earthquake on March 11, 2011. One other tsunami was recorded on the Humboldt Bay tide gauge during the period of ADCP operation, but was not visible on the ADCP, suggesting a threshold water level value of about 0.2 m to produce an observable ADCP record. The 2010 tsunami currents persisted in Humboldt Bay for approximately 30 h with peak amplitudes of about 0.35 m/s. The 2011 tsunami signal lasted for over 40 h with peak amplitude of 0.84 m/s. The strongest currents corresponded to the maximum change in water level approximately 67 min after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and one-half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master, approximately 70 m away from the NOAA-NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities both in Humboldt Bay and in Crescent City were compared to calculated velocities from the Method of Splitting Tsunamis (MOST) numerical model. The frequency and pattern of current amplification and decay at both locations are replicated by the MOST model for the first several hours after the tsunami onset. MOST generally underestimates 2011 peak current velocities by about 10-30 %, with a few peaks by as much as 50 %. At Humboldt Bay, MOST predicted attenuation of the signal after 4 h but the actual signal persisted at a nearly constant level for at least twice as long. The results from this project demonstrate that ADCPs can effectively record tsunami currents for small to moderate events and can be used to calibrate and validate models (i.e., MOST) in order to better understand hazardous tsunami conditions within harbors. [ABSTRACT FROM AUTHOR]

Post-tsunami field surveys in the Minami-Soma exclusion zone in the Fukushima Prefecture were delayed for 15 months after the 2011 Tohoku tsunami. The area was subject to access restrictions until June 2012 due to high radiation levels caused by the meltdown at the Fukushima Dai-ichi Nuclear Power Plant. The distribution of the measured tsunami heights is presented in combination with observed infrastructure damage. The enhanced tsunami heights in the areas along the shoreline are attributed to wave reflection, funneling and splash-up at cliffs and seawalls, as well as the increased flow resistance as the tsunami plowed through coastal pine-tree forests. Consequently, large tsunami heights exceeding 10 m were limited to areas within 500 m from the shoreline. Onshore profiles of the maximum inundation levels were dependent on inland topography: tsunami heights increased inland in steep V-shaped valleys, while decaying with inundation distance along flat coastal plains. Tsunami flood levels in the coastal plains are affected by the extent of seawall damage: coastal flood levels are higher behind completely destroyed seawalls than behind partially damaged coastal defenses. Remnant seawalls provided valuable lessons to be implemented in future designs of tenacious structures based on the Japanese concept of 'nebari' representing resiliency to endure tsunami overflow as the original design height is exceeded. [ABSTRACT FROM AUTHOR]

This study visualized the spatio-temporal changes in the tsunami inundation area and analyzed its expansion mechanism. The most characteristic of the Great East Japan Earthquake is the damage caused by the tsunami. And 90% of the dead was caused by it. One of the factors is that the preparation of countermeasures corresponding to the huge tsunami was not fully prepared. Therefore, after the Great East Japan Earthquake, the Japanese government has emphasized the importance of the advance preparation of the hugest tsunami expected. According to the past experience the occurring of huge tsunami is very rare. Earthquake researchers have observed same scale tsunami in every 1000 years in Japan. According prediction, next huge tsunami may be happened around the 2030. Therefore, analyzing the tsunami inundation mechanism of the Great East Japan Great Eastern is important for the future tsunami countermeasure. The arrival time and spatial distribution of tsunami inundation can be considered as a main important component of evacuation planning. In addition, a wide range of inundation area caused by huge tsunami is suitable for analyzing the inundation mechanism compared with a small-scale tsunami inundation. In this study I would like to examine the tsunami inundation process caused by the Great East Japan Earthquake in 2011. The method is as follows. First, movies shooting the tsunami inundation are collected from DVDs and TV hosting services. And they are examined as analysis materials. As a result, movies that taken from the ground were impossible to shoot the dynamic process of tsunami flooding. So that movies that taken from the helicopter or airplane was selected in this research. Next, the movies are converted into images at regular intervals of time. And adding position information to images (geo-reference), images are imported on the geographic information system (GIS). After that, Inundation limit lines are digitized. In this study, inundation limit lines are created at intervals of around 5 seconds. However, when the image is disturbed by dust etc., images of around 5 seconds are used. Basic information on the tsunami inundation handled in this study is shown in Table 1 and Figure 1. As the result, tsunami inundation process was strongly affected by the location of buildings (Figure 2). On the other hand, the inundation distance declined even where the fields spread. The spatio-temporal variation of the inundation process was quantitatively clarified. Regression analysis was performed with variables of inundation time and inundation distance. As a result, changes in correlation were observed in a certain section. In order to analyze the factors, two regression analyses were conducted. First is the inundation time and elevation as variables. Second is the inundation time and distance from buildings as variables. The building data had acquired the image before the earthquake (April 4, 2010) from Google Earth, and created the building shape data. As a result of each analysis, it became clear that sections where the elevation suddenly changes and the short distance from buildings, overlapped sections where the inundation distance does not extend (Figure 3). These results suggest that it is possible to predict inundation time and distance in other areas if parameters can be acquired. [ABSTRACT FROM AUTHOR]

This paper reviews achievements and findings from studies associated with numerical modeling of tsunami since the 2011 Tohoku earthquake, and addresses challenges for future advances. The topics cover improvements in tsunami numerical modeling including multi-physics simulations, applications to source modeling, hazard assessment and real-time forecasting and warning. During the last 10 years, tsunami numerical modeling has been improved, validated and applied to better predict tsunami's behavior and impacts, with aids from the groundbreaking data of the 2011 Tohoku earthquake tsunami. Marked progresses have been made for propagation and inundation modeling, multi-physics simulations such as sediment transport modeling and real-time forecasting and warning. Sediment transport modeling since the Tohoku earthquake tsunami has shown that it may profit from bridging different disciplines to gain further advance in disaster science. Despite the progresses, further exploration for better accuracy and capability, and improved understanding of model limitations and uncertainties is needed. Source modeling of the Tohoku earthquake tsunami, with aids from tsunami records and other geophysical datasets, have provided detailed depiction of the spatial distribution of initial water level, fault slip and mechanism and process of tsunami amplification. To improve assessment of tsunami hazards and related damages, the source features of the Tohoku earthquake tsunami were characterized and applied to hazard assessments of future tsunamis in other areas. The characterization will benefit from not overlooking 'unexpected' hazards and damages, although some other processes, such as rupture propagation and submarine mass failure, cannot be excluded from uncertainty quantification in tsunami source modeling. As in past years, tsunami numerical modeling will play a crucial role in policy making and consensus building for tsunami disaster mitigation actions, with efforts for better transmission of the model's intent, limitation and uncertainty. [ABSTRACT FROM AUTHOR]

• First stress calculations for Greenland due to ice-sheet melting. • Possible glacially-triggered earthquake close to Nanortalik in the Holocene. • Potential contamination of relative-sea level data by glacially-triggered earthquakes. • Possible earthquake induced palaeotsunami in the North Atlantic. Due to their large mass, ice sheets induce significant stresses in the Earth's crust. Stress release during deglaciation can trigger large-magnitude earthquakes, as indicated by surface faults in northern Europe. Although glacially-induced stresses have been analyzed in northern Europe, they have not yet been analyzed for Greenland. We know that the Greenland Ice Sheet experienced a large melting period in the early Holocene, and so here, we analyze glacially-induced stresses during deglaciation for Greenland for the first time. Instability occurs in southern Greenland, where we use a combined analysis of past sea level indicators and a model of glacially-induced fault reactivation to show that deglaciation of the Greenland Ice Sheet may have caused a large magnitude earthquake or a series of smaller magnitude earthquakes around 10,600 years ago offshore south-western Greenland. The earthquake(s) may have shifted relative sea level observations by several meters. If the earthquake-induced stress release was created during a single event, it could have produced a tsunami in the North Atlantic Ocean with runup heights of up to 7.2 m in the British Isles and up to 7.8 m along Canadian coasts. [ABSTRACT FROM AUTHOR]

A large amount of tsunami debris from the Great East Japan Earthquake in 2011 was sunk on the seafloor and threatened the marine ecosystem and local communities' economy, especially in fisheries. However, few studies estimated spatial accumulations of tsunami benthic debris, comparing to their flows on the ocean surface. Here, a spatially varying coefficient model was used to estimate tsunami debris accumulation considering the spatial structure of the data off the Tohoku region. Our model revealed the number of vessels nearest the coast at the tsunami event had the highest positive impact, whereas the distance from the coast and kinetic energy influenced negatively. However, the effect of the proximity to the coast wasn't detected in the Sendai bay, indicating spatial dependency of these effects. Our model estimation provides the fundamental information of tsunami debris accumulation on the seafloor, supporting early reconstruction and risk reduction in marine ecosystems and local communities. Unlabelled Image • Effects of land-based and oceanographic factors could be spatially dependent. • Distance from the coast and kinetic energy decreased the accumulation. • River could be a potential route for outflow of tsunami debris. • Tsunami backwash strongly affected in the Sendai bay, leading to more depositions. [ABSTRACT FROM AUTHOR]

The Bering Sea meteor explosion that occurred on 18 December 2018 provides a good opportunity to study the ionospheric disturbances caused by meteor explosions. Total electron content (TEC) is the core parameter of ionospheric analysis. TEC and its changes can be accurately estimated based on the Global Positioning System (GPS). TID is detected in time and frequency domain based on power spectrum and Butterworth filtering method. By analyzing the waveform, period, wavelength, propagation speed and space-time distribution of TID, the location of the TID source is determined, and the process of TID formation and propagation is understood. The TID caused by meteor explosions has significant anisotropy characteristic. Two types of TID were found. For the first type, the average horizontal propagation velocity is 250.22 ± 5.98 m/s, the wavelength is ~135–240 km, the average period is about 12 min, and the propagation distance is less than 1400 km. About 8 min after the meteor explosion, the first type of TID source formed and propagated radially at the velocity of 250.22 ± 5.98 m/s. For the second type, the propagation velocity is ~434.02 m/s. According to the waveform, period, wavelength and propagation velocity of the TID, it is diagnosed to be the midscale traveling ionospheric disturbances (MSTID). Based on the characteristics of TID, we infer that the TID is excited by the gravity waves generated by the meteor explosion, which is in accordance with the propagation law of gravity waves in the ionosphere. And it is estimated that the average velocity of the up-going gravity waves is about 464.58 m/s. A simple model was established to explain the formation and the propagation of this TID, and to verify the characteristics of the TID propagation caused by nuclear explosion, earthquake, tsunami, and Chelyabinsk meteorite blast. It is estimated that the position of the TID source is consistent with the meteor explosion point, which further indicates that the TID is caused by the meteor explosion and propagates radially. [ABSTRACT FROM AUTHOR]

This paper addresses the tsunami propagation and subsequent coastal areas flooding by means of a depth-integrated numerical model. Such an approach is fundamental in order to assess the inundation hazard in coastal areas generated by seismogenic tsunami. In this study we adopted, an interdisciplinary approach, in order to consider the tsunami propagation, relates both to geomorphological characteristics of the coast and the bathymetry. In order to validate the numerical model, comparisons with results of other studies were performed. This manuscript presents first applicative results achieved using the weakly dispersive Boussinesq model in the field of tsunami propagation and coastal inundation. Ionic coast of Sicily (Italy) was chosen as a case study due to its high level of exposure to tsunamis. Indeed, the tsunami could be generated by an earthquake in the external Calabrian arc or in the Hellenic arc, both active seismic zones. Finally, in order to demonstrate the possibility to give indications to local authorities, an inundation map, over a small area, was produced by means of the numerical model. [ABSTRACT FROM AUTHOR]

Lee, K.-J. and Cho, Y.-S., 2020. Focusing of tsunami energy at Imwon Port. In: Malvárez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 247–251. Coconut Creek (Florida), ISSN 0749-0208. In the last few decades, several catastrophic tsunamis triggered by undersea earthquakes have occurred and struck not only neighboring but also distant coastal communities around the world. These tsunamis have caused a large number of human casualties and severe property damage. In this study, a geographical feature of the Imwon Port located at eastern coast of the Korean Peninsula, is investigated by studying a group of historical and virtual tsunamis caused by 3 historical and 11 virtual undersea earthquakes suggested by KEDO (1999). In addition, the effectiveness of the wave ray model is then examined by estimating tsunami heights at specific positions. Finally, the location of wave energy focusing is predicted by estimating tsunami heights and wave ray tracing, and whether the location is right is reconfirmed by the actual particle velocity vector map. The results of this study shall be used by a civil defense authority to mitigate the tsunami hazards in the case of a real tsunami attack. [ABSTRACT FROM AUTHOR]

• Different response of reinforced concrete frame to earthquake and tsunami. • The prior earthquake slightly influences the earthquake-tsunami fragility curves. • Column shear failure is found to govern collapse mechanism under tsunami. Many coastal regions lying on subduction zones are likely to experience the catastrophic effects of cascading earthquake and tsunami observed in recent events, e.g., 2011 Tohoku Earthquake and Tsunami. The influence of earthquake on the response of the structure to tsunami is difficult to quantify through damage observations from past events, since they only provide information on the combined effects of both perils. Hence, the use of analytical methodologies is fundamental. This paper investigates the response of a reinforced concrete frame subjected to realistic ground motion and tsunami inundation time histories that have been simulated considering a seismic source representative of the M9 2011 Tohoku earthquake event. The structure is analysed via nonlinear time-history analyses under (a) tsunami inundation only and (b) earthquake ground motion and tsunami inundation in sequence. Comparison of these analyses shows that there is a small impact of the preceding earthquake ground shaking on the tsunami fragility. The fragility curves constructed for the cascading hazards show less than 15% reduction in the median estimate of tsunami capacity compared to the fragility functions for tsunami only. This outcome reflects the fundamentally different response of the structure to the two perils: while the ground motion response of the structure is governed by its strength, ductility and stiffness, the tsunami performance of the structure is dominated by its strength. It is found that the ground shaking influences the tsunami displacement response of the considered structure due to the stiffness degradation induced in the ground motion cyclic response, but this effect decreases with increasing tsunami force. [ABSTRACT FROM AUTHOR]