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Modern tsunami events have highlighted the vulnerability of port structures to these high-impact but infrequent occurrences. However, port planning rarely includes adaptation measures to address tsunami hazards. The 2011 Tohoku tsunami presented us with an opportunity to characterise the vulnerability of port industries to tsunami impacts. Here, we provide a spatial assessment and photographic interpretation of freely available data sources. Approximately 5000 port structures were assessed for damage and stored in a database. Using the newly developed damage database, tsunami damage is quantified statistically for the first time, through the development of damage fragility functions for eight common port industries. In contrast to tsunami damage fragility functions produced for buildings from an existing damage database, our fragility functions showed higher prediction accuracies (up to 75 % accuracy). Pre-tsunami earthquake damage was also assessed in this study and was found to influence overall damage assessment. The damage database and fragility functions for port industries can inform structural improvements and mitigation plans for ports against future events. Published version SCOR Asia Pacific Tokio Marine & Nichido Fire Insurance Co. Ltd. Willis Research Network

The present study proposes an MPM (material point method)–FEM (finite element method) hybrid analysis method for simulating granular mass–water interaction problems, in which the granular mass causes dynamic motion of the surrounding water. While the MPM is applied to the solid (soil) phase whose motion is suitably represented by Lagrangian description, the FEM is applied to the fluid (water) phase that is adapted for Eulerian description. Also, the phase-field approach is employed to capture the free surface. After the accuracy of the proposed method is tested by comparing the results to some analytical solutions of the consolidation theory, several numerical examples are presented to demonstrate its capability in simulating fluid motions induced by granular mass movements.

When considering a tsunami disaster, many researchers have considered the tsunami's flow depth and velocity as the primary contributors to the building damage. Additionally, the majority of these studies have used the maximum value as the measure of each of these two factors. However, building damage may not occur when the maximum flow depth and the maximum flow velocity of the tsunami are reached. This study addressed two objectives based on the 2011 Great East Japan Earthquake and Tsunami. Firstly, to find out whether the maximum values of the flow depth and flow velocity are the same as their critical values and, secondly, to verify which combination of the parameters is the best predictor of the building damage level. The data from 18,000 buildings in Ishinomaki City, Japan, with the cooperation of the Japanese joint survey team, were analyzed using the decision tree related algorithms. The critical variables were the simulated data at the time when the buildings collapsed. The analysis showed the accuracy of the prediction based on the group of variables. Finally, the findings showed that the combination of the critical flow depth and maximum flow velocity provided the highest accuracy for classifying the level of building damage.

To predict and suppress human casualty in a future tsunami disaster, it is crucial to analyze victim information from past disasters and clarify the causes of human casualty. Examining the causes of human casualty requires analyses that combine various hazard information and victim information in subregional units. This study aims to grasp the factors that caused human casualty during the Great East Japan Earthquake in 2011 using Miyagi Prefectural Police Headquarters’ victim information. Therefore, at Ishinomaki City, Miyagi Prefecture, we researched the spatial distribution of causes of death based on the victims’ addresses and the corpse location, as well as the occurrence factor of each cause of death. As a result, we obtain the following results. (1) The spatial distribution of victims based on the corpse location is more clearly related to the hazard than the victim’s address. In other words, it is proved that the detection site of the body is significant when examining the relationship between human casualty and hazards. (2) The hypothesis of each cause of death is verified based on the spatial distribution of each cause of death, hazard information, the victim’s age, and the date of detecting the body. As a result, it is suggested that drowning, death due to fire, and hypothermia are causes of death related to external forces. It is also suggested that hypothermia and heart disease are causes of death related to individual fragility. (3) Such a possibility showed that the cause of death could not be identified for death from unknown origin due to the bodies’ decay resulting from taking time to detect the dead bodies. (4) We propose a diagram of relationship between the causes of death and the occurrence of factors of death at Ishinomaki City. In the future, to generalize the relationship, it is considered that the same analysis will be required in the coastal municipalities of Miyagi Prefecture.

In November 2013, Super Typhoon Haiyan (Yolanda) hit the Philippines. It caused heavy loss of lives and extensive damages to buildings and infrastructure. When collapsed buildings are focused on, it is interesting to find that these buildings did not collapse for the same reasons after the landfall of the typhoon and storm surge. The objective of this study is to develop a statistical model for building damage due to Super Typhoon Haiyan and its storm surge. The data were collected in collaboration with Tanauan Municipality, the Philippines. The data for the inundation map were obtained by field surveys conducted on-site to determine the cause of the damages inferred from satellite data. The maximum wind speed was derived from the Holland parametric hurricane model based on the Japan Meteorological Agency (JMA) typhoon track data and the inundation depth of storm surge was calculated using the MIKE model. Multinomial logistic regression was used to develop a model to identify the significant factors influencing the damage to buildings. The result of this work is expected to be used to prepare urban plans for preventing damage from future storms.

The Sendai Framework for Disaster Risk Reduction 2015–2030 (SFDRR) represents an inclusive approach to disaster risk reduction, linked to development and recovery. Building on previous international guidelines, the SFDRR promotes practical and measurable outcomes for reducing disaster losses, including indicators to measure progress towards seven specific global targets. Evaluated in the context of the priorities and global targets of the SFDRR, the article considers the case of the Great East Japan Earthquake and Tsunami of 2011 to illustrate advances and limitations in pre-disaster tsunami hazard engineering and post-disaster recovery. With respect to the targets set out in the Sendai Framework related to risk reduction and tsunami engineering, especially Priority 1, understanding disaster risk, there have been significant advances in hazard assessment and systems for tsunami detection and warning. Although the SFDRR emphasizes actions in the recovery phase through Priority 4, enhancing disaster preparedness with an emphasis on the concept of build back better, on its own this does not function as a clear directive for guiding recovery. However, the overall people-centered and inclusive approach of the SFDRR, as well as the global targets and several sub-priorities, can be a useful way to shape good practices in recovery and evaluate recovery progress.

On 22 December 2018, a tsunami was generated from the Mount Anak Krakatau area that was caused by volcanic flank failures. The tsunami had severe impacts on the western coast of Banten and the southern coasts of Lampung in Indonesia. A series of surveys to measure the impacts of the tsunami was started 3 d after the tsunami and lasted for 10 d. Immediate investigations allowed the collection of relatively authentic images of the tsunami impacts before the clearing process started. This article investigates the impacts of the 2018 Sunda Strait tsunami on the affected areas and presents an analysis of the impacts of pure hydrodynamic tsunami forces on buildings. Impacts of the tsunami were expected to exhibit different characteristics than those found following the 2004 Indian Ocean tsunami in Aceh. Data were collected from 117 flow depths along the Banten and Lampung coasts. Furthermore, 98 buildings or houses were assessed for damage. Results of this study revealed that the flow depths were higher in Banten than in Lampung. Directions of the tsunami arrays created by the complex bathymetry around the strait caused these differences. Tsunami-induced damage to buildings was mostly the result of impact forces and drag forces. Damping forces could not be associated with the damage. The tsunami warning system in Indonesia should be extended to anticipate non-seismic tsunamis, such as landslides and volcanic processes driven by tsunamis. The lack of a tsunami warning during the first few minutes after the generation of the first wave led to a significant number of human casualties in both of the affected areas.

The 2011 Tohoku earthquake and tsunami caused the loss of 20,000 lives in Japan. According to the National Police Agency (2012), 90% of deaths in the Iwate, Miyagi, and Fukushima prefectures were due to drowning. On the other hand, this report also showed that the remaining 10% died from circumstances other than drowning, as suggested by the Japanese Society of Legal Medicine (2012). A new solution is needed to propose practical measures against a tsunami. In this paper, the authors suggest the science of human survival from disaster as one of the solutions and illustrate the research design implemented to build it. Constructing the science of human survival shall be important to mitigate human damages in future tsunami disasters.

Compared to other countries, Thailand has fewer seismic hazards. Hazardous experiences greatly influence the expertise and abilities of actors that implement and execute public disaster responses. In domestic disaster situations, there are protocols and resources that facilitate a national disaster response. However, in overseas responses, disaster response becomes more challenging as more responsibilities with limited authorities and resources are required. In this research, the public disaster response of the Royal Thai Embassy in Tokyo was explored and evaluated on the basis of several disaster scenarios. This research was developed to understand the state of disaster response, enhance the effectiveness of disaster response protocols, and reduce unnecessary resource consumption. This study intended to fulfill organizational needs and responsibilities. The study converts existing protocol that is written in document form into a time series disaster response plan for disaster drills based on a possible worst-case scenario, i.e., the Kumamoto Earthquake scenario in 2016 and the Great Tohoku Earthquake and Tsunami in 2011. The plan was used in a disaster drill to evaluate organizational responses. The results from drills and discussions and comments from participant information flow primarily manage communications, cooperation, and connections, which are dependent on experiences and expertise in disaster management. This further affects information flow management and assistance capabilities. The outputs and outcomes from this research can be used as a guideline for application to other embassies in Japan, the Royal Thai Embassy in other countries, and general overseas organizations. This work may apply to other public disaster responses aside from natural disasters.

Tsunami fragility functions describe the probability of structural damage to tsunami flow characteristics. Fragility functions developed from past tsunami events (e.g. 2004 Indian Ocean tsunami) are often applied directly, without modifications, to other areas at risk of tsunami for the purpose of damage and loss estimations. Consequentially, estimates carry uncertainty due to disparities in construction standards and coastal morphology between the specific region for which the fragility functions were originally derived and the region where they were being used. The main objective of this study is to provide an alternative approach to assessing tsunami damage, especially for buildings in regions where previously developed fragility functions do not exist. A damage assessment model is proposed in this study, where load-resistance analysis is performed for each building by evaluating hydrodynamic forces, buoyancies and debris impacts and comparing them to the resistance forces of each building. Numerical simulation was performed in this study to reproduce the 2011 Great East Japan tsunami in Ishinomaki city, which is chosen as a study site. Flow depths and velocities were calculated for approximately 20 000 wooden buildings in Ishinomaki city. Similarly, resistance forces (lateral and vertical) are estimated for each of these buildings. The buildings are then evaluated for its potential to collapse. Results from this study reflect a higher accuracy in predicting building collapse when using the proposed load-resistance analysis as compared to previously developed fragility functions in the same study area. Damage is also observed to have likely occurred before flow depth and velocity reach maximum values. With the above considerations, the proposed damage model might well be an alternative for building damage assessments in areas which have yet to be affected by modern tsunami events.

This research aimed to assess the tsunami flow velocity and height reduction produced by a planned elevated road parallel to the coast of Banda Aceh, called the Banda Aceh Outer Ring Road (BORR). The road will transect several lagoons, settlements, and bare land around the coast of Banda Aceh. Beside its main function to reduce traffic congestion in the city, the BORR is also proposed to reduce the impacts of future tsunamis. The Cornell Multi-grid Coupled Tsunami Model (COMCOT) was used to simulate eight scenarios of the tsunami. One of them was based on the 2004 Indian Ocean tsunami. Two magnitudes of earthquake were used, that is, 8.5 and 9.15 Mw. Both the earthquakes were generated from the same source location as in the 2004 case, around the Andaman Sea. Land use data of the innermost layer of the simulation area were adopted based on the 2004 condition and the land use planning of the city for 2029. The results of this study reveal that the tsunami inundation area can be reduced by about 9 % by using the elevated road for the earthquake of magnitude 9.15 Mw and about 22 % for the earthquake of magnitude 8.5 Mw. Combined with the land use planning 2029, the elevated road could reduce the maximum flow velocities behind the road by about 72 %. Notably, the proposed land use for 2029 will not be sufficient to deliver any effects on the tsunami mitigation without the elevated road structures. We recommend the city to construct the elevated road as this could be part of the co-benefit structures for tsunami mitigation. The proposed BORR appears to deliver a significant reduction of impacts of the smaller intensity tsunamis compared to the 2004 Indian Ocean tsunami.

Perceptions of volcanic hazard-related information relevant to volcano tourism areas in Japan were investigated using an Internet questionnaire survey. This study focused on the possibilities of tourism activities as a method of disseminating disaster information not only to residents but also to visitors. We evaluated the effects of educational programs (EP) including recreational activities at geopark, for the purpose of further enhancing information content and establishment of cooperation system. The survey focused on the roles and perspectives of residents, the tourism industry, scientists, and the government in volcanic disaster mitigation, as well as the dissemination of volcanic information with regard to daily activities and the actions to be taken in the event of an emergency. Hazard perceptions tended to be actuate in areas where knowledge dissemination activities were active, but this did not lead to evacuation awareness. Evacuation awareness was correlated with disaster awareness, specifically regarding the degree of interest in a volcano, eruption frequency and style, perceptions of eruption predictability, and trust in information source. Disaster awareness correlated somewhat with eruption style and with the time elapsed science the most recent eruption. Our results showed that the perceptions of residents living near volcanoes depended on eruption frequency, their experience during previous eruptions, and local government assessments of the severity of the volcanic hazard. Despite advances in tools of social media, that is not yet to take advantage under disaster circumstances. A disaster prevention system that incorporates disaster prevention education and open lines of communication among scientists, government, media, residents, and the tourism industry is necessary to improve the disaster resilience of communities in volcanic areas.

This paper assesses the suitability of the early warning systems and post-disaster housing for the elderly population of Japan in the immediate and transitional recovery phase of the 2011 Great East Japan Earthquake and Tsunami. Written questionnaires and informal group interviews were conducted with residents of six temporary housing complexes in Miyagi and Iwate three and half years after the disaster. The median age of participants was 70, with an age range of 48 years. We assess rates of warning receipt in the immediacy of the event, evacuation actions thereafter, and the experience of living in temporary accommodation. 81% of those surveyed received at least one type of earthquake or tsunami warning, the most common being an audio mobile phone (AMP) message (which is received through a smart phone), heard by 45% of the sample. Radio, siren, and AMP notifications were most effective at informing the elderly overall. 84% of recipients took action in response to a tsunami warning, with 79% of respondents evacuating their homes prior to the arrival of the first wave. During the transitional phase of recovery, residents within temporary housing highlighted issues including a lack of floor space, poor thermal insulation, solitary living environments, and reduced privacy, which lead to stressed domestic relationships within families and social groups. Recommendations are made to consider the elderly to a greater degree in planning for the early warning and immediate phases of disaster, and throughout the long-term recovery process, in order to improve their psychological and physiological well-being.

The 2011 Great East Japan earthquake caused a wide-ranging and devastating tsunami that reached a maximum height of 40 m and caused 19,000 fatalities, particularly along the Tohoku coast of Japan. The purpose of this study is to present a new estimation of the fatality ratios based on tsunami arrival times and evacuation perspectives and to present lessons learned for future tsunami loss assessments in other areas. In addition, this study investigates influencing factors, such as age, gender, and two coastal topography types (Sanriku ria-coast and Sendai plain). The fatality ratio is calculated by the number of fatalities divided by the population at the town scale along the shoreline, and the tsunami arrival time is calculated using the TUNAMI model with nesting grids of 1350 m, 450 m, 150 m, and 50 m. Then, linear and nonlinear regression analyses are performed to develop a relationship between the fatality ratios and tsunami arrival times. For different topography types, different distributions of fatality ratios with tsunami arrival times were observed; the fatality ratios of the Sendai plain were generally higher than those of the Sanriku ria-coast for the same arrival time. Based on the results, a strong inverse correlation between the fatality ratios and the tsunami arrival times was found in the Sendai plain, while the Sanriku ria-coast must be divided into two groups to obtain this correlation. Furthermore, other influencing factors, such as age and gender, contributed to differences in estimating the fatality ratios.

Since the two devastating tsunamis in 2004 (Indian Ocean) and 2011 (Great East Japan), new findings have emerged on the relationship between tsunami characteristics and damage in terms of fragility functions. Human loss and damage to buildings and infrastructures are the primary target of recovery and reconstruction; thus, such relationships for offshore properties and marine ecosystems remain unclear. To overcome this lack of knowledge, this study used the available data from two possible target areas (Mangokuura Lake and Matsushima Bay) from the 2011 Japan tsunami. This study has three main components: (1) reproduction of the 2011 tsunami, (2) damage investigation, and (3) fragility function development. First, the source models of the 2011 tsunami were verified and adjusted to reproduce the tsunami characteristics in the target areas. Second, the damage ratio (complete damage) of the aquaculture raft and eelgrass was investigated using satellite images taken before and after the 2011 tsunami through visual inspection and binarization. Third, the tsunami fragility functions were developed using the relationship between the simulated tsunami characteristics and the estimated damage ratio. Based on the statistical analysis results, fragility functions were developed for Mangokuura Lake, and the flow velocity was the main contributor to the damage instead of the wave amplitude. For example, the damage ratio above 0.9 was found to be equal to the maximum flow velocities of 1.3 m s−1 (aquaculture raft) and 3.0 m s−1 (eelgrass). This finding is consistent with the previously proposed damage criterion of 1 m s−1 for the aquaculture raft. This study is the first step in the development of damage assessment and planning for marine products and environmental factors to mitigate the effects of future tsunamis.

Given the recent historical disastrous tsunamis and the knowledge that the Arabian Gulf (AG) is tectonically active, this study aimed to evaluate tsunami hazards in Kuwait from both submarine earthquakes and subaerial landslides. Despite the low or unknown tsunami risks that impose potential threats to the coastal area’s infrastructures and population of Kuwait, such an investigation is important to sustain the economy and safety of life. This study focused on tsunamis generated by submarine earthquakes with earthquake magnitudes (M w ) of 8.3–9.0 along the Makran Subduction Zone (MSZ) and subaerial landslides with volumes of 0.75–2.0 km3 from six sources along the Iranian coast inside the AG and one source at the Gulf entrance in Oman. The level of tsunami hazards associated with these tsunamigenic sources was evaluated using numerical modeling. Tsunami model was applied to conduct a numerical tsunami simulation and predict tsunami propagation. For landslide sources, a two-layer model was proposed to solve nonlinear longwave equations within two interfacing layers with appropriate kinematic and dynamic boundary conditions. Threat level maps along the coasts of the AG and Kuwait were developed to illustrate the impacts of potential tsunamis triggered by submarine earthquakes of different scales and subaerial landslides at different sources. GEBCO 30 arc-second grid data and others were used as bathymetry and topography data for numerical modeling. Earthquakes of M w 8.3 and M w 8.6 along the MSZ had low and considerable impacts, respectively, at the Gulf entrance, but negligible impacts on Kuwait. An earthquake of M w 9.0 had a remarkable impact for the entire Gulf region and generated a maximum tsunami amplitude of up to 0.5 m along the Kuwaiti coastline 12 h after the earthquake. In the case of landslides inside the AG, the majority impact occurred locally near the sources. The landslide source opposite to Kuwait Bay generated the maximum tsunami amplitudes reaching 0.3 m inside Kuwait Bay and 1.8 m along the southern coasts of Kuwait.

The 2016 Fukushima earthquake and tsunami presented several new issues of tsunami generation mechanism and propagation, as well as of organizational responses such as evacuation procedures and dissemination of tsunami warning. This study focuses on explanations to issues of public interest based on the experiences during the 2016 tsunami: (1) Despite Fukushima Prefecture's proximity to the earthquake's epicenter, why was the largest wave observed in the neighboring Miyagi Prefecture? (2) Why was the second wave of the tsunami larger than the first? (3) Why was the tsunami advisory elevated to a tsunami warning in Miyagi Prefecture? (4) Why did tsunami intrusions into rivers occur? (5) And why were local tsunami runup values much higher than the broadcasted tsunami amplitudes from local tide gauges? In the wake of the 2011 Great East Japan earthquake and tsunami, this study also points out remaining problems and new perspectives related to tsunami disaster risk reduction. These include tsunami warnings and advisories by emergency management agencies, the fact that tsunami waves are higher near the coast than in the open ocean, and refraining from being close to rivers in case of a tsunami. Based to Japan's experiences with disaster mitigation, lessons were learned from numerous events that could lead to revisions and improvements of current warning systems and provide useful guidelines for other countries.

It has been a decade and a half since the 2004 Indian Ocean Tsunami devastated people's lives in Aceh, Indonesia. Over the years, there was a massive reconstruction process, which was conducted between 2005 and 2009, to rebuild the areas affected by the tsunami. The recovery process was later continued by the local government in Aceh. Up until 2019, there have been four different recovery process assessments, i.e. (1) in 2009 performed by the Aceh-Nias Rehabilitation and Reconstruction Agency (BRR Aceh-Nias), (2) in 2012 by Tsunami and the Disaster Mitigation Research Center (TDMRC) and the United Nations Development Program (UNDP), (3) in 2014 by TDMRC and the Aceh Provincial Disaster Management Agency (BPBA), and (4) in 2019 by TDMRC and BPBA. This study is aimed at reporting the progress of the long-term tsunami recovery process from a perspective of disaster management (preparedness, mitigation, and policies). The first three recovery process assessment reports were synthesized using comprehensive literature reviews. During the reviews, this study applied Hyogo Frameworks for Actions (HFA) to identified key achievements during the recovery phases. The fourth tsunami recovery assessment was performed between March and October 2019 through a questionnaire survey involving 1087 respondents within three groups (Individuals, Public Health Clinics/Puskesmas, and Schools) and a focus group discussion. The questionnaire survey was performed in 9 districts in Aceh, which were once severely affected by the 2004 tsunami. The literature reviews of the reports that were previously conducted, identified that large achievements in tsunami mitigation and preparedness were found at the end of 2009. However, the frequency and involving parties in the mitigation and preparedness decreased significantly, especially after 2012. This study also reveals that tsunami preparedness at the community level is in a good condition. However, some schools and Puskesmas are unprepared to face a tsunami emergency situation, due to lack of emergency drills and operational guidelines for efficient tsunami responses.

Tsunami fragility curves are statistical models which form a key component of tsunami risk models, as they provide a probabilistic link between a tsunami intensity measure (TIM) and building damage. Existing studies apply different TIMs (e.g. depth, velocity, force etc.) with conflicting recommendations of which to use. This paper presents a rigorous methodology using advanced statistical methods for the selection of the optimal TIM for fragility function derivation for any given dataset. This methodology is demonstrated using a unique, detailed, disaggregated damage dataset from the 2011 Great East Japan earthquake and tsunami (total 67,125 buildings), identifying the optimum TIM for describing observed damage for the case study locations. This paper first presents the proposed methodology, which is broken into three steps: (1) exploratory analysis, (2) statistical model selection and trend analysis and (3) comparison and selection of TIMs. The case study dataset is then presented, and the methodology is then applied to this dataset. In Step 1, exploratory analysis on the case study dataset suggests that fragility curves should be constructed for the sub-categories of engineered (RC and steel) and non-engineered (wood and masonry) construction materials. It is shown that the exclusion of buildings of unknown construction material (common practice in existing studies) may introduce bias in the results; hence, these buildings are estimated as engineered or non-engineered through use of multiple imputation (MI) techniques. In Step 2, a sensitivity analysis of several statistical methods for fragility curve derivation is conducted in order to select multiple statistical models with which to conduct further exploratory analysis and the TIM comparison (to draw conclusions which are non-model-specific). Methods of data aggregation and ordinary least squares parameter estimation (both used in existing studies) are rejected as they are quantitatively shown to reduce fragility curve accuracy and increase uncertainty. Partially ordered probit models and generalised additive models (GAMs) are selected for the TIM comparison of Step 3. In Step 3, fragility curves are then constructed for a number of TIMs, obtained from numerical simulation of the tsunami inundation of the 2011 GEJE. These fragility curves are compared using K-fold cross-validation (KFCV), and it is found that for the case study dataset a force-based measure that considers different flow regimes (indicated by Froude number) proves the most efficient TIM. It is recommended that the methodology proposed in this paper be applied for defining future fragility functions based on optimum TIMs. With the introduction of several concepts novel to the field of fragility assessment (MI, GAMs, KFCV for model optimisation and comparison), this study has significant implications for the future generation of empirical and analytical fragility functions.

This paper presents a methodology to develop hurricane induced coastal flood vulnerability functions for residential construction based on empirical tsunami fragility functions. A force equivalency mapping procedure first transforms the tsunami fragility functions into coastal flood fragility functions. Following the quantification of the damage states and the incorporation of repair costs, the coastal flood fragility functions translate into coastal flood vulnerability functions. Insurance claims data from the National Flood Insurance Program and vulnerability functions independently derived by the US Army Corps of Engineers are employed to validate single-story on-grade timber and reinforced masonry structure model outputs. The limitations of the model and future developments are discussed.

Fifteen years since the 2004 Indian Ocean tsunami, which caused massive destruction around the Andaman Sea, people have participated in efforts to reduce tsunami risks in Indonesia. However, the most important question continues to be on whether such efforts are sufficient in dealing with tsunami risks. Among the most striking challenges here is bridging the gap in tsunami risk reduction between the Sumatra mainland and among communities in several small islands. Thus, this research aims to investigate the recent conditions of selected towns/cities in tsunami-prone small islands and identify the impediments to their tsunami hazard preparedness. It focuses on comparing efforts in terms of available facilities for tsunami evacuation plans and the tsunami estimated time of arrival (ETA), which is computed based on deterministic tsunami propagation models. In this regard, five of the observed locations are classified as being in a critical tsunami preparedness condition, namely Balai island, Lahewa of Nias Island, Sabeugunggung of North pagai Island, Surat Aban of South Pagai island, and Enggano Island. Most of them have limited space for tsunami evacuation and a short tsunami ETA, which constitutes an extreme condition requiring immediate tsunami mitigation measures. One possible approach is to construct a vertical tsunami evacuation building or modify existing buildings that can be used for tsunami evacuation on the islands. This article also highlights societal aspects related to tsunami preparedness.

The aim of this study is to assess the performances of different infrastructures as structural tsunami countermeasures in Sendai City, based on the lessons from the 11 March 2011, Great East Japan Tsunami, which is an example of a worst-case scenario. The tsunami source model Ver. 1.2 proposed by Tohoku University uses 10 subfaults, determined based on the tsunami height and the run-up heights measured for all tsunami affected areas. The TUNAMI-N2 model is used to simulate 24 cases of tsunami defense in Sendai City based on a combination of 5 scenarios of structural measures, namely, a seawall (existing and new seawall), a greenbelt, an elevated road and a highway. The results of a 2D tsunami numerical analysis show a significant difference in the tsunami inundations in the areas protected by several combinations of structures. The elevated road provides the highest performance of the single schemes, whereas the highest performance of the 2-layer schemes is the combination of an existing seawall and an elevated road. For the 3-layer scenarios, the highest performance is achieved by the grouping of an existing seawall, a new seawall, and an elevated road. The combination of an existing seawall, a new seawall, a greenbelt and an elevated road is the highest performing 4-layer scenario. The Sendai City plan, with a 5-layer scenario, reduces the tsunami inundation area by 20 sq. km with existing structural conditions. We found that the combination of an existing seawall, a greenbelt, an elevated road and a highway (a 4-layer scheme) is the optimum case to protect the city against a tsunami similar to the 2011 Great East Japan Tsunami. The proposed approach can be a guideline for future tsunami protection and the evaluation of countermeasure schemes.

Based on the definition of tsunami risk, we quantitatively evaluated the annual expected tsunami loss ratio (Tsunami Risk Index) and clarified the quantitative effects of epistemic uncertainties in tsunami hazard assessments on the tsunami risk of buildings by combining probabilistic information regarding tsunami inundation depths at target points and tsunami fragility assessments of buildings. For the risk assessment, we targeted buildings with four different structures (reinforced concrete, steel, brick, wood) located in three different areas (Soma, Sendai, Kesennuma). In conclusion, we demonstrated that the expected tsunami risk could vary by approximately two orders of magnitude when considering tsunami hazard uncertainties between the 95th percentile and the 5th percentile. In addition, we quantitatively clarified the fact that we cannot properly understand the tsunami risk by evaluating the tsunami fragility alone. For example, the analysis results indicate that the tsunami risk of a wood building located in Kesennuma is lower than that of a reinforced concrete building located in either Soma or Sendai.

The 63,605 damaged buildings from the 2011 Tohoku-oki tsunami in Ishinomaki were used to develop 52 fragility curves using linear regression. The data comprise the damage level and the measured inundation depth for each building. In agreement with previous studies, the present results indicate that reinforced concrete and steel buildings with three stories or more perform better under tsunami loading. Performance with respect to their intended function was found to depend mainly on structural material. Moreover, based on Japan's design code for earthquake-resistant buildings, buildings constructed after 1981 do not display a better performance compared to more recent constructions. Finally, the results show that for the same inundation depth, a higher damage probability exists along a ria coast due to higher flow velocities, confirmed by numerical simulation and survivor videos. These new findings are useful for building damage assessment, town reconstruction, and comparison of vulnerability functions in future studies.

The world is encountering climate change and severe natural disasters. Floods have been one of the most disruptive disasters these decades. The 2011 flood in Thailand affected 13.6 million people and caused damage of USD 46.5 billion, while the 2013 flood in Jakarta, despite its short period, affected more than 45,000 people. This study intends to examine the changes of disaster information preference before and during each disaster. Questionnaire surveys were conducted in July 2013 in Thailand and Indonesia. The results found that the preferences for information increased once the disaster approached, except for preparedness plans and warnings in both cases and waste disposal in the Indonesian case. While most of the information preferences show no significant difference in mean between the two disasters, the results found significant differences in preferences for traffic/transportation infrastructure both before and during the arrival of disasters, availability of food and water, waste disposal before disaster impact, and overall damage information during the impact. The findings are crucial in terms of information gathering and dissemination to maintain the lives and livelihoods of human being during disasters. This study can contribute to both research and practice in terms of disaster information analysis and better preliminary examination of the preference for information needs from similar disasters with different scales and geographies.

This paper reports results from a study of business owners carried out in 2016 in the region around Mount Zao, an active stratovolcano in Japan. In April 2015, Mount Zao experienced a period of unrest consistent with magma rising in the volcanic system. This led to alerts and public awareness campaigns, which provoked extensive media interest. This project used a survey and 12 semi-structured interviews to examine the opinions of business people on how the crisis was managed, and how it affected them. It also examined the perceptions of risk and the stories that were told about the potential eruption. Business owners who thought that an eruption would be harmful and that forecasting eruptions is difficult were more likely to be trusting. In general, respondents were very unaware of the risk from the volcano and the hazards that it could produce. The data also show that the impacts of disasters and even warning periods can cascade, much as hazards do: respondents noted that the crisis period effectively extended the time it has taken them to recover from the impact of the Tohoku earthquake in 2011, or brought them low just as they recovered. With increased vulnerability, the warning period at Zao exacerbated their situation, and this was not helped by a lack of scientific information and some perceived “rumours”. The paper suggests that public engagement via participatory strategies would be beneficial in reducing risk in this region, because it would enable stakeholders to own their risk and understand it.

Six buildings were overturned in the town of Onagawa during the 2011 Great East Japan tsunami. This study investigates the possible failure mechanisms of building overturning during tsunami flow. The tsunami inundation depth and flow velocity at each overturned building were recalculated by using a tsunami numerical simulation and verified using a recorded video. The overturning moment is a result of hydrodynamic and buoyancy forces, whereas the resisting moment is a result of building self-weight and pile resistance force. This study aimed to demonstrate that the building foundation design is critical for preventing buildings from overturning. The analysis results suggest that buoyancy force can generate a larger overturning moment than hydrodynamic force, and the failure of a pile foundation could occur during both ground shaking and tsunami flow. For the pile foundation, pile resistance force plays a significant role due to both tension and shear capacities at the pile head and skin friction capacity between the pile and soil, which can be calculated from 18 soil boring data in Onagawa using a conventional method in the AIJ standards. In addition, soil liquefaction can reduce skin friction capacity between the pile and soil resulting in a decrease of the resisting moment from pile resistance force.

This study presents a new analysis of spatial variation in fatality ratios in the 2011 Great East Japan tsunami, in order to overcome the limitations of previous studies that tended to underestimate the fatality ratios. In addition, this analysis was performed in a manner that allows the results to be compared to those from analyses of fatality ratios in other historical tsunamis. To do this, it uses population and fatality data at the village scale in areas of less than 3 km2 where the inundation ratio was greater than 70%, rather than the lower-resolution data used in previous studies. The median value of the tsunami inundation depth at each location was extracted at the original 5-m grid resolution. All of the data were obtained from the Reconstruction Support Survey Archive. Based on the results, a strong correlation between the fatality ratio and inundation depth was found only in some areas of the Sendai Plain, whereas no strong correlation was observed along the Sanriku ria coastline. Fatality ratios in Sanriku were likely related not only to the force of the tsunami but also to other factors, such as the ria topography and the population’s experience of past historical tsunamis. Data from other tsunamis in regions where tsunamis frequently occur also indicate that historical tsunami experience is a key factor in reducing fatality ratios. In contrast, the Sendai Plain shows smaller variation in local tsunami amplification effect compared to that of the Sanriku ria coastline, as well as fewer coastal defence structures. Therefore, the fatality ratio in that region was predominantly affected by the force of the tsunami and the residents’ individual characteristics. On the Sendai Plain, Ishinomaki City exhibited a strong correlation between the fatality ratio and inundation depth, as well as between fatality ratio and building damage because its low evacuation ratio meant that many fatalities occurred in victims’ homes. Therefore, the fatality ratio in Ishinomaki City was higher than those in other areas at the same inundation depth. Simple empirical formulas were developed for estimation of human fatalities based on inundation depths and building damage ratios.

Understanding the impacts of tsunamis, especially in terms of damage and losses, is important for disaster mitigation and management. The aim of this study is to present our estimations of the potential losses from tsunami damage on Okinawa Island. We combine the use of a tsunami hazard map and our proposed economic loss model to estimate the potential losses that would be sustained by Okinawa Island in the event of a tsunami. First, to produce the tsunami hazard map, we calculated tsunami flow characteristics using the mathematical model TUNAMI-N2 and incorporating 6 earthquake fault scenarios around the study area. The earthquake scenarios are based on historical records along the Ryukyu Trench and the Okinawa. The resulting inundation map is overlaid with economic land use type and topography maps to identify vulnerable regions, which are then employed to compute potential economic losses. Second, we used our proposed economic model for this study area to calculate the potential losses that would be sustained in these vulnerable regions. Our economic model extends the multi-regional-input-output (MRIO) model, where the economic values of industrial sectors are scaled to correlate with land use and topography types (coastal and inland areas) to calculate losses through the Chenery&ndash, Moses estimation method. Direct losses can be estimated from the total input of the MRIO table, while indirect losses are computed from the direct losses and interaction parameter of the MRIO table. The interaction parameter is formed by linear programming and calculated using the Leontief methodology. Our results show that the maximum total damaged area under the 6 earthquake scenarios is approximately 30 km2. Inundation ranging from 2.0 to 5.0 m in depth covers the largest area of approximately 10 km2 and is followed by areas with inundation depths of 1.0&ndash, 2.0 m and &gt, 5.0 m. Our findings show that direct losses will occur, while indirect losses are only approximately 56% that of direct losses. This approach could be applied to other areas and tsunami scenarios, which will aid disaster management and adaptation policies.

The 2011 Great East Japan Tsunami exposed many hidden weaknesses in Japan’s tsunami countermeasures. Since then, many improvements have been made in both structural measures (numerical simulations, coastal defense structures, building damage assessment and control forests) and nonstructural measures (warning/observation and evacuation). This review summarizes the lessons and improvements in the five-year time period after the 2011 event. After five years, most of the lessons from the 2011 tsunami have been applied, including more realistic tsunami simulations using very fine grids, methods to strengthen coastal defense structures, building evacuations and coastal forests, improved warning content and key points to improve evacuation measures. Nevertheless, large future challenges remain, such as an advanced simulation technique and system for real-time hazard and risk prediction, implementation of coastal defense structures/multilayer countermeasures and encouraging evacuation. In addition, among papers presented at the coastal engineering conference in Japan, the proportion of tsunami-related research in Japan increased from 15% to 35% because of the 2011 tsunami, and approximately 65–70% of tsunami-related studies involve numerical simulation, coastal structures and building damage. These results show the impact of the 2011 tsunami on coastal engineering related to academic institutions and consulting industries in Japan as well as the interest in each tsunami countermeasure.

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.

The 2004 Indian Ocean tsunami damaged a number of buildings in many Asian countries. The research objective of this paper is to determine the significant predictor variables and the direction of their relationships regarding the building damage level. This quantitative study used data collected by Murao and Nakazato [“Recovery curves for housing reconstruction in Sri Lanka after the 2004 Indian Ocean tsunami,” J. Earthquake Tsunami 4(2), 51–60; “Vulnerability functions for buildings based on damage survey data in Sri Lanka after the 2004 Indian Ocean Tsunami,” Proc. 1st Int. Conf. Sustainable Built Environment, Kandy, Sri Lanka, pp. 371–378] in Sri Lanka for analysis via the statistical approach. The tested explanatory parameters included the inundation depth, the structural materials, and the areas. This research is among the first pioneering efforts in applying the statistical analysis to investigate the influential parameters in tsunami damage areas. This work can contribute to the damage analysis research area in terms of providing the proved parameters as well as contributing to the practical understanding of urban planners, engineers, and related persons who are involved in building construction and disaster management.

Japan was hit by the tsunami generated by the greatest earthquake in the history of Japan. The authors conducted the post-tsunami field survey in Miyagi prefecture immediately after the event to me...

On March 11th, 2011, the Pacific coast of Japan was hit by a tsunami generated by the largest earthquake (M9.0) in the history of the country and causing a wide range of devastating damage. Using p...

In 2011, Japan was hit by a tsunami that was generated by the greatest earthquake in its history. The first tsunami warning was announced 3 min after the earthquake, as is normal, but failed to estimate the actual tsunami height. Most of the structural countermeasures were not designed for the huge tsunami that was generated by the magnitude M = 9.0 earthquake; as a result, many were destroyed and did not stop the tsunami. These structures included breakwaters, seawalls, water gates, and control forests. In this paper we discuss the performance of these countermeasures, and the mechanisms by which they were damaged; we also discuss damage to residential houses, commercial and public buildings, and evacuation buildings. Some topics regarding tsunami awareness and mitigation are discussed. The failures of structural defenses are a reminder that structural (hard) measures alone were not sufficient to protect people and buildings from a major disaster such as this. These defenses might be able to reduce the impact but should be designed so that they can survive even if the tsunami flows over them. Coastal residents should also understand the function and limit of the hard measures. For this purpose, non-structural (soft) measures, for example experience and awareness, are very important for promoting rapid evacuation in the event of a tsunami. An adequate communication system for tsunami warning messages and more evacuation shelters with evacuation routes in good condition might support a safe evacuation process. The combination of both hard and soft measures is very important for reducing the loss caused by a major tsunami. This tsunami has taught us that natural disasters can occur repeatedly and that their scale is sometimes larger than expected.