This study describes the stability of PC sleeper applied to the base of Inochi-yama, one of the tsunami evacuation facilities, against tsunami based on laboratory experiments. The experimental results showed that there are three representative damage patterns of PC sleeper, which are the damage in lower layer, upper layer and total layer. The lower and higher number of installed PC sleeper tend to be susceptible to damage in the upper and lower layer, respectively. The wave pressures acting on the PC sleeper are dominated by the impulsive wave pressure at the time of arrival of the tsunami. Especially, when the damage in lower layer, there are a tendency for large impulsive wave pressure to occur in a wide range of the lower layer. In addition, the stability against tsunami improves when the number of installed PC sleeper is increased.

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 In order to establish a design method for a breakwater for tsunami, it is necessary to clarify the progressive fracture mechanism until the collapse of a breakwater during tsunami action. Nowadays, since discrete element method become popular, it has become possible to grasp the behavior at the time of tsunami action taking account of deformation of the ground. However, it is difficult to grasp how the progresses destruction progresses in deformation analysis, because sliding failure, overturn failure, bearing capacity failure and the like are mixed behavior. Therefore, in this research, sliding amount and rolling angle of breakwaters during tsunami action were grasped using tsunami wave force and lifting pressure calculated by CADMAS-SURF with the aim of revealing basic behavioral characteristics. We revealed amount of sliding and turning angle of breakwaters by the equations of motion and angular motion equations taking into consideration the penetration of breakwaters into the mound. We also examined bearing capacity fracture by toe pressure acting on the mound from the bottom of a breakwater. As a result, we are able to evaluate quantitatively that breakwater under the action of tsunami quantitatively shows that destruction progresses in the order of sliding, bearing capacity failure, and overturn. In addition, we also confirmed that there is the possibility of bearing capacity failure occurring in some cases before sliding occurred.

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 Using tsunami-induced velocity data measured at the mouth of Monterey Bay in US during the 2010 Chilean Earthquakes Tsunami, an investigation of bottom boundary layer characteristics beaneath tsunami was carried out. The observed velocity profile is highly similar to that in a wave boundary layer, rather than depth-limited velocity distribution as normally assumed under long waves. In order to distinguish a depth-limited boundary layer from wave boundary layer, theoretical criterion is obtained by using an empirical formula for wave boundary layer thickness, and the effectiveness of this criterion is examined for sea bottom boundary layer under shoaling hypothetical tsunami. It is found that the entire region of shoaling from tsunami source area with 4000m depth to shallow area with 10m depth is classified into wave friction zone. This result coincides with the measurement result in Monterey Bay. Furthermore, condition for the predominace of bottom frictiona term in shallow water equation is obtained from the ratio to local accerlations term, which is epressed in terms of two dimensionless parameters.

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 In this study, hydraulic model tests and numerical simulations were conducted in order to verify the reproducibility of a tsunami movable bed model in coastal sea area with narrow pass. This study also examined the differences of flow pattern, sediment transport and bottom topography change depending on the width and shape of the narrow pass. Moreover, the influence of saturation concentration of suspended sediment on accuracy of the tsunami movale bed mode was investigated.
 As a result, the simulation results were confirmed to coincide reasonably with the experimental ones in spite of the treatment of saturation concentration of suspended sediment. The spatial distribution of erosion area and the time variation of suspended sediment concentration were better reproduced by using the saturation concentration which varies depending on the flow fields.

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 In this study, factors causing the underestimation of morphological changes due to tsunami-induced sediment transport in Kesennuma Bay with narrows during the Great East Japan Earthquake and Tsunami have been numerically investigaed. Based on the estimation, the saturated concentration of suspention model was improved. It was found out that strong unsdeady flows occerred at narrows. The numerical results from conventional saturated concentration model implied that at the narrows, suspension concentration and sediment supply from the bottom to the suspension were limited by high concentration in suspension, leading to underestimation of morphological change, i.e., erosion and deposition. By considering effects of strong unsteady flows on concentration of suspention, a new form of saturated concentration model based on log-wake law and Kármán constant theory has been proposed. Numerical results of the erosion and deposition in Kesennuma Bay were improved. It is expected that accuracy of evaluation about not only morphological changes but also inundation area and damages are improved.

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 Numerical simulation is an effective method to study sand transport and bed level change due to the tsunami, but many problems remain to the accuracy of numerical simulation. Thus, it's important to grasp the phenomenon of sand transport by experiments for verification of the simulation. In this study, the measurement of the bed level change and the detailed sand transport tracking using color sand were conducted simultaneously in the movable bed experiment, and the characteristics of sand transport due to the tsunami run-up to a land area was investigated. As a result, it was confirmed that the tendency of the bed level change is the same as that in the past experiment. In addition, it was also confirmed that the tendancy of sand transport differs depending on the sand supply position with respect to the shoreline using the color sand coverage. From the observation of the sedimentary layer, it was revealed that the sand movement was occurred even though the bed level changes were not measured because the color sand mixed layer was found under the bottom surface. This result indecates the importance of simultaneous measurements of the bed level change and the sand movement on the movable bed experiment.

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 Validity and accuracy of numerical model of tsunami-induced sediment transport is the key to clarify the whole picture of the sediment transport by 2011 Tohoku-oki Tsunami, and to predict nearshore disasters by future tsunamis. Thus, verification of the numerical simulations based on the field data and its interpretations are essential to improve the numerical model.
 The numerical simulation of the 2011 Tsunami demonstrated that intensive tsunami sediment transport mainly occurred by the backwash on the shallow seafloor at southern part of the Sendai Bay. The simulations by medium- and coarse-grained sands are generally consistent with the transport process inferred from the field data by seafloor and subseafloor survey. In addition, the simulation supports the interpretation for increase, stagnant, and decrease of flow speed and suspended load on the seafloor that is derived from the grain-size analysis of a sediment core. The present research that verifies the interpretation of the sediment transport affected by the difference in grain size, represents new prospect for improvement of the sediment transport model.

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 Coastal forest in the Tohoku and Kanto districts of Japan were destroyed by the Great East Japan tsunami on 2011. However, coastal forest had some ability to reduce the damage by a tsunami even when they were broken. In this study, the effects of coastal forests on scouring behind coastal embankment induced by tsunami overflow have been investigated by the hydraulic model experiments with erodible-bed. The scouring at landward toe of embankment becomes small with arrangement of coastal forest. Moreover, considering washed-out trees is not so much influenced on scouring size.

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 Fall flow due to tsunami overtopping causes scouring on mound behind breakwater, which finally results in failure of caisson breakwater. The scouring process includes complex interactions as well as highly deformed interface between fluid and solid phases. Due to aforementioned difficulties, both numerical and experimental investigations toward scouring mechanism has not been sufficiently investigated. In this regard, fully Lagrangian numerical method, namely particle method, is supposed to be an appropriate candidate to tackle this issue owing to its distinct advantage in dealing with complex boundaries. In this study, both experimental and numerical studies on mound scouring are carried out. For numerical simulation, one of Lagrange-Lagrange coupling methods, namely DEM-MPS, is utilized for 3D simulation of scouring on mound behind breakwater. The performance of DEM-MPS method and its potential applicability toward scouring problems are validated by comparing the reproduced numerical results with those of conducted model experiment.

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 The 2011 Tohoku Tsunami severely damaged the Tohoku areas. Failures of seawall, mainly due to scour on the land side, appeared to increase the inland tsunami damage. Recently, the local scour is successfully simulated based on ISPH (Incompressible Smoothed Particle Hydrodunamics) model, while it does not include the deposition process in the model. In this study, the deposition proess was introduced to the ISPH method to improve the model appicability. By using this new model, a countermeasure for tsunami overflow is proposed for the condition where the land side area is so limited that the land fill is not able to be introduced behind the seawall. It is suggested that sill structure behind dyke is able to reduce the scour around the land side of the seawall as well as the momentum of tsunami flow.

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 Boulders made of coral limestone transported shoreward have been observed many times in the tropics and subtropical coastal zones, and are called tsunami boulders or storm boulders. They can become lasting evidence of historical mega-tsunami or super typhoon occurrence during the past hundreds to thousands of years, even if no literature record remains. Since there is limited observational record of their detailed motion, movement limit, and spatial distribution of transport by tsunami or storm waves, detailed movement mechanisms are still poorly known. This increases the difficulty of developing a model of boulder transport, and interpreting field observations. This study aims to measure transport characteristics of coastal boulders through a series of experiments in the tsunami-wave laboratory flume. Transport distance of boulders increases in the dry reef conditions for solitary waves whereas in the wet reef conditions for irregular waves. Transport distance is strongly affected by fluid force variation according to the change of wave breaking point in solitary wave conditions. On the other hand, in irregular wave conditions, apparent weight become light in the submerged condition resulting smaller friction and more movable. In addition, we calculated the force required to move boulders from the fluid force and the maximum static frictional force.

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 At the Tohoku Tsunami in 2011, it is confirmed that drifting objects collide with buildings and structures while colliding and contacting each other. Collisions of drifting objects are factors for the expansion of damage caused by the tsunami. Damage that buildings and civil engineering structures suffer from the tsunami needs to be predicted considering not only the depth of flooding but also the influence of drifting objects. In this research, the collision forces by multiple tsunami drifting objects are obtained by hydraulic model experiments and numerical simulations. The characteristics of collision of multiple drift objects of different sizes and shapes are considered. The two-dimensional shallow water model and the tsunami drift model which is based on the DEM are used to calculate the tsunami wave force and the impact force of a drifting object.

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 In order to grasp behavior of water driven debris generated by tsunami inundation flow when the debris was impacted to apparatus established on land, hydraulic model experiments were carried out. We confirmed that drift velocity of debris was reduced than tsunami velocity because refrected wave was formed in front of collided object, and there were some debris that was not impacted on conditions that the debris was shorter than the length of the reflected wave. Moreover, we confirmed that considerating additional mass was also important in the collision phenomenon of a floating body when the debris was accelerated, and have the possibility of applying the past evaluation method using additional mass. It is indicated that reasonable predicted collision force can be calculated with the proposed load estimation formula by using the effective stiffness calculated from the structure of the object related in the collision and assuming the deformation at collision as elastic deformation.

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 In the aftermath of tsunami disaster, it is significant to re-open the port affected by the tsunami through the work of removing tsunami-induced debris in the port, especially navigation channels, for transportation of emergency supplies to the affected area. In this study, a method was investigated to estimate the number of work vessels and days necessary for removing debris in the port, in relation with the objective period for restarting the transportation of emergency supplies. The objective period was determined based on the analysis of resources in port physical distribution as well as the analysis of existing port business continuity plans. The amount of debris including cars and boats was estimated concretely based on the numerical simulation of tsunami propagation and inundation in Yokkaichi Port as a model port. As a result of this study, it was shown that four work vessels could attain the objective period for the emergency supply transportation under assumption of the use of seismic resistance quays which were expected to suffer less or light seismic impacts. The method proposed in this study can provide the in-depth discussion of the plan and process for cleaning navigation channels in the port business continuity.

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 Crowd evacuation after a tsunami warning may suffer from stagnant at bottlenecks with congestion. In the present study, we improved a tsunami evacuation model to simulate crowd behaviors with congestion, and it was applied to a crowded beach. It is expected that most of evacuees fail to escape from a significant tsunami under the current guideline of tsunami evacuation. We carried out evacuation simulations with various conditions for the beach and found for a large tsunami scenario with wave height over 7 m that 80% of evacuees would successfully escape by incorporating additional exits and evacuation buildings into the current guideline. For effective evacuations, proactive awareness of potential evacuees for the guideline and appropriate preparation by adimistrators are needed as well as installation of hard countermeasures.

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 Inundation areas exposed to a future Nankai-Trough tsunami are broad, and we will need much time and money to complete countermeasures. In order to reduce human damages, it will be practical to utilize and allocate proper routes and shelters for the evacuation, which may be instructed by local governments. This study developed a tsunami evacuation simulation model in which agents can select a evacuation route with escaping expected inundation areas, and also change a shelter according to the modified evacuation route. The developed model was applied to a local city in Kochi Prefecture, Japan. We evaluated the number of expected victims due to several disastrous tsunami scenarios. We compared the results to that derived from a conventional method in which agents take a minimum-distance route to a shelter, and verified that our method can find effective instructions that more agents can successfully evacuate.

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 In this study, we conducted inundation calculation of multiple tsunami sources with tsunami simulation and constructed the database of tsunami arrival times considering uncertainty of tsunami sources and aimed to propose a method to search evacuation routes not encountering the tsunami. The tsunami risk on evacuation route calculated by tsunami database, and evacuation behavior to select evacuation route that does not encounter the tsunami was incorporated into multi agent simulation. As a result, the method of selecting a route that does not encounter the tsunami during the evacuation behavior was established by changing the moving direction to the direction of the shortest distance of another evacuation shelter when there is a possibility of encountering a tsunami during the evacuation behavior calculated from the degree of danger. The area was simulated by this method, and confirmed that the mortality rate was reduced.

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 Evacuation planning against tsunami inundation is actively investigated. In the inundation planning, numerical simulations for crowd evacuation will be one of the key tool to determine suitable evacuation routes. Authors have been developed the crowd behavior simulator based on the DEM. In the conventional simulator, the behavior of each human element has been described with a translational motion of unit cylinder, and the vertical motion of legs has been neglected for simplification of human modelling. With considering the actual walking process, authors have tried to develop the bipedal model by modifying the unit cylinder model. In this study, hydraulic experiments for walking process in the inundated water condition below knee have been performed to collect fundamental data for modelling of the bipedal motion. Differences between the conventional unit cylinder model and the newly developed bipedal model are shown by comparison of numerical results to the pedestrian contra flows under inundated condition.

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 Approximately 340,000 people's evacuation behaviours were simulated with a supercomputer for investigations of tsunami evacuation risks in a coastal urban city. The large-scale simulation that models individual detail movements clarified potential risks such as delays of evacuation due to congestions in evacuation routes and overcrowded situations at evacuation sites. Additionally, the simulation demonstrated that those potential risks could be reduced by an evacuation control based on tsunami inundation forecasts. Simulated results with different departure scenarios indicated that approximately 40 minutes lead time is available for evacuations without casualties in the study area. These results suggest that tsunami forecast that can be completed within the lead time can contribute to smoother evacuation behaviours.

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 In order to create communities where people can promptly evacuate from tsunamis, it is essential to understand when, where, or how people begin an evacuation. The aim of this study is to understand the characteristics of the start of a tsunami evacuation using data on evacuation behaviors obtained from evacuation drills. The authors obtained data from evacuation drills held in Ama-Nakanishi district, Minami-Awaji city, Hyogo prefecture in 2016 and 2017. Specifically, data were obtained by shooting an aerial video using an unmanned aerial vehicle (UAV) and another video taken at ground level that moved along with residents during the drill. The authors used this spatio-temporal data to analyze the behaviors of 248 people.
 Data revealed that the process of beginning a tsunami evacuation actually constitutes two parts. In the first, people decide whether to start an evacuation based on either logical judgment concerning infor-mation about the tsunami evacuation or intuitive judgment concerning social reality (sense of urgency) as constructed by not only information about the tsunami evacuation but also all stakeholders in society. In the second, people's decisions to move to safe areas are affected by obstructive factors (e.g., concern for family members or the need to fulfill an assigned role when disaster happens). While slight differences are noted, the overall structure of the process in evacuation drills is closely similar to the process occurring during actual tsunami disasters.

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 Safety inspections of concrete block walls in Tokushima City were conducted with the aim of improving the safety of tsunami evacuation routes. The results showed that there are 2,048 concrete block walls in the area, many of which would collapse in the event of an earthquake with a seismic intensity of 7 (on the Japanese scale), potentially blocking 6% of roads in the area. Meanwhile, there is little appetite for safety inspections of concrete block walls around citizen's homes, which may be partly due to concern about day-to-day relationships with neighbors. Future measures were considered using the ARCS model, and this made it possible to propose the following: (1) first, specify the routes for children going to and from school, and implement concrete block wall measures; (2) indicate low-cost block wall measures; (3) use virtual reality to allow people to experience the landscape that will be created taking into consideration the wall and the surrounding area.

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 In this study, probabilistic tsunami heights were estimated based on two different methods, random phase and logic tree analysis, targeting the Pacific coast of Mexico. A large number of synthetic fault slip distributions covering moment magnitude from 7.8 to 8.6 were generated by the random phase method. The random phase and the logic tree stochastic tsunami methods were compared by considering 500 and 3 of the slip distributions for each magnitude, respectively. PDF and exceedance probabilities and annual occurrence probabilities of tsunami heights were compared by two different methods directly. The large difference of the two tsunami hazard models was shown based on the same slip source. The logic tree method tended to estimate the smaller for long-term tsunami heights and probabilities in comparison with the random phase method.

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 Although two tsunami levels are set for disaster protection and prevention, in order to make measures precisely stepwise and implement those, and furthermore to calculate the expected value for cost benefit, the scale and the probability of tsunamis are necessary from low frequency to high frequency. This study examined the applicability of the Gutenberg - Richter low showing the probability of earthquake to the tsunami probability evaluation with incorporating a rate of earthquake occurrence to tsunami occurrence in each magnitude of earthquake. The tsunami probability based on the Gutenberg-Richter low and the tsunami height were comparing with the result of the logic tree method and the extreme statistic. It is summarized that possibility of applying Gutenberg-Richter rule for high frequency probability of tsunami and future works of low frequency that.

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 It necessary to set relatively high frequency tsunami for preservation of coastal facilities.We called this tsunami "tsunami for designing". However, tsunami was occur less frequently, and different characteristic, history by each region. Suzuki et al., tryed to set "tsunami for designing" that focus to average occurence interval of earthquake by Headquarters for Earthquake Research Promotion, proposed the method that used comulative incidence rate of tsunami. In this study, targets Japan Sea side of Hokkaido that has be character that considerably lower frequency of earthquake than ocean-trench earthquake, and have be many active fault. We verificated applicability of this method on Japan Sea side of Hokkaido.

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 Based on the tsunami risk assessment on the global scale, by comparing the tsunami risks of each country or region, it is possible to preferentially identify areas requiring tsunami countermeasures. In order to achieve this, we conducted a tsunami hazard evaluation integrating the wave height and the propagation time of the tsunami, and newly introduced tsunami hazard indicators, considering tsunami countermeasures that are considered effective for each region . From the historical earthquake records, we selected 103 events in total for each area, and conducted tsunami numerical analysis. As results, it was possible to calculate the tsunami hazard value combining the wave height, the propagation time, and the number of tsunami incidents in each region, making it possible to quantitatively compare tsunami hazards in each region.

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 Macro scale assessment of building damage by tsunami can be performed using two classical methods namely, fragility functions and weight factors based on their vulnerability. However, these methods do not consider the actual performance nor strength of the buildings and damage might occur before either of flow depth and flow velocity reach maximum values. This study aims to investigate if instead analytical force estimation of tsunami forces and building strength is able to predict building damage. About 20,000 damaged wooden buildings data in Ishinomaki City from the 2011 Great East Japan tsunami were used for this analytical experiment. The impact of floating debris was also added based on weight. Building strength from bearing wall is estimated from building design standard which is mainly based on floor area and building height. Resistance reduction coefficient was also added for aged buildings. Two damage (collapse) patterns (washed away and destroyed) were analytically assessed using sliding and overturning mechanisms. As results, it was found the proposed method could reproduce the actual damage condition with very high accuracy for both collapse patterns. Almost destroyed and washed away buildings occurred when the flow velocity is higher than 2 m/s regardless of flow depth. Besides, it was found using the maximum flow depth and flow velocity could underestimate the damage by up to 2-4 times. This new method will be useful for building damage assessment in areas that have no actual tsunami damage experience.

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 Hierarchical Bayesian estimation of fragility curve of specific building damage is investigated by using the prior distribution of fragility curve of similar building damage and the likelihood inputting a few data samples and by minimizing the Akaike's Bayesian Information Criterion (ABIC). It is applied to building damage by the 2011 Tohoku Earthquake Tsunami. Bayesian estimation results of tsunami fragility curve of building damage in Minami Souma using the prior distribution of that in all inundation area are agree with estimation results by the minimum square method of corresponding observation data. Bayesian estimation results of tsunami fragility curve of RC damage with more than the third floor using the prior distribution of that of all RC damage are also agree with estimation results by the minimum square method of corresponding observation data. Bayesian estimation of tsunami fragility curve of building damage of thermal power plant using the prior distribution of that of similar building damage can be properly performed without effect of input order of used observation data on the likelihood.

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 Various methods such as a logic tree method and a random phase model have been proposed as a probabilistic tsunami hazard evaluation method. However, the calculation load is high because most of the methods require vast numbers of tsunami calculations. In this research, we aimed at evaluating probabilistic tsunami damage of a building using a method to estimate the uncertainty of the tsunami hazard with the Sagami trough earthquake by using the response surface method, which can be evaluated by suppressing the computation load and flexibly incorporating the uncertainty due to the probability distribution.
 As a result, we confirmed that the expectation of conditional damage of a steel building located on the Sagami Bay coast was estimated to be around 36.9%, and that we can evaluate the earthquake regions contributing to the extreme value of the frequency distribution of the tsunami inudation depth and the conditional excess probability distribution of the loss ratio of the building.

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 Osaka bay area are concerned that they will suffer tremendous tsunami due to the Nankai Trough Earthquake which is believed to occur reliably in the near future. In this area, highways, national routes and major provincial roads are constructed along the coast, and transportation and logistics networks essential to securing the lives of local residents are being formed. In this study, we investigated the risk of tsunami damage at river bridges and major traffic nodes in the coastal area of the Osaka bay area using the damage estimation of the Nankai Trough massive earthquake by the Cabinet Office in 2012. As a result, it was revealed that river bridges and transportation nodes potentially inundated become bottlenecks of ambulance transport and transportation of relief supplies. Moreover, we found that there are spots in the main roads of coastal areas that are difficult to use as evacuation routes. In addition, it showed that there is a possibility that traffic and logistics functions may be interrupted due to inundated area near the entrance on highway with seismic reinforcement reinforced.

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 To consider the optimum way to improve coastal embankments from two perspectives, disaster prevention and town planning, this study discusses the setting method of optimum height of coastal embankment using cost-benefit analysis. The target area of our case study is a coastal town in Izu Peninsula, Shizuoka Prefecture, utilizing coasts as tourism resources. The target area is expected to suffer damage caused by earthquake and tsunami along Nankai Trough near future. This study conducts cost-benefit analysis of improving coastal embankment in consideration of declining coastal value caused by the increasing of coastal embankment height. The principal aim of this study is to show the options of the coastal embankment heights for decision making process. The results indicate importance of increasing the evacuation success rate by the non-structural measures and possibility of becoming negative value of net benefit by raising coastal embankment by considering the value of coastal environment.

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 For keeping lives of the people against low frequency-huge tsunami, it is necessary for the disaster reduction to consider the efficiency improvement. The acceptance risk for people's lives is generally said to be borderline 10-5 (/year). This study challenged to develop the method for implementing policies to protect lives on the target level against tsunami disasters. the numerical simulation on probabilistic tsunami for getting inundation depth and that arrival time are carried out to synchronize evacuation simulation In order to reach the target survival probability, this study reevaluated with adding countermeasure.

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 In this paper, we conducted a questionnaire survey for survivors affected by the Great East Japan Earthquake in Natori city, Miyagi prefecture. Thereby, we clarified the actual conditions of tsunami risk perception, disaster prevention literacy, preparedness for next earthquakes and tsunami of inhabitants who rebuilt in the area inundated by the tsunami. As a result, the following main results were obtained. 1) Compared with the inhabitants who relocated to inland, the inhabitants who rebuilt in the area inundated by the tsunami have lower tsunami risk perception. And the proportion of those who think that tsunami will come again while they are alive is high. 2) Many people think that they will not be affected themselves by tsunami even if they predict the return of tsunami. 3) There is a possibility that the disaster prevention literacy of the inhabitants who rebuilt in the area inundated by tsunami is lower than that of the inhabitants who relocated to inland. 4) The inhabitants who rebuilt in the area inundated by tsunami is higher for the proportion of those who implement the preparation for tsunami. On the one hand, for other preparations and the total number of the preparations, the inhabitants who relocated to inland is higher.

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 Disaster Response drills are held actively in various places in Japan, and an effectiveness of participating the drills is evaluated variously. Meanwhile, in the year 2016 there was a typhoon No. 10 in August and a Tsunami from Fukushima earthquake in November. In this research, we focus on typhoon or tsunami disasters, and examined that could people lived there make use of the experiences of disaster response drills participating, or act on the drills.The results were following. 1) The experiences at dis-aster response drills has been more utilized in the case that an assumption was the same as the actual. 2) Even if the assumption is different from the actual disaster, people may be act the same behavior as at the time of drills. 3) The older in tsunami disaster, the younger in typhoon disaster, experiences of disaster response drills were utilized, and the same behaviors were done.

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 This study examines the effect of human casualty reduction due to tsunami tradition based on questionnaire survey in Kesennuma City, Miyagi Prefecture which was affected by the 2011 Great East Japan Earthquake. We analyzed the relationships of tsunami tradition and preparedness, recognition of tsunami risk, and evacuation behavior. The results are summarized as follows. Respondents who have known past tsunami prepared for tsunami and recognized tsunami risk before the 2011 disaster more than affected people who have not known past event knowledge. On the other hand, the relationship between tsunami tradition and evacuation behavior at the event was unclear in this case study.

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 This paper presents the results of interregional comparative evaluation of awareness of past tsunami event in affected area just before the 2011 East Great Japan Disaster occurring based on existing three survey data by Cabinet Office and authors. The results are summarized as follows. 1) Respondents who recalled the past tsunami event in Iwate at the earthquake occurrence are more than in Miyagi and Fukushima. 2) Rikuzentakada City residents have known 1896 and 1933 Sanriku Earthquake Tsunami more than Kesennuma City. 3) This case study is suggested that relocation to higher ground and subsequent damage mitigation affected past tsunami awareness. 4) Respondent in both cities often recognized through voice transfer from own parents and grandparents and mass media such as newspaper, book and TV program.

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 In the 2011 Tohoku earthquake tsunami disaster, the oceanographic radars installed at the coastal area of Japan and USA observed the tsunami, which proved the possibility for tsunami observation by using oceanographic radar. After the Tohoku tsunami, studies by using oceanographic radar were reported, but the research topics were mainly on tsunami observation and detection. Quantitative evaluations such as the estimation of wave peak is important in order that oceanographic radar contributes to tsunami disaster prevention and mitigation. In this study, the method to estimate a wave peak of tsunami by using a single oceanographic radar was examined and applied for a tsunami scenario in the Nankai Trough. The tsunami numerical modeling for the tsunami source of Mw9.1 and 8.6 in the Nankai Trough was carried out and gave radial velocity distributions to be observed by oceanographic radar. The wave peak was estimated by using the radial velocity distribution and was compared with the wave peak calculated by the outputted water distribution. As a result, the location of the wave peak is estimated well. And the water level of the wave peak is estimated with an error range of -20% to 10%.

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 We proposed a coastal tsunami forecasting method based on data assimilation using radial flow velocity distribution obtained with an ocean HF radar. The optimal interpolation method was adopted considering light calculation load. After confirming the effectiveness of the method using a simple uniform depth model with the linear long wave theory, we examined the effectiveness using a real topography model near Kashiwazaki Kariwa Nuclear Power Station with nonlinear long wave theory. Comparing tsunami waveform at the plant by the assumed tsunami source and the data assimilation tsunami forecasting, it was shown that the tsunami waveform can be predicted with high accuracy. And we confirmed that it can predict about 30 minutes later by several data assimilation.

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 We conducted a virtual tsunami observation experiment to evaluate the tsunami detection performance of oceanographic radar in Ensyu-nada near Omaezaki with a relatively complicated submarine topography. At Hamaoka Nuclear Power Station, an oceanographic radar has been installed, and using this measured data, two cases of different tsunamis were examined. By using the virtual tsunami observation experiment, it was possible to grasp how the tsunami propagates from the vicinity of the trough axis and the appearance of the tsunami striking from the southeastern side. It is estimated that the tsunami can be measured with a high accuracy of about 80 % or more in the range where the tsunami was detected by a method in which the correlation coefficient of the top 1 % in the 2 point correlation is used as the threshold value. Regarding the detection performance of the marine radar, the influence of the sea condition is small, and a tsunami can be detected approximately 30 km offshore. As for the influence on the tsunami detection performance due to the accumulation time of the observation data, tsunamis can be detected with high accuracy in one minute or two minutes observation, but the accuracy decreases in 4 minutes.

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 To identify paleo-tsunami history, we studied coastal lowland on Happo town, northern part of Akita Prefecture, at the eastern margin of Japan Sea. The study area faces near source region of the 1983 Japan Sea earthquake. From boring cores in these study area, we found some coarse grained sediments in organic mud and peat that were deposited in marsh. One of these coarse grained sediments has some sedimentological characteristics, such as, erosional lower contact, rip-up crusts, parallel and cross stratifications, some upward coarsening and fining units, and plant fragment laminae. These sedimentary features indicate that the deposited layer was formed by strong currents. Therefore, we interpreted these sediments as a tsunami deposits based on their sedimentary features and geographic setting around the study area. We used radiocarbon ages from plant materials to determine the ages of deposition of these tsunami deposit. Depositional age of the tsunami deposit was interpreted 13^th to 15^th-century by calibrated age of the ¹⁴C dating. We estimate that the tsunami event similar to the 1983 Japan Sea earthquake occurred 500 to 700 years ago.

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 The present tsunami forecasting and warning system uses quantitative tsunami assessment by searching from the pre-simulated database at the time of earthquake occurrence. The database was created based on numerical tsunami simulation of assumes earthquake scenarios and operated by Japan Meteorological Agency (JMA). However, the 2016 Fukushima earthquake pointed out some problems regarding to under-estimation of tsunami in Miyagi Prefecture. The main reason for this was the accuracy of the assumed fault parameters and simulation condition used in the database. It was found that the actual strike was largely different from the assumed values. Therefore, lessons from the 2016 earthquake were summarized and tsunami characteristics in Sendai Bay was newly assessed using database as earthquake scenarios located off Fukushima and Miyagi Prefectures. As results, it was confirmed that earthquakes with magnitude of 7.0 could generated tsunamis larger than 1 m in Sendai port depending on the strike values. In addition, there are scenarios that reach tsunami warning level when considering tsunami amplitude at the Sendai port according to the newly simulated 3,168 scenarios. Therefore, accuracy of the simulated tsunami in the current forecast system based on the numerical simulation condition is important and should be improved in the future.

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 The reliable tsunami inundation estimations require information on paleo-tsunamis. Tsunami deposits contain extensive information on the tsunamis. However, tsunami deposits have been used mainly to indicate tsunami occurrence. In this research, we developed a database that enables an estimate of the tsunami source that formed the tsunami deposits based on field investigations. A tsunami sediment transport simulation was carried out with multiple tsunami scenarios along the Japan Trench, and the distributions of deposition and erosion were estimated along the Pacific coast of Tohoku District. The computed results were stored in the database, and a function to search possible tsunami sources from the tsunami deposits and their distribution was implemented. The database provides a list of tsunami sources that formed multiple tsunami deposits identified in field investigations. Furthermore, it is also possible to sample the potential area in a field investigation to narrow down the list of potential sources.

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 This study developed the coupled model of Surge-WAve-Tide (SuWAT) by integrating a model of Transient Wave Runup, Overtopping and Overflow (IFORM) to improve the accuracy of inundation due to extreme surge heights. IFORM was incorporated into SuWAT in which overflow due to wave overtopping occurs before a sea level exceeds the freeboard; such phenomena were not modeled in conventional storm surge models. In estimating overtopping, the imaginary slope of foreshore and seawall can be fixed as 1:2 slope since an actual calculation to get imaginary slope is not changed so much as a model condition if wave characteristics at the toe of structures are employed. Results show that SuWAT-IFORM is able to well simulate a flooding event induced by a set of transient wave runup, overtopping and overflow.

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 This study proposed a transient wave runup, overtopping and overflow model to improve the accuracy of simulated inundation due to extremely large storm surges, like for the design of Level II tsunami after the Great East Japan Earthquake and Tsunami. To make an inundation hazard map for such extreme storm surge is essential for risk management and evacuation plan. Since studies considering the transient phenomena of wave overtopping and overflow is few, the present study proposed such modelling using the Integrated Formula of wave Overtopping and Runup Modeling (IFORM) including wave runup which can give output for a criterion of coastal structure damage. The present model output is almost the same as that based on an experiment-based model.

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 Tsunami simulator “T-STOC” has released as an analysis program to calculate tsunami behavior from ocean to coastal area integrally. However, T-STOC does not support a storm surge simulation because wind speed and air pressure cannot be set on free surface boundary. In this study, we added the input function of meteorological field into T-STOC so as to calculate storm surge. From the test calculation results with the meteorological field, we confirmed the validation of domain division setting and nesting method. Next, we calculated storm surge caused by previous typhoon in Seto Inland Sea, and compared the numerical results with the field observation ones in terms of storm surge deviation. As a result, T-STOC with the function of meteorological field was confirmed to reproduce the maximum value of storm surge deviation, and T-STOC is said to be able to simulate storm surge inundation. Furthermore, the influence of the number of vertical layer on storm surge analysis was also examined in this study.

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 Effects of various countermeasures facilities for storm surge in the Saga plain are investigated using the storm surge simulation. First, the worst typhoon course for the Saga plain was determined by simulating storm surges under various courses of catastrophic typhoon. Subsequently, effects of various countermeasures facilities against storm surge such as the dike raising, the ancient dikes on land which made along coastline in the past, the coastal road on banking near the Ariake Sea and discharge pumps on storm surge inundation were verified. To investigate the changes in the inundation depth, areas and start time due to the countermeasures facilities has been quantitatively clarified. Although the damages are mitigated in some areas, the damages in some areas are amplified due to the countermeasures facilities.

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 In August 2016, the accident occurred that four swimming people curried away to offshore and die at Ishikari-hama beach in Hokkaido. The several other accident that the swimming people curried away occurred around the Ishikari coast in recently years. The current analysis in Ishikari Bay due to the sea-sonal wind was studied in the past research. However, the current dynamics due to the wind direction change in short time has not studied yet. Therefore, we tried to comprehend the feature of the current dynamics in Ishikari bay, expressly around Ishikari-hama beach.
 As research contents, we grasped the history of the accident around the Ishikari coast. In this case, we used the on-line database and extract the newspaper article about the accident at Ishikari coast. As the result, we comprehended the feature of the accident in Ishikari Bay. Secondary, we made the field survey at Ishikari-hama beach in July 2017. This beach has cusp topography. The interval spacing of cusp topography was about 100m, and the slope of the bottom was about 1/80. In the field, we pig-mented the rip current by the sea water colorant, and the pigmented current was recorded as the aerial photography by the UAV. Thirdly, we confirmed the fluctuation of the current in Ishikari Bay due to the wind direction fluctuation. As a result, we comprehended that the current direction changed in several hours after the wind direction changed. Finally, we simulated the rip current and the wind driven current in Ishilari Bay.

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 This paper presents a study on picking out of typhoon track which is affected by the largest storm surge. In order to set up a condition of typhoon which the largest storm surge occurs, it is important to pick out not only the central pressure and radius but also the track of the typhoon. The sensitive analysis of the tide level deviation was estimated in several model topographies using the numerical simulation. Furthermore, the simulation was applied to locally as well for grasping the trend. As a result, the trend of the tide deviation in the actual field was in good agreement with that of the numerical experiment. The proposed method was shown to be useful for the set of the typhoon track causing the largest storm surge.

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 The 2018 edition of the technical standards and commentaries for port and harbor facilities in Japan recommends employing a scenario typhoon as one of accidental actions for the estimation of ocean wave and storm surge. The simulations of storm surge and wave in Shibushi Bay for various typhoons with different moving speeds and typhoon radii predicted that a typhoon with the moving speed of 50km/h slower than the speed of 73km/h estimated from Typhoon Vera in 1959 (Typhoon Ise-wan) conditionally generated more severe storm surge and wave in the bay. The simultaneous occurrence of two peaks of storm surge and wave induced most unstable state for a breakwater caisson.

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 Characteristics of a difference of peak time between wave heights and storm surge deviations during each storm at Ise Bay are discussed based on hourly hindcasts data during 67 typhoon and 37 non-typhoon storms in the past 45 years. Occurrence rates of the differences for the peak time are illustrated by histograms at selected 10 sights. The characteristics of the occurrence rates are distributed between three areas, Hamada and Fukue at southern coast sights, Nagoya and Mikawa at the inner sights of the bay and the other sights. As the waves at the inner sights require a longer developing time than the other sights, peak time of the wave heights at the inner sights is later than the storm surge deviations. Differences of the occurrence rate between the typhoon and the non-typhoon storms are not remarkable except the sights in Mikawa Bay which are affected strongly by western monsoon winds. And a rate that the peak of wave heights and that of storm surge deviations occurs simultaneously at Ise Bay is estimated to be approximately once every 6 years.

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 In the revision of the Flood Control Act in 2015, it is obliged to set the flood danger water level for storm surge. However, it is unknown that how often actual tide level reaches the flood danger water level since the flood danger water level vary according to lead time. In this paper, numerical simulation of possible maximum storm surge is performed and flood danger water level is set on the coast in Aichi Prefecture using simulation results. Comparing flood danger water level with observed tidal data in Port of Nagoya., it is confirmed that flood danger information of storm surge is not often issued and that the flood danger water level can be reached about once in four years assuming that storm surge coinsides with normal high tide.

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