Great East Japan Earthquake Tsunami Research Articles

Numerical Study on the Turbulent Structure of Tsunami Bottom Boundary Layer Using the 2011 Tohoku Tsunami Waveform

In this study, the tsunami-induced bottom boundary layer was investigated based on actual waveforms obtained by the GPS buoys along the coast of the Tohoku region during the 2011 Great East Japan Earthquake tsunami. The k-ω model was utilized for the numerical analysis in this study. As a result, the tsunami boundary layer thickness was found to be extremely thin compared to the water depth. The velocity distribution was similar to that of the bottom boundary layer under wind-generated waves. The flow regime is located in the transition from smooth turbulence to rough turbulence. Because of this, the gradient of the flow across the layer is much greater than the gradients in the steady flow direction. Therefore, the bottom friction is underestimated if the steady friction factor, such as in the Manning formula, is used. This study proposes a new simple method for calculating the bottom shear stress due to an irregular tsunami based on the wave friction law, and the k-ω model results are used to validate the proposed methods.

Lecture 2-2: Miyagi Great East Japan Earthquake Tsunami Heritage Hall

Lecture 2-2: Miyagi Great East Japan Earthquake Tsunami Heritage Hall

Rationale and Processes of Residential Buyout and its Effects in a Decade of Coastal Recovery and Mitigation: The Cases of the Great East Japan Earthquake Tsunami and Superstorm Sandy in the United States

Rationale and Processes of Residential Buyout and its Effects in a Decade of Coastal Recovery and Mitigation: The Cases of the Great East Japan Earthquake Tsunami and Superstorm Sandy in the United States

Knowledge-Building Approach for Tsunami Impact Analysis Aided by Citizen Science

Large tsunami events are devastating even though the impacts are limited to coastal areas. Knowledge is the key to minimize the losses from natural disasters by more proactive and better preparation. Targeting on natural hazards mitigation in Asia, a collaboration among 10 Asian and 2 European countries based on deeper understanding approach has been conducted since 2015. Deeper understanding is to discover the physical mechanisms and drivers behind a hazard event. Innovative model and simulation facilities are developed correspondingly to achieve more accurate numerical simulations of the whole lifespan of the target event. Application framework composed by the knowledge, data, simulation facility, software tools and case studies is designed to provide advanced estimation of hazard risk and would be evolved progressively with more case studies and observation data. For tsunami, based on the COMCOT (COrnell Multi-grid Coupled Tsunami Model), the simulation portal (iCOMCOT) implementing parallelized tsunami wave propagation calculation over distributed cloud had been established. iCOMCOT system finished the simulation of whole lifecycle of the 2011 Great East Japan Earthquake Tsunami in one minute. In this regional collaboration, case studies on historical events and tsunami impact analysis were conducted. The goal is to capture the physical characteristics of tsunami as much as possible such as tsunami wave propagation, tsunami refraction, tsunami run-up on land, as well as their drivers and root causes. The whole processes of tsunami from its initiation to its impacts in selected locations then could be simulated accurately by iCOMCOT based on the scientific explorations and the revised models quantitatively. Sulawesi Tsunami (2018) case is presented to demonstrate the processes of deeper understanding approach and how to achieve the capacity building. At the same time, the ways to take advantages of citizen science are also explored. Citizen science model is valuable in supporting data collection such as data of run up height, inundation range, flow depth, disruption information, impact area, from publication, news report, and interviews of local people. According to experiences on case studies, suggestions to simplify and optimize the integration of citizen science model with deeper understanding approach to lower operation cost are provided.

Message from the Winner

After the 1960 Great Chilean Tsunami, coastal dikes were remodeled and new ones constructed in Japan. In 1968, immediately after the completion of those construction and remodeling works, the Tokachi-Oki Earthquake struck, but fortunately the structures involved sustained very little damage. This led to a general feeling that it was possible to protect against the tsunamis completely by simply building coastal dikes and other defense structures. Japan did not see an increase in the number of tsunami researchers, but things were worse in the U.S. The National Science Foundation allocated its tsunami-related budget only to the NOAA, which issues tsunami forecasts, and allocated the rest of the budget entirely to ocean development. This situation continued until the 1983 Nihonkai-Chubu Earthquake Tsunami struck. In 1992, there was a tsunami earthquake off the coast of Nicaragua. Following that, research was conducted based on international cooperation through fax communications. Then cooperative international research continued to be done on tsunamis such as the 1992 Flores Tsunami, the 1993 Hokkaido Nansei-Oki Earthquake Tsunami, and the 1996 Irian Jaya Tsunami. However, their findings were provided only through Proceedings of the International Tsunami Symposium every two years, and most of the findings were limited to factual information about tsunamis. Requests for information on tsunamis rapidly increased after the 2004 Great Indian Ocean Tsunami, information not only on the tsunami itself but also on tsunami countermeasures. It was when JDR made its appearance. The JDR disseminated the latest information for practical use. It also benefitted those who were the sources of information, as they no longer had to deal with the frustration of having to wait for conferences held only every two years. In addition, the JDR reviews submissions much more quickly than do other journals. Tsunamis, such as the 2011 Great East Japan Earthquake Tsunami and the 2018 Sulawesi Earthquake Tsunami, continue to strike. As a platform for sharing knowledge related to reconstruction and countermeasures, as well as to tsunamis themselves, the importance the JDR is growing. This is why you are encouraged to contribute to the JDR.

Tsunami hazard mitigation.

The effect of giant tsunamis such as the Indian Ocean Tsunami in 2004 and the Great East Japan Earthquake Tsunami in 2011 has been devastating. In this study, a numerical simulation of the tsunami has been developed to estimate the physical characteristics of tsunamis and their effect on human society. Several laws and equations have been introduced for the simulation of tsunami propagation in the ocean, tsunami refraction, and tsunami run-up on land under a stable computational condition with acceptable accuracy. Our proposed method has been accepted as the world standard since 1997 and has been widely distributed to many countries through UNESCO.1) Computer graphic animations prepared by using the results of numerical simulation have been effectively used in public education and to increase the understanding of behaviors of the tsunami on the earth. When the numerical prediction of tsunami becomes possible with sufficient accuracy, then their results can be used to predict future damages and prevent the occurrence of a disaster. Data in the past were collected and expressed in terms of a newly introduced tsunami intensity which is related to the locally observed tsunami heights.

BEACH MORPHOLOGICAL CHANGES ON SENDAI COAST BY TYPHOON LIONROCK

In 2016, a few typhoons attacked Tohoku Area of Japan, and one of them, named Typhoon Lionrock, approached and hit Tohoku Area from the Pacific Coast, which is the first observed typhoon to have such a course in the observation history of Japan. In order to know magnitude of the storm surge and high waves induced by the typhoon and their influence on the coastal area, field surveys were conducted on the day of the typhoon arrival and also the next day. The target of the survey was Sendai Coast, which is a part of the Pacific Coast of Tohoku Area. The coast was severely affected by the 2011 Great East Japan Earthquake Tsunami, and its effect on the beach morphology still remains according to shoreline change analysis with aerial photographs by Hoang et al. (2016). In this paper, the shoreline changes by and after the typhoon were analyzed with the aerial photographs taken in every one or two months to understand its effect on the beach processes. And the results were combined with the shoreline data after the 2011 tsunami to see the impact of the typhoon on the beach processes under the recovery from the tsunami event.

Changes in pulmonary function of residents in Sanriku Seacoast following the tsunami disaster from the Great East Japan Earthquake.

Residents in the district struck by the Great East Japan Earthquake Tsunami (GEJET) suffered from adverse living conditions and various pulmonary diseases. To evaluate the influence of GEJET, we performed serial assessment of pulmonary function of approximately 10,000 residents in the district struck by GEJET. Using a spirometer, we assessed the pulmonary function of approximately 10,000 residents older than 18 years in the Sanriku seacoast, which was struck by the tsunami. Measurements were performed in 2011 and 2012. We compared FVC (forced vital capacity) % pred. and FEV1 (forced expiratory volume in 1second) % pred. of subjects between 2011 and 2012, by serial spirometry. Of the 7053 subjects studied, including 2611 men and 4442 women, FVC% pred. and FEV1% pred. were significantly higher in 2012 than in 2011. Physical indices including height, body weight and the body mass index (BMI) did not change significantly during this period. Smoking prevalence changed significantly between 2010, 2011, and 2012. Both FVC% pred. and FEV1% pred. of subjects who had quit smoking increased significantly on spirometry carried out in 2012, compared with those in 2011. The pulmonary function expressed as FVC% pred. and FEV1% pred. were significantly higher in 2012 than in 2011 among the subjects studied. The changes in the smoking status may be one of the reasons for the increase in values observed. However, other undetermined factors during recovery from a disaster might have resulted in improved pulmonary function.

Estuarine morphology recovery after the 2011 Great East Japan earthquake tsunami

The 2011 Great East Japan Tsunami caused severe morphological changes along the affected coastline on the northeast part of Japan. This study investigates the recovery of river mouths and breaching of sandy coast at the place used to be river mouth in Miyagi Prefecture, Japan after severe erosion induced by the tsunami through analyzing aerial photograph and investigating field data. After several years since the tsunami took place, the morphology of some river mouths has mostly recovered while others still have some damage. Results on the analysis of aerial photograph clearly indicate that the total length of sandy coast on both sides of river mouth plays important role in the recovery process. Moreover, the relevant phenomenon occurring during the morphological recovery process is also investigated. The findings demonstrated the intrusion of sand spit into river mouths due to the tsunami having scoured river mouth deeper than the depth of closure. Interestingly, the intrusion distance was found to be positively correlated with the width of river mouth. In addition, there is an important finding on the practical problem which is related to the intrusion upstream of sand spit. That intrusion shifts the boundary of fresh-sea water upstream, therefore external wave forces must be considered when implementing the design of river structures.

An Offline‐Based On‐Demand Visualization System of Large‐Scale Particle Simulation for Tsunami Disaster Prevention

SUMMARYAfter the Great East Japan Earthquake Tsunami, new Tsunami disaster‐prevention and mitigation methods for the next millennium Tsunami are actively being discussed. Consequently, the methods have highlighted the importance of both hard disaster‐prevention method, which means direct prevention using infrastructure such as breakwater, and soft disaster‐prevention method, including disaster‐prevention education. In this paper, a visualization and polygonization system that can be effectively utilized for Tsunami disaster prevention is proposed for large‐scale particle simulation. The system includes two important features, such as engineering‐purposed visualization and polygonization for hard and soft tsunami disaster‐prevention methods, respectively. Moreover, the system can handle the large‐scale particle simulation data that are computed by a high‐performance computer via an offline on‐demand tool without data transfer.

Development and Application of a Building Group Destruction Probability Model Based on the Great East Japan Earthquake Tsunami Experience

Development and Application of a Building Group Destruction Probability Model Based on the Great East Japan Earthquake Tsunami Experience

Innovation for Resilient Coastal Structures to Reduce Tsunami Disaster

The Great East Japan Earthquake Tsunami on March 11, 2011, caused unprecedented damage mainly in northeast Japan. This paper introduces the characteristics of the tsunami and resultant damage. The mechanism of the breaching of coastal structures and the effect of surviving structures on damage reduction in land are discussed. Then, a two-level tsunami mitigation concept, proposed and adopted by a committee hosted by the Government for recovery and reconstruction, is introduced. Within this framework, coastal structures are required to be resilient to external forces exceeding the design level. Various technologies that have been developed based on experience and research after the tsunami are introduced.

Public Attitudes toward an Epidemiological Study with Genomic Analysis in the Great East Japan Earthquake Disaster Area.

Introduction The Great East Japan Earthquake of March 11, 2011 may have influenced the long-term health of those in the disaster area. It is important to collect current and future health information of the people living in the post-disaster area to provide appropriate health support and quality-oriented care. However, public perceptions of health and genomic studies in the Great East Japan Earthquake disaster area are still unknown. A questionnaire survey was conducted in one town affected by the Great East Japan Earthquake and subsequent tsunami. The results of the questionnaire were tailed and the differences in responses to each question were assessed by sex and age. In 284 eligible people (137 men, 147 women), almost all participants agreed to join a health survey investigating the adverse effects of the disaster, and over 80% of the total participants agreed to genomic analysis. Over 70% of the participants wanted to receive pharmacogenetic testing and to receive feedback on which medications were suitable or unsuitable for them. Most people living in the disaster area are interested in health surveys. Most of the participants also showed interest in genomic analysis. Ishikuro M , Nakaya N , Obara T , Sato Y , Metoki H , Kikuya M , Tsuchiya N , Nakamura T , Nagami F , Kuriyama S , Hozawa A , the ToMMo Study Group. Public attitudes toward an epidemiological study with genomic analysis in the Great East Japan Earthquake disaster area. Prehosp Disaster Med. 2016;31(3):330-334.

Multi-Scale Bridge Wash Out Simulation During Tsunami by Using a Particle Method

n 2011, the huge tsunami caused by the great east Japan earthquake devastated many infrastructures in pacific coast of north eastern Japan. Particularly, collapse of bridges caused a traffic disorder and these collapse behaviors led to delay of recovery after the disaster. In this study, the bridge wash away accident is selected as a target issue, and it is represented by a numerical simulation. For this purpose, Smoothed Particle Hydrodynamics (SPH) Method, which is one of the pure mesh free methods, is utilized for the rigid body motion simulation. In this study, rigid body motion is introduced for the fluid-rigid interaction behavior during bridge wash away simulation. In the numerical analysis, the upper bridge structure is washed away by receiving an impact fluid force. The wash away simulation of two types of the bridge girder showed good agreement with the real accident on the great east Japan earthquake tsunami. © Owned by the authors, published by EDP Sciences, 2016 Language: en

The influence of the Great East Japan Earthquake on tuberculosis control in Japan.

WPSAR Vol 6, No 4, 2015 | doi: 10.5365/wpsar.2015.6.2.009 www.wpro.who.int/wpsar 30 a Nishinari District Public Health Offi ce, Osaka City, Japan. b The Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Tokyo, Japan. Submitted: 4 June 2015; Published: 21 December 2015 doi: 10.5365/wpsar.2015.6.2.009 The Great East Japan Earthquake and subsequent tsunami hit the Pacific Ocean side of north-eastern Japan on 11 March 2011,1 resulting in more than 18 000 deaths and missing people in three prefectures: Iwate, Miyagi and Fukushima.2 Of those deaths, 65% were aged 60 years and older, and more than 90% were caused by drowning.3 The earthquake also destroyed nuclear power plants in Fukushima, causing high levels of radioactive contamination.4 As a result, there were 386 739 evacuees staying in 2182 temporary shelters such as community centres, schools and gymnasiums one week after the disaster.5

Impact of the Great East Japan Earthquake tsunami on growth and survival of Pacific cod (Gadus macrocephalus)

A massive tsunami hit the north Pacific coast of Japan on 11 March 2011. We evaluated the effects of the tsunami on the distribution, growth, and survival of young Pacific cod (Gadus macrocephalus) using data from benthic trawl surveys and otolith microstructure analysis. The distribution of Pacific cod juveniles differed between 2011 and 2008–2010. The 2011 year class was smaller in body size than those in 2008–2010. The majority of 2011 year-class juveniles was captured in deeper areas at a smaller body size, whereas those of previous year classes were primarily distributed in shallower water. The peak hatch of the 2011 year-class juveniles was from early to late February, which was several days later than those of the 2008 and 2010 year classes. The 2011 year class grew at the same rate as those from 2008 and 2010 until the day of the tsunami, but had a lower growth rate during the 30 days after the tsunami, resulting in a decrease in fish size at settlement. Growth of the 2011 year class was also inferior soon after the day of the tsunami in almost all groups divided by the hatching period. Growth of juveniles captured in shallower water following the tsunami in 2011 tended to be slower than that of juveniles captured in deeper water. Our results suggest that the tsunami caused a decrease in growth rates for approximately 30 days and a change in the distribution of juvenile fish relative to prior years. The change in distribution was primarily the result of mortality in shallow water caused by physical damage and (or) subsequent decreased growth. Considering these results and the finding that the recruitment level and the recruits per spawning in the 2011 year class were low, the tsunami may have affected the determination of the recruitment level.

Response to the 2011 Great East Japan Earthquake and Tsunami disaster.

We revisited the lessons of the 2011 Great East Japan Earthquake Tsunami disaster specifically on the response and impact, and discussed the paradigm shift of Japan's tsunami disaster management policies and the perspectives for reconstruction. Revisiting the modern histories of Tohoku tsunami disasters and pre-2011 tsunami countermeasures, we clarified how Japan's coastal communities have prepared for tsunamis. The discussion mainly focuses on structural measures such as seawalls and breakwaters and non-structural measures of hazard map and evacuation. The responses to the 2011 event are discussed specifically on the tsunami warning system and efforts to identify the tsunami impacts. The nation-wide post-tsunami survey results shed light on the mechanisms of structural destruction, tsunami loads and structural vulnerability to inform structural rehabilitation measures and land-use planning. Remarkable paradigm shifts in designing coastal protection and disaster mitigation measures were introduced, leading with a new concept of potential tsunami levels: Prevention (Level 1) and Mitigation (Level 2) levels according to the level of 'protection'. The seawall is designed with reference to Level 1 tsunami scenario, while comprehensive disaster management measures should refer to Level 2 tsunami for protection of human lives and reducing potential losses and damage. Throughout the case study in Sendai city, the proposed reconstruction plan was evaluated from the tsunami engineering point of view to discuss how the post 2011 paradigm was implemented in coastal communities for future disaster mitigation. The analysis revealed that Sendai city's multiple protection measures for Level 2 tsunami will contribute to a substantial reduction of the tsunami inundation zone and potential losses, combined with an effective tsunami evacuation plan.

Initial Responses of the Government of Japan to the Great East Japan Earthquake (Earthquake and Tsunami) and Lessons Learned from Them

Various lessons regarding initial and emergency responses to huge disasters in future can be derived from the processes of establishing and managing the Government's Extreme Disaster Management Headquarters for the Great East Japan Earthquake. Huge disasters (L2) that might occur at a very low frequency and could cause tremendous damage can be controlled only to a limited extent by constructing infrastructure alone. In addition, because the picture of disasters that occur in different manners cannot be fixed, it is necessary to accumulate various infrastructural and non-infrastructural measures in the order of effectiveness from the standpoint of disaster risk reduction to accept and mitigate damage. Supports to disaster-affected people such as early recovery, evacuation, rescue, emergency medical life-saving, and emergency supplies in initial responses should be strengthened to promptly respond to disasters. For that purpose, it is important to establish a system that allows the government or prefectures to temporarily take disaster emergency measures when prefectures or municipalities lose administrative functions, formulate a system for the government to respond to huge disasters, and improve disaster information functionality, conduct drills and prepare for rehabilitation and reconstruction.

Modeling of the Drift and Accumulation of Tsunami-Driven Combustible Objects: Towards Tsunami-Induced Fire Spread Simulation

Fires that break out in tsunami inundation areas are collectively referred to as “tsunami-induced fires” in contrast with “seismic-induced fires” which have been conventionally a serious concern in Japan. Scenario of this new fire is basically as follows: (1) combustible objects such as houses are washed away by a tsunami, (2) combustible objects accumulate in tsunami inundation area as debris, (3) debris are ignited by some kind of cause, and (4) fires spread to adjacent debris resulting in conflagration in tsunami inundation area. We have been modeling tsunami-driven combustible objects as the first step towards development of tsunami-induced fire spread simulation. This modeling aims to know how combustible objects accumulate in tsunami inundation area to be the input data to fire models for ignition and fire spread. The proposed model is the extension of the existing model for driftwood by incorporating the debris release model and the effect of debris’s collision with surviving buildings. This model collaborates with the existing numerical simulation of tsunamis and is able to predict the drift and accumulation behavior of individual debris by solving the equation of horizontal translational motion. In this paper, we conducted debris diffusion simulation for Yamada, Iwate prefecture, Japan for model’s validation, where 16 ha of area were affected by tsunami-induced fire spread after the 2011 Great East Japan Earthquake Tsunami. The total number of debris tracked in the simulation was 1,850,560. A constant of proportionality, which determines the severity of force acting on drifting debris due to the collision with onshore surviving buildings, was identified by trial and error to maximize the eventual amount of accumulating debris within the fire-damaged zone. As a result, this maximum amount was predicted to be 4654 tons in the case that the constant is 0.1. Two thirds of the released debris, about 12,000 tons, accumulated onshore at the end of computation, and most of the fire-damaged zone was covered by these debris.

海岸堤防背後の落堀をモデルにした津波減勢施設とその効果

A facility for dissipating tsunami flood energy that modeled a pool dug by a tsunami flood has developed and evaluated its effect. Reducing tsunami flood energy is one of the important problem for a future huge tsunami counter- measure. The formation of pools at the toe of back slope of the coastal levees caused breaking a lot of coastal levees at the 2011 Great East Japan Earthquake tsunami. However, it is pointed out that the pools also played a roll of reducing flood disaster in backyard of coastal zone. The tsunami flood energy dissipator is settled in the foot of coastal levee. Two types of the tsunami flood energy dissipator that change its slope in the coast side were examined by the hydraulic model experiment. We evaluate the effect of reduction of tsunami flood velocity in three tsunami wave height. Results of the hydraulic experiment indicate that constructing the energy dissipator that has mild slope in the coast side can decrease almost 30% of the tsunami flood velocity.