Great East Japan Earthquake Research Articles

Incoming plate structure at the Japan Trench subduction zone revealed in densely spaced reflection seismic profiles

The structure of the incoming plate is an important element that is often considered to be related to the occurrence of great earthquakes in subduction zones. In the Japan Trench, where the 2011 Tohoku earthquake occurred, we collected seismic profiles along survey lines separated by 2–8 km to examine the structural characteristics of the incoming Pacific plate in detail. The average thickness of the incoming sediments was < 500 m along most of the Japan Trench, and it was < 300 m at ~ 38° N, where the large shallow megathrust slip occurred during the 2011 Tohoku earthquake. We mapped bending-related normal faults, including their dip direction and amount of throw. The numbers of eastward (oceanward) and westward (trenchward) dipping normal faults were generally comparable in the Japan Trench. Eastward dipping normal faults were dominant in the northern and southern parts of the Japan Trench, whereas westward dipping normal faults were more numerous in the central part. Graben-fill sediments deposited at the landward edge of the graben were bounded by eastward dipping normal faults. Trench-fill sediments were also observed along the trench axis. The sediment fills locally increased the thickness of the input sediments where they were deposited. The along-axis variation in input sediment and sediment fill distribution, and the variations in normal fault dip direction between the central and other parts of the Japan Trench may correspond to different slip styles along the plate boundary.

Establishment of Training System to Cope with Mental Health and Social Issues in Disaster Recovery Public Housing After the Great East Japan Earthquake

This study aimed to establish a training system for non-mental health professionals to cope with the mental health and social issues of impacted residents in disaster recovery public housing after more than 10 years since the Great East Japan Earthquake (GEJE). In September 2021, a group interview was conducted with seven life support advisors (LSAs) in charge of providing continuous support for impacted residents. These advisors possess a good understanding of the situation of impacted residents in disaster recovery public housing. Isolation emerged as an apparent issue, especially during the COVID-19 outbreak in which interactions among residents were reduced. Then, a training program for coping with isolation, as well as other issues identified through the interviews, such as delusions, troublesome behaviors, alcohol-related issues, wandering, suicidal ideation, and social withdrawal, was developed. For infection prevention and ease of obtaining training opportunities, this program was distributed online. Eleven participants were trained to use the developed program and were subsequently asked to complete an anonymous questionnaire. Results showed a considerable increase in the participants’ comprehension in addressing the impacted residents’ mental health issues. Although further investigation is warranted given that the representativeness and validity of our findings are somewhat limited, this study revealed the current situation of impacted residents in disaster recovery public housing following the GEJE. It also established a mental health training system for non-mental health professionals that addresses the identified issues. The developed training system for advisors would contribute to preparedness and risk reduction for future disasters.

Resilience, Keiretsu and Dependence on Buyers: Evidence from the Great East Japan Earthquake

Resilience, Keiretsu and Dependence on Buyers: Evidence from the Great East Japan Earthquake

E-Defense Shake Table Experiments Implemented by NIED and Collaborative Research Projects in 2005–2022

The three-dimensional full-scale earthquake testing facility, “E-Defense” was constructed using the 1995 Great Hanshin-Awaji Earthquake as a lesson. Until October 2022, this facility has conducted 123 experiments as part of the research and development on earthquake engineering for various purposes (e.g., the clarification of destruction processes, evaluations of seismic structural performances, functional maintenance, collapse margins, and damage control technologies). Even after its commencement, large earthquakes that significantly affected human life and socioeconomic activities occurred such as the 2011 off the Pacific coast of Tohoku Earthquake caused the Great East Japan Earthquake Disaster. These earthquakes revealed some new challenges for disaster prevention and mitigation. Such issues have also been incorporated as subjects to be addressed by the facility. This article introduces the researches and developments using E-Defense, chronologically linking them with the major earthquakes occurred in Japan after 1995. By summarizing the activities, its near-future direction is also briefly indicated.

Post-traumatic growth caused by the Great East Japan Earthquake and response to coronavirus disease 2019

The occurrence of human growth after a stressful experience, such as a disaster, is called post-traumatic growth (PTG). PTG has been confirmed among people affected by the Great East Japan Earthquake (GEJE). We hypothesised that people who experienced PTG during the GEJE would be able to better respond to the coronavirus disease 2019 (COVID-19) compared to those who did not. This cross-sectional study conducted a survey via a posting method between 25 January and February 16, 2021. We randomly distributed questionnaires to 1800 residents of Fukushima and Miyagi prefectures aged 20–26 years. We included 582 participants who responded. PTG caused by the GEJE was significantly higher in the affected prefectures, especially among those who experienced the earthquake and tsunami. Furthermore, it was significantly associated with COVID-19-related responses, such as avoiding the three-Cs (i.e., closed spaces, crowded places, and close-contact settings), basic infection control, taking care of oneself under self-restraint, and getting enough rest and nutrition. This suggested that experiencing PTG may have enabled people affected by the GEJE to better respond to the COVID-19 pandemic. However, PTG was also associated with exclusive behaviours, although this association was weaker than that for other COVID-19-related responses. Hence, support for increased PTG during the post-disaster period was suggested.

Lectio Praecursoria: Aspired Communities—The communities of long-term recovery after the 3.11 disaster in the town of Yamamoto

I argue in this thesis that we can understand the various ways in which community is ontologized as a tangible, affective and compelling social reality through the analytical lens of the future orientation of collective aspiring. The social and material lives of the residents in the disaster-stricken Tohoku region of northeast Japan were drastically altered after the Great East Japan Earthquake and the tsunami on March 11 in 2011. Based on eight months of ethnographic fieldwork in 2014–2015 in the town of Yamamoto, I seek to understand in this PhD thesis how the local communities were recovering during the still-ongoing reconstruction then. The main objective of this thesis is to offer analytical tools to explore how people come to interpret, experience and feel their social existence as community.

Giving of time or giving of money? An empirical analysis of nationwide prosocial behavior in times of disaster

This study aims to clarify the behavioral principles of volunteering (giving of time) and monetary donation (giving of money) in times of major disaster, including the interrelationship between the two behaviors, using the Great East Japan Earthquake (3.11) as a case study and tries to find out how different they are from those in normal times. Specifically, I use a simultaneous decision model (bivariate probit model) to estimate the participation factors of volunteering and monetary donation and compare the estimation results in times of disaster with those in normal times.The results revealed that the probability of participation in volunteering decreased with distance from the disaster area, while the probability of participation in monetary donation increased with the distance from the disaster area, and that the relationship between volunteering and monetary donation, which was complementary under normal circumstances, turned into substitutional during the disaster.These prosocial behaviors during the disaster are expected not due to the fact that certain citizens with a socially oriented mindset are mainly involved in various prosocial activities as is the case in normal times but rather due to the fact that a wide range of citizens tries to be involved in the disaster relief activities within the time and place constraints in order to recover the emotional balance they have lost after the disaster and improve their own subjective well-being.

Regional Agriculture and Social Capital after Massive Natural Disasters: The Case of Miyagi Prefecture after the Great East Japan Earthquake

This study aimed to clarify how local agriculture and social capital in disaster-affected areas were transformed by the Great East Japan Earthquake and tsunami in March 2011 and to identify the factors that influenced the transformation of social capital—especially trust—after the disaster. A questionnaire survey was conducted in the Miyagi prefecture’s disaster-affected areas. Survey responses were analyzed using descriptive statistics and linear regression analysis with ordinary least squares; the trust index was used for explained variables and personal-attribute disaster-related variables as explanatory variables. The results indicate that regional agriculture was integrated into agricultural corporations or communal management as individual farmers were unable to recover their disaster-related losses. After the disaster, participation in collaborative efforts to manage community resources decreased, while participation in community activities, such as volunteering, increased. Respondents lost trust in the people around them owing to relocation after the disaster and exposure to crime. Steps necessary to maintain or improve social capital in disaster areas include maintaining public safety in the disaster area, securing sources of income, and providing people with interaction opportunities, such as hobby groups. The findings offer practical applications for post-disaster agricultural resource management in developed countries.

Implications of the evacuation of hospitalized patients in a nuclear emergency.

In the accident at the Fukushima Daiichi nuclear power station following the Great East Japan Earthquake and tsunami, more than 50 hospital patients died during or soon after evacuation, primarily owing to the interruption of necessary medical care. To prevent the occurrence of such losses in the future, the focus of evacuation decisions should be on the health status of individual patients and not on currently evaluated non-human aspects such as the geophysical conditions and the status of the accident facility. This brief research report provides a conceptual basis considering the principle of justification for making more appropriate decisions on the evacuation of hospitalized patients by balancing radiological risks and evacuation-induced health risks. This research report is expected to foster discussions among stakeholders on how to protect vulnerable people more appropriately in nuclear emergencies.

Experimental analysis of Tsunami–Current interaction in river channel

The 2011 Tohoku Tsunami caused severe human and property damage along the east coast of Japan. In particular, the tsunami introduced through the river mouth damaged inland areas as it traveled up the river. In this study, a laboratory experiment was performed by applying funnel-shaped river mouth characteristics to investigate the hydraulic characteristics of a tsunami traveling up a river. In the river channel, the tsunami and wave heights were increased by the non-linear interaction between the tsunami and river current, which intensified as the river flow velocity increased. The river current in the opposite direction delayed tsunami propagation, thereby reducing the average celerity. The dispersion relation of the tsunami increased the time difference between the large first peak and small second peak. Additionally, the river current increased the effective volume of the tsunami wave peak. These hydraulic phenomena occurred because the flow characteristics of the tsunami are stronger than those of oscillating waves in the non-linear interaction between the tsunami and river current.

Analysis of the Quality and Quantity of Antiepileptic Drugs Required in Communities during Large-Scale Disasters: Focused on a Small Local City in Japan

The Tohoku earthquake off the Pacific coast in March 2011 led to massive medical requirements. Although the availability of drugs is essential in the disaster-affected area, a shortage of drugs and a lack of supply of drugs were reported. Moreover, in Japan, there are concerns regarding the occurrence of a large-scale earthquake, such as the Nankai Trough megathrust earthquake, in the near future. Therefore, drug requirements in a disaster-affected area need to be determined in advance. This study uses national health insurance data (KDB), which are medical big data, to determine the drug requirements in the region from insurance claim information. This study focuses on epilepsy as the target disease and determines the quantity and quality of antiepileptic drugs required in the region via analysis.

Do Adverse Childhood Experiences Modify the Association Between Disaster-Related Trauma and Cognitive Disability?

Identifying subpopulations that are particularly vulnerable to long-term adverse health consequences of disaster-related trauma is needed. We examined whether adverse childhood experiences (ACEs) potentiate the association between disaster-related trauma and subsequent cognitive disability among older adult disaster survivors. Data were from a prospective cohort study of older adults who survived the 2011 Great East Japan Earthquake. The baseline survey pre-dated the disaster by 7 months. We included participants who completed follow-up surveys (2013 and 2016) and did not have a cognitive disability before the disaster (n= 602). Disaster-related traumas (i.e., home loss, loss of friends or pets) and ACEs were retrospectively assessed in 2013. Cognitive disability levels in 2016 were objectively assessed. After adjusting for pre-disaster characteristics using a machine learning-based estimation approach, home loss (0.19, 95% confidence interval (CI): 0.09, 0.28) was, on average, associated with greater cognitive disability. Among individuals with ACEs, home loss was associated with even higher cognitive disability levels (0.64, 95% CI: 0.24, 1.03). Losses of friends (0.18, 95% CI: 0.05, 0.32) and pets (0.13, 95% CI: 0.02, 0.25) were associated with higher cognitive disability levels only among those with ACEs. Our findings suggest that individuals with a history of ACEs may be particularly vulnerable to adverse health consequences related to disasters.

Visualizing the annual transition of ocean policy in Japan using text mining

Research on evidence-based marine policymaking is still immature, especially regarding the utilization of text data. This study visualized the transition of ocean policy in Japan using text mining technique applied to the text data of three annual reports: the Fishery white paper from 2007 to 2020, Environmental white paper from 2008 to 2020, and Ocean white paper from 2004 to 2020. The results of the analysis were compared with the expert interviews on each subject. Based on latent Dirichlet allocation (LDA) topic model analysis, significant differences in topics were observed among these white papers, while they all clearly responded to the Great East Japan Earthquake occurred in 2011 with their unique topics. Major transitions in topics occurred several times over the years for all white papers. For the Fishery white paper and Environmental white paper issued by the government agencies, notable transitions occurred in 2011, 2013, 2017 and 2012, 2018, respectively, which were mainly caused by the revisions of relevant laws; while for the Ocean white paper issued by non-government organization, transitions occurred in 2009 and 2016, which were closely related to the development of worldwide ocean initiatives. The expert interviews revealed that the experts’ views on the topics and the transitions of policy focuses were generally consistent with the unsupervised analysis results. Automated visualization of policy transition in each organization accelerates the extraction of their directions and roles in policymaking which will help provide scientific evidence for identifying future opportunities for inter-organizational collaboration.

Analysing Civilian Video Footage for Enhanced Scientific Understanding of the 2011 Tohoku Earthquake and Tsunami, Japan, with Implications for PNG and Pacific Islands

Approximately 70% of global tsunamis are generated within the pan Pacific Ocean region. This paper reports on detailed analysis of civilian video footage from the 2011 Tohoku earthquake, Japan. Comprehensive scientific analysis of tsunami video footage can yield valuable insights into geophysical processes and impacts. Civili22an video footage captured during the 2011 Tohoku, East Honshu, Japan tsunami was critically examined to identify key tsunami processes and estimate local inundation heights and flow velocity in Kesennuma City. Significant tsunami processes within the video were captured and orientated in ArcGIS Pro to create an OIC (Oriented Imagery Catalogue). The OIC was published to ArcGIS Online, and the oriented imagery was configured into an interactive website. Flow velocity was estimated by quantifying the distance and time taken for an object to travel between two known points in the video. Estimating inundation height was achieved by taking objects with known or calculable dimensions and measuring them against maximum local inundation height observations. The oriented imagery process produced an interactive Experience Builder app in ArcGIS Online, highlighting key tsunami processes captured within the video. The estimations of flow velocity and local inundation height quantified during video analysis indicate flow speeds ranging from 2.5–4.29 m/s and an estimated maximum local run-up height of 7.85 m in Kesennuma City. The analysis of civilian video footage provides a remarkable opportunity to investigate tsunami impact in localised areas of Japan and around the world. These data and analyses inform tsunami hazard maps, particularly in reasonably well-mapped terrains with remote access to landscape data. The results can aid in the understanding of tsunami behaviours and help inform effective mitigation strategies in tsunami-vulnerable areas. The affordable, widely accessible analysis and methodology presented here has numerous applications, and does not require highly sophisticated equipment. Tsunamis are a significant to major geohazard globally including many Pacific Island states, e.g., Papua New Guinea, Solomon Islands, and Tonga. Video footage geoscientific analysis, as here reported, can benefit tsunami and cyclone storm surge hazards in the Pacific Islands region and elsewhere.

Response of Sandy and Clayey Soils to Weak And Strong Seismic Loading

The response of sandy and clayey near-surface soils representing the classes of noncohesive and cohesive soils to seismic loading of various intensities is analyzed from the in situ data —from the records by vertical groups of the Japanese nationwide KiK-net strong motion seismograph network. For the analysis, out of a total of ~800 stations, we selected five stations with near-surface sandy soils and five stations with near-surface clayey soils, most purely represented in the upper layers. Using the method (Pavlenko and Irikura, 2003), we have constructed and analyzed the models of strong ground motion behavior for “sandy” and “clayey” stations, showing the distributions of earthquake-induced stresses and strains in the soil layers. Close estimates of the amplification of seismic waves in sands and clays at weak seismic ground motion and close stress-strain relationships characterizing the behavior of the near-surface soils at moderate seismic ground motion are obtained. The liquefaction of sandy soils under strong shaking (the 2011 Tohoku earthquake with Мw ~ 9.0) is analyzed. The effects of the extended seismic sources (directivity of their radiation pattern) on the behavior of sandy and clayey soils and the amplification of seismic waves in these soils is studied. Differences in the behavior of sandy and clayey soils are noted only at strong seismic motions: liquefaction in sandy soils is possible if the groundwater level is on the order of a few meters from the surface, while in clayey soils there is no liquefaction.

Intercomparison of hydrostatic and nonhydrostatic modeling for tsunami inundation mapping

Nonhydrostatic modeling has emerged as an effective tool for seismological and tsunami research for over a decade, but its general application in hazard mapping and engineering design remains a topic of discussion. The approach incorporates the depth-averaged vertical velocity and nonhydrostatic pressure in the nonlinear shallow-water equations that provide a Poisson-type equation via the conservation of mass for quasi-three-dimensional flows. After the 2011 Tohoku tsunami, the State of Hawaii augmented the existing inundation maps to account for probable maximum tsunamis from Mw 9.3 and 9.6 Aleutian earthquakes. The use of both hydrostatic and nonhydrostatic modeling with a common set of telescopic computational grids covering 1330 km of shorelines facilitates a thorough intercomparison under distinct extreme events over a range of tropical island terrain and bathymetry. Including vertical flow dynamics can enhance the formation of a slowly attenuating trough behind the leading crest across the ocean as well as drawdown of receding water over steep nearshore slopes. The nonhydrostatic approach consistently gives lower predictions of the offshore tsunami amplitude due to frequency dispersion but can produce more severe coastal surges from resonance of the leading crest and trough over insular slopes as well as trapping of tsunami waves by wide shelves. Despite the potential for underestimating coastal surges, the lack of vertical inertia in hydrostatic models can result in substantially larger runup over steep terrain. The tsunami processes leading to inundation are complex with a strong dependence on the waveform and topography that can be well elucidated by the nonhydrostatic approach.

지역 커뮤니티를 통한 지역 방재력 향상에 관한 연구

This study analyzed the characteristics of regional disaster prevention-related laws and cases through residents' communities in Japan, with the purpose of presenting policy direction for improving disaster preparedness in the event of a disaster in Korea. As a result of the study, the following conclusions were obtained. First, when large-scale disasters such as the Hanshin-Awaji earthquake and the Great East Japan Earthquake occurred in Japan, residents' activities through self-help and mutual assistance became important due to the limitations of public assistance. Public awareness also decreased that “emphasis should be placed on public assistance”, but the proportion of those who responded that “public assistance, mutual assistance and self-help should be balanced” increased. Second, due to the revision of the “Framework Act on Disaster Countermeasures” in 2014, the “District Disaster-Prevention Plan” for autonomous, local disaster -prevention activities was introduced. The characteristics of the “District Disaster- Prevention Plan” are ① bottom-up plans in which plans are established and proposed by residents. ② It is a plan that is directly prepared by a resident who is familiar with the current issues of the region and is in line with the reality and characteristics of the region. ③ It is a plan to enhance the disaster prevention capacity of the region based on the “District Disaster-Prevention Plan” by emphasizing the implementation of disaster prevention activities, regular evaluation, and continuity of disaster prevention activities. Third, since the implementation of the “District Disaster-Prevention Plan” in 2014, various disaster prevention organizations have been working to establish plans in various parts of Japan. There are various representative disaster prevention activities ① centered on residents' associations, neighborhood associations, and elementary schools, ② local disaster prevention activities centered on private businesses, and ③ those centered on universities.

일본의 구승문예 연구동향과 전망

This paper was written to share tasks with Korean oral literature researchers by summarizing the genre of old Seung Literature in Japan and introducing the genre that has recently attracted attention in Japan.&#x0D; Japanese and Korean oral literature genres do not differ very much. However, some genres are similar and have unique characteristics. Similar to Korean pansori, masquerade, and exorcism, "Katarimono" has been delivered in various and rich ways throughout Japan. However, since the early 20th century, the transmission has been cut off, from a significant number of branches, so it is difficult to assert that "Katarimono" is common literature. In addition, unlike Korean literature, which is rich in Chinese literature written by intellectuals, there is a difference in that oral literature was a major genre of Japanese literature. In other words, it is worth keeping in mind that the existence of oral literature in Japanese literature is significant.&#x0D; In recent Japanese oral literature, the genres that have attracted attention are ghost stories and disaster legends. The Japanese have painted strange beings in literature and painting works since ancient times, and even in modern times, rumors and legends of strange beings have been discussed among the population. Recently, the word "Yokai(specter)" has been used as a generic term encompassing all strange beings, and new characters have been born. Japanese people, regardless of age or gender, enjoy the world of monsters through various works such as novels, cartoons, animations, and game software. The ghost story is a genre of oral literature that remains alive in modern society. In addition, the value of disaster legends was re-examined in the wake of the 2011 Great East Japan Earthquake. In Japan, where natural disasters are frequent, legends related to disasters-that is, stories about avoiding disasters-are told in various places. As these stories were discovered, recorded, and published, the need to inherit future disaster legends was raised.&#x0D; Among recent trends in Japanese literature, researchers demonstrate interest in nature, which is a notable topic in the field of oral literature. Literary researchers are accumulating achievements in how the Japanese perceive nature and expressed it in literary works a topic that East Asian researchers belonging to the Chinese character culture should share and think about in the era of the climate crisis.

Longitudinal changes in depressive symptoms associated with social isolation after the Great East Japan Earthquake in Iwate Prefecture: findings from the TMM CommCohort study

BackgroundWhether past disaster experiences affect the association between changes in social isolation and depressive symptoms is largely unknown. This study examined the association between changes in social isolation and depressive symptoms among survivors who experienced earthquake damage in the aftermath of the Great East Japan Earthquake (GEJE).MethodsWe analyzed longitudinal data from 10,314 participants who responded to self-report questionnaires on the Lubben Social Network Scale-6 (LSNS-6) and the Center for Epidemiological Studies-Depressive Scale (CES-D) in both the baseline survey (FY2013 to FY2015) and follow-up survey (FY2017 to FY2019) after the GEJE. According to changes in the presence of social isolation (< 12 of LSNS-6) at two time points, participants were categorized into four groups: “not socially isolated,” “improved socially isolated,” “newly socially isolated,” and “continuously socially isolated.” At the follow-up survey, a CES-D score of ≥ 16 indicates the presence of depressive symptoms. The adjusted odds ratios (AORs) and 95% confidence intervals (CIs) were estimated using the logistic regression analysis to examine the influence of the change in social isolation over four years on depressive symptoms.ResultsParticipants who were newly socially isolated had a significantly higher prevalence of depressive symptoms than those who were not socially isolated (AOR = 1.89, 95% CI = 1.61 − 2.23). In addition, AORs were highest for those who were continuously socially isolated and had experienced house damage (AOR = 2.17, 95% CI = 1.73 − 2.72) and those who were newly socially isolated and had not experienced the death of family members due to the GEJE (AOR = 1.88, 95%CI = 1.60 − 2.22).ConclusionOur longitudinal findings suggest that being newly or continuously socially isolated is associated with a risk of depressive symptoms, not only among those who had experienced house damage or the death of a family member, but also those who had not, in the disaster-affected area. Our study underlines the clinical importance of social isolation after a large-scale natural disaster and draws attention to the need for appropriate prevention measures.

Exploring the experiences and learning of young primary care physicians in disaster-affected areas: A qualitative study on the Great East Japan Earthquake.

Primary care physicians (PCPs) play a critical role in disaster medicine. However, it is unclear how PCPs who provide chronic support to disaster-affected areas learn from their experiences. This qualitative study investigates the learnings of young PCPs who provided medical care during the chronic phase of the Great East Japan Earthquake disaster. Thematic analysis of interviews with five physicians revealed the challenges faced by them and their learnings in providing medical support to disaster-affected areas. They not only learned medical skills but also humanistic aspects such as empathizing with the survivors' loss.