Great East Japan Earthquake Research Articles

In the arena: contesting disaster creation in cities.

Space is a feature of all disasters, and it is through decisions on how space is developed, used, and reproduced that disasters manifest themselves. Critical urban theory sees urban space-cities-as an arena of contestation expressed through the relationship between people, power, and the built environment. Cities allow for an unpacking of this process of contestation through the interpretation of various temporal, spatial, social, and physical elements that together create complex issues and 'wicked problems'. In these urban spaces in all their complexity, disasters reveal both the worst injustices and inequalities present in a society. By drawing on three well-known cases-Hurricane Katrina in 2010; the Haiti earthquake in 2010; and the Great East Japan Earthquake and Tsunami in 2011-this paper not only explores the opportunities that critical urban theory presents for gaining a deeper understanding of disaster risk creation, but also it encourages disaster scholars to engage with it.

Kinematic and inertial effects on piled rafts in soft ground supporting isolated and non-isolated buildings observed during the 2011 Tohoku earthquake

Based on previous studies on the seismic monitoring of isolated (IS) and non-isolated (NI) buildings supported by piled rafts with a DMW (deep mixing wall) grid, under similar soft-soil conditions during the 2011 Tohoku earthquake, the effects of kinematic and inertial forces on the piled rafts, for which the natural periods of the superstructures were significantly different, were investigated. To evaluate the degree of contribution of the kinematic and inertial forces on the maximum bending moments and incremental axial forces near the pile heads, the coefficients related to the kinematic and inertial forces were presented. The coefficients of inertial force were separated into those of the superstructure and raft inertias to consider the embedment effects. Furthermore, the mechanisms of the inelastic behavior of the settlement and the load transfer in the piled raft systems, observed during the principal motion, were discussed. Consequently, it was found that the ratio of the natural period of the soil-pile-structure system to the predominant period of the ground, Ts/Tg, plays an important role in the contribution of the kinematic and inertial forces to the maximum bending moments near the pile head. Moreover, the Ts/Tg values were seen to be closely related to the differences in the inelastic settlement and load transfer mechanisms of the piled raft systems.

Simulating Strong Ground Motion from the Great 1923 Kanto Earthquake in the Tokyo Metropolitan Area Based on Source Model Derived from Seismic Intensity Data

ABSTRACT This study simulates strong ground motions in the Tokyo metropolitan area during the 1923 Kanto earthquake using the stochastic Green’s function method. Source characteristics were modeled using seismic intensity inversion analysis, and path and site characteristics were modeled using inhomogeneous attenuation structure and empirical amplification factors. The results of these simulations were consistent with seismic intensities estimated based on the collapse rate of wooden houses. The distribution of pseudovelocity response spectra averaged at periods of 1–2 s was large: ∼200 cm/s in southern Kanagawa and southern Chiba prefectures, ∼100–200 cm/s in eastern Tokyo, and ∼50–100 cm/s in eastern Saitama prefecture despite its distance from strong-motion generation areas (SMGAs). The simulation results were regressed on site characteristics and fault distance, and the residuals were interpolated using the Kriging method to estimate detailed maps of seismic intensity and response spectra on an ∼250 m mesh reflecting site-specific characteristics. The following conclusions can be made: (1) all SMGAs, other than those in northern Tokyo Bay, were located near large slip areas based on coseismic geodetic and seismic waveform data. Although the SMGAs in the northern part of Tokyo Bay exerted little influence on the southern part of the Kanto region, their consideration was required to reproduce the seismic intensity at the northwest Tokyo and Saitama; (2) intense strong motion in central Tokyo occurred at the back marsh, delta, coastal lowlands, and filled lands, whereas low levels of strong motion were determined at terraces covered with volcanic ash soil. Combined with building distribution, this indicates areas of high seismic risk; (3) the seismic intensity and response spectra in the Tokyo metropolitan area obtained through this simulation were larger than those obtained from seismic records of the 2011 Tohoku earthquake—the most recent megathrust earthquake.

Association between the deaths indirectly caused by the Fukushima Daiichi nuclear power plant accident (disaster-related deaths) and pre-disaster long-term care certificate level: A retrospective observational analysis

The health of the vulnerable populations receiving the Long-Term Care (LTC) Insurance Programs was threatened by the direct and indirect effects of disasters. The 2011 Great East Japan Earthquake and Tsunami and the explosion at the Fukushima Daiichi nuclear power plant (FDNPP) forced 164,865 people's evacuation and caused many disaster-related deaths. We examined the relationship between these deaths and LTC certification. Data were collected from 520 people who were living in Minamisoma City during the earthquake and whose deaths were certified as disaster-related by the Minamisoma City Committee for Certification of Disaster-Related Deaths from September 2011 to February 2021; 467 (90.0%) responded to the LTC item on the survey form, of which 200 (38.5%) were not certified and 266 (51.3%) were certified for LTC. People with high levels of LTC certification needs during the acute phase of the earthquake were found to be more likely to die from circulatory and respiratory diseases. The mean time from disaster to death was shorter for those with higher levels of LTC; it was significantly shorter for those with long-term care level 3 and above. This study points out the importance of timely response with regard to disaster-related deaths and long-term care. Further studies are needed to examine how medical resources can be deployed in a timely manner.

Against an insufficient intervention for patients with alcoholism or PTSD: An activity report on a psychiatric clinic after the 2011 complex disaster in Fukushima, Japan

Despite numerous studies using questionnaires to assess mental health problems among disaster victims following a disaster, only a few have examined actual medical treatment situations. Surveys of residents in disaster-affected areas following the Great East Japan Earthquake and Fukushima nuclear power plant disaster also indicate deteriorated mental health among survivors; however, concrete evidence of increased individuals seeking treatment at psychiatric institutions is still scarce.Using medical records of a psychiatric clinic in an affected area during the chronic phase after a disaster, this study investigated the status of interventions for patients with alcoholism, post-traumatic stress disorder (PTSD), and others, including whether violence occurred during treatment.We found that 730 patients visited the clinic for a year, but a few with alcoholism received treatment. Patients who experienced traumatic stress during the disaster had a higher treatment discontinuation rate, though it is not correlated with their involvement in violence. However, a diagnosis of complex PTSD was correlated with involvement in violence during the treatment.The psychiatric clinic providing care during the chronic phase of the post-disaster period did not provide sufficient treatment for alcoholism, where therapeutic interpersonal interaction is emphasized, or for PTSD, where trauma-focused psychotherapy is the standard of care. It is difficult to ensure the availability of highly specialized resources and the establishment of comprehensive ties with the local people in affected areas, however, such a situation poses a challenge.

Formulation of Dissemination Process of Phase-Free Concept for Effective Promotion of Disaster Prevention Education: A Case Study of Naruto City, Japan

During the Great Kanto Earthquake, fire ravaged the city beyond its firefighting capabilities at that time. This also applies to contemporary society. Today, as Japan is facing a declining birthrate and an aging population, resources for public assistance-led disaster prevention measures are also dwindling. We have experienced the limitations of public-assistance-led disaster reduction measures for numerous disasters; for example, the Great East Japan Earthquake. Following the background, in recent years, the concept of “phase-free” has attracted the consideration as a means of preparing for disasters that exceed the scope of our corresponding range. The purpose of this study was to formulate a process of disseminating disaster prevention education that is effective in terms of both children’s learning ability and disaster preparedness through an analysis of a case study on the application of the phase-free concept (PFC) to school disaster prevention education. In PFC, disaster prevention and mitigation considerations are integrated into daily life. In Japan, several companies and local governments have begun to implement this concept. This study is based on a case study of phase-free efforts in school disaster prevention education in Naruto City, Japan. Through qualitative surveys conducted from the stakeholders, this research is focused to answer the question “Why was the PFC able to spread in actual schools throughout Naruto City?” These findings indicate that the PFC helps explain Naruto City’s proactive approach to disaster management as well as explains actors’ dynamic participation in phase-free activities. Furthermore, the research findings suggest that the term “phase-free” has become a marker of the perception of quality (Merkmal in German) in disaster prevention that promotes collaboration among diverse stakeholders.

FAILURE OF SEAWALLS DUE TO TSUNAMI-INDUCED SCOUR

The Indian Ocean tsunami in 2004 and the Tohoku tsunami in 2011 have shown that tsunami-induced scour is one of the primary reasons for the failure of coastal defence structures (Bricker et al., 2012; Jayaratne et al., 2016). In a coastal structure, scour can occur when the plunging jet impacts the landward toe of the structure, resulting in digging a hole around the foundation which eventually may destabilize the structure. This can be exacerbated by rapid drawdown induced liquefaction during the receding wave, and can lead to the failure of the structure. Therefore, accurate prediction of local and plunging scour is very vital in order to ensure the safety of the coastal structures under such conditions. Data we have at present are based on final or equilibrium scour depths, not the maximum scour depths. Survey teams measure scour profile once the extreme event is over. However, the trough or scour hole made can be partly filled by sediment transport from upstream (in the live bed case) or from sediment suspended within the scour hole that settles after the flow slows down. Thus, the scour depth survey teams measure are less than the actual maximum depths. Therefore, a novel experimental and numerical study is proposed to tackle this problem with the funding of the Royal Society, UK.

PROBABILISTIC APPROACH FOR PREDICTING THE DRIFT OF BODIES BY TSUNAMIS

The Great East Japan Earthquake of 2011 triggered a massive tsunami, and most of the dead and missing were killed by the tsunami. About 12 years after the disaster, search activities for missing persons are still ongoing. So far, the drift behavior of drifting debris (Nistor et al., 2017) has been studied. However, the human body's drift behavior and area due to tsunamis have not been studied. It is important to establish a prediction method for the drift behavior of the human body in order to quickly rescue people who are drowned by tsunamis. On the other hand, according to Mateus et al.(2020), probabilistic and statistical approaches are important. Therefore, in this study, it is clarified that the drifting behavior of the human body based on the results of the interview survey in Otsuchi Town, Iwate Prefecture, and performs reproduction calculations to verify the validity of the method and to examine the influence of the initial configuration of the drifting position of the human body.

EXPERIMENTAL INVESTIGATION OF DENSITY EFFECT ON TSUNAMI BORE FORCES ON VERTICAL WALLS

In the tsunami generated by the 2011 Great East Japan Earthquake, black tsunamis were identified in many locations. According to Kise and Arikawa (2020), in the areas where samples were obtained, the seawater was found to be mixed with silt components by about 10 percent. They also reported that a large impulsive wave pressure might be generated when the silt-mixed seawater acted on a vertical wall as a bore. Although there have been many studies on the mechanism of impulsive wave pressure in bore-shaped tsunamis (e.g., Co and Yeh, 2018), the effects of sand and silt mixing have rarely been investigated. Therefore, in this research, bore-shaped tsunami pressure experiments with sand and silt in various states of density were conducted to clarify the mechanism of impulsive pressure on a vertical wall and to verify the effect of density on impulsive pressures.

SIMULATION OF CONTAINER DRIFT UNDER EXTREME HYDRODYNAMIC CONDITIONS

In Great East Japan Earthquake of 2011, debris entrained within the incoming tsunami waves was responsible for widespread infrastructure damage (Chock et al., 2011). The presence of debris within the inundating wave needs to be taken into consideration; however, few methodologies and tools exist to estimate debris hazards. Therefore, one option to evaluate the behavior of drifting debris is using numerical models. Currently, the particle method, which is a meshless analysis method, is expected to be utilized for analyzing the behavior of drifting objects (Goaseberg et al., 2017). However, the ability of models to properly capture the interaction between multiple drifting objects has not yet been verified. This study will be among the first to model drift behavior of multiple debris under tsunami-like conditions, using the DualSPHysics model suite.

EFFECTIVENESS OF TSUNAMI MITIGATION STRUCTURES ON UNDERUTILIZED URBAN AREAS: A CASE STUDY ON REDUCING DAMAGE CAUSED BY TSUNAMI TO BUILDINGS

There are concerns that a Nankai Trough Mega Earthquake may occur soon, and may cause widespread damage. This demands not only functional enhancement of seacoast environments, but also pre-disaster recovery planning that includes evacuation drills and securing evacuation sites in coastal areas. One of the most effective measures for this is relocation to higher ground in urban areas. However, financial restrictions and topographical conditions do not make relocation to higher ground easy. Thus, new countermeasures must be investigated that can facilitate early recovery and reconstruction. We believe that reducing the collapse and washing away of buildings due to tsunamis in densely populated areas could be one of the ways to approach this problem. Here, we find that the risk of building collapse and washing away depends on the type of building1) and inundation height. Thus, inundation due to tsunami must be lowered to avoid the low risk of collapse or wash away. Therefore, we look at the example2) of Miyagi Prefecture amid the lessons of the Great East Japan Earthquake, and expand upon the idea of multiple countermeasures to cover the urban areas. Specifically, low-lying underutilized lands in urban areas must be utilized to provide multifunction disaster prevention facilities enabling multiple countermeasures. Based on the above-mentioned points, the purpose of the present study is to propose multiple tsunami countermeasures for urban areas and numerically investigate their effects. Thus, we conducted a case study in a port town with a small river, which is an area where disasters are a concern.

TSUNAMI WAVE LOADING ON A STRUCTURAL ARRAY PARTIALLY SHELTERED BY A SEAWALL

In recent years tsunamis have been recognized as one of the most catastrophic natural disasters in the world, highlighted by the 2004 Indian Ocean tsunami and the 2011 Tohoku earthquake and tsunami. These countries affected by tsunamis like Indonesia, Thailand and Japan usually arm their coast with sea walls to provide protection for coastal urban regions; however, surveys have found during both tsunami events, several sections of breached sea walls had led to extensive damage in those coastal regions (Dalrymple and Kriebel, 2005; Sato, 2015). Previous studies have examined the sheltering effect by macroroughness to individual structures, but limited knowledge is available on the sheltering and flow concentration effect by a partially standing wall to a field of structural array. The result from this experiment will serve to provide a better understanding on the tsunami loading variation induced by different length of partial seawalls, and help prepare more accurate hazard maps for tsunami events.

TSUNAMI FLOW PARAMETERS INFLUENCING PORT DAMAGE: A CASE-STUDY OF THE 2011 TOHOKU TSUNAMI

In the past decade, tsunami fragility models have emerged as a common way of quantifying the relationship between tsunami flow characteristics and structural vulnerability. Fragility functions describe the probability that a structure exceeds a prescribed damage threshold for a given tsunami intensity. Tsunami flow characteristics are represented by tsunami intensity measures (hereafter referred to as TIM) in fragility modelling. The use of an appropriate TIM is imperative to deriving models with as much accuracy as possible. This aspect of research is still an area of debate. In this study, the aim is to assess TIMs that are most optimal for the estimation of structural fragility of port structures. The 2011 Tohoku tsunami was selected as our case study, and we use the damage data for port structures obtained from Chua et al. (2021). We investigate the relationship between three TIMs – depth, velocity and hydrodynamic drag force, and structural response.

Beyond tsunami fragility functions: experimental assessment for building damage estimation

Tsunami fragility functions (TFF) are statistical models that relate a tsunami intensity measure to a given building damage state, expressed as cumulative probability. Advances in computational and data retrieval speeds, coupled with novel deep learning applications to disaster science, have shifted research focus away from statistical estimators. TFFs offer a “disaster signature” with comparative value, though these models are seldom applied to generate damage estimates. With applicability in mind, we challenge this notion and investigate a portion of TFF literature, selecting three TFFs and two application methodologies to generate a building damage estimation baseline. Further, we propose a simple machine learning method, trained on physical parameters inspired by, but expanded beyond, TFF intensity measures. We test these three methods on the 2011 Ishinomaki dataset after the Great East Japan Earthquake and Tsunami in both binary and multi-class cases. We explore: (1) the quality of building damage estimation using TFF application methods; (2) whether TFF can generalize to out-of-domain building damage datasets; (3) a novel machine learning approach to perform the same task. Our findings suggest that: both TFF methods and our model have the potential to achieve good binary results; TFF methods struggle with multiple classes and out-of-domain tasks, while our proposed method appears to generalize better.

A Study on the Strategy for Responding to Large-Scale Complex Disasters

Purpose: A large-scale complex disaster refers to a disaster that develops on a huge scale outside the predictable range as natural disasters and social disasters occur serially or simultaneously. The local community must take into account the diversity of residents' situations and organize an evacuation cooperation system in advance in order to respond to such large-scale, complex disasters. The purpose of this paper is to present a direction for improving community response to disasters through a review of large-scale complex disasters.
 Method: This study examines the large-scale flood damage evacuation plan in the 5th district of Koto, Tokyo, Japan, which established an evacuation plan led by the local community after the Great East Japan Earthquake. Evacuation was divided into vertical evacuation, evacuating within the community, and wide area evacuation, evacuating outside the community.
 Results: The main features of these evacuation plans were that they encouraged local residents to make independent judgements, to implement the plans, and to proactively request and prepare for administrative support for the parts that were insufficient.
 Conclusion: First of all, for efficient evacuation from large-scale-complex disasters, various stakeholders need to be recognized and systematically organize, and cooperation with relevant and upper-level administrative agencies is needed to solve problems that are beyond the capacity of local governments. It is also necessary for residents to recognize their own role in disaster response along with the proper implementation of disaster prevention administration, and for the administration to support factors that residents cannot do as much as possible, as the basic structure of the crisis.

“What could be spoken?”: Lessons on disaster memories and narratives from the case of the Great East Japan Earthquake

“What could be spoken?”: Lessons on disaster memories and narratives from the case of the Great East Japan Earthquake

Toward the creation of disaster-resilient communities: The Machizukuri initiative – The 2011 Tōhoku Great East Japan Earthquake and Tsunami

Community engagement and involvement are essential components in managing and responding to disasters. The March 2011 natural disaster on Japan’s northwest coast was extensive. Despite the country’s well-positioned response framework, relief organisations needed to relocate and faced ongoing infrastructure disruption and significant concerns for rescue and recovery operations. This article aimed to understand better the role and impact of local communities in responding to and recovering from disasters by examining the role of the Machizukuri following the Tōhoku Great East Japan Earthquake and Tsunami (GEJET). We used an exploratory approach, and in-depth interviews were undertaken with eight key decision-makers involved in recovery efforts. Key findings from these interviews showed that, while the central government enacted their disaster management plans, responses were slow and failed to address local priorities. To compensate, the local community and Machizukuri assisted and successfully united the local community to address gaps left by the centralised governments' approach. It is an example of self-reliance and the use of an effective bottom-up approach to address critical disasters. However, efforts were hindered by a lack of coordination between the various government bodies and aid organisations and communication failures that prevented a more coherent response. Furthermore, the forms of creative, bottom-up recovery and response resulted in long-term rebuilding practices that has been a key factor in maintaining the vitality and culture of the affected community. These findings should assist societies in remediating these shortcomings, responding more effectively to future disasters, and enhancing community resilience necessary for long-term recovery.

Policy Review and Regional Development in Disaster Mitigation (Case Study: 2004 Aceh Tsunami and 2011 Tōhoku Tsunami)

The geological location of Indonesia and Japan means that both countries experience frequent disasters. On December 26, 2004, Aceh, located on the northern tip of the island of Sumatra and the westernmost province in Indonesia, was hit by a tsunami that left 166,000 people dead or missing and 500,000 people displaced. While on March 11, 2011, the Great East Japan Earthquake and Tōhoku Tsunami with a magnitude of 9.0 occurred and resulted in approximately 15,800 fatalities and 220,000 displaced persons. This study uses a descriptive comparative study method by reviewing policies and regional development in disaster mitigation after the Aceh Tsunami (2004) and the Tōhoku Tsunami (2011) occurred. Policies related to disaster mitigation in Aceh show that tsunamis were never considered in urban planning before the 2004 Aceh Tsunami, while Japan has developed them since 1896 after the Great Meiji Sanriku Tsunami occurred. Existing disaster mitigation policies in Aceh's spatial planning have also not been implemented optimally and consistently. Japan's policies and regional development in disaster mitigation can be a lesson learned as Japan is considered worldwide as a model country in the field of tsunami preparedness and resilience.

PTSD Symptom dynamics after the great east japan earthquake: mapping the temporal structure using Dynamic Time Warping

ABSTRACT Background: After the Great East Japan Earthquake [GEJE], approximately 70,000 Japan Ground Self Defense Force [JGSDF] personnel were deployed, risking Post-Traumatic Stress Disorder [PTSD]. The network approach to psychopathology suggests that symptoms may cause and exacerbate each other, resulting in the emergence and maintenance of disorders, including PTSD. It is therefore important to further explore the temporal interplay between symptoms. Most studies assessing the factor structure of the Impact of Event Scale-Revised [IES-R] have used cross-sectional designs. In this study, the structure of the IES-R was re-evaluated while incorporating the temporal interplay between symptoms. Methods: Using Dynamic Time Warping [DTW] the distances between PTSD symptoms on the IES-R were modelled in 1120 JGSDF personnel. Highly correlated symptoms were clustered at the group level using Distatis three-way principal component analyses of the distance matrices. The resulting clusters were compared to the original three subscales of the IES-R using a Confirmatory Factor Analysis (CFA). Results: The DTW analysis yielded four symptom clusters: Intrusion (five items), Hyperarousal (six items), Avoidance (six items), and Dissociation (five items). CFA yielded better fit estimates for this four-factor solution (RMSEA = 0.084, CFI = 0.918, TLI = 0.906), compared to the original three subscales of the IES-R (RMSEA = 0.103, CFI = 0.873, TLI = 0.858). Conclusions: DTW offers a new method of modelling the temporal relationships between symptoms. It yielded four IES-R symptom clusters, which may facilitate understanding of PTSD as a complex dynamic system.

Eight-Year Trends in the Effect of the Great East Japan Earthquake on Obstetrics Outcomes: A Study from the Fukushima Health Management Survey.

Information regarding the longitudinal effects of natural/environmental disasters on obstetrics outcomes is limited. This study aimed to analyze the longitudinal changes in obstetrics outcomes over 8 years after the Great East Japan Earthquake and the Fukushima power plant accident. We used data from the first 8 years of the Pregnancy and Birth Survey by the Fukushima prefectural government, launched in 2011. We compared data on obstetrics outcomes by year and divided Fukushima Prefecture into six districts based on administrative districts. Longitudinal changes in the occurrence of preterm birth before 37 gestational weeks, low birth weight, and anomalies in newborns were accessed using the Mantel-Haenszel test for trends in all six districts. Overall, 57,537 participants were included. In 8 years, maternal age, conception rate after sterility treatment, and cesarean section delivery incidence increased. Although significant differences were observed in preterm birth and low birth weight occurrence among districts, there was no significant trend in the occurrence of preterm birth, low birth weight, and anomalies in newborns in all six districts of Fukushima Prefecture. The Great East Japan Earthquake and Fukushima power plant accident were associated with increased cesarean section delivery incidence but had no significant adverse effects on obstetrics outcomes.