Search Results (108)

Liquefaction in urban areas has repeatedly caused severe damage to infrastructure, including manhole uplift, road subsidence, and failure of buried utility lines, as evidenced by reports during major earthquakes such as the 1964 Niigata earthquake and the 2011 Great East Japan Earthquake. Although natural sand has been widely used as backfill, excess pore water pressure leads to rapid loosening. This study evaluates slag–dried sludge mixed soil as a new liquefaction-resistant backfill that improves disaster mitigation while promoting resource recycling. Compaction, cone penetration, and shaking table tests were conducted with sludge mixing ratios of 0–30%, identifying 20% as optimal. Liquefaction in slag-only soil occurred at 1013 s (7 m/s²), whereas the 20% mixture delayed it to 1380 s (11 m/s²), increasing the acceleration threshold by 1.5 times and extending the onset time by 36%. Therefore, the acceleration required for liquefaction to begin was approximately 1.5 times higher, and the occurrence time was extended by approximately 36%. Also, the cone index reached 7750 kPa, exceeding the traffic load requirement of 1200 kN/m², while still allowing for sufficient permeability and workability compared to the use of natural clay particles. The improved backfill material proposed is promising as a sustainable urban infrastructure technology that simultaneously reduces liquefaction damage, improves the resilience of urban infrastructure, and reduces environmental impact through waste recycling. Full article

How does digital technology mediate decision-making and shape our understanding of disaster recovery? I address this question by examining both the administrative and cinematic uses of digital images in the reconstruction process following the 2011 Great East Japan Earthquake. Post-disaster digital mediation is characterized by the administrative use of what has been termed “operational images,” designed not for interpretation but for action, particularly in disaster response and prevention. I connect the social and ethical dimensions of post-disaster recovery with the ontological dimensions of the technological characteristics of digital photography. By comparing Japanese independent filmmaker Haruka Komori’s digital filmmaking practice with the operational images utilized by administrative and research bodies, I aim to demonstrate how her particular digital aesthetics elicit the latent capacity of the “digital unconscious” and offer new modes of perceiving post-disaster recovery, in contrast to both other forms of post-disaster digital mediation and to analog photography. Through close analyses, I argue that her work articulates an alternative vision of recovery—one rooted not in spatial management or predictive planning, but in physical attachment to place, trust in the future, and imaginative engagement with survivors and the dead. Full article

Many countries around the world repeatedly suffer from natural disasters such as earthquakes, tsunamis, floods, and hurricanes due to geographical factors, including plate boundaries, tropical cyclone zones, and coastal regions. Representative examples include Hurricane Katrina, which struck the United States in 2005, and the Great East Japan Earthquake in 2011. Both were large-scale disasters that occurred in developed countries and caused enormous human and economic losses regardless of disaster type or location. As the occurrence of such catastrophic events remains inevitable, establishing effective preparedness and rapid response systems for large-scale disasters has become an urgent global challenge. One of the critical issues in disaster response is the rapid estimation of the number of affected individuals required for effective rescue operations. During large-scale disasters, terrestrial communication infrastructure is often rendered unusable, which severely hampers the collection of situational information. If the population within a disaster-affected area can be estimated without relying on ground-based communication networks, rescue resources can be more appropriately allocated based on the estimated number of people in need, thereby accelerating rescue operations and potentially reducing casualties. In this study, we propose a population-estimation system that remotely senses radio signals emitted from smartphones in disaster areas using Low Earth Orbit (LEO) satellites. Through numerical analysis conducted in MATLAB R2023b, the feasibility of the proposed system is examined. The numerical results demonstrate that, under ideal conditions, the proposed system can estimate the number of smartphones within the observation area with an average error of 2.254 devices. Furthermore, an additional evaluation incorporating a 3D urban model demonstrates that the proposed system can estimate the number of smartphones with an average error of 19.03 devices. To the best of our knowledge, this is the first attempt to estimate post-disaster population using wireless LAN signals sensed by LEO satellites, offering a novel remote-sensing-based approach for rapid disaster response. Full article

Following the Great East Japan Earthquake in 2011, there has been an increased focus on risk assessment and the practical application of its findings to safety enhancement. In particular, dynamic probabilistic risk assessment (PRA) used in conjunction with plant dynamics analysis is being considered for accident management (AM) and operational support. Determining countermeasure priorities in AM can be challenging due to the diversity of accident scenarios. In multi-unit operations, the complexity of scenarios increases in cases of simultaneous disasters, which makes establishing response operations priorities more difficult. Dynamic PRA methods can efficiently generate and assess complex scenarios by incorporating changes in plant state. This paper introduces the continuous Markov chain Monte Carlo (CMMC) method, a dynamic PRA approach, as a tool for prioritizing countermeasures to support nuclear power plant operations. The proposed method involves three steps: (1) generating exhaustive scenarios that include events, operator actions, and system responses; (2) classifying scenarios according to countermeasure patterns; and (3) assigning priority based on risk data for each pattern. An evaluation was conducted using a simple plant model to analyze event countermeasure patterns for addressing steam generator tube rupture during single-unit operation. The generated scenario patterns included depressurization by opening a pressurizer relief valve (DP), depressurization via heat removal through the steam generator (DSG), and both operations combined (DP + DSG). The timing of the response operations varied randomly, resulting in multiple scenarios. The assessment, based on reactor pressure vessel water level and the potential for core damage, showed that the time margin to core damage depended on the countermeasure pattern. The findings indicate that the effectiveness of each countermeasure can be evaluated and that it is feasible to identify which countermeasure should be prioritized. Full article

A framework utilizing Information and Communication Technology (ICT) in tsunami evacuation training is proposed to counteract the adverse effects of evacuation by car despite the evacuation on foot principle during tsunamis. This approach involves tsunami evacuation simulation technology and Kiken Yochi (hazard prediction) training (KYT). The simulator was validated based on the insights acquired from Ishinomaki City residents who lived through the Great East Japan earthquake. Data were collected on safe evacuations in chaotic traffic situations, to create a quiz-like training application for traffic safety education. Training effectiveness was assessed using the simulator and KYT-based application, focusing on Nishio City, which is a projected tsunami target following a potential Nankai Trough earthquake. Most participants experiencing the simulator understood the drawbacks of using cars and were willing to evacuate on foot if a nearby safe place was accessible. However, some participants still opted for car evacuation despite acknowledging the risks. A comprehensive approach is required to achieve a significant reduction in car usage during evacuations. Application-oriented experiments indicated heightened situational awareness and hazard prediction among participants although no statistically significant differences in gaze duration were found. Further research is required to objectively and quantitatively evaluate the application’s impact on traffic safety. Full article

Since the Great East Japan Earthquake, floriculture has expanded in Namie Town, Fukushima Prefecture, as part of agricultural recovery. Growth surveys are essential for floriculture production, cultivation management, and trials as they help assess plant growth. However, these surveys are labor-intensive, and the standards used can vary owing to subjective judgments and individual differences. To address this issue, image-processing technologies are expected to enable more consistent and objective evaluations. In this study, we explored image processing in growth surveys by estimating plant growth parameters from three-dimensional (3D) point clouds acquired using a smartphone-based 3D scanner. Focusing on lisianthus (Eustoma grandiflorum), we estimated the plant height and the number of nodes above the bolting. The results showed that plant height could be estimated with high accuracy, with a root mean square error (RMSE) of 1.2 cm. By contrast, the node number estimation showed a mean error exceeding one node. This error was attributed to the challenges in handling variations in point cloud density, which stem from the 3D point cloud generation method and leaf occlusion caused by dense foliage. Future work should focus on developing analysis methods that are robust to point-cloud density and capable of handling complex vegetative structures. Full article

The ongoing war in Ukraine poses an uncertain future, highlighting the need to prioritize reconstruction efforts even before the war ends. Japan’s recovery mechanisms have developed based on the experiences and lessons learned from natural disasters such as the Great Kanto Earthquake in 1923 and from war damage by World War II. This study aims to draw practical insights and lessons from the 2011 Great East Japan Earthquake for Ukraine’s postwar recovery and help achieve rapid and high-quality results. This study reviews the literature, policy documents, and reports on recovery from the disaster. It was found that streamlining environmental impact assessments, land use regulations, and land acquisition could accelerate recovery. Engaging the private sector promoted the reconstruction of critical infrastructure and housing projects. This Japanese case study highlights the importance of ensuring sustained commitment and avoiding setbacks in the recovery process by establishing legislative, planning, and institutional frameworks, as well as financial mechanisms. Protecting human health is paramount, even if more resources are needed to manage hazardous materials. Applying these valuable lessons to Ukraine requires careful consideration, including leveraging foreign investments to supplement limited domestic resources and establishing effective governance structures that promote transparency, accountability, and coordination. Full article

The Kashima Lighthouse, one of the lighthouses that suffered damage in the 2011 Great East Japan Earthquake, required a careful investigation to estimate its long-term behavior and seismic vulnerability. This study, therefore, undertook a meticulous process of the dynamic testing, dynamic identification, and long-term structural health monitoring of the Kashima Lighthouse. The results of dynamic tests reveal that the fundamental frequencies of the Kashima Lighthouse are estimated to be around 2.60 Hz and 2.63 Hz in the east–west and north–south directions, respectively. The natural modes and damping factors are identified using an SSIM (Stochastic Subspace Identification Method). This paper also discusses the result of long-term structural health monitoring, where machine learning techniques were applied for data processing, highlighting the rigor and thoroughness of this research. Full article

This report presents the follow-up treatment course of a previously published case that demonstrated the effectiveness of prolonged exposure (PE) therapy for a disaster relief worker. The patient, a municipal employee in Fukushima Prefecture, developed post-traumatic stress disorder (PTSD) and mood disorders after the 2011 Great East Japan Earthquake and subsequent disasters. This follow-up focuses on the period from 2021 to early 2024, during which the patient experienced symptom recurrence after his father’s death. This event revealed psychological patterns similar to his disaster-related responses. Schema therapy was introduced to address over-adaptive work behaviors and vulnerabilities in relationships, identified as relapse risk factors. Combined with antidepressants, schema therapy achieved sustained improvement. This longitudinal perspective demonstrates schema therapy’s effectiveness in addressing underlying vulnerabilities when symptoms re-emerge after trauma-focused treatment. The findings underscore how initial trauma responses may interact with subsequent life events and suggest schema therapy’s potential as a secondary intervention for disaster relief workers facing complex challenges. Full article

Following the Great East Japan Earthquake, dark tourism was developed in the Tohoku Region of Japan. Notably, two government-built tsunami memorial parks in Ishinomaki and Rikuzentakata have obtained attention for their profound disaster narratives, iconic disaster sites, and expansive layouts. This study is the first to compare the projected destination image presented by destination management organizations with the perceived destination image held by visitors in these parks, and in dark tourism. Using online text data from both supply and demand sides of dark tourism and text mining analyses such as word frequency analysis, co-occurrence network analysis, and affection tendency examination, we revealed similarities and disparities between these two perspectives. Furthermore, this study concluded dimensions specific to dark tourism sites within the cognitive and affective destination image. Based on the findings, the study provides advice for destination managers to improve these sites, including developing non-dark tourism products and improving infrastructures. Additionally, it proposes placing greater emphasis on themes of revitalization and future development, while fostering visitor engagement in local non-profit and citizen activities to strengthen connections with residents. The findings demonstrate the effectiveness of text mining in comparing projected and perceived destination images in the context of dark tourism sites. Full article

Disaster memorials have emerged as pivotal approaches for not only commemorating disasters but also imparting lessons to future generations. However, despite discussions on preservation, little involvement has been reflected in the impacts of different memorial patterns in disaster risk reduction (DRR). This study examines the roles of disaster-related memorial facilities in DRR, exploring how distinct memorial patterns transfer disaster experiences to future generations. This research is based on a quantitative strategy, applying an online questionnaire with 538 respondents who visited the three selected sites under the background of the Great East Japan Earthquake and Tsunami (GEJET) to identify their triggers and purpose for visiting, the impact of facilities on raising disaster awareness, the practical contents, and the important roles of DRR. The findings reveal that while all three facilities contribute to DRR with the same most important role as disseminating the lessons of the GEJET, their impact on visitors’ disaster awareness varies. Sendai Arahama Elementary School particularly raises awareness of disaster threats, while the Higashi-Matsushima Memorial Museums and the 3.11 Memorial Community Center enhance visitors’ disaster-related knowledge. Visually stimulating exhibits in the facilities, such as remains, photos, and videos, underscore the importance of disaster preparedness, while panels and science exhibits offer comprehensive insights into disaster-related knowledge. However, none of the three sites have significant roles in deepening regional exchange. Full article

The year 2023 marks the 12th anniversary of the Great East Japan Earthquake (GEJE). Immediately after the disaster, the number of evacuees reached approximately 470,000, but by November 2022, the number had decreased to approximately 31,000. The reconstruction of housing, disposal of debris, public infrastructure development, and overall restoration and reconstruction has progressed steadily. However, a re-examination of the status of industrial restoration and reconstruction reveals that restoration and reconstruction have not progressed in some areas. This research statistically analyzes how the Japanese public perceives the issues around the recovery process and what memories and records they would like to learn from regarding the GEJE. The purpose of this study is to ask about reconstruction issues and lessons learned from the GEJE by conducting a web-based survey with 2000 respondents in Japan. The method of estimation is the use of ordinal logistic regression analysis to statistically estimate whether there are differences in recovery issues and lessons learned depending on individual attributes. The results suggest that those who are interested in, remember, and express anxiety about the recovery issues and lessons learned tend to be men, do not have children, are highly educated, and have a higher income. In sum, many of Japan’s citizens are highly interested in the reconstruction of agriculture, forestry, fisheries, housing, urban development, living environment, industry, and livelihood in the affected areas. In the future, they will play a central role in modernizing, scaling up, and integrating the agriculture, forestry, and fisheries industries, as well as in rebuilding towns and livelihoods. In the affected areas, it will be necessary to draw on the lessons learned from the GEJE and create reconstruction plans for the future, and then, policymakers will need to formulate reconstruction policies that reflect the concerns of the Japanese people. Full article

Community-based businesses have emerged as a means of addressing socio-economic challenges in the aftermath of disasters. This study investigates the contribution of women-led community-based businesses to recovery and their long-term sustainability. It draws upon case studies in the Tohoku region of Japan and Banda Aceh, Indonesia, areas impacted by major earthquakes and tsunamis over a decade ago. Qualitative data were collected through semi-structured interviews. The findings reveal that the community-based businesses surveyed had evolved from mere “reconstruction goods” by maintaining sustained commitment and developing products. Enhancing organizational credibility through quality improvement efforts was crucial for securing long-term contracts with private companies, a key factor for business continuity. However, prioritizing sustainability often came at the cost of diminished community inclusivity, as differences in skill levels and misaligned values among participants led to departures. This study highlights the challenges in balancing business longevity with maintaining businesses’ role as spaces for social interaction and community rebuilding. Full article

Memorial facilities are one of the crucial places where citizens conduct activities facilitating disaster risk reduction (DRR). However, previous studies have primarily focused on the post-construction phase of official memorial facilities, neglecting the citizen activities collaborating with the official memorial construction process before and during the construction process. This research gap is important considering the urgency of disaster-affected regions to recover from spatial, social, and psychological voids while working towards the goal of DRR, including the efforts of citizens in the official efforts. This study addresses this gap by examining the case of the official memorial park in Ishinomaki, Tohoku region, following the Great East Japan Earthquake. Here, local citizens actively participated in activities before, during, and after park construction, engaging with official efforts. Data were gathered from various online sources to capture activity, space, and management information. Employing a mixed methods research approach, we conducted both quantitative analysis, counting labels of structural coding, and qualitative description of original texts. Our findings reveal that fostering mutual respect built on communication and collaborative tree-planting activities were crucial for maintaining the pre-existing citizen activities and collaborative construction during the official construction period. Additionally, the implementation of a collaborative regulation system was vital for integrating and managing spontaneous citizen activities to achieve the park’s intended objectives post-opening. In conclusion, we highlighted a framework elucidating the mechanisms through which these processes contribute to DRR across key phases of disaster risk management: preparedness, prevention, response, and recovery (PPRR). These insights are important in guiding efforts to engage citizens in DRR initiatives through recovery and reconstruction facilitated by memorial facilities. Full article

Since the 2011 Great East Japan Earthquake, 13 years have passed, and many areas have completed post-disaster reconstruction. Therefore, it is necessary to further summarise and analyse the experiences gained from this post-disaster reconstruction. This study conducted door-to-door interviews with residents of Ōtsuchi-chō, Iwate Prefecture, in the 13 years following the earthquake. It recorded the residents’ perspectives on post-disaster reconstruction and its shortcomings. By collecting locally published materials like newspapers, and local government records and integrating them with interview records, the first “Great East Japan Earthquake Timeline” for Ōtsuchi-chō was compiled. We primarily divided this timeline into the following three phases: the disaster and early reconstruction period (2011), the mid-reconstruction period (2012–2015), and the late reconstruction period (2016–Present). This timeline has yielded the following results: firstly, some issues have arisen during this prolonged reconstruction process. For example, continuous relocation hinders community rebuilding, especially in the context of an ageing society. Secondly, the “Ōtsuchi-chō Reconstruction Timeline” was created, which can be used for post-disaster reconstruction in contemporary Japanese villages facing severe ageing. This timeline provides a clear understanding of how disaster-affected areas can rebuild housing and infrastructure, and recover economically. It offers guidance for the reconstruction of Japanese villages after a disaster. Therefore, post-disaster reconstruction in the region should accelerate infrastructure development and continuously listen to residents’ voices, providing corresponding services to make reconstruction comprehensive and specific. At the same time, it also contributes to the post-disaster reconstruction of villages in other developed countries. Full article