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This study aims to enhance the inter-municipal sharing and transfer of practical disaster response knowledge, thereby strengthening the operational capabilities of municipal officers. In Japan, large-scale disasters require nationwide mutual aid dispatches, during which officers support essential municipal functions such as shelter management, housing damage assessment, and issuing disaster damage certificates. Because housing damage assessment is conducted only during disasters, officers have limited opportunities to gain experience, making prior exercise indispensable for timely and consistent assessments. To facilitate the transfer of lessons, we created a disaster lessons database (DB) that organizes field insights collected by support officers during previous major disasters. Lessons were gathered from twelve activity reports published by four prefectures and eight designated cities in Japan, and these lessons were then categorized into four key municipal functions. Each lesson was rewritten into a brief, attribute-tagged statement to serve as material for exercises that demonstrate operational realities not covered in manuals. This presentation introduces a workshop-based exercise method implemented in Kitakyushu City, Japan, that uses the DB. Participants extract keywords from lesson statements and visualize their relationships through concept mapping, enabling them to identify essential concepts and judgment elements embedded in assessment tasks. In a previous study, the method was applied to administrative staff and university students who had little or no experience in shelter management. In this study, to examine its practical application, the method was used in a leadership exercise program for twelve municipal officers and firefighters in Kitakyushu City responsible for assessing housing damage. According to the instructor, concept mapping helped participants understand the structure of lessons, clarify the basis of operational judgment, and develop shared perspectives. These results suggest that combining a structured lessons DB with workshops is an effective approach for transferring disaster knowledge, improving assessment operations, fostering shared situational understanding, and supporting early recovery for affected residents.

Background and Objective:With the recent expansion of Public-Private Partnerships (PPP) in Japan’s water sector, disaster response is increasingly handled by "matrix organizations" involving public, private, and local governments. However, chronic management inadequacies persist due to top-to-bottom organizational structures. Specifically, a lack of unified terminology and the persistence of vertical silos even during emergencies remain significant issues. This study presents a methodology for identifying tasks that require standardization by analyzing disaster response data from the past 30 years. Our approach utilizes the Incident Command System (ICS) and the Disaster Research Center (DRC) Typology to address structural bottlenecks. Methods:We conducted a comprehensive analysis of 1994-2024 water-related disaster reports, applying the ICS temporary organizational framework. Subsequently, focusing on several PPP projects, we categorized and analyzed existing emergency response operations through a combined lens of the ICS frame and DRC Typology. Finally, we quantitatively calculated the impact of task standardization on the efficiency of initial emergency responses. Results and Discussion:The literature review revealed three fundamental structural issues: (1) insufficient dynamic resource matching, (2) insufficient prioritization between conflicting operations, such as emergency water supply versus pipeline restoration, and (3) communication breakdowns resulting from non-standardized information protocols. Furthermore, the analysis confirmed that using ICS and DRC typology to standardize work can reduce workloads during initial response operations by up to 70%. For example, standardizing tasks such as aggregating external information and requesting aid categorized under "Operational units × Regular and Expanded" facilitates smoother reception of external assistance. Conclusion:In the context of "matrix organizations," the combined use of ICS and DRC Typology serves as an effective tool for logically determining which tasks should remain internal and which should be standardized for external delegation. As a result, it was indicated that the approach provides a framework for optimizing resource allocation in complex disaster scenarios.

With the progress of population aging and population decline, the deterioration of disaster response capacity at the local government level has become an increasingly serious issue in Japan. Previous studies have pointed out that enhancing disaster response capacity requires multifaceted approaches, including technological solutions, human resources, and institutional and organizational frameworks. This study aims to contribute to the enhancement of disaster response capacity by describing the actual conditions of disaster response operations as explicit knowledge and by conducting an exploratory analysis to identify key issues in disaster response practices. Following the 2024 Noto Peninsula Earthquake, the housing damage assessment operations conducted in Himi City, Toyama Prefecture—one of the affected municipalities—gained attention as an advanced case of counterpart support, in which Himi City coordinated paired assistance and engineers with expertise in housing damage assessment collaboratively responded to post-disaster needs. In this study, semi-structured interviews were conducted twice with each participant, targeting operational personnel from Fukushima Prefecture and Okayama Prefecture who were responsible for providing counterpart support in this case. The interviews aimed to facilitate reflection on their experiences during the disaster response. As a result, the interview data were classified into 97 labels and grouped into 14 categories. These categories were treated as analytical units, and an exploratory qualitative analysis focusing on counterpart support in housing damage assessment operations was conducted using methods such as the Steps for Coding and Theorization (SCAT). This paper reports the results of the analysis and discusses key issues in counterpart support for housing damage assessment.

This study investigates the social vulnerability indicators affecting the operational safety of fire service agencies at disaster scenes in Taiwan. A questionnaire survey was conducted among 841 full-time firefighters from 22 local fire departments, based on an established indicator framework. Data were analyzed using descriptive statistics, correlation analysis, independent samples t-tests, one-way ANOVA, and multiple regression. The results reveal a significant negative correlation between perceived current status and improvement priority, indicating that weaker indicators are considered more urgent for improvement. Significant differences were found across age, years of service, unit, and rank, suggesting disparities in experience, organizational roles, and resource accessibility within fire service agencies. Multiple regression analysis identified “Comprehensive Personnel Management” as the most influential factor affecting disaster-scene safety, followed by “Coordination and Liaison Management” and other operational indicators. The model demonstrated substantial explanatory power, accounting for 62.8% of the variance in safety performance. These findings highlight that manpower shortages, communication inefficiencies, and coordination challenges are critical issues influencing operational safety. Therefore, it is recommended that fire service agencies prioritize improvements in personnel allocation, communication systems, and inter-unit coordination mechanisms to enhance overall safety and organizational resilience. The results provide empirical evidence to support policy-making and resource allocation for improving disaster response effectiveness and firefighter safety under conditions of limited resources.

Landslides represent a critical threat to transportation systems in developing countries characterized by complex topography and high exposure to meteorological hazards. In such contexts, slope failures are among the primary causes of road network disruptions, significantly affecting connectivity, accessibility, and emergency response capacity. Despite extensive research on landslide susceptibility, limited studies integrate hazard identification with transportation network performance and infrastructure planning. This study proposes a resilience-based framework to evaluate road network connectivity under landslide-induced disruptions. The first component develops a landslide susceptibility model using terrain-based indicators derived from digital elevation models, particularly slope, to classify areas into different risk levels. High-slope zones are identified as potential failure areas and validated against historical landslide records. The second component integrates susceptibility results with road network data to identify vulnerable infrastructure segments. A disruption scenario is simulated by removing road segments exposed to high-risk zones, and a graph-based network analysis is conducted to evaluate the impact on connectivity. Key urban nodes are selected to assess changes in accessibility between regions. Preliminary results indicate that a significant portion of the road network is exposed to high-risk areas, particularly in mountainous regions. The simulated disruption scenario reveals substantial increases in travel distance and the potential isolation of critical regions, especially in northern and southern corridors. The results also highlight limited redundancy in the network, emphasizing the vulnerability of key transportation links. The proposed framework provides a practical and transferable tool for identifying critical infrastructure and supporting strategic planning of alternative routes. The methodology is particularly relevant for developing regions such as the Philippines and Guatemala, where terrain and infrastructure constraints increase susceptibility to disruption. This approach contributes to enhancing transportation resilience and disaster risk reduction.

Integrated modeling approaches are essential for understanding and mitigating extreme hydrometeorological events and their associated disaster impacts under changing climate conditions. This study integrates the Weather Research and Forecasting (WRF) model with WRF-Hydro into a coupled modeling framework to assess climate change impacts on extreme hydrometeorological events and to quantify the resulting flood disaster risks. This coupled approach enables seamless integration of atmospheric and hydrological processes through synchronized exchange of surface conditions and physical parameters, providing a comprehensive basis for disaster impact analysis. This research focuses on Typhoon Hinnamnor, which brought record-breaking rainfall, severe flooding, and significant socioeconomic damage to South Korea in 2022. The study area includes the Nakdong and Geum River basins, as well as the eastern coastal regions (Pohang, Uljin). Multiple WRF simulations with various microphysics schemes are conducted to determine the optimal configuration, and hydrological simulations using both ground-based and WRF-generated forcings are analyzed to evaluate hydrological responses. Furthermore, flood inundation analysis, flood frequency and return period estimation, and a disaster vulnerability assessment incorporating land use, population density, and critical infrastructure exposure are performed to evaluate flood risk under current and future climate scenarios. Extreme hydrometeorological conditions under climate change scenarios are assessed based on key variables such as typhoon trajectory, precipitation, wind speed, soil moisture, and streamflow. The discussion highlights the benefits and challenges of the coupled modeling approach and its applicability for disaster impact assessment in vulnerable regions of South Korea.

Evacuation centers are highly dynamic, making historical, cross-sectional comparisons difficult in Japan. Understanding these historical transitions is essential for developing highly inclusive shelter environments for the future. To address this gap, this study proposes a functional abstraction model to deconstruct and compare evacuation centers across different eras. By doing so, it aims to clarify the 30-year evolution of shelter environments, with a specific focus on support for vulnerable populations. Methodologically, historical floor plans of evacuation centers were collected to create functional diagrams (capturing function, size, and spatial relationships). To these diagrams, implementing actors were added, categorized into three groups: evacuees, shelter operators, and external supporters (e.g., medical staff, volunteer organizations). Because comparing full spatial layouts proved difficult due to varying facility types, the data was abstracted to focus solely on "functions" and "actors" to enable cross-era comparison. The analysis revealed that across five major eras, basic functions (residence, hygiene, management, medical, and supply storage) remained constant. In contrast, functions dedicated to vulnerable groups significantly expanded. Support evolved from basic nursing care spaces to accommodating childcare and study areas, and more recently, spaces for pet care and night-shift workers. This evolution highlights a paradigm shift in Japanese shelters from ensuring mere survival to accommodating diverse needs to maintain pre-disaster normalcy. Ultimately, simplifying shelter elements into functions and actors enables objective historical comparison. Furthermore, this abstraction provides a structural framework to effectively compare Japanese shelter environments with international benchmarks like the Sphere Standards. Recognizing these structural differences globally will facilitate the development of better, more inclusive shelter models.

Urban flooding and stormwater runoff have become major challenges in rapidly urbanizing cities, particularly under the influence of climate change and extreme rainfall events. Stormwater generated during urban floods often contains a wide range of contaminants, including pharmaceuticals, and other persistent organic pollutants that threaten aquatic ecosystems and public health. These pollutants in stormwater runoff end up in local streams, lakes, rivers, and even the ocean, where they can harm wildlife and degrade the health of these water bodies. Conventional treatment methods are often insufficient for removing these micropollutants, especially in decentralized or emergency water management systems. Advanced oxidation processes(AOPs) have therefore attracted attention for their ability to degrade recalcitrant organic contaminants through the generation of highly reactive radical species. Various oxidants, including peroxymonosulfate(PMS), peroxydisulfate(PDS), ozone, and periodate(PI) can be activated to produce reactive oxygen species capable of efficiently degrading organic pollutants. However, the conventional homogeneous AOP systems utilizing water-soluble chemical reagents are often limited by environmental release of unreacted chemicals, narrow pH operating ranges, and continuous chemical dosing or energy demand, which restrict their practical application in large scale stormwater management. In this context, single atom catalysts(SACs) as emerging materials for oxidant activators in heterogeneous AOPs provide an alternative due to their high catalytic activity, efficient metal utilization, and structural stability. SACs-based AOP systems can effectively activate oxidants such as PMS, PDS, ozone, and PI to generate reactive species for rapid pollutant degradation. In addition, the heterogeneous nature of SACs enables easy separation and reuse, making them particularly suitable for decentralized treatment systems integrated with urban stormwater infrastructure. These features make SACs-based AOP systems suited for integration into decentralized, technology enabled water treatment in disaster response. This approach supports safe and reliable stormwater management, contributing to improved protection of public health and conservation of ecosystems in flood affected areas.

As urban shrinking areas face increasing risks of social vulnerability, these conditions have become critical not only for addressing everyday concerns but also for supporting communities in responding to disaster situations. In Semboku New Town, Osaka, population decline, ageing, and weakened local structures have intensified concerns related to social isolation, lack of support, and disaster preparedness among residents. Using a case study of Chayamadai public housing in the Semboku area, this study conceptualizes social infrastructure as a system of facility-based and service-oriented support that may enable residents to reduce perceived vulnerability in both everyday and risk-related conditions. Drawing on survey data, the analysis examines how social infrastructure relates to residents’ perceived ability to manage daily challenges, including participation in community facilities, access to support, emergency response concerns, and disaster evacuation concerns. The findings suggest that social infrastructure may strengthen social connection, perceived security, and functional support, particularly among elderly residents. It operates as a localized social support system that shapes how residents experience and respond to both everyday and disaster-related vulnerabilities. The study highlights that sustaining urban shrinking area may depends on how social infrastructure is organized to support both everyday life and potential crisis situations. Strengthening social infrastructure may therefore play a critical role in enhancing daily well-being while also supporting communities in addressing disaster challenges.

In many disaster-prone regions, residents often choose to remain in place despite recurring hazards due to economic constraints, livelihood dependency, and social attachments. While staying exposed to continued risk, relocation represents a trade-off between improved safety and uncertain economic costs. Such a phenomenon poses a significant challenge for governments in urban disaster management and public resources allocation. To address this complexity, this study aims to propose a decision-making framework. The framework integrates economic evaluation into spatial planning to analyze the feasibility of different mitigation strategies. This study supports the evaluation of relocation policies and informed decision-making in high-risk areas. The research focuses on the affected area of the Mataian Creek incident that occurred in September 2025 in Hualien. This documented event serves as the baseline for the analysis. The methodology is structured into two parts. First, we use GIS for the spatial analysis to reconstruct the verified extent of the affected area. By overlaying the actual flood footprints with building data, the study identifies the spatial exposure of the settlement. It also categorizes specific types of structures, such as residential dwellings and public infrastructure. Second, we apply an economic evaluation to develop a comparative cost estimation method. This method contrasts proactive relocation costs, including land acquisition and new construction, with the actual post-disaster damage losses recorded during the 2025 event. The research applies simulation to determine whether early relocation would have reduced total economic loss. The findings show the difference in cost effectiveness between active mitigation and reactive recovery. Furthermore, the results highlights the potential for long-term fiscal savings by reducing the need for repeated reconstruction efforts. This study provides a practical framework to assist urban planners in optimizing budget distribution. It ensures that limited resources are directed toward the most effective prevention strategies for regions with verified disaster potential.

Reinforced concrete (RC) structures strengthened using conventional techniques such as steel plates or fiber-reinforced polymers (FRP) often exhibit significant vulnerability under fire conditions, which are among the most critical structural disasters, due to rapid thermal degradation and loss of bond performance. In this context, ultra-high performance concrete (UHPC) jacketing has emerged as a promising strengthening method for enhancing disaster resilience owing to its superior mechanical properties and non-combustible nature. However, conventional UHPC remains susceptible to explosive spalling and thermo-mechanical degradation at elevated temperatures. To address these limitations, this study investigates the fire performance of RC beams strengthened with thermally enhanced UHPC (TE-UHPC) incorporating coal bottom ash and hybrid fibers. Full-scale fire tests were conducted on TE-UHPC beams, normal-strength concrete (NSC) beams, and composite beams strengthened with TE-UHPC jacketing under combined mechanical loading and ISO 834 standard fire exposure. The results showed that TE-UHPC exhibited improved thermal insulation performance, resulting in a slower temperature rise within the cross-section than conventional UHPC. Although TE-UHPC beams alone demonstrated lower fire resistance than NSC beams, the application of TE-UHPC jacketing significantly enhanced fire performance, achieving approximately 12% greater fire resistance than unstrengthened RC beams. A finite element model was developed and validated against experimental results, showing excellent agreement in both thermal and structural responses. Parametric analyses revealed that fire resistance increases linearly with jacketing thickness and decreases logarithmically with increasing load level, while TE-UHPC consistently outperformed conventional UHPC due to its reduced thermal conductivity. Based on the numerical database, simplified predictive relationships were established to support performance-based fire design of strengthened RC members. The proposed approach provides an efficient and disaster-resilient strengthening strategy for RC structures exposed to fire hazards.

As metropolitan areas face escalating risks from seismic threats like the Shanchiao Active Fault, the efficiency of temporary shelters is a vital metric for urban resilience. This paper evaluates the operational model of the Shilin Official Residence Disaster Prevention Park, focusing on its ability to transition from a public park to a functional emergency community within a 4-hour rapid deployment lead time. The study presents an empirical analysis of two core pillars: Smart Operations and Social Inclusivity. On the technical side, the integration of the "Taipei Pass APP" for digital registration, combined with physical GIS-based mapping, demonstrates a robust framework of Digital Redundancy. This dual-track system ensures administrative continuity and data accuracy even during potential communication disruptions—a critical lesson for high-density urban governance. A key contribution of this research is the evaluation of dynamic responses through the Master Scenario Events List (MSEL). During the 2024 validation exercise, the model effectively addressed complex social demands, including psychological first aid, gender-sensitive logistics (infant and female-specific kits), and cross-agency resource dispatching (e.g., inter-district food supply). By aligning with international Sphere Standards, the facility design ensures that vulnerable populations receive prioritized care within a high-density environment of 1,930 evacuees. The findings conclude with a scalable Standardized Operational Model (SOM), providing a pragmatic and validated reference for smart city disaster management in hyper-dense Asian contexts.

This study aims to prevent and minimize industrial accidents and their recurrence in complex chemical pnts located near urban areas by addressing human errors through an AI-integrated risk management approach. Modern chemical plants have become increasingly large-scale and complex, handling hazardous materials with properties such as toxicity, flammability, and explosiveness. Despite technological advancement in design and construction, the risk of accidents continues to increase due to aging facilities, operational complexity, and insufficient safety management practices. A significant proportion of these accidents originates from human errors, including design flaws, operational mistakes, and inadequate management systems. Such incidents not only result in severe loss of life but also causes substantial environmental damage and societal disruption. To address these challenges, this research proposes a Knowledge-based Process Safety Total Management (PSTM) framework that integrates AI technologies with systematic safety management principles. The proposed approach focuses on identifying root causes of accidents through precise data analysis, enhancing decision-making processes, and establishing proactive prevention mechanisms. The study contributes to the development of a more resilient and intelligent safety management system by emphasizing the synergistic coexistence between human expertise and AI. Ultimately, this research provides a practical framework for minimizing risks and improving safety performance in complex chemical plants, particularly those located in urban environments.

This study examines disaster awareness and preparedness among international students in Japan, with a focus on the role of Japanese language proficiency. A questionnaire survey was conducted with 195 international students in Tochigi Prefecture, followed by chi-square analysis to explore differences between students who use Japanese and those who do not. The findings indicate that a high proportion of international students (over 85%) possess sufficient Japanese language skills for daily communication, while about 15% have limited proficiency. Only around 30% had prior disaster experience in their home countries, highlighting the need for targeted support, particularly for newly arrived students. Universities play a critical role in providing orientation and training to improve students’ understanding of disasters in Japan. The study also reveals that international students tend to evacuate to familiar locations, such as their universities or places where acquaintances are present, rather than officially designated evacuation centers. This suggests the importance of preparing non-designated locations, especially universities, to function effectively as evacuation sites during emergencies. Regarding the relationship between language ability and disaster awareness, students who can speak Japanese demonstrate greater knowledge of evacuation centers. However, Japanese proficiency does not necessarily reduce anxiety or improve overall preparedness. In some areas, such as first aid knowledge and communication with local residents, students with limited Japanese skills showed higher levels of preparedness. These results indicate that disaster preparedness education should be provided to all students, regardless of language ability. Finally, the study highlights limited interaction between international students and local communities. Strengthening these connections is essential, as international students—particularly those with strong Japanese skills—have the potential to contribute as disaster volunteers and community leaders, supporting mutual aid in aging and depopulating regions.

Over the past century, Japan has experienced repeated large-scale and complex disasters, and academic knowledge related to disaster response, recovery, and prevention has expanded across diverse fields. However, the increasing specialization of academic fields has made it difficult to comprehensively understand how disaster research has evolved and how different fields have interacted over time. Since Japan now faces the imminent risk of future major disasters such as the Nankai Trough earthquake or the Tokyo metropolitan earthquake, there is a growing need to integrate existing knowledge and strengthen interdisciplinary collaboration. By visualizing long-term trends and identifying the relationships among academic societies, this study provides a foundation for more coordinated and effective disaster management strategies. This study aims to clarify the historical trends in disaster research in Japan by conducting a text mining analysis of academic papers on major disasters from the perspective of the disaster management cycle. The main findings are as follows: (1) A significant number of academic societies related to disaster prevention were established between 1923 and 2010, with the field of disaster research notably expanding after the Great Hanshin-Awaji Earthquake; (2) As understanding of the mechanisms of hazards, destruction, and recovery in natural disasters has advanced, the importance of research on disaster prevention and mitigation measures is expected to grow even further in the future.

This study explores risk communication and institutional reform dilemmas in compound disasters, focusing on the September 23, 2025, Mataian Creek landslide-dammed lake overflow in Hualien. Originating from geological destabilization caused by the magnitude 7.2 Hualien earthquake on April 3, 2024, typhoon-induced massive landslides formed a dammed lake that ultimately overflowed during torrential rains. Encompassing seismic activity, slope failure, and flooding, this compound disaster's complexity far exceeds Taiwan's current single-hazard-oriented disaster management framework. Grounded in Comprehensive Emergency Management and Disaster Risk Management frameworks, this study utilizes literature and secondary data analyses to cross-compare normative deficiencies and practical execution within central and local government disaster management plans. Findings highlight four primary institutional deficiencies: lacking SOPs for compound disaster chain drills; excluding landslide-dammed lake overflows from statutory disasters, causing jurisdictional ambiguity; frequent risk assessment fluctuations that undermine public trust in early warnings; and insufficient frontline personnel, resulting in an "emphasis on resettlement over preparedness." Implementation challenges further reveal that Cell Broadcast Service (CBS) alerts have limited efficacy among elderly indigenous populations; "vertical evacuation" protocols sparked controversy due to inadequate prior assessment and public education; and spontaneous volunteers caused logistical disruptions owing to insufficient regulatory frameworks. Future research will incorporate in-depth stakeholder interviews to elucidate the discrepancies between institutional design and practical execution, aiming to propose actionable policy recommendations for refining compound disaster governance in Taiwan.

Despite Japan’s high vulnerability to natural disasters, a substantial gap persists in disaster education. A 2025 survey in Japan reported that 74.3% of residents have never participated in disaster-related activities. While school-based education provides structured learning, its reach is limited to specific age groups, leaving much of the population unaddressed after graduation. In addition, conventional approaches rely on voluntary participation, which limits their reach to already motivated individuals. Explicit disaster-related framing further triggers psychological avoidance, reducing engagement among low-engagement populations, defined here as individuals with low levels of interest, attention, and participation in disaster preparedness. This study proposes “Delivery-Oriented Disaster Education (Delivery-Bousai),” shifting the focus from content to delivery. Grounded in Phase-Free and user-centered design, the framework embeds disaster elements into everyday activities and entertainment, creating engagement without requiring conscious participation. Using a design-research approach, five cases (2024–2025) were analyzed across diverse contexts, including sports events, festivals, business competitions, media, and commercial facilities, targeting youth, families, and professionals. The study conceptualizes the reach structure through four dimensions: reach context, reach pathways, contact structure, and ripple structure. The findings show that effective reach is shaped by these four elements. Reach context embeds disaster elements into non-disaster settings to avoid psychological resistance. Reach pathways include five typologies—automatic, spatial, evaluation-mediated, latent, and traffic-adjacent—that enable unintentional contact. Contact structure reduces reliance on voluntary participation, allowing engagement regardless of prior interest. Ripple structure generates secondary diffusion through social networks, extending reach beyond direct participants. The study concludes that the key challenge lies not in what is taught but in how it is delivered. The proposed framework expands reach by lowering psychological barriers and integrating learning into everyday life, offering a transferable design principle for enhancing societal resilience.

Rapid industrialization and reconstruction efforts resulting from various wars have produced significant pollution and overconsumption of natural resources causing significant global climate anomalies, especially within the concrete industry. As such, the last few decades have called for increasing demand in both eco-friendly concrete developments and concrete for protective structure implementation. This study aims to investigate avenues for the development of an eco-friendlier HSC for use in both general and protective applications. Two methods will be explored, firstly, the heavy reduction of cement targeting a minimum of 40% and maximum of 80% cement replacement when compared to a reference mix that is comparatively low in cement to other typical high-strength concretes. And secondly, the application of functionally graded concrete where the newly developed HSC will be placed in the most functional regions of the member assessing flexural capacity. Research findings detail small or large strength reductions in the HSC material up to 80% replacement compared to the reference material. HSC with 80% replacement of cement detailed an early strength of 41 MPa, and 60% replacement detailed strengths of up to 75 MPa when reinforced with 2.0 wt% of arc steel fibers, exceeding the target strength of 70 MPa. Furthermore, for FGC specimens, early age strength development under normal curing regimes led to reduced strength compared to HSC specimens, due to strength development in the NC region. However, steam cured specimens and 28-day strength specimens detailed near similar strengths to similar mono- HSC specimens. These materials show suitability for use in general construction and the protective construction industry. Reduced material emissions, and use of zero(low)-cost by products will significantly reduce the financial and environmental impact of restoration as well as strengthening of existing structures. Further supporting construction and recovery efforts pre- and post-destruction event, through reduced economic and environmental impacts.

This survey focuses on the Sekimachi Nanboku-cho Neighborhood Associations in Nerima Ward, Tokyo. It is a interviewbased survey examining the current state of voluntary disaster prevention activities in preparation for emergencies. In Tokyo, the nation’s capital, where population density is high and multiple social functions are concentrated, the fire department will inevitably have to prioritize firefighting and rescue operations in the event of a direct-hit earthquake, meaning there are limits to what public assistance can provide. In other words, the city faces the challenge of a severe shortage of personnel to respond to disasters. Self-help and mutual-helps by Tokyo residents—particularly ordinary citizens in densely populated urban areas—are indispensable. The Seki-machi area in Nerima Ward is striving to build strategic partnerships with multiple organizations to encourage active participation by local residents in voluntary disaster prevention activities, where a shortage of personnel is anticipated. We conducted interviews with six key members, including the neighborhood association president, regarding the characteristics of the area and their efforts to establish mutually beneficial strategic relationships. The results of the survey revealed that this community features mechanisms—referred to as “Kakawarishiro” points of engagement—that encourage multiple stakeholders to get involved. Key findings included the “concept that everyone is an active participant,” which signifies a shift away from the adversarial relationship of “giver and receiver”; “flexibility,” which loosens social norms that could act as barriers to participation; and an “attitude of seeking to enhance mutual aid through collaboration,” which aims to positively leverage the community’s vulnerability to disaster risks.

The trend toward longer bridge spans has increased the length and slenderness of PSC I-girders, which in turn amplifies the risk that small lateral displacements arising during fabrication and erection may develop into global toppling failures. This study numerically investigates the toppling behavior of long-span girders induced by initial lateral curvature during lifting, and validates the reliability of the analysis model by comparison with theoretical equilibrium equations. Finite element analyses were performed using the general-purpose program Abaqus for PSC I-girders with spans of 40 m, 60 m, and 80 m. The eccentricity due to initial lateral curvature was modeled as a parabolic profile with maximum offsets at midspan of 30 mm, 50 mm, and 100 mm, selected with reference to practical limiting values used in the field. The lifting condition was simulated by explicitly modeling the upper rotation center and the girder connection points so as to reflect the geometric configuration of the lifting wires, while the concrete was assumed to behave linearly elastically using its elastic modulus and unit weight. The analysis results show that, under the critical initial eccentricity condition for each span, the equilibrium rotation angle induced by self‑weight exceeds approximately 1.0°, corresponding to additional horizontal displacements of more than 44 mm at the top of the girder. This rotational response approaches the limit of the available restoring moment, indicating a highly unstable state with very low safety margin against toppling during erection. Furthermore, when the numerically obtained rotation angles were substituted into the static equilibrium equations for overturning and restoring moments, the theoretical and numerical results exhibited close agreement, thereby confirming the reliability of the proposed finite element model.

Local governments need to continuously enhance their staff’s disaster response capabilities by incorporating the latest knowledge and experience. Recently, after-action reports have been frequently published by local governments to review their disaster responses. Although learning from these reports is effective for improving disaster response capacity, it is not easy for local government officers to spend sufficient time learning from them. In this study, a method to efficiently extract lessons learned from after-action reports on local government disaster response was developed. First, cases of critical situations during emergency responses were collected from after-action reports published after recent disasters. Next, a deep learning model based on a language model (BERT) was developed using the collected cases as training data. The model enables the extraction of new cases similar to the collected ones from after-action reports. As the developed model was able to extract new cases with high accuracy, it may contribute to the efficient learning and analysis of lessons learned from after-action reports. On the other hand, the findings suggested the need to explore the optimal amount of training data required to achieve high accuracy and stable learning performance. After these efforts were started with after-action reports of flood disasters, the reports of earthquake and tsunami disasters were also added as the targets. Finally, a support system was developed to extract lessons from after-action reports using the proposed model and to present accumulated lessons efficiently. This system enables users to explore the latest lessons from recently published after-action reports and enhance their capabilities based on these lessons.

In disaster safety, the key to evacuation strategies lies in redefining the smallest unit of disaster management as a social group and understanding the influence of social relationships on evacuation behavior. To this end, the quantitative strength of social relationships should be measured, and relationship uncertainty is assessed through the concept of trust. At each level of analysis, this influences the physical composition of evacuation groups, their spatial interactions, route selection, and response times. Based on a trust scale, participants were divided into low trust groups(LTG) and high trust groups(HTG), to analyze psychological and physiological stress responses, spatial distance within the group, and evacuation performance. The results showed that the HTG exhibited lower levels of stress response, subjective negative emotion scores, and objective physiological indicators. In the HTG, spatial distance—that is, the distance between group members—was shorter, and there was greater decision-making, consistent route selection within the group, and focus on the optimal route. The HTG demonstrated superior evacuation performance and reduced travel time. Emergency situations reduce the time spent on coordination behavior, such as waiting back, but increase the proximity between group members. Future evacuation plans for disasters and emergency should consider social relationships between groups, in addition to methods that simulate people as simple particles.

Evacuation decision-making during tsunami and flood events is a complex cognitive process that is often constrained by the quality and clarity of available risk information. Conventional hazard maps provide static spatial information but offer limited support for the decision-making processes that lead to protective action. This study theoretically examines how the progressive development of smart hazard map (SHM) systems addresses key cognitive barriers in evacuation decision-making, using the Protective Action Decision Model (PADM) by Lindell and Perry as an evaluative framework. Through a systematic mapping of hazard map systems — static hazard maps, SHM 1.0, and SHM 1.5 — against the stages of PADM, this study identifies which cognitive stages each system facilitates and which barriers remain unresolved. The analysis reveals a progressive pattern in which each system generation incrementally addresses additional PADM stages. In particular, SHM 1.5 introduces an explicit trade-off framework between route travel time and risk level, targeting cognitive stages not fully addressed by prior generations. This design approach is theorized to facilitate a shift in user orientation — from a distance-efficiency orientation, in which users prioritize the shortest route, toward a more comprehensive risk awareness in evacuation route selection. The findings suggest that aligning hazard map design with the cognitive structure of PADM provides a meaningful theoretical basis for supporting protective action in evacuation contexts. However, the extent to which this theoretical orientation shift translates into actual behavioral change requires further empirical validation. This study contributes a structured framework for evaluating and designing hazard map systems that are responsive to human cognitive processes in emergency situations.

Smart city discourse predominantly focuses on growing urban centers, yet a growing number of regions worldwide face the opposite trajectory: depopulation, aging infrastructure, and the erosion of centralized services that underpin conventional disaster resilience. In Japan, “structural blank areas” (zones where public emergency services cannot physically reach) are expanding as rural communities shrink. This study argues that the principle of shared disaster safety must extend beyond smart cities to encompass shrinking societies, and proposes a socio-technical framework grounded in “Smart Shrinkage,” the strategic adaptation to population decline rather than futile resistance. Two complementary design concepts are introduced. Personal Infrastructure Space (PIS) redefines the minimum unit of resilience from centralized facilities to each individual’s immediate environment, ensuring autonomous energy supply, multi-modal communication via LEO satellites and LPWA networks, and decentralized data management even when macro-infrastructure is severed. Preliminary prototyping of core components has informed the technical specifications of this framework. Regional Life Care Stations (RLCS) function as phase-free community hubs comprising functional modules spanning energy, water, healthcare, logistics, and governance. These operate as productive assets for regional green and digital transformation during normal times while converting surplus capacity to life-saving functions during emergencies. The framework’s applicability is examined through the diverse geography of Miyagi Prefecture, comprising coastal, inland, and urban zones, to explore how inter-zonal resource synergies under the 4S (Smart Shrink for Sustainable Society) concept could create economic resilience in peacetime and dynamic mutual complementation during disasters, minimizing cascading failures. A trust-based decentralized governance mechanism enables autonomous resource allocation without centralized authority, which is critical when administrative functions contract alongside population decline. This study contributes a replicable socio-technical template demonstrating that smart shrinkage can transform demographic decline into an opportunity for resilient redesign, broadening the shared disaster safety agenda beyond conventional smart city boundaries.

Water distribution networks (WDNs) are critical urban infrastructures responsible for delivering sufficient quantity and quality of water to end users. As WDNs are subject to direct damage during disasters, can trigger cascading failures, and significantly affect emergency response capacity, they represent a key target in urban disaster management. In this context, scenario-based planning has been applied in WDN design to address uncertainties in system performance arising from disaster events. Building on this, the concept of regret cost from behavioral economics has recently been incorporated into scenario-based planning to capture the gap between actual design decisions and scenario-optimal solutions. This regret cost formulation can be defined in various ways depending on how recovery is represented. However, studies that systematically compare these different definitions remain limited. To address this gap, this study proposes regret cost assessment methodologies defined by different design response strategies and examines their implications for design evaluation. Three types of methodologies are proposed, and regret costs are quantified for each approach. These methodologies were applied to the Anytown network, a hypothetical benchmark system (Walski et al., 1987), under various disaster scenarios. The results demonstrate that regret cost evaluation depends on how penalties are formulated, and different approaches provide distinct insights, with certain methodologies identifying the boundaries of acceptable performance for each design alternative. The proposed approach supports informed decisionmaking by deriving compromise solutions that account for a range of disaster scenarios, enabling effective mitigation investments and advancing the development of more resilient and preventive water distribution systems.

This study presents a framework for resilient reconstruction in smart cities using design for manufacturing and assembly– based modular concrete box girder bridge systems. Increasing demands for rapid recovery and reconstruction following disasters require infrastructure solutions that enable fast deployment, adaptability, and efficient resource utilization. The proposed approach integrates segmental design, constructability, and transportability to address limitations of conventional bridge construction in dense urban environments, particularly for curved bridge applications. Key structural behaviors, including joint shear performance and composite action in segmented members, were evaluated and incorporated into system-level design. The modular system was validated through experimental testing and numerical analysis, demonstrating its structural reliability and applicability for accelerated reconstruction. In addition, digital modeling was adopted to support implementation and integration with advanced planning and construction workflows. The results highlight the potential of modular bridge systems as practice-ready solutions for resilient reconstruction and sustainable urban infrastructure development.

With the emergence of smart cities, urban spaces are increasingly expanding underground to overcome surface space limitations and efficiently manage urban lifelines. Beyond their conventional roles in transportation and utility networks, underground spaces are also attracting attention for their potential use as protective and emergency refuge facilities. This growing multifunctional role highlights the need for underground structural systems that can ensure an adequate level of protective performance while providing high mechanical performance, long-term durability, and construction efficiency through precast technologies. Lightweight Ultra-High-Performance Concrete (LW-UHPC) has gained attention as a promising material for precast underground shelter infrastructure because it can reduce self-weight while maintaining superior mechanical properties. However, its low water-to-binder ratio and dense microstructure make it vulnerable to early-age shrinkage, which may induce cracking and reduce long-term performance. This study evaluates the application of Superabsorbent Polymer (SAP) as a strategy to mitigate this shrinkage without compromising the lightweight advantage of LW-UHPC. The effects of SAP dosage by binder mass (0, 0.1, 0.2, 0.3, 0.4, 0.5, and 0.6%) on compressive strength and unit weight were analyzed. The results indicate that while both properties generally decreased with increasing SAP content, a dosage range of 0.1–0.2% was optimal. In contrast, SAP dosages exceeding 0.4% led to a sharp decline in compressive strength. These findings suggest that SAP can be an effective additive for shrinkage control in LW-UHPC for precast underground shelter infrastructure, provided that its dosage is carefully optimized to minimize loss of mechanical performance.

The International Nuclear and Radiological Event Scale (INES) measures the severity of nuclear events. Level 7, the highest classification, has only been applied to two disasters: Chernobyl in 1986 and Fukushima Daiichi in 2011. While many questions remain unanswered, the former is largely attributed to faulty design and operational errors (UNSCEAR, 2000). The latter is described as a consequence of overconfidence in the “safety myth” and a lack of preparedness by TEPCO and the Japanese government (Khan et al., 2018). Although both accidents stemmed from a lack of safety culture and resulted in severe human, environmental, and economic impacts, one triggered a profound geopolitical shift, including the collapse of a superpower, while the other did not. The author argues that information transparency in crisis management was one factor contributing to this difference. While Chernobyl involved state-level systematic concealment, Fukushima Daiichi was able to operate within a set of guidelines while having some issues with disclosure. To solidify this claim, the author presents a multidimensional index, the Nuclear Crisis Transparency Index (NCTI), based on factors such as disclosure speed and frequency of updates. The index serves as a framework (the NCTI Framework) for comparing and contrasting transparency in nuclear accidents. Moreover, following an inspection of past nuclear accidents, it has become apparent that issues surrounding transparency during nuclear disasters were previously centred on complete concealment and denial; however, recent disasters tend to involve insufficient public communication.

Post-disaster relocation, necessitated by housing destruction, displaces people from hazard-prone areas. While the new sites reduce exposure to hazard, the relocation also reshape residents’ daily lives. Relocation can involve an accessibility trade-off between reduced hazard exposure and access to services, despite being a commonly implemented Build Back Better (BBB) measures. Past research evaluated relocation impacts mainly on housing structural quality and hazard risk reduction. However, the existing evaluation frameworks have rarely assessed the impact of relocation on residents’ ability to access essential services. Following the 2018 Sulawesi earthquake, tsunami and liquefaction disaster, the Indonesian government introduced the Huntap (permanent housing) program, relocating over 11,000 households under the BBB framework. The majority of Huntap sites are located at the urban periphery of Palu City, raising questions about whether residents exchanged hazard exposure for spatial accessibility to daily services. This study aims to evaluates the extent of spatial accessibility changes from pre-disaster settlements to post-disaster relocation sites, focusing on essential urban services (e.g., markets, public transport, schools, mosques) and emergency facilities (e.g., hospital and evacuation sites). Using GIS-based network analysis, we assess changes in accessibility between pre-disaster origin zones (A0) and Huntap destinations (A1) based on weighted travel time score and Cumulative Opportunity Measure (COM). The difference in accessibility scores (ΔA) indicates the size of changes in accessibility at each site. It also shows whether accessibility has improved or declined, revealing variations in urban positioning across Huntap locations. Preliminary findings provide spatial evidence of an accessibility trade-off in Palu’s post-disaster relocation. The proposed method also provides a quantitative measure for evaluating the relocation outcomes of BBB implementation.