In this investigation, we have conducted a long period teleseismic and tsunami waveform inversion to obtain the slip distribution of the 1974 Lima-Perú earthquake occurred in the central region of Peru. According to teleseismic inversion, the rupture process was complex with a duration of 90 s approximately and the main asperity was located in the northern side of the rupture geometry, offshore Lima and Callao. According to tsunami waveform inversion the main asperity was located in the southern side of the fault plane, offshore Cañete. However, a joint inversion of teleseismic and tsunami waveforms averaged the contribution of the two datasets and could give a better result. The maximum slip from the joint inversion was 7.25 m, and the moment magnitude was Mw 8.1. Despite the occurrence of this earthquake (almost 50 years ago), there is a high seismic potential to trigger a tsunamigenic earthquake in the central region of Peru. According to the interseismic coupling the next earthquake in the central region of Peru is ready to occur and it would be of 8.5–8.8 Mw.

The northern part of the Japan Sea is a seismically active region where several large earthquakes were recorded in the past. Some of the earthquakes were accompanied by tsunamis. However, there is insufficient information on them. In this study, we aimed to examine a sea surface abnormality that occurred in 1415, as described in the Chosŏn Wangjo Sillok (“The Chronology of the Li Dynasty of Korea”). This sea surface abnormality was widely observed along the east coast of the Korean Peninsula, and seawater run-up and withdrawal occurred several times. Volcanic eruptions or earthquakes can be considered the cause of this sea surface abnormality, with the possibility of heavy rain or wind.

The Earthquake Research Committee (ERC) of the Headquarters for Earthquake Research Promotion conducted a probabilistic tsunami hazard assessment due to large earthquakes along the Nankai Trough for the next 30 years. Utilizing the basic data of earthquake source models and calculated maximum tsunami heights, the authors propose a method to evaluate the hazard curves of the first and second earthquakes separately, considering the sequence of earthquake occurrence in one cycle of large earthquake activities along the Nankai Trough. First, based on the relative weights allocated to the 176 occurrence patterns of 79 earthquake source regions, the weights for the 2,720 characterized earthquake fault models (CEFMs) are calculated. The hazard curve of the first earthquake is evaluated using the 2,720 sets of maximum tsunami heights and weights under the condition that one of the CEFMs causes an earthquake. Next, the conditional hazard curves for the possible second earthquakes conditional on each individual first earthquake are calculated. Finally, the hazard curve for the second earthquake is evaluated as a weighted average of the conditional hazard curves. Numerical examples are shown for 15 sites. The first earthquake accounts for about 60% or more of the total hazard evaluated by ERC, and its contribution increases with increasing maximum tsunami height. The first and second earthquakes account for 80%–90% of the total hazard.

Palu City is one of the city centers in the world which is located on a fault line that is prone to earthquakes and tsunamis. The latest earthquake and tsunami occurred on September 28, 2018 with a magnitude of Mw 7.4, which was centered on the ground and caused a large tsunami in Palu City. The earthquake and tsunami claimed 4,194 lives and damaged 55,102 buildings while missing, heavily, and lightly damaged. To reduce the impact of disasters, it is necessary to make efforts to increase awareness based on local wisdom so that it can be easily implemented in the community of Palu City. Local wisdom was explored by the people of Palu City and saw its effect on the level of alertness to disasters caused by the earthquake and tsunami. Local wisdom ombo is obtained from the people of Palu City, which contains a prohibition on building close to clean water sources. Data collection was carried out by conducting interviews with 121 affected communities regarding their knowledge, attitudes, and environmental conditions related to the level of vigilance. For environmental variables, local activity was a parameter included in the survey. The results of the analysis showed that the level of knowledge about the earthquake and tsunami as well as attitudes based on local wisdom increased the level of vigilance in disaster risk reduction efforts in Palu City. The results of the analysis showed that the implementation of attitudes based on local wisdom can affect the level of alertness with a value of 0.87, which means that the application of local wisdom can increase preparedness for earthquake and tsunami disaster. Indigenous latent variables (knowledge, attitudes, and environmental conditions) had a strong effect on exogenous latent variables (earthquake and tsunami preparedness) with an R² value of 0.741.

The authors have proposed a modified intensity–duration (I-D) method that incorporates field measurements of tensiometer to improve the accuracy of predicting the risk of slope failure. This method uses an indicator that considers the relationship of the duration from the time point at which the saturated zone is assumed to have formed to the average rainfall intensity during that period. The usefulness of this method has been verified, but its applicability to different slopes has not yet been investigated. Here, the authors collected long-term observations on a natural slope in Minamiashigara City, Kanagawa Prefecture, and examined the Modified I-D method using data on slope failures in the surrounding area. The authors also compared the results with plots of previous rainfall index (soil water index–accumulated rainfall in 60 min, effective rainfall amount with a half-life of 72 h–effective rainfall amount with a half-life of 1.5 h, and accumulated rainfall–accumulated rainfall in 60 min). The snake curves for rainfall events during slope failure and non-failure were clearly separated. The accuracy was high, confirming the applicability of the modified I-D method.

A precipitation dataset is created to estimate a reproduction period of several thousand years for stochastic flood risk assessment in the non-life insurance sector. A stochastic precipitation model for natural hazard risk assessment developed in a previous study was applied to a large ensemble data. The model was used to obtain the precipitation ensembles for the recent and future climate by +2 K and +4 K increases in mean temperature, respectively. We successfully created 10,000 years of precipitation data, which makes it possible to obtain precipitation data over a 1,000-year return period.

Asia-Pacific countries are facing growing risks from water-related disasters that are being exacerbated by climate change, urbanization, population growth, and development activities. Effective disaster risk reduction (DRR) and climate change adaptation (CCA) are crucial for building quality-oriented societies. This study proposes approaches to DRR and CCA by examining cases and approaches from a special session at the 9th International Conference on Flood Management. This session was held to follow up on the Kumamoto Declaration adopted at the 4th Asia-Pacific Water Summit in Kumamoto in April 2022, and demonstrated the determination of heads of states and governments to resolve water issues in the region. The recent disaster cases in Pakistan, the Republic of Korea, the Philippines, and Indonesia highlight the unprecedented scale of water-related disasters. These countries have developed integrated structural and non-structural measures as fundamental solutions, including planning supported by scientific evidence, institutional reforms, and capacity building. However, there is a need to prioritize and strengthen urban planning and land use regulations for effective DRR and CCA. The Kumamoto Declaration emphasized three critical approaches: science and technology, finance, and governance, while the session clarified the effectiveness of these approaches. Leveraging science and technology can help societies develop and implement effective strategies to mitigate climate risks and safeguard vulnerable populations and ecosystems. However, there is a significant investment gap for flood protection, estimated at USD 64 billion per year. Thus, financial arrangements must be established. Meanwhile, good governance is essential for collaboration between local bodies, national governments, and international assistance. Such governance can leverage green infrastructure as a key solution and promote disaster resilience that is both locally driven and nationally relevant.

The authors used a data-driven reinforcement learning model for the post-disaster rapid recovery of human mobility, considering human-mobility recovery rate, road connectivity, and travel cost as the recovery components, to generate the reward framework. Each component has relative importance with respect to the others. However, if the preference is different from the original one, the optimal policy may not always be identified. This limitation must be addressed to enhance the robustness and generalizability of the proposed deep Q-network model. Therefore, a set of optimal policies were identified over a predetermined preference space, and the underlying importance was evaluated by applying envelope multi-objective reinforcement learning. The agent used in this study could distinguish the importance of each damaged road based on a given relative preference and derive a road-recovery policy suitable for each criterion. Furthermore, the authors provided the guidelines for constructing the optimal road-management plan. Based on the generalized policy network, the government can access diverse restoration strategies and select the most appropriate one depending on the disaster situation.

An extreme dry-slab snow avalanche occurred on January 10, 2021, at Mt. Nodanishoji, Gifu, Japan, during a heavy snowfall. The avalanche ran down a horizontal distance of approximately 2,800 m and damaged trees and infrastructures. This was estimated to be the second largest recorded avalanche in Japan. However, physical snowpack properties and their vertical profiles and spatial distribution, which caused the avalanche, were not addressed in the release area immediately following the avalanche, mainly due to unsafe and lousy weather conditions. Based on a snow depth distribution observed by an unmanned aerial vehicle and a numerical snowpack simulation in the avalanche release area, the spatial distributions of the mechanical snowpack stability and slab mass and their temporal evolution were estimated in this study. The procedure was validated by comparing the calculation results with the observed snowpit and spatial snow depth data. The results indicated that two heavy snowfall events, approximately 3 and 10 days before the avalanche onset, generated two different weak layers made of precipitation particles and associated slabs above the weak layers. The older weak layer was only generated on the northward slope due to its low temperature, whereas the newer layer was predominant over the avalanche release area. The procedure employed in this study is expected to be applied to other avalanche cases in the future.

The Japan Atomic Energy Agency (JAEA) established a telephone consultation system at the request of the Ministry of Education, Culture, Sports, Science and Technology in response to residents’ concerns about the radiation health effects following the nuclear accidents at the Fukushima Daiichi Nuclear Power Station of the Tokyo Electric Power Company (TEPCO) in March 2011. Eight toll-free telephone lines were established and employees with knowledge of radiation health effects were assigned for consultation. The JAEA expert response group for telephone inquiries comprised a telephone response team, a question-and-answer team, and a manager. Approximately 35,000 consultations were conducted from March 17, 2011 to September 18, 2012. Japan’s Basic Disaster Prevention Plan was revised following the accident, where one of the JAEA’s roles for nuclear emergency response was to provide telephone consultation on radiation health effects. The JAEA’s system for telephone consultation was improved following this experience. The description of telephone hotlines in the International Atomic Energy Agency’s guide, GSG-14, published in 2020, was discussed for further improvement in the JAEA’s telephone consultation system.

Multiple reports have emphasized the significance of protecting cladding from windborne debris or falling cinders during strong winds or volcanic eruptions. Japan has no available building codes or standards for protecting the cladding against the windborne debris or falling cinders. In contrast, certain specifications for cladding performance when impacted by windborne debris, along with associated testing methods, are outlined in American, ISO, and JIS standards. A series of impact tests was conducted on selected specimens, like cladding used for residential projects, to evaluate their impact resistance performance. This study presents the outcomes of the impact performance tests, including their destruction modes, for representative materials of cladding like float glass, Japanese tiled roof, batten-seam roof, and slate-tiled roof. The tests were conducted using an air cannon as the gravel-propulsion device. The impact-resistant speed corresponding to the mass of gravel was clarified for the specimens.

This study assessed health literacy (HL) and its associated factors among the elderly during the COVID-19 pandemic, in which HL affected disaster risk management. This cross-sectional study included elderly individuals from Dusit District, Bangkok, Thailand. A total sample of 500 was obtained through simple random sampling conducted between March and October 2022. Spearman’s rank correlation and the eta coefficient were used to analyze the relationships. As for the results, the total HL of the elderly was fair (x̄ = 54.01, S.D. = 14.05). Considering each aspect, it was found that 1) access to information and health services was poor (x̄ = 11.91, S.D. = 2.97), 2) comprehension of health information was fair (x̄ = 14.01, S.D. = 3.65), 3) assessment of health information and services was fair (x̄ = 13.60, S.D. = 3.83), and 4) application of information and health services was fair (x̄ = 14.49, S.D. = 3.60). Age, education, and comorbidity were factors related to the HL of the elderly during the COVID-19 pandemic in Dusit District (p < 0.001). The results elucidate the HL of the population of this community during the COVID-19 pandemic, providing an indicator of the community’s potential for disaster risk management, including the preparedness, mitigation, response, and recovery phases.