Japan Earthquake Research Articles

Increase in traffic injury crashes following the 2016 Kumamoto earthquake in Japan: A model comparison

Objective Following natural disasters, the number of motor vehicle crashes may increase as drivers are often forced to drive under stressful conditions. This study aims to analyze the changes in motor vehicle crashes that resulted in injury or death (injury crash) following the 2016 Kumamoto earthquake in Japan. An existing study reported that the increased crashes resulted in property damage following the earthquake; however, the effects on injury crashes remain unreported. Methods Interrupted time series analysis is employed to investigate the changes in injury crashes following the earthquake. The results are compared based on several time series models, including negative binomial and autoregressive integrated moving average models. Monthly injury-crash data from 2011 to 2020 in Kumamoto and Fukuoka city is used. Results The results reveal a 1,642-count or 20% increase (1.20-times increase, 95% confidence interval: 1.12, 1.27) in injury crashes due to the earthquake in Kumamoto city, where the earthquake damage was heavy. In contrast, statistically significant change is not detected in Fukuoka city, where the earthquake damage is negligible. Conclusion The results indicate that the earthquake has increased the motor-vehicle-crash risk and that traffic crash alerts are important following disasters.

Chemical Fires Associated with Two Major Earthquakes in Japan

This study describes the characteristics of chemical fires (fires in laboratories, oil factories, etc.,) caused by earthquakes. First, the relationship between earthquakes and fires (particularly chemical laboratory fires) in Japan is described; afterward, the relationship between chemical substances and the natural environment (particularly fires) is described. Next, we explain the relationship between fire and chemistry after explaining the two past major earthquakes in Japan, the great Hanshin-Awaji earthquake and the great East Japan earthquake, based on statistics and records. Finally, we describe the measures taken against chemical fires and future earthquakes.

Study of the Crustal Displacement Fields by Space Geodesy Method at the Primorie

This work presents the results of GPS observations (2003–2020) carried out in Primorsky Krai (aka the Primorie) and Khabarovsk Krai in southeastern Russia. The objectives of our study were to obtain displacement velocities, to test the relation of current velocities with seismicity, with the specific features of the geological structure of the Primorie, and to study the rheological parameters of the crust and asthenosphere at the continental margin. This paper analyzes the results of measurements made in the Primorie at the Central Sikhote-Alin fault. The study includes the effects of the Tohoku-Oki earthquake in Japan with magnitude M = 9, which occurred on March 11, 2011. The zone of coseismic and postseismic displacements extends to a distance of over 1,000 km from the epicenter. The postseismic attenuations of the multi-year horizontal and vertical displacements allow us to estimate the relaxation time for the elastic-viscous model. With attenuation times of 4 to 8 years, the following viscosity values were obtained for the lower layer according to the two-layer rheological model: 8 × 1018–3 × 1019 Pa s. Using the bending model of the Earth’s surface and the bottom of the Sea of Japan, we estimated the thickness (20–25 km) of the elastic upper part of the Earth's crust in the continent–ocean contact zone.

USAR decision-making: the role of hazard-specific expertise and risk assessment

The accepted detrimental effects of climate change and the anticipated increased frequency of cascading disasters means there is a pressing requirement to equip search and rescue teams with the capability to perform effective and complex risk assessments. This paper investigates risk-based decision-making expertise in the aftermath of the 2011 earthquake and tsunami in Japan. It compares the actual decisions made by an Urban Search and Rescue (USAR) commander, with the decisions that a cohort of people working within search and rescue made, when provided with the same decision context using 3 vignettes. Variations in the results are explored in terms of the complexity of the risk decision and the type of expertise required. The findings indicate that as the risk becomes more complex, the percentage of answers that were the same as the USAR commander (that we deem as ‘correct’ as they did not result in any adverse outcomes for the USAR team) decreased. Training entities need to provide decision-makers with the necessary human capabilities so they can perform the complex risk assessments required to make decisions in low-probability yet high-consequence disasters.

Application of Drones in Nuclear Contaminated Sites

The impact of nuclear radiation following the Japan earthquake has been significant. This article states that on March 11, 2011, a 9.0 magnitude earthquake occurred near Honshu Island, Japan, followed by a tsunami. The Fukushima Daiichi nuclear power plant was severely damaged by the earthquake and tsunami and triggered the Fukushima nuclear leakage event, which had an impact beyond the national boundaries of Japan and caused a global nuclear pollution accident. Nuclear pollution can have severe and long-lasting impacts on the environment and human health. Exposure to radioactive materials can cause radiation sickness, cancer, and genetic mutations. Unmanned aerial vehicle (UAV) technology is the best monitoring mechanical, can carry out monitor and post-quake repairs. This paper explores the application of drones in nuclear contaminated sites from the perspective of drone technology characteristics, the special features of nuclear contaminated sites, and the advantages of drone application in these sites, such as reducing radiation risks, improving operational efficiency, and lowering operating costs. For example, it can be used in nuclear radiation restoration investigation, image collection communication in disaster areas, operational assistance. It improves the nuclear emergency rescue system. Additionally, this paper provides an outlook on the future of drone application in nuclear contaminated sites. Drones can be equipped with more advanced sensors and equipment, enabling more efficient work and restoration.

The cosmic energy gravitational genesis of the strongest earthquakes of the earth occurred near the date 2021.1

We have presented (on January 27, 2023) to the Advances in Environment and Energies the convincing evidence of the cosmic energy gravitational genesis of the strongest earthquakes of the Earth (especially, the Japanese earthquakes) occurred (on February 10, 2021 AD; February 13, 2021 AD and March 4, 2021 AD) near the previously published (in 2019 AD) date 2021.1 AD (corresponding to February 7, 2021 AD) of the local maximal combined planetary and solar integral energy gravitational influence on the internal rigid core of the Earth (and on the Earth as a whole). The date 2021.1 AD is calculated according to the global prediction thermohydrogravidynamic principles (in the frame of the established thermohydrogravidynamic technology) under the first approximation of the circular orbits of the planets around the Sun. The revealed convincing cosmic energy gravitational genesis of the strongest earthquakes of the Earth (occurred near the date 2021.1 AD) is based on the detailed analysis (in the frame of the thermohydrogravidynamic technology) of the strongest earthquakes (according to the U.S. Geological Survey) of the Earth occurred near the local maximal values of the calculated combined planetary and solar integral energy gravitational influences on the internal rigid core of the Earth.

Fossil diatom assemblage changes due to paleoenvironment change, tsunami, and typhoon in southern Japan

AbstractTracking paleoenvironmental change and past event deposits is very important to evaluate the natural hazard spatially. This paper presents how the environment changes and implies the event deposit depending on the diatom assemblage change. To investigate paleoenvironmental change and identify the difference between tsunami and typhoon deposits, we analyze diatoms from the sediments in two coastal lakes in southern Japan where flood deposits have been linked to historical typhoon and tsunami events (Lakes Kawahara and Ryuo). The sediment cores extend from B.C.E. 500 to approximately C.E. 1000 and the downcore variation in diatom assemblages indicates a series of transitions from saline to fresher conditions in both Lake Kawahara and Lake Ryuo between approximately C.E. 500 and 1700. We observe an obvious deviation in diatom assemblages in event deposits previously identified to be either of tsunami or typhoon in origin. For the most prominent event deposit preserved in Lake Ryuo by the Hoei tsunami of C.E. 1707, the deposition of marine diatoms serves as evidence of marine flooding, while the subsequent deposition of soil and freshwater diatoms indicates the mobilization of terrigenous sediment during returning seaward flows. In contrast, the most prominent event deposit in Lake Kawahara is associated with freshwater flooding by the Kamikaze typhoon of C.E. 1281 and contains very low diatom abundances and a peak of freshwater taxa, followed by a peak in diatom counts potentially due to greater biological activity induced by a resultant influx of nutrients and re‐oxygenation during the event.

Performance Evaluation of DualSPHysics and COMCOT Programs through Numerical Testing for Simulating Tsunami Propagation and Overtopping on Seawalls

A tsunami is a destructive wave that can cause massive damage to coastal infrastructure. One of the disaster mitigation measures that can be chosen is the construction of coastal protection infrastructure, such as a seawall. Seawalls play a crucial role in protecting coastal areas as they can reduce wave energy and minimize the impact of tsunami-induced damage. However, during the 2011 Japan tsunami, the seawall built in Taro city failed as it proved to be less effective in handling the tsunami waves. The research conducted aims to model the propagation and overtopping of tsunami waves on the seawall, initially carried out through physical laboratory experiments, and later transformed into numerical test models using the Smoothed Particle Hydrodynamics (SPH) method and the Cornell Multigrid Coupled Tsunami (COMCOT) model. In this study, the parameters being compared include wave height, wave propagation, and overtopping on the seawall under two scenarios : the run-up of solitary waves on a shore without a seawall and the overtopping condition with a seawall using the Solitary Wave generation type, following the experiments conducted by Huang et al en 2022. Several parameters in the laboratory case study should be considered to expand our understanding of the systematically discussed tsunami propagation and overtopping processes and evaluate the capabilities of the SPH and COMCOT models.

Temporary Organizations in Disaster Response: Crisis, Temporality, and Governance

For most modern governments, disasters are events that are demarcated from so-called normalcy by changes in organization and temporality. As much as the changes in procedures or staffing, these new structures are distinguished by their temporality. They are explicitly temporary organizations, designed to accomplish a specific task before dissolving and returning authority to the permanent organization. The choice to change to temporary organizations in times of crisis carries a number of implications. The switch to an entity that is both a part of the government, and distinct from it and that will disappear at some unspecified but unswervingly expected point in the future when the crisis is “over” points to a distinct separation between the disaster period and “normalcy,” and indicates that the disaster period will give way to normalcy again. It allows the government to portray the crisis as exogenous and separate from on-going policies, depicting it as the result of uncontrollable natural forces that must be dealt with on an ad hoc basis and ignoring links to long-term governance in areas of education, housing, health, and other areas. This paper uses original interviews and documentary data, collected as dissertation research, to look at the formation, dissolution, and occasional failure of temporary, government-based disaster management organizations across two events: Hurricane Katrina in the United States in 2005, and the 2011 earthquake and tsunami in northeastern Japan.

A Mobile Application for Earthquake Education Targeting Foreigners Intending to Visit Japan

Japan is in the Pacific Rim Seismic Belt, and earthquakes happen frequently. Foreigners who lack the necessary earthquake knowledge and escape skills may not survive strong earthquakes in Japan. Therefore, it is essential to provide earthquake education to these foreigners. Since rich-formed earthquake education has been available for foreigners living in Japan, this research works to improve the earthquake education situation for foreigners who intend to visit Japan. Receiving earthquake education in advance helps enhance foreigners’ earthquake risk awareness, gain more opportunities to master earthquake survival knowledge, and build earthquake survival confidence. This paper proposed a learning model called ‘FOE+G’ to achieve this research goal. ‘FOE’ means the frequency of occurrence of earthquakes in Japan, and ‘G’ means gamification. A prototype system in the form of a cross-platform application has been developed to confirm that the learning model improves earthquake education for the target audience. The application delivers an earthquake notification to target objects each time an eligible earthquake occurs in Japan. The High-frequency earthquakes in Japan lead to relatively frequent updates, which enable users to build earthquake awareness, realise the importance of earthquake education, and participate more actively in it. Furthermore, gamification is employed in the application to prompt participation in earthquake education.

Seismic performance of concrete-filled steel tube columns using ultra-high-strength steel under long-period ground motion demands

The long-period ground motions observed in recent subduction-zone earthquake events (e.g., 2011 Tohoku earthquake in Japan) have subjected high-rise buildings to large numbers of lateral cyclic deformations. Concrete-filled steel tube (CFT) columns, which are often utilized in high-rise buildings in Japan, have been studied under lateral demands with a few loading cycles. However, their seismic performance under a larger number of repeated loading cycles is a considerable concern for future seismic events. Moreover, the use of ultra-high-strength steel materials in CFT columns has recently gained popularity. However, studies on CFT columns made using ultra-high-strength steel materials are still limited. In this study, the seismic performance of CFT columns made using conventional steel or ultra-high-strength steel were investigated experimentally under repeated lateral loading cycles. Four cantilever CFT column specimens were tested with a combined constant compressive axial loading and cyclic symmetric lateral loading. Each specimen was tested with two different lateral loading protocols: the conventional protocol with two cycles at each drift amplitude level, and a second protocol with twenty cycles at each amplitude level to represent the lateral drift demand under a long-period ground motion. The effects of the number of loading cycles on the seismic performance of the CFT columns are discussed. Based on the experimental observations, design recommendations are also presented. Moreover, an approach is proposed to estimate the onset of local buckling of the CFT columns under seismic loading.

Observation of free oscillations after the 2010 Chile and 2011 Japan earthquakes by superconducting gravimeter in Kutch, Gujarat, India

In this paper, we present observations of free oscillations of the Earth after major earthquakes in Chile (February 27, 2010, MW8.8) and Japan (March 11, 2011, MW9.1) using data from the dual-sphere superconducting gravimeter (SG - 055), installed at Badargadh (23°0.47 N, 70°0.62 E), Kutch, Gujarat, India in March 2009. To see the noise characteristics, we calculated the power spectral density of the gravity time series of 5 quiet days in the frequency band 0.05–20 mHz using the new low noise model (NLNM) as a reference. We compared the noise level of the Badargadh site to other SG sites around the world. This shows that the Badargadh SG is in a low noise state. We find that the noise increases at frequencies below 1 mHz. Such a characteristic is also observed in Djougou (Afrique, Benin) and Strasbourg (France). Using theoretical tides for Gujarat, we estimated a scale factor of about −814 nm/s2/V for Grav1 (lower-sphere) and about −775 nm/s2/V for Grav2 (upper-sphere). We corrected the influence of atmospheric pressure from the one-second gravity data before switching to the frequency domain. We extracted a total of 53 Earth's Free Oscillations (EFO) modes during the earthquake in Japan and about 47 EFO modes during the earthquake in Chile. We are able to extract the lowest 0S2 spheroidal mode (0.30945 mHz or 54 min) and 0S0 radial mode (0.81439 mHz or 20 min). The longer time series shows individual 0S2 singlets and 0S3 (0.46855 mHz) singlets due to the Coriolis splitting effect. We cross-referenced the frequencies of these modes using the PREM model and previous global observations. The correlation coefficient between the observed and the PREM model for these two events are 0.999 for Japan earthquake and 0.993 for Chile earthquake. This validates the quality of the data useful for low-frequency studies in seismology. We also calculated the relative deviations of our observed fundamental modes with previously determined observed and theoretical values. We found that the relative deviations of our observed free oscillations do not exceed 0.5%, indicating good correlations.

Erratum to Spatial Complexity Characteristics of Fault Slip from Japanese Earthquakes Based on Self-Similar Models: Comparison with Worldwide Empirical Models

<i>Erratum to</i> Spatial Complexity Characteristics of Fault Slip from Japanese Earthquakes Based on Self-Similar Models: Comparison with Worldwide Empirical Models

Investigation of the Receiving United States National Disaster Medical System (NDMS) Disaster Medical Assistant Team (DMAT) in Japan: Development of Standard Operation Procedures for Receiving International Medical Teams

Background/Introduction:Japan DMAT and US DMAT have been collaborating in the past to prepare for expected and unexpected disasters in Japan. Japan is predicting overwhelming disasters on Japanese soil soon, which needs efficient and optimum use of resources in medical assistance, including additional support from overseas, particularly from the US. The Japanese government established a large-scale Earthquake/Tsunami Disaster Emergency Response protocol in 2020. However, this protocol does not include any standard operation procedure (SOP) to receive an international medical team.Objectives:Establishing the SOP of receiving medical assistance from US-DMAT based on the WHO International Emergency Team (EMT) initiative.Method/Description:Collaborated with the Office of the Assistant Secretary for Preparedness and Response (ASPR) of the United States Health and Human Services, tabletop exercises assuming that a large-scale earthquake occurred during hosting the 2025 Osaka Expo was conducted online meeting system.Results/Outcomes:Provisional SOP was formed by the Japan research team and ASPR representatives. Even though Japan had several disaster medical assistance collaborations with US DMAT and is well-familiarized with the Classification and Minimum Standards for Emergency Medical Teams, many issues need to be prepared to accept US DMAT.Conclusion:Numerous procedures need to be conducted to receive US DMAT assistance during a large-scale earthquake in Japan. With this SOP, receiving US medical team assistance will be conducted promptly, eventually saving many lives. This SOP can be modified for other international teams’ acceptance in Japan. It could reference other countries seeking to have SOPs for receiving international medical team assistance in the near future.

Groundwater as emergency water supply: case study of the 2016 Kumamoto Earthquake, Japan

Securing water supply is an extremely important issue following an earthquake. Recent earthquakes in Japan have prompted focus on the use of groundwater or disaster emergency wells (DEWs). Water supply networks are vulnerable to earthquakes because they comprise long-distance pipelines that are not always earthquake-resistant. Groundwater, however, can usually be found directly below an area where water is required and can serve as an alternative water source. Although previous studies discussed the importance of groundwater in relation to natural disasters, with special reference to drought, little attention has been given to the use of groundwater following earthquakes. In this study, two questionnaire surveys were conducted of DEW owners and welfare facilities for elderly people in Kumamoto (Japan), which was struck by an Mw 7.3 earthquake in 2016, to identify the advantages and disadvantages of using groundwater as an emergency water supply and ascertain policy issues to be resolved for making DEWs effective. Results showed that not only 30 DEWs but also at least 25 privately owned wells not registered as DEWs were open to the public in the early restoration stage, improving people’s access to water and decreasing the burden on the Kumamoto city government’s emergency water supply. However, it was revealed that groundwater might not always be potable owing to quality concerns. Additionally, only a limited number of welfare facilities used the available adjacent DEWs and DEW recognition level remains low. These findings indicate that improving information disclosure regarding emergency groundwater use is a policy issue to be resolved.

Subgrid-scale modeling of tsunami inundation in coastal urban areas

Numerical tsunami inundation simulations using high-resolution (HR) topographical data are important to predict tsunami damage in urban areas at individual building levels accurately but are challenging due to the high computational cost. To address this issue, a subgrid-scale (SGS) model of tsunami inundation, called the individual drag force model (iDFM), is developed. In this model, the sum of the building drag forces in a computational mesh is fed back to the flow field by taking into account spatial information about multiple structures in the mesh. To evaluate the model performance, idealized numerical experiments using simple urban topography with several types of spatial layout patterns and hindcast physical experiments focusing upon Onagawa Town affected by the 2011 Tohoku, Japan tsunami as a historical event are conducted. Results are compared with HR tsunami simulations using building-resolved topographical data, called the structure resolving model (SRM). In general, the iDFM (and other SGS models) characterizes the effects of structures as resistance elements that reduce the fluid velocity in momentum conservation. On the other hand, the SRM evaluates these effects as topography and feeds them back into not only momentum conservation but also mass conservation and wet/dry boundary conditions. Therefore, the iDFM can model the overall inundation characteristics, such as the limits of inundation, more than 10 2 times efficiently compared with the SRM, although it cannot capture local phenomena driven by structures, such as surface rising due to blocking and contracting current between structures. In both numerical and historical tsunami (Onagawa) cases, there were small differences between the modeled inundation characteristics, such as the maximum surface elevation and fluid velocity, and the time series of inundation leading edges determined by the iDFM due to the computational grid cell sizes. The observed differences between the idealized numerical experiment and the historical tsunami case can be affected by the drag coefficient and the Froude number during the tsunami run-up.

Development of the Japan Tsunami Hazard Information Station (J-THIS)

To promote effective disaster countermeasures against possible tsunamis in the future, an effective application of tsunami hazard information is important. However, there were insufficient systems available for utilizing and applying various tsunami hazard information. Based on this situation, we developed and have been improving the Japan Tsunami Hazard Information Station (J-THIS), an open Web system available as a public portal for providing tsunami hazard information based on the probabilistic tsunami hazard assessment (PTHA). It provides tsunami hazard information through the following services: map services, data download services, and Web application programming interface (API) services. Based on the PTHA along the Nankai Trough, the J-THIS provides distributions of exceedance probability of tsunami heights for 30 years, tsunami hazard curves, earthquake fault models, tsunami heights for each earthquake fault model, and bathymetric charts. To illustrate the use of the J-THIS, understanding how existing coastal structures will protect us against tsunamis while enabling the local governments to set investment priorities in disaster risk reduction and resilience is key.

Special Issue on NIED Frontier Research on Science and Technology for Disaster Risk Reduction and Resilience 2022

We are very pleased to publish this special issue, dedicated to NIED Frontier Research on Science and Technology for Disaster Risk Reduction and Resilience 2022. There are four papers, two reviews, and one note in this issue. In the last year of the NIED’s fourth mid/long term plan period, which began in 2016, natural disasters have occurred every year, including earthquake disasters such as the 2016 Kumamoto earthquake (M7.3) and the 2018 Iburi, Hokkaido earthquake (M7.1). Rainfall disasters include the heavy rainfall in northern Kyushu in July 2017, southwestern Japan in July 2018, northern Kyushu in August 2019, Kanto and Tohoku in October 2019, and Kyushu in July 2020. In the summer of 2022, the heavy rainfall and extreme weather continued over Japan. The first three papers and one note contain hazard and risk information. Dohi et al. present the development of Japan Tsunami Hazard Information Station (J-THIS), Cui et al. present a study of the estimation of damage based on analysis of SNS Information, Nakamura provides avalanche risk information, and Ise et al. note information linkage by the Shared Information Platform for Disaster Management (SIP4D). Horiuchi et al. review the contribution of the E-Defence shaking table. This special issue also includes two social science works. Nagata et al. present tsunami disaster risk reduction education programs, and Yamazaki-Honda reviews promoting coherence among disaster risk reduction, climate change adaptation, and sustainable development for disaster resilience. In the first half of the 21st century, a mega disaster such as the Nankai Trough earthquake is expected to occur. Extreme climatic events are also becoming more frequent: typhoons, floods, heavy rains and snows, landslides, and heat waves. We hope this issue provides information useful to all readers who study natural disasters.

Fine Structure of the Subducting Slab and the 2022 M 7.4 Fukushima–Oki Intraslab Earthquake

Abstract The 16 March 2022 M 7.4 Fukushima–Oki earthquake is the largest one among forearc intraslab earthquakes in Japan since 2000. These subcoast events can cause severe damage to the local society because of their proximity to inhabited areas. However, their generating mechanism is still not clear. Here, we present 3D high-resolution seismic tomography of the source zone of four large intraslab events (M ≥7.0) during 2003–2022 in northeast Japan, which is obtained by inverting high-quality arrival-time data recorded at both onshore and offshore seismic stations. Aftershocks of the subcoast intraslab earthquakes are mainly distributed in gaps of high-velocity bodies with high Poisson’s ratio and at the upper ∼20 km depth of the subducting Pacific slab. Our results indicate that the four large intraslab events were caused by rupturing of buried hydrated faults that formed at the outer rise and dehydration embrittlement on the fault planes.

Static pushover test of spring-underground structure system for seismic performance analysis of underground structure

The static test is appropriate for studying the seismic performance of underground structures due to the large size of the model structure and the controllable stress level. By setting elastic elements around the model structure, the static pushover test of the spring-underground structure system could simulate the initial stress state of the underground structure and soil-structure interactions during the pushover process. Taking the Daikai subway station damaged in the 1995 Hanshin earthquake in Japan as the model structure, a series of static pushover tests of underground structures with a geometric scale of 1/5 were performed. The impact of vertical ground motion on the seismic performance of underground structures was studied by conducting two static pushover tests of spring-underground structure system under different vertical loads; the impact of surrounding soil on the seismic performance and failure process of underground structures was studied by conducting static pushover tests with and without springs under the same vertical load. The relationship between the horizontal pushover force and the structural interstory drift, the concrete strain change process of structural weak vertical member, the structural failure phenomenon, and the seismic performance of the test object can be obtained from the tests, which can provide valuable information for experimental research on the seismic performance of underground structures. The test results demonstrate that the vertical ground motion decreases the ductility of underground structure, and the surrounding soil improves the lateral collapse resistance of underground structure.