Chuetsu-oki Earthquake Research Articles

Sensitivity analysis on long-term subsidence of soft clay due to The Niigataken Chuetsu-oki Earthquake in 2007

Sensitivity analysis on long-term subsidence of soft clay due to The Niigataken Chuetsu-oki Earthquake in 2007

Changes in the carbon mitigation responsibility of Japan's capital city, Tokyo – analysis of power supply shocks due to nuclear power plant accidents

Tokyo is the capital of Japan and the hub of the country's economic and administrative activities. To maintain the momentum of sustained economic growth, Tokyo is transforming the structure of its economic activities, production efficiency, and consumption patterns. Consequently, the supply and demand structure of energy and material in the city has been changing over time with a dramatic increase in the external dependency of supply. In particular, Tokyo depends on the supply of the Tokyo Electric Power Company (TEPCO), which has power plants outside of Tokyo's boundaries. However, TEPCO suspended its nuclear power plants for inspection purposes in 2003. Kashiwazaki-Kariwa Nuclear Power Plant was suspended following Niigata Prefecture Chuetsu-oki Earthquake in 2007; the Fukushima Nuclear Power Plant (the first and second power plants) was suspended following the Great East Japan Earthquake in 2011. In this study, we analyze the changes in the carbon mitigation responsibility of Tokyo, the capital of Japan, after the electricity supply shock caused by the nuclear power plant accident and examine how dependence on electricity supply affects CO2 emissions. We compare CO2 emissions in terms of 1) the changes in Tokyo's electricity supply, 2) the long-term changes in the local economy (flows of goods and services) in 1990, 1995, 2000, 2005, 2011, and 2015, and 3) different carbon accounting methods applied to consumption-based emissions. In this study, we have adopted a method that is based on four system boundaries to identify and compare per capita CO2 emissions from 1990 to 2015 using data from Tokyo's statistical data. Results show that although CO2 emissions associated with Tokyo's electricity consumption fluctuated significantly due to the suspension of the nuclear power plant, there was no significant change in Tokyo's consumption-based emissions. Since Tokyo's consumption structure has remained steady despite these major changes in electricity supply, we assume that Tokyo's emission responsibility will not change unless there is a major switch to lower carbon goods and services consumed in the city.

Support That Disaster Victims of the 2011 Great East Japan Earthquake Felt and Considerations on How to Formulate Measures for Disaster Management in the Future – Based on a Comparison with the 1995 Great Hanshin Awaji (Kobe) Earthquake, the 2004 Mid-Niigata Earthquake and the 2007 Chuetsu-Oki Earthquake

In this study, the results of a large-scale random sampled questionnaire survey of the disaster victims of the 2011 Great East Japan Earthquake are summarized. This survey was conducted during the period between March and June 2016, five years after the earthquake disaster, and included all men and women of age 20 and older who resided in the three disaster-stricken prefectures that suffered significant damage. In this study, the situation at the time of the disaster and the effective measures for disaster management in the future are examined through two questions: “Who does the disaster victims rely on for life recovery?” and “Based on this experience, who should responsibly implement the measures for disaster management in the future?” The results of these large-scale random sampled questionnaire surveys for the disasters in the past are referenced to compare the 1995 Great Hanshin Awaji (Kobe) Earthquake, the 2004 Mid-Niigata Earthquake, and the 2007 Chuetsu-Oki Earthquake. Analysis of the question, “Which persons and organizations (supporters) were relied upon in life recovery?” shows that three persons and organizations, including, a partner, children, and the town or city administration, are relied upon in all the aspects of personal or emotional, material or financial, and vital information. From all generations and kinds of supporters, people sixty and over constitute the demographic from which the least support is expected. For this generation. the family of a partner, children, mutual assistance from community associations and governmental assistance from the town/city administration are considered as the common support in all aspects. Then, comparing this with other earthquake disasters showed that a quick and careful response to all the earthquake victims by the administrative organizations is limited in large cities where relations between organizations and locals cannot be evaluated and expected. In the analysis of the question, “Who should implement the measures for disaster management in a responsible way?” it is made clear that the division of roles among self-help, mutual assistance, and governmental assistance can be summarized in the following four patterns: Mainly by governmental assistance, mainly by self-help, in cooperation with mutual assistance and governmental assistance, and in cooperation with of self-help, mutual assistance, and governmental assistance, altogether. Comparisons between all the earthquake disasters, lead to the understanding that the disaster victims who experienced a large-scale disaster consider that the measures for disaster management should be implemented by through self-help, mutual assistance, and governmental assistance, altogether, regardless of the disaster and local characteristics. In Japanese society it seems that the division of roles among self-help, mutual assistance, and governmental assistance could generally be proposed.

Mini Special Issue on the Role of Quantitative Questionnaire Surveys on the “Build Back Better” Component of the Sendai Framework for Disaster Risk Reduction (2015–2030): The Life Recovery Survey Five Years After the Great East Japan Earthquake

This special issue focuses on “Build Back Better,” which is the key concept of the Sendai Framework for Disaster Risk Reduction (2015–2030). The Sendai Framework for Disaster Risk Reduction provides United Nations member states and economies concrete actions to protect their economic development achievements from disaster risk. However, how “Build Back Better” can be measured and linked to disaster risk reduction remain unclear. Three papers here analyze the results of the “Life Recovery Survey Five Years After the 2011 Great East Japan Earthquake,” which was conducted in June of 2016. The first Life Recovery Survey was conducted four years after the 1995 Great Hanshin-Awaji Earthquake to document the extent to which the disaster victims had been able to rebuild their lives. Subsequently, the survey was conducted every two years until ten years after the earthquake. The survey was also conducted in the areas affected by the 2004 Niigata Chuetsu Earthquake and the 2007 Niigata Chuetsu-Oki Earthquake. Five years after the Great East Japan Earthquake of 2011, the present authors conducted a survey to document the actual situation of the disaster victims in Iwate, Miyagi, and Fukushima prefectures, which were the hardest hit by the disaster. In addition, we analyzed the history of Nankai Trough earthquakes with the goal of preparing for the next Nankai Trough earthquake, which is predicted to occur in the near future. These results make it possible to identify issues and make recommendations on the kinds of systems that should be implemented. It is our hope that this special issue will provide basic data to elucidate these issues.

3D FEM Soil-Structure Interaction Analysis for Kashiwazaki–Kariwa Nuclear Power Plant Considering Soil Separation and Sliding

In the 2007 Niigataken Chuetsu-oki earthquake, soil settlement, considered to be a result of the relative displacement between the soil and the structure, occurred alongside buildings at Kashiwazaki–Kariwa nuclear power plant. The objective of this study is to evaluate accurately the influence of the nonlinear behavior of the soil-structure interface on the response of the reactor building using a three-dimensional finite element model. To achieve this, we modeled the separation and sliding from sidewalls during a severe earthquake using joint elements, and evaluated the effect on the horizontal response of the structure. Through the soil-structure interaction analyses based on the recorded seismic data on the foundation for unit 7 reactor building using the three-dimensional finite element model, it was confirmed that the simulated horizontal responses of the building corresponded to the recorded seismic data. In addition, the comparison of the cases with and without separation and sliding revealed that the separation and sliding of soil from sidewalls reduces the embedment effects of the structure and that the reduction causes an occurrence of the foundation uplift. Moreover, in this study, it was clarified that the increase of the foundation uplift affected both the soil pressure characteristics beneath the foundation and along the sidewalls, and the maximum acceleration response of structures. In this study, the separation and sliding of soil from sidewalls had only a limited influence on the structural responses; however, under severe seismic excitation, it is expected that the embedment effects will be significantly reduced due to the separation and sliding of soil. Therefore, a precise response evaluation of the building including the nonlinear behavior due to separation and sliding should be considered in the seismic response analyses under severe seismic excitation.

Expanded Byrne model for evaluating seismic compression

Seismic compression is the accrual of contractive volumetric strain in unsaturated or partially saturated sandy soils during earthquake shaking and has caused significant distress to overlying and nearby structures. The phenomenon can be well characterized by load-dependent, interaction macro-level fatigue theories. Toward this end, the Byrne cyclic shear-volumetric strain coupling model is expanded and calibrated for evaluating seismic compression for several soil types. In addition, the model was transformed to allow it to be implemented in a “simplified” manner, in addition to the original “non-simplified” formulation. Both implementation approaches are used to analyze a site in Japan impacted by the 2007, Mw6.6 Niigata-ken Chuetsu-oki earthquake. The results from the analyses are in general accord with the post-earthquake field observations and highlight the sensitivity of predicted magnitude of the seismic compression to the input variables used and modeling assumptions (e.g. relative density of the soil, magnitude of the volumetric threshold strain, orientation of the ground motions, settlement of soils below the ground water table, and accounting for multidirectional shaking). Although additional studies are needed to further validate the findings presented herein, estimation of relative density and threshold shear strain of the soil and ground motion orientation individually have moderate-to-significant influence on the computed magnitude of seismic compression, but they have a significant influence when taken in combination. Also, the seismic compression models can seemingly be used to predict the settlement in fully saturated sand when the excess pore water pressures are limited. Finally, accounting for multidirectional shaking has a significant influence on the computed magnitude of seismic compression.

マルチエージェントシミュレーションを用いた 地震災害時多数傷病者搬送活動のモデル化に関する研究 －2007年新潟県中越沖地震時の傷病者搬送活動を考慮した事例－

マルチエージェントシミュレーションを用いた 地震災害時多数傷病者搬送活動のモデル化に関する研究 －2007年新潟県中越沖地震時の傷病者搬送活動を考慮した事例－

Relationship between high intensity transient signals at common carotid artery by paste type probe and cerebro-cardiovascular disease in the residents in the area of Chu-etsu Oki Earthquake

Relationship between high intensity transient signals at common carotid artery by paste type probe and cerebro-cardiovascular disease in the residents in the area of Chu-etsu Oki Earthquake

Using Agent Simulations to Evaluate the Effect of a Regional BCP on Disaster Response

The 2016 Kumamoto earthquake caused severe damage to economic activities and livelihood of residents by disrupting the supply chains of common resources, such as food, water, roads, and other infrastructure. This disaster has made recovery difficult for businesses in the region. The importance of addressing BCP in regional areas was made clear by the 2004 Niigataken Chuetsu earthquake and the 2007 Niigataken Chuetsu-oki earthquake. The 2011 Greate East Japan earthquake revealed that individual business continuity efforts were interrupted by disruption of common infrastructure. Therefore, a new concept of a region-wide business continuity plans (BCP) that focuses on collaboration among stakeholders, including private corporations, local government, and communities, was urgently required to enhance the resilience of the region against disasters. A new concept of Area BCP was proposed by JICA and Prefectural-scale District BCP was formulated by prefectural governments of Kyoto and Kagawa.In order to evaluate the effect of the presence of a regional BCP on disaster response, this study focuses on one of the most important elements of a regional BCP: the disaster relief chain information-sharing factor. Based on the supply of relief goods from the distribution center in Tosu City, Saga Prefecture to the evacuation centers in Kumamoto Prefecture during the Kumamoto earthquake, the evaluation was conducted by quantitative analysis using agent simulations of relief logistics.

Time-Series Analysis of Workload for Support in Rebuilding Disaster Victims’ Lives – Comparison of the 2016 Kumamoto Earthquake with the 2007 Niigataken Chuetsu-oki Earthquake –

Japan has experienced many disasters. However, the question of when and how much work is generated in support of rebuilding disaster victims’ lives remains unsolved. Considering this situation, this study solves the question through a time-series analysis of daily workload in support of rebuilding the lives of victims of the 2016 Kumamoto Earthquake. In addition, a correlation analysis is conducted through comparison with the case of the 2007 Chuetsu-oki Earthquake that a prior study focused on, and another correlation analysis is conducted between municipalities affected by the Kumamoto Earthquake. These analyses do not indicate the presence of a high correlation in tasks for which the requirements for payment vary depending on the disaster but do indicate the presence of a high correlation between disasters in tasks for which the requirements for payment are uniform, thereby indicating the presence of a possible generalization. In addition, the correlation analysis results of comparisons between municipalities affected by the Kumamoto Earthquake indicate a high correlation between local public entities that have suffered great human and property damage. These results indicate that when a certain condition is met, it is highly likely that daily workload can be estimated.

Near-source effects and non-linear site response at Kashiwazaki-Kariwa Nuclear Power Plant, in the 2007 Chuetsu-Oki earthquake: evidence from surface and downhole records and 1D numerical simulations

The aim of this paper is to clarify the extent of near-source effects and non-linear soil response that took place at the Japanese nuclear site of Kashiwazaki-Kariwa, during the MW 6.6 Niigata-Ken Chūetsu-Oki earthquake (July, 16th 2007). The interest of this case study stems from the relative small source-to-site distance and shallow hypocenter depth, coupled with the consistent seismic record database available from two down-hole arrays of strong motion accelerometers, installed within the nuclear site. Records were processed first to highlight those features related to near-source conditions, such as directivity and polarization, and, subsequently, to identify dependence of site response on the direction of motion and on the non-linear soil behaviour. Moreover, borehole interferometry was used to check the two available velocity profiles (estimated by in situ PS logging) used for 1D linear equivalent numerical simulations. In one case, an improved agreement with the empirical amplification functions was obtained using a smoothed profile. The main non-linear features highlighted by signal processing were globally reproduced by means of linear-equivalent analyses, that pointed out the strong influence of the input motion direction. Among the principal results of this research, it was found that the hanging-wall and directivity effects along with the non-linear site-effects dominate the ground response during the main shock, and that the site amplification features are strongly dependent on the rotation angle of the horizontal components.

Relations between Reconstruction Situation after the Chuetsu-oki Earthquake and Ownership of Lands and Buildings in Kashiwazaki Central District

Relations between Reconstruction Situation after the Chuetsu-oki Earthquake and Ownership of Lands and Buildings in Kashiwazaki Central District

Special Issue on Resilience Science and Resilience Engineering to Enhance Resilience in Shikoku Region of Japan

Japan has one of the highest levels of seismicity in the world. In the last few decades, Japan has been the site of many destructive earthquakes, such as the 1995 Kobe earthquake, 2003 Tokachi-oki earthquake, 2004 Chuetsu earthquake, 2007 Chuetsu-oki earthquake, and 2016 Kumamoto earthquake/Tottori-chubu earthquakes. Furthermore, we need to take disaster mitigation countermeasures in preparation for the next Nankai Trough megathrust earthquake, Tokyo earthquake, etc. Disaster countermeasures against these earthquakes will be of vital importance to Japanese society in the future. As a specific example, if and when the next Nankai Trough megathrust earthquake strikes, it will cause widespread and compound disasters on the island of Shikoku and in southwestern Japan in general. The prefectures of Kagawa, Tokushima, Kochi, and Ehime are all on the island of Shikoku, yet the damages that a future Nankai Trough megathrust earthquake will cause are predicted to be quite different in each prefecture. Therefore, in preparing disaster mitigation strategies for the coming Nankai Trough megathrust earthquake, these four prefectures and the distinguished universities involved in disaster mitigation research and education in them must be united in collaboration while making the best use of the individual characteristics of the prefectures and universities. Specifically, in terms of disaster mitigation preparations, universities on Shikoku have to develop and advance resilience science as it relates to upcoming disasters from a Nankai Trough megathrust earthquake, inland earthquakes, typhoons, floods, etc. In this special issue, many significant research papers from the fields of engineering, geoscience, and the social sciences by researchers from distinguished universities on the island of Shikoku focus on resilience science. We must apply their findings to society, putting them into practice to mitigate potential damages from any future natural events.

2007年新潟県中越沖地震の地震活動の特徴と地質学的要因について( 島弧の深部構造-地質・地震・地震波トモグラフィによる解析(II))

2007年新潟県中越沖地震の地震活動の特徴と地質学的要因について( 島弧の深部構造-地質・地震・地震波トモグラフィによる解析(II))

Improved Approach for Modeling Nonlinear Site Response of Highly Strained Soils: Case Study of the Service Hall Array in Japan

A nonlinear ground response analysis is conducted for the Niigata-ken Chuetsu-oki earthquake recorded at a free-field vertical array near the Kashiwazaki-Kariwa Nuclear Power Plant in Japan. A bidirectional site response analysis is carried out using LS-DYNA which allows user defined stress-strain relationships to dictate soil behavior subjected to dynamic loading. Dynamic soil behavior is characterized using a two-stage hyperbolic backbone curve implemented with modifications to consider the peak strength of soil layers as well as the strain at which the peak strength is fully mobilized. The effects of bidirectional input motions, strain rate, and the shape of the shear modulus degradation curves are investigated, and it is demonstrated that each factor can have a significant influence on the results.

Analysis of Ground Motion Amplification during Soil Liquefaction via Nonstationary Fourier Spectra

ABSTRACTIn this study, the transient properties of dominant frequencies and their components during soil liquefaction were evaluated by the nonstationary Fourier spectra of the records at Kawagishi-cho during the Niigata-ken Chuetsu-oki earthquake in 1964, at Port Island during the Hyogoken-Nanbu earthquake in 1995, and at K-NET CHB024 during the 2011 off the Pacific Coast of Tohoku earthquake. The deterioration ratio of soil shear stiffness was calculated from the ratio of dominant frequencies at the beginning and the ending of the liquefaction process. The displacement profile was calculated through numerical integration of the acceleration record, and the shear strain was calculated from the relative underground displacement of Port Island from 0 to 83 m from ground level (GL-0m to GL-83m) to GL-83m. The deterioration ratio of shear stiffness was also evaluated by fitting the maximum shear strain to the G-γ relation, and the deterioration ratio was evaluated by the nonstationary spectrum was confirmed ...

Investigating the Gap Between Actual and Perceived Distance from a Nuclear Power Plant: A Case Study in Japan

This study investigates factors in gaps between perceived and actual straight-line distance to Japan’s Kashiwazaki-Kariwa nuclear power plant (KKNPP). The distance to areas in the official accident response plan is defined using straight lines from the NPP, making it important to determine whether area residents understand these distances correctly. Adults living in the two municipalities cohosting the NPP were surveyed randomly in 2005, 2010 and 2011. In this study, we consider three groups of factors — geographical features, personal attributes, and experience in events highlighting nuclear safety. The Niigata-ken Chuetsu-oki earthquake hit the NPP between the first and second of these three surveys, and the Tohoku earthquake and the March 2011 Fukushima nuclear accident occurred between the second and the third surveys. Before the Fukushima accident, overestimations of straight-line distance were common among respondents, and geographical features such as lack of NPP visibility aggravated bias between actual and perceived distance. After the Fukushima accident, underestimation of the distance became common and personal attributes became more influential as the factor of the perceived-actual distance gap.

Comparison Between the Life Recovery Processes After the Mid-Niigata Earthquake and the Chuetsu-Oki Earthquake – Results of a Random Sampled Social Survey Using the Life Recovery Calendar and GIS-Based Spatiotemporal Analysis

This study focuses on recovery efforts following the Mid-Niigata Earthquake in October 2004 and the Chuetsu-Oki Earthquake in July 2007 in Niigata Prefecture. Results of a randomsample questionnaire survey conducted in affected areas and throughout the prefecture are analyzed using a life recovery calendar, which identifies disaster damage in affected areas and in Niigata with the objective of systematically understanding the status and process of rebuilding lives. Although the magnitude of devastation and the nature of the disasters differ, both have similar life recovery processes. It is to be noted, however, that the impact of the Mid-Niigata Earthquake lingered over a larger area for a longer period than for the Chuetsu-Oki Earthquake.

(U-6)液状化－流動化被害地域における暗渠排水の効果―2007年中越沖地震の際の柏崎市長崎での液状化－流動化被害調査から―

(U-6)液状化－流動化被害地域における暗渠排水の効果―2007年中越沖地震の際の柏崎市長崎での液状化－流動化被害調査から―

(U-1)2007年新潟県中越沖地震による柏崎市北東部の砂丘内陸側緩斜面上の大規模液状化災害

(U-1)2007年新潟県中越沖地震による柏崎市北東部の砂丘内陸側緩斜面上の大規模液状化災害