Niigataken 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

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－

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.

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.

(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

(U-4)2007年新潟県中越沖地震による地盤災害と旧地形

(U-4)2007年新潟県中越沖地震による地盤災害と旧地形

(U-3)2007年新潟県中越沖地震による柏崎・刈羽地域の建物被害と地盤災害

(U-3)2007年新潟県中越沖地震による柏崎・刈羽地域の建物被害と地盤災害

(U-5)2007年新潟県中越沖地震の強振動方向

(U-5)2007年新潟県中越沖地震の強振動方向

Seismic response analysis of full-scale boiling water reactor using three-dimensional finite element method

This paper presents the three-dimensional finite element seismic response analysis of full-scale boiling water reactor BWR5 at Kashiwazaki-Kariwa Nuclear Power Station subjected to the Niigata-ken Chuetsu-Oki earthquake that occurred on 16 July 2007. During the earthquake, the automatic shutdown system of the reactors was activated successfully. Although the monitored seismic acceleration significantly exceeded the design level, it was found that there were no significant damages of the reactor cores or other important systems, structures and components through in-depth investigation. In the seismic design commonly used in Japan, a lumped mass model is employed to evaluate the seismic response of structures and components. Although the lumped mass model has worked well so far for a seismic proof design, it is still needed to develop more precise methods for the visual understanding of response behaviors. In the present study, we propose the three-dimensional finite element seismic response analysis of the full-scale and precise BWR model in order to directly visualize its dynamic behaviors. Through the comparison between both analysis results, we discuss the characteristics of both models. The stress values were also found to be generally under the design value.

Field investigation and model tests on differential settlement of houses due to liquefaction in the Niigata-ken Chuetsu-Oki earthquake of 2007

A massive earthquake struck the Niigata Chuetsu-Oki region of Japan on July 16th, 2007, claiming 11 lives and damaging about 6000 houses. The earthquake had a magnitude of 6.8, with data from an accelerograph managed by a nationwide strong-motion observation network known as Kyoshin Net (K-net) showing a maximum value of 668gal (NS). In the Matsunami district of Kashiwazaki city (located on land filled and developed as a residential area from around 1970 onward) about 3km northeast of Kashiwazaki Railway Station, many houses were damaged due to liquefaction. A field investigation, including a boring survey, surface wave exploration and measurement of differential settlement of houses knocked aslant by soil liquefaction, was conducted to determine the relationship between the extent of damage to houses and the area׳s geological structure. It was found that most houses severely damaged due to liquefaction were located around the boundary between sand dunes and the local river delta. Additionally, the relationships linking sloping geological structure, the thickness of the liquefaction layer and total/differential settlement of houses were clarified from the results of shaking table model tests conducted in this study. Test results showed that it is important to consider multidimensional influences caused by sloping geological structure in the estimation method of liquefaction potential in order to predict and assess degree of damage to houses due to liquefaction.

A new interpretation of large amplitude earthquake acceleration from non-linear local soil-structure interaction

A new interpretation of large amplitude earthquake accelerations recorded at the Kashiwazaki-Kariwa nuclear power station during the Niigata-ken Chuetsu-oki earthquake in 2007 is provided from the viewpoint of non-linear local interaction between an embedded building and its surrounding soil. An occurrence mechanism is investigated by the dynamic response analysis in which a bi-linear restoring-force characteristic with a gap-slip process is used. The Ricker wavelet and the continuous sweep sinusoidal wave are adopted as an input. The amplification is explained to be induced by an additional higher mode due to the change of a support condition, such as a gap between an embedded building and its surrounding soil.

Series: Physicians and disaster medical care: Third stage, Management and education for disaster medicine: disaster medical coordination system (1). Mid Niigata Prefecture earthquake in 2004 & Niigataken Chuetsu-oki earthquake in 2007

Series: Physicians and disaster medical care: Third stage, Management and education for disaster medicine: disaster medical coordination system (1). Mid Niigata Prefecture earthquake in 2004 & Niigataken Chuetsu-oki earthquake in 2007

Experimental and Analytical Studies on the Effect of Excessive Loading on Fatigue Crack Propagation in Piping Materials

The seismic design review guide in Japan was revised in September 2006 to address the occurrence of a large earthquake beyond the design basis. In addition, Japanese nuclear power plants (NPPs) experienced multiple large earthquakes, such as Niigata-ken Chuetsu-Oki Earthquake in 2007 and the Great East Japan Earthquake in 2011. Therefore, it is very important to assess the structural integrity of reactor piping under such a large earthquake when a crack exists in the piping. In this work, crack growth behavior after excessive loading during the large-scale earthquake were experimentally and analytically evaluated for carbon steel and austenitic stainless steel. Some cyclic loading patterns with increasing and decreasing load amplitudes and maximum loads were applied to fatigue crack growth test specimens. From the results, the retardation of crack growth rate was clearly observed after excessive loading. In addition, the applicability to the retardation effect of the modified Wheeler model was confirmed. It is also concluded that the retardation effect has little influence on the failure probability due to seismic loading using probabilistic fracture mechanics (PFM) analyses with the modified Wheeler model.

Beam-Mode Buckling of Buried Pipeline Subjected to Seismic Ground Motion

During seismic events, buried pipelines are subjected to deformation by seismic ground motion. In such cases, it is important to ensure the integrity of the pipeline. Both beam-mode and shell-mode buckling may occur in the event of compressive loading induced by seismic ground motion. In this study, the beam-mode buckling of a buried pipeline that occurred after the 2007 Niigataken Chuetsu-oki earthquake in Japan is investigated. A simple formula for estimating the critical buckling strain, which is the strain at the peak load, is derived, and the formula is validated by finite-element analysis. In the formula, the critical buckling strain increases with the pipeline diameter and hardness of the surrounding soil. By comparing the critical strain derived in this study for beam-mode buckling with the critical strain derived in a past study for shell-mode buckling, the formula facilitates the selection of the mode to be considered for evaluating the earthquake resistance of a pipeline. In addition to the critical buckling strain, a method to estimate the deformation caused by seismic ground motion is proposed; the method can be used to evaluate the earthquake resistance of buried pipelines. This method uses finite-element analyses, and the soil–pipe interaction is considered. This method is used to reproduce the actual beam-mode buckling observed after the Niigataken Chuetsu-oki earthquake, and the earthquake resistance of a buried pipeline with general properties is evaluated as an example.