Niigata-ken Chuetsu Earthquake Research Articles

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.

Three-Phase Seepage-Deformation Coupled Analysis about Unsaturated Embankment Damaged by Earthquake

AbstractThe 2004 Niigata-ken Chuetsu Earthquake in Japan caused serious damage to embankments. Considerable damage occurred in mountainous regions, and the recorded rainfall before this earthquake exceeded the annual rainfall. In this study, numerical simulations were performed to reproduce the damage and to investigate the effect of rainfall on seismic behavior. In the simulations, a three-phase (soil, water, and air) coupled analysis was adopted to consider the behavior of unsaturated soil, and a conventional elastoplastic constitutive model was used for unsaturated soil. The deformation of the embankments was quantitatively reproduced by incorporating rainfall in the seepage analysis before the dynamic response analysis, and it was found that heavy rainfall significantly affected the dynamic behavior. Furthermore, parametric studies of countermeasures showed that the embankments would deform as a result of poor-quality materials even if sufficient drainage or impermeable roadbeds were constructed.

Three-phase seepage-deformation coupled analysis for railway embankment damaged in 2004 Niigata-ken Chuetsu earthquake

Three-phase seepage-deformation coupled analysis for railway embankment damaged in 2004 Niigata-ken Chuetsu earthquake

Geotechnical Distinction of Landslides Induced by Near-Field Earthquakes in Niigata, Japan

Landslides triggered by near-field earthquakes with epicentres directly beneath towns have attracted intense attention since the 2004 Mid-Niigata (Niigata-ken Chuetsu) Earthquake. Hilly and mountainous areas sustained heavy damage. Social problems developed when many towns became isolated because landslides cut off traffic and public service lifelines. Soil from landslides closed river channels and formed natural dams. The natural dams submerged some towns. Emergency measures were undertaken promptly to prevent debris flows caused by natural dam breaks. Subsequently, the 2007 Mid-Niigata Offshore (Niigata-ken Chuetsu-oki) Earthquake and the 2011 Northern Nagano Earthquake struck the Niigata region. Landslides triggered by those earthquakes differed in terms of their number, scale, and location. Therefore, characteristics of the landslide sites of the respective earthquakes were examined to ascertain their topographical and geological features. Furthermore, differences in groundwater level and damage related to compound disasters were explained for discussion of the stability progress of damaged slopes.

Re-calibrating the thresholds for the classification of liquefaction potential index based on the 2004 Niigata-ken Chuetsu earthquake

The liquefaction potential index (LPI) has been applied with increasing frequency to assess the potential for liquefaction-induced ground failures. This paper describes strategies used to re-calibrate the LPI using accepted methods for screening the liquefaction potential and evaluates its application to the seismic hazard mapping of political tracts. In this study soil profiles using standard penetration tests were evaluated using two methods, the Chinese criteria and the Bray–Sancio criteria. The LPI values were then calculated from these profiles at non-liquefied and liquefied sites in Nagaoka City during the 2004 Niigata-ken Chuetsu earthquake in Japan. Our results suggest that 50% of the liquefied sites exhibited LPI values >15, and 75% of the non-liquefied sites exhibited LPI values <11 when applying the Chinese criteria. For the Bray–Sancio criteria, 50% of the liquefied sites and 75% of the non-liquefied sites exhibited LPI values >21 and <14, respectively. We then attempted to map liquefaction hazards using the alternative LPI thresholds (low hazard if LPI<14; moderate if 14≤LPI<21; high if 21≤LPI) and applied regression analyses between the LPI and the controlling variables (i.e., groundwater depth and peak ground acceleration). Based on the comparison of the predictions with the liquefaction inventory for the 2004 earthquake, our LPI thresholds and mapping method were able to predict ~70% of damaged areas.

Reinforcement of railway ballasted track with geosynthetic bags for preventing derailment

ABSTRACT: In order to prevent a long-term service interruption of Tokaido Shinkansen (bullet train) in Japan after an earthquake, various structures have been undergoing constant seismic retrofit. Despite these efforts, a Shinkansen train derailed during the Niigataken-Chuetsu earthquake in 2004. In order to prevent train derailments, it is important to prevent ballast from collapsing and flowing out during large earthquakes. Precast concrete blocks are in use on the Tokaido Shinkansen line for this purpose. However, precast concrete blocks have problems concerning workability and cost. Therefore, a new method of reinforcing ballasted track has been developed in which polymeric geomesh bags filled with ballast are stacked and strengthened by reinforcing bars. The results of shaking table tests confirmed that the reinforced ballasted track has sufficient seismic resistance against a severe seismic load matching the Tokai earthquake. Several durability tests were also performed, confirming that bags exposed to ultraviolet radiation for a long time have sufficient durability. Furthermore, a construction test on a commercial line demonstrated that the new method provides good workability. Thus the current study demonstrates that the seismic reinforcement of ballasted track using stacked bags and reinforcing bars is effective and practicable.

How to Optimize the Urban Recovery After Earthquake Disaster – Preparedness for Recovery from the Next Tokyo Earthquake –

In Japan of recent 16 years, we have experienced three strong earthquake disasters, that are Hanshin-Awaji earthquake (1995) which hit metropolitan area, Niigata-ken Chuetsu earthquake (2004) which hit the aging rural and mountain area, and Eastern Japan Tsunami earthquake(2011) which hit coastal area. We learned from Hanshin-Awaji earthquake the importance of preparedness of urban recovery and reconstruction to optimize the post-disaster recovery and reconstruction from urban earthquake disaster. The author suggested Tokyo Metropolitan Government to prepare the pre-disaster recovery and reconstruction from the next Tokyo Earthquake. We continue to develop and revise the pre-disaster recovery and reconstruction measures and to implement the exercises of the pre-disaster recovery measures of officials and the community-based urban recovery and reconstruction collaborated with residents. Trough these developments of pre-disaster recovery measures and implementation of exercises, the concept of pre-disaster recovery and reconstruction are cleared. It is the important to publish the image and concept of urban reconstruction after disaster before the disaster, which is produced according to damage estimation research. In case of the next Tokyo earthquake, damages of houses are very huge. Approximately 850,000 buildings are collapsed and burned, and 1,600,000 homes are lost. It is important to prepare the reconstruction plan making and reconstruction procedure of projects. And also, it is important to prepare the methodology of individual recovery and reconstruction.

齋藤ほか(2011)「中越地震で発生した横渡地すべりにおける過剰間隙水圧の発生根拠としてのサンドダイクの発見」に対する討論

齋藤ほか(2011)「中越地震で発生した横渡地すべりにおける過剰間隙水圧の発生根拠としてのサンドダイクの発見」に対する討論

Shear Plane Found in the Interior of Soil/Rock near a Tunnel Damaged in 2004 Niigata-Ken Chuetsu Earthquake

Landslides triggered by earthquakes are one of the most damaging natural disasters. Recently, cutting-edge technologies such as Light Detection and Ranging (LiDAR), Interferometric Synthetic Aperture Radar (InSAR) method have allowed us to combine a spatial data set of landslides with topographical information etc. However, remote detection of landslides may cause missing slightest signs of hidden landslides. Damages to Kizawa Tunnel and other facilities in its vicinity in the 2004 Niigata-ken Chuetsu Earthquakee are firstly introduced. Moreover, two wells at #1 and #2 respectively to the south of Kizawa tunnel were found dislocated in further survey. Dislocated wells together with other previous findings indicate that Kizawa helmet are all lying on about the same plane suggesting the presence of large shear plane and therefore the importance of thorough investigations.

Study on Dip Slope Failure at Higashi Takezawa Induced by 2004 Niigata-Ken Chuetsu Earthquake

ABSTRACT An extensive number of slopes failed in the 2004 Niigata-ken Chuetsu Earthquake. Among them, a dip slope containing a weak layer in Yamakoshi Village (currently Nagaoka City) was investigated intensively. Regarding its morphological characteristics, it is argued that the earthquake reactivated a pre-existing failure plane which then formed most of the present sliding plane. In order to reveal the strength properties of the weak layer that formed the sliding plane, including the behavior against cyclic loading, a series of triaxial compression tests and simple shear tests was performed on undisturbed specimens that were retrieved by block sampling from the site. Based on the test results, a stability analysis and the calculation of the earthquake-induced displacement were performed. By extending Newmark's sliding block analysis, while considering the effects of the irregular geometry of the sliding plane and its strain-softening properties, a reasonable simulation of the process of this slope failure could be provided.

Study on a failed dip slope with a thin sandy layer in 2004 Niigata-ken Chuetsu Earthquake

Among the extensive failed slopes in the 2004 Niigata-ken Chuetsu Earthquake, Japan, a dip slope at Yokowatashi, Ojiya, was investigated intensively. The sliding plane was along a weak thin tuff sandy layer which had been deeply weathered. Triaxial compression tests and plane strain compression tests were performed on undisturbed specimens obtained by block sampling and boring sampling to evaluate the strength that was mobilized on the sliding plane. Stability analysis based on the test results reveals that, at normal time, without earthquake and without an extremely high groundwater level, the slope is stable. Furthermore, the calculation of earthquake-induced displacement provides a reasonable simulation of the failure of this slope.

Effects of System Compliance on Liquefaction Behavior of Thin Sandy Layer in Undrained Cyclic Triaxial Tests

ABSTRACT In a case history of dip slope failure caused by the 2004 Niigata-ken Chuetsu Earthquake, it has been reported that the slope contained a thin sandy soil layer. The layer may have liquefied if it had been saturated at the time of the earthquake. Undrained cyclic triaxial tests comprise one of the available experimental approaches for evaluating the liquefaction behavior of such thin sandy soil layers. In this study, a series of undrained cyclic triaxial tests was performed on specimens containing an artificial sand layer in order to investigate the effects of system compliance that are possibly induced by partial drainage caused by the changes in volume of the filter paper used to saturate the sand layer and the local drainage at the interface among the specimen, the top cap and pedestal, and the rubber membrane. The observed liquefaction behavior depended on the thickness of the sand layer under otherwise similar conditions, suggesting the significant effect of system compliance. By conducting special tests, while correcting the partial drainage, it was possible to reduce its effect on the liquefaction behavior. Cylindrical specimens with a top cap and pedestal, all having the same diameter, exhibited a smaller effect from partial drainage than prismatic specimens with an oversized top cap and pedestal.

A Quantitative Approach for Estimating Coseismic Displacements in the Near Field from Strong-Motion Accelerographs

The translational accelerations recorded by strong-motion seismometers are often contaminated by baseline offsets that prevent recovering theground displace- ments by double integration. Detailed analysis of the K-NET95 strong-motion seis- mometer, and the improvement of the visual display of the recorded accelerations' Fourier transform by addition of long zero pads to the acceleration records, made it possible to distinguish the origins of the long-period noise that contaminate the translational accelerations recorded in the near field of two studied earthquakes, the 2004 Niigata-ken Chuetsu earthquake and the 2007 Niigata-ken Chuetsu-Oki earthquake, Japan. They are the residual rotation of the instrument (residual tilt) or the 1=f digital semiconductor noise. The quantification of these two terms allows us to discuss the low-frequency content of the records and to describe when it is possible to obtain realistic displacement time histories. It happens when the residual tilt is removed in the time-domain or when the 1=f semiconductor noise overshadows the translational acceleration records up to sufficiently small frequencies. As a check of the method, displacement time histories obtained from acceleration records are compared with nearby 1-Hz GPS data. Good similitudes are obtained in the near field for collocated instruments. Online Material: Figures showing acceleration, velocity, and displacement time series, and acceleration spectra for 18 records.

Strengthening the Regional Resiliency of Industrialized Suburban Cities through BCP Consolidation: Case Study Based on the Niigataken Chuetsu Earthquake

In Japan, business continuity plan/management (BCP/BCM) is recognized as a very significant issue as in other advanced countries, because of the great earthquake disasters in 2004 and 2007 in Niigata Prefecture that caused disruptions of many small and medium sized production companies as well as forcing all Japanese automobile manufacturers to cease production for several days. However, according to some reports the BCP establishment rate in Japan is still low. This study focuses on Ojiya City, which was seriously affected by the Niigataken Chuetsu Earthquake in 2004. The production industries have a concentrated presence in Ojiya City, making it an excellent case study for clarifying the disincentives to BC planning at small and medium sized enterprises (SMEs) as well as demonstrating a new concept for increasing regional resilience, because it represents areas of potential resource consolidation for cooperation within the industrial community, the regional civic community and other remote regions. As a result, several key elements are proposed that may support l regional BCPr that may consequently lead to true l regional resiliency.rJEL Classification: L29, R00, Z00

Characterized Source Model and Strong Ground Motion Simulation for the 2004 Mid Niigata Prefecture (Niigata-ken Chuetsu) Earthquake Based on Empirical Site Amplification and Phase Effects

経験的サイト増幅・位相特性を考慮した統計的グリーン関数法を用いて2004年新潟県中越地震の特性化震源モデルの構築を試みた．波形インバージョンの結果を参照し，4つのアスペリティを配置することにより，波形の良好な再現が可能となることを示した．さらに本地震での大きな特徴であるK-NET小千谷における大速度パルスの生成要因として破壊開始点付近の2つのアスペリティの重要性について確認した．また波形合成の際に経験的位相特性を用いることの妥当性について，構造物の非線形応答という観点から検討を行った．その結果，対象地点において観測された位相特性を用いることで，構造物の非線形応答の再現性が向上することを明らかにした．

Building Comprehensive Disaster Victim Support System

Our research team of industrial, governmental, and academic organizations had supported local governments using geographic information systems (GIS) at Odiya city in the 2004 Niigata-ken Chuetsu Earthquake. We developed GIS applications for damage certification based on specific needs enabling municipal personnel to operate effectively during the initial post-disaster confusion. The team developed GIS and other databases and applications, and designed the certification desk layout. Based on our work in Odiya, we applied these solutions in the 2004 Niigataken Chuetsu Earthquake, 2007 Noto Hanto Earthquake, and 2007 Niigata-ken Chuetsuoki Earthquake. We damage citification issuance and set up a master database for victims to help victims rebuild their lives. We discuss comprehensive solutions to damage assessment, database registration, damage certification, and victim assistance.

Earthquake Early Warning and Derailment of Shinkansen Train at the 2004 Niigataken-Chuetsu Earthquake

Earthquake Early Warning and Derailment of Shinkansen Train at the 2004 Niigataken-Chuetsu Earthquake

Inexpensive Integrated GIS for Local Government to Implement Emergency Response and Management Effectively

We are exposed to various kinds of Multi-hazards due to natural disasters, terrorist attacks and epidemic’s outbreak. In any of these crises, national and local governments must take in managing emergency responses effectively. Though one of the many measures is to build information systems against disaster, these systems are tools for estimating post disaster damage. This effort is not, however, implemented either well or effectively in most cases. Our research team had supported local governments using GIS in cases such as the 2004 Niigata-ken Chuetsu Earthquake, the 2007 Noto Hanto Earthquake, and the 2007 Niigataken Chuetsuoki Earthquake. Through these experiences, we reconfirmed the positive effects of location information and GIS. We also reconfirmed the need for both implementation speed and flexible use in their implementation. This paper describes how we built inexpensive integrated GIS for local governments to implement in emergency response andmanagement from experiences and knowledge on disaster affected area.

地震時の自然斜面崩壊に関する調査と解析

地震時の自然斜面崩壊に関する調査と解析

Crustal Deformation After 2004 Niigataken-Chuetsu Earthquake, Central Japan, Investigated by Persistent Scatterer Interferometry

Crustal Deformation After 2004 Niigataken-Chuetsu Earthquake, Central Japan, Investigated by Persistent Scatterer Interferometry