2007 Fiscal Year Final Research Report Summary
Integrated Research for 2007 Niigata-Ken Chuetsu-Oki Earthquake
| Project/Area Number |
19900003
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| Allocation Type | Single-year Grants |
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| Research Institution | The University of Tokyo |
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Principal Investigator |
IWASAKI Takaya The University of Tokyo, Earthquake Research Institute, Professor (70151719)
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| Co-Investigator(Kenkyū-buntansha) |
KANAZAWA Toshihiko The University of Tokyo, Earthquake Research Institute, Professor (30114698)
MATSUZAWA Toru Tohoku University, Graduate School of Science, Profesor (20190449)
MIURA Satoshi Tohoku University, Graduate School of Science, Associate Professor (70181849)
KABEYASAWA Toshimi The University of Tokyo, Earthquake Research Institute, Professor (00134479)
TADANO Yuichi Kyoto University, Disaster Prevention Research Institute, 教授 (20207038)
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| Project Period (FY) |
2007 – 2008
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| Keywords | Niigata-Ken Chuetsu-Oki Earthquake / Inland earthquake / Aftershock observation / OBS observation / Strong motion observation / Earthquake disaster / Earthquake damage / Earthquake fault |
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| Research Abstract |
The Niigata-Ken Chuetsu-Oki earthquake took place on July 16, 2007, off the Japan Sea coast, Niigata Prefecture. This event, of a reverse fault type with NW-ES compression axis, caused serious damages around its fault area. The fault plane of this earthquake is buried within thick sedimentary basin, and quite difficult to understand the mechanism of earthquake generation only from surface observations. This scientific research was conducted to clarify the basic geophysical features as well as social effect of the event. Temporal OBS and land arrays delineated the detailed aftershock distribution of this event, characterized by SE dipping plane. In the northern part of the fault area, NW dipping distribution pattern was also recognized. It was also elucidated that there exists rather clear structural boundary between northern and southern segments, which probably gave a strong effect to the rupture process of the main shock. In this project, researches of earthquake engineering and social sciences were also undertaken. Strong motion analysis indicates that the main asperity exists in the southern part of the fault area although rupture initiated from the northern part. From the GPS data, it was difficult to constrain the fault model for this earthquake, but clear postseismic deformation was observed with a time-scale of 0.35-2.83 day.
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