| Project/Area Number |
16310125
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Natural disaster science
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| Research Institution | The University of Tokyo |
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Principal Investigator |
KUDO Kazuyoshi The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (50012935)
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| Co-Investigator(Kenkyū-buntansha) |
KOKETSU Kazuki The University of Tokyo, Earthquake Research Institute, Professor, 地震研究所, 教授 (90134634)
SASATANI Tsutomu Hokkaido University, Graduate School of Science, Associate Professor, 大学院・理学研究科, 助教授 (10002148)
ZAMA Shinsaku National Research Institute of Fire and Disaster, Senior Research Fellow, 消防大学校・消防研究センター, 上席研究官 (50358777)
FURUMURA Takashi The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (80241404)
HATAYAMA Ken National Research Institute of Fire and Disaster, Chief Researcher, 消防大学校・消防研究センター, 主任研究官 (00358798)
神野 達夫 広島大学, 大学院・工学研究科, 助手 (80363026)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥11,800,000 (Direct Cost: ¥11,800,000)
Fiscal Year 2005: ¥4,800,000 (Direct Cost: ¥4,800,000)
Fiscal Year 2004: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | Lone-period ground motion / Sedimentary basin / 3-D S-wave velocity structure / Array measurements of microtremor / Surface waves / Simulation / Oil tanks / Base-isolation building / スロッシング / S波速度構造 / 3次元地下構造 / 長周期構造物 |
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| Research Abstract |
We investigated into the generation and propagation of the long-period ground motion from large earthquakes, by conducting surveys of S-wave velocity structures and synthesizing earthquake ground motion at the Yufutsu basin in Hokkaido, where oils sloshed from the large tanks and the tanks were burnt in a fire during the 2003 Tokachi-oki earthquake, the Niigata basin, and the Metropolitan area.
We conducted the array measurements of microtremors for determining the S-wave velocity structure along the coast of the Yufutsu basin including the Tomakomai west port. The depth to seismic bedrock at Tomakomai, where the largest amplitudes of long-period (7 sec.) motion was observed, was shallower than those of both east and west Tomakomai. It is generally considered that the long-period ground motion correlates with the depth to a seismic bedrock, however, this is the case that the intermediate near surface layer of low velocity (Vs〜0.8 km/s) plays most significant role in amplification of lon
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g-period motion in a sedimentary basin. We confirmed this evidence by the 2-D simulation of ground motion.
We found some features through the spatial comparison of observed ground motions from the 2004 Kii-hanto-oki and the 2003 Niigata Chuetsu earthquakes that the long-period ground motion at the Tokyo bay area were strongly dominated by surface waves, especially that of longer than 10 sec. was prominent near the coast of Chiba prefecture.
We also carried out the survey of S-wave velocity structure in the Niigata basin, where the significance of the long-period motion had been indicated. We obtained the structure model consists of 7 layers in the central part of the basin. The depth to the basement layer of Vs〜2 km/s was about 5 km.
We confirmed that these three test sites dominated long-period motion and their deep sedimentary layers correlate well with the increasing of long-period motion. The estimated ground motions at these areas indicate that urgent countermeasures are necessary for long-period man-made structures, such as base-isolation buildings and large storage oil tanks. Less
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