Site Amplification of Strong Ground Motion Observed at CCHG Site in Small-Titan Network during the 2011 Off the Pacific Coast of Tohoku Earthquake
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- TANAKA Kohei
- Railway Technology Research Institute
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- TSUNO Seiji
- Railway Technology Research Institute
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- YAMANAKA Hiroaki
- Tokyo Institute of Technology
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- CHIMOTO Kosuke
- Tokyo Institute of Technology
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- KATAOKA Shun’ichi
- Hirosaki University
Bibliographic Information
- Other Title
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- Small-Titan CCHG観測点における2011年東北地方太平洋沖地震の強震記録に見られた地盤増幅特性
Abstract
The strong ground motion which has a large peak ground velocity of more than 100cm/s was observed at CCHG site in Small-Titan network during the 2011 off the Pacific coast of Tohoku earthquake. In this paper, we specified the interpretation of site amplification of CCHG site. First, S-wave velocity structure at CCHG site was estimated from the array observation of microtremors to represent the site amplification factor in case of linear soil using seismic data by small earthquakes. As a result, it is shown that the deep S-wave velocity structure to seismic bedrock is necessary to interpret the large amplification factor in CCHG site. Second, we compared the ground motion calculated by linear soil response analysis using the estimated S-wave structure to the strong ground motion observed at CCHG site during the 2011 off the Pacific coast of Tohoku earthquake. It is shown that the calculated Fourier spectrum in high frequency range (5-10Hz) is large and the dominant frequency move to the higher frequency compared to the observed spectrum. Therefore, the soil nonlinear response is also related to the origin of the observed ground motion at CCHG site.
Journal
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- Journal of Japan Association for Earthquake Engineering
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Journal of Japan Association for Earthquake Engineering 16 (4), 4_126-4_141, 2016
JAPAN ASSOCIATION FOR EARTHQUAKE ENGINEERING
