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| | Abstract | | We conducted high-resolution shallow seismic reflection surveying by means of Land Streamer and S-wave VSP near the K-NET Anamizu observatory station, Ishikawa Prefecture, central Japan. The survey site has been characterized as damage concentrated zone caused by the 2007 Noto Hanto earthquake. Aftershock observations and following field geophysical surveys had revealed an irregular shape of bedrock surface beneath the overlying very soft sediments. However the detailed geotechnical properties of the near-surface around the station were still uncertain. We then aimed to image the detailed structure of the near-surface at the site along with to obtain geophysical properties. As a result, CMP stacked sections clearly imaged the bedrock surface and detailed structure in the overlying sediments down to 20 m in depth. The bedrock surface rose southeast from 16 m to 4 m within 20 m along the lines. Measured S-wave velocities ranged from 60 m/s to 80 m/s for the overlying soft sediments. |
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