| 講演要旨(和文) | | 富士川河口断層帯周辺の強震動予測のための地下構造モデルの高度化を目的として、臨時地震観測網により観測された連続微動記録を利用して地震波干渉法を適用して、深部地盤のS波速度構造モデルの妥当性を検証する。臨時地震観測点では連続観測を実施しているため、数か月分の記録を用いて観測点間の相互相関関数を得た。相互相関関数には明瞭な信号が現れており、そのマルチプルフィルタ解析によってレイリー波群速度分散曲線を推定した。分散曲線に基づき、スローネストモグラフィ解析を行い、断層帯周辺の群速度分布を明らかにした。セルごとに、推定された分散曲線と、S波速度構造モデルから計算される理論分散曲線を比較したところ、北側では推定値が理論値よりも小さく、広域で、低周波数帯域の推定値が理論値よりも小さいことが分かった。 |
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| | 講演要旨(英文) | | In order to upgrade the subsurface structure model for strong motion prediction around the Fujikawa-kako fault zone, we apply seismic interferometry to the microtremor record continuously observed at the temporary ground motion station network to validate the S-wave velocity structure model. Crosscorrelation function between the station pair was calculated using several months of records observed at the temporary stations. Multiple filter analysis was used to observe group velocity dispersion curve of Rayleigh wave from the clear peak which is observed in the crosscorrelation function. We performed slowness tomography analysis for Rayleigh wave to obtain the spatial distribution of group velocity around the fault zone. We then compared the dispersion curves estimated from the tomography with theoretical curve that can be calculated from the S-wave velocity structure model at each cell. In the northern part of the fault zone, the estimated curve was lower than the calculated curve. The calculated dispersion curve was lower than that estimated in the lower frequency range in wide area of the fault zone. |
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