| 講演要旨(和文) | | 地震波干渉法は受動的な地震記録を使うことで人工震源を用いずに地下構造をイメージングする手法である．自然地震記録を使えば，深部の地殻構造やプレート境界のイメージングが可能になる．我々は2008年に行われた東海アレイ観測で取得された深発地震記録に自己相関及び相互相関解析を適用し，東海地域におけるP波及びS波の地震波構造をイメージングした．自己相関解析の結果はこの地域における地震波トモグラフィやレシーバー関数（Kato et al., 2010；高岡ほか，2012）とよく一致しており，大陸モホ面や沈み込むフィリピン海プレート上面に対応する反射面が得られた．さらに比較的明瞭な反射面を得たS波記録に対して相互相関解析を適用した．相互相関解析の結果では強い反射面が得られたが，その反射面は自己相関解析の結果及びKato et al. (2010)で推定された構造よりやや浅部にイメージングされた． |
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| | 講演要旨(英文) | | Seismic interferometry is an imaging method of subsurface structures using passive seismic records without artificial energy sources. Imaging of deep crustal structures and plate boundaries is expected, using natural earthquake records. We applied the auto- and cross-correlation analysis to deep earthquake records, acquired by a wide-aperture linear seismometer array called Tokai Array, temporarily deployed in 2008 to image the P- and S-wave seismic structures under the Tokai region. The result of auto-correlation analysis shows good agreement with previous research results in the area, such as seismic tomography and receiver function (Kato et al., 2010, Takaoka et al., 2012). P- and S-wave reflection profiles show reflectors corresponding to continental Moho and subducting Philippine Sea plate boundary. Discontinuity of reflectors is also found at the interface of geological structure such as MTL in shallow part. Then we applied the cross-correlation analysis to S-wave records. The current result of cross-correlation analysis shows strong reflectors, however, the reflectors were imaged shallower than those in auto-correlation analysis and the seismic structure estimated in Kato et al. (2010). |
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