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Title: 山崎断層におけるトラフィックノイズを用いた地震波干渉法の適用
Other Titles: Application of Seismic Interferometry Using Traffic Noise at the Yamasaki Fault
Authors: 宮澤, 理稔  kyouindb  KAKEN_id  orcid (unconfirmed)
Author's alias: MIYAZAWA, Masatoshi
Keywords: 山崎断層
Yamasaki Fault
seismic interferometry
traffic noise
Issue Date: 30-Sep-2012
Publisher: 京都大学防災研究所
Journal title: 京都大学防災研究所年報. B = Disaster Prevention Research Institute Annuals. B
Volume: 55
Issue: B
Start page: 141
End page: 144
Abstract: 地震波干渉法はノイズ記録を用いて,2観測点間を伝播する地震波を取り出すことができる手法である。本研究ではこの手法を山崎断層(兵庫県)に適用し,地下構造調査への利用可能性を調べた。山崎断層帯は長さが約80km,走向が西北西―東南東であり,5つの左横ずれの断層セグメントからなる。断層の走向に沿って走る中国自動車道の地下約6mの観測坑道等に地震計を配置した。約10Hzに卓越周期をもつ地表からのトラフィックノイズ等が,一日を通じて安定して観測され,地震波干渉法を利用して構造をモニターし調査するに理想的であるように思える。実際,任意の2観測点間の相互相関関数を求めたところ,2観測点間を両方向に伝わる波が現れ,グリーン関数のRayleigh波成分の推定に利用することができると考えられる。この結果を踏まえ,通常は表面波に隠れて取り出すことの難しい実体波を抽出するための観測を開始した。
Seismic interferometry is a powerful method for retrieving seismic waves propagating between two seismic stations by using only noise data. I apply this method to noise data observed at the Yamasaki Fault in Hyogo prefecture to see if it is useful to investigate the subsurface structure. The Yamasaki Fault is about 80 km long, strikes WNW-ESE, and consists of five left-lateral fault segments. Seismometers are deployed at a ~6 m-deep vault across the fault zone, above which the freeway goes along a strike of the fault. The stable noise including traffic noise with a dominant frequency of ~10 Hz observed throughout a day from the surface, is likely ideal to monitor and investigate the structure by using seismic interferometry. I take the cross-correlation of waveforms at two seismometers installed. The result shows the propagation of signals between two stations in both directions that can be used to extract estimates of the Rayleigh wave component of the Green's function. I also started observations to try to extract estimates of body waves, whish are usually masked by larger amplitude surface waves, from the traffic noise.
Appears in Collections:Vol.55 B

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