Love wave phase velocity estimation by using rotational components obtained from microtremor array records
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- Yoshida Kunikazu
- Geo-Research Institute
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- Uebayashi Hirotoshi
- Kyoto University Research Reactor Institute
Bibliographic Information
- Other Title
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- 微動アレイ記録から求めた回転成分によるラブ波位相速度の推定
- ビドウ アレイ キロク カラ モトメタ カイテン セイブン ニ ヨル ラブハ イソウ ソクド ノ スイテイ
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Abstract
<p>We proposed a procedure to estimate Love wave phase velocities based on rotational motions obtained from a triangular array of ordinal three-component seismometers. Rotational motions depends on only SH wavefiled, including SH and Love waves. Thus, phase velocities of the rotational motions of microtremors are expected to be same as ones of Love waves. Spatial derivatives to calculate rotational motions were approximated from the first-order Taylor series expansion of observed array records. Synthetic validation test shows that the rotational motions estimated from both of the SH-wave field synthetic microtremors and the full wave (P, SV and SH) synthetic ones agree very well. This agreement indicates that this approach well estimates rotational motions from the observed microtremor records. We calculated rotational motions of a triangular array configured with combinations of the three stations in the double triangular array of 6 stations (without the center point of the array). Phase velocities were obtained from the array rotational motions by using SPAC method. The obtained phase velocities agree well with the theoretical Love wave phase velocities. Expected amplitudes of rotational motions observed on the array of common size were estimated to be enough large for the typical microtremor observation system.</p>
Journal
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- BUTSURI-TANSA(Geophysical Exploration)
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BUTSURI-TANSA(Geophysical Exploration) 71 (0), 15-23, 2018
The Society of Exploration Geophysicists of Japan
