Crustal shear wave anisotropy in Taiwan
碩士 === 國立成功大學 === 地球科學系碩博士班 === 90 === Crustal shear wave anisotropy is analyzed from local earthquakes recorded at the short-period seismic network in the Taiwan region. Through the property of seismic anisotropy, the purpose of this study is to investigate the origin of crustal anisotropy in Taiwa...
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| Format: | Others |
| Language: | zh-TW |
| Published: |
2002
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| Online Access: | http://ndltd.ncl.edu.tw/handle/ben3f6 |
| Summary: | 碩士 === 國立成功大學 === 地球科學系碩博士班 === 90 === Crustal shear wave anisotropy is analyzed from local earthquakes recorded at the short-period seismic network in the Taiwan region. Through the property of seismic anisotropy, the purpose of this study is to investigate the origin of crustal anisotropy in Taiwan by analyzing splitting in local shear waves recorded at the seismic stations. The splitting changes the shape of the wave and can be characterized by a fast polarization direction f and a time delay dt between fast and slow shear waves. We measure the splitting parameters (f,dt) of local shear waves by applying particle motion analysis and cross-correlation method (Rau et al., 2000). Data coverage started since the upgrade of the Taiwan seismic network in 1991 up to 1999. The results show the fast polarization directions are complex. Stations in the Coastal Plain show consistent alignment of the fast polarization directions that are parallel to the maximum horizontal compressive stress directions interpreted from both GPS and geological measurements. Most stations east of the Coastal Plain display mainly two fast polarization directions: one parallel and the other perpendicular to the local structural trend or the preferential mineral alignment direction. The delay time is about 0.01 to 0.27s.
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