【摘要】 本文使用的数据来源于2004、2005和2008年台湾CWBSN(Central Weather Bureau Seismic Network)的18个宽频带台站记录的数据,2008年中国国家地震台网的2个宽频带台站数据和日本MASN(MeteorologicalAgency Seismic Network)的1个宽频带台站数据.通过互相关方法提取瑞利波的经验格林函数,利用相匹配滤波的时频分析技术测量瑞利波相速度频散曲线.利用面波层析成像方法给出台湾地区8s、12s、16s、20s的瑞利波相速度分布图,结果较好地揭示了地壳内部、尤其是浅部地壳的横向速度变化.研究表明,短周期的相速度分布同地表地质结构、地形密切相关,滨海平原、屏东盆地以及宜兰平原为低速区,西部丘陵、中央山脉以及海岸山脉地区为高速区;不同周期的相速度分布图显示,整体上低速区随相速度周期的增大逐渐向东移,这与台湾地区地壳内部速度的分布特征和构造特征基本一致.此外,屏东地区一直处于低速区,这可能与该地区布格重力负值异常有关.更多还原

【Abstract】 The data used in this study are continuous seismic waveforms recorded at broadband stations include the 18 stations of Taiwan Central Weather Bureau Seismic Network(CWBSN) from 2004 to 2005 and 2008,2 stations of China National Seismic Network in 2008,and 1 station of Japan Meteorological Agency Seismic Network in 2008.Cross-correlations are computed in daily segment to retrieve the empirical Rayleigh wave Green’s function,and Rayleigh wave group dispersion curves are measured using a phase-matched filter,frequency time analysis technique.We apply seismic ambient noise tomography to image the 8 s,12 s,16 s,20 s period phase velocity maps of Taiwan,which reveal the lateral velocity changes in the crust,especially in upper crust very well.Our results indicated that the short period phase map is agreement with known geological and tectonic features,namely,the coastal plain、Pingtung basin and Ilan plain have low velocities and the central range and coastal range have high velocities.The different period phase velocity maps show that the whole low velocity zone moves from western to eastern Taiwan,which is consistent with the character of crustal velocity structure and orogeny.The velocity at Pingtung plain from upper crust to low crust is low,which agree with the Bouguer gravity anomaly.更多还原