1 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China 2 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China 3 Earthquake Administration of Yunnan Province, Kunming 650041, China
Shear-wave splitting beneath Yunnan area of Southwest China
1 Institute of Geophysics, China Earthquake Administration, Beijing 100081, China 2 Institute of Earthquake Science, China Earthquake Administration, Beijing 100036, China 3 Earthquake Administration of Yunnan Province, Kunming 650041, China
摘要Systematic analyses of seismic data recorded by the Yunnan regional seismograph network reveal significant crustal and upper mantle anisotropy. Splitting of the S phase of local earthquakes and teleseismic SKS, PKS, and SKKS phases indicates time-delays from 1.60 ms/km to 2.30 ms/km in the crust, and from 0.55 s to 1.65 s in the upper mantle which corresponds to an anisotropic layer with a thickness about between 55–165 km. The polarization orientations of fast shear waves in the crust are complicated with a predominantly north-south direction, and the mantle anisotropy has a nearly west-east direction. Our results show different deformation styles and mechanisms exist between the crust and upper mantle.
Abstract：Systematic analyses of seismic data recorded by the Yunnan regional seismograph network reveal significant crustal and upper mantle anisotropy. Splitting of the S phase of local earthquakes and teleseismic SKS, PKS, and SKKS phases indicates time-delays from 1.60 ms/km to 2.30 ms/km in the crust, and from 0.55 s to 1.65 s in the upper mantle which corresponds to an anisotropic layer with a thickness about between 55–165 km. The polarization orientations of fast shear waves in the crust are complicated with a predominantly north-south direction, and the mantle anisotropy has a nearly west-east direction. Our results show different deformation styles and mechanisms exist between the crust and upper mantle.
基金资助:National Natural Science Foundation of China Project (No. 41174042), China National Special Fund for Earthquake Scientific Research in Public Interest (No. 201008001) and Basic Research Project of Institute of Earthquake Science, CEA (No. 2009-21)
通讯作者:
Yutao Shi
E-mail: shiyt@seis.ac.cn
引用本文:
Yutao Shi, Yuan Gao, Youjin Su, Qiong Wang. Shear-wave splitting beneath Yunnan area of Southwest China[J]. 《地震学报》英文版, 2012, 25(1): 25-34.
Yutao Shi, Yuan Gao, Youjin Su, Qiong Wang. Shear-wave splitting beneath Yunnan area of Southwest China. Earthquake Science, 2012, 25(1): 25-34.
