摘要
本文分析云南地区中周期ＳＫＳ偏振，得出观测台附近上地幔Ｓ波快速方向和分裂时间为：昆明，８５°，１．０秒；洱源，８９°，１．０秒；腾冲，１６５°，０．７秒；昭通１６７°，０．９秒。按上地幔地震各向异性是应力作用下矿物优势取向所致的观点，腾冲和昭通的各向异性观测与现代应力场作用相符。但昆明和洱源的观测与现代应力场作用矛盾，它可能是古生代至中生代间攀西裂谷张裂时期，地幔物质流动引起矿物有序排列的结果。
In this paper, we analyze the polarization of intermediate period SKS waves in Yunnan reigon and obtain the fast velocity directions and splitting times for S waves of the upper mantle around the following stations:Kunming, 85°, 1.0s; Eryuan, 89°, 1.0s; Tengchong, 165°, 0.7s and Zhaotong, 167°, 0.9s.Based on the point of view that the seismic anisotropy is caused by predominant orientation of the mantle minerals under the stress field, the observations at stations of Tengchong and Zhaotong are consistent with the effect of the present stress field. At stations Kunming and Eryuan, however, the Seismic anisotropy contradicts the effects of the present stress field. It is likely the results of aligned mineral crystals caused by the flow of mass in the mantle during the opening up of the Panxi rift through Paleozoic to Mesozoic.
出处
《地震研究》
CSCD
北大核心
1995年第3期227-236,共10页
Journal of Seismological Research
