澜沧-耿马地震的S波偏振及P波、S波振幅比变化特征  

S-WAVE POLARIZATION AND VARIATION CHARACTERISTICS OF AMPLITUDE RATIO OF P-AND S-WAVES FOR THE LANCANG-GENGMA EARTHQUAKE

作　　者：杨桂芬[1] 

机构地区：[1]云南省地震局

出　　处：《西北地震学报》1991年第3期38-44,共7页Northwestern Seismological Journal

摘　　要：本文通过对1988年11月6日云南澜沧—耿马7.6、7.2级强震前后S波偏振角的计算分析,得出大震前后U_(SH)—U_(Sv)的三种变化图象,这种变化特征具有一定的前兆意义。与此同时,对大震前后P波、S波最大振幅比值分布和S波偏振角空间分布进行研究发现,北纬22°57′可能是澜沧、耿马两地区介质差异的分界面。Three variation patterns of U_(SH)—U_(SV) of the Nov. 6,1988, Lancang-Gengma earthquakes(M=7.6, 7.2)have been obtained through calculating and analysing the S-wave polarization angles before and after the earthquakes. The variation characteristics possess precursory meaning. Study on the distribution of maximum amplitude ratio of P-and Swaves and spatial distribution of S-wave polarization angles before and after the earthquakes shows the line of 22°57′north latitude may be the medium boundary between Lancang and Gengma areas.

关 键 词：地震 澜沧-耿马 S波 P波 振幅比 

分 类 号：P315.3[天文地球—地震学]