云南地区地震序列早期地震波动力学特征

研究了云南地区各类型地震序列的早期地震波动力学特征——地震波垂直分量P波初动和P、S波最大振幅比,结果表明:前震序列振幅比为过原点的直线,比值稳定,P波初动一致;双震型地震序列在第一主震后P波初动出现一组时,仍有一类波形(“大头波”或“小头波”)的振幅比保持为过原点的直线,第一主震后P波初动出现两组时,仍有初动相同的一组地震振幅比保持为过原点的直线,或者两组初动的地震振幅比分别、共同成过原点的直线;主余震地震序列在非大震孕育期间,地震振幅比离散,与大震孕育有关的主余震地震序列振幅比仍可为过原点的直线。地震波动力学特征在上述三类地震序列的早期判断能力分别为75％、55％—73％、90％。

THE EARLY DYNAMICAL CHARACTERISTICS OF SEISMIC WAVE OF EARTHQUAKE SEQUENCES IN YUNNAN REGION

In this paper, the early dynamical characteristics of seismic wave of earthquake sequences in Yunnan Region, the first motion of P-wave and amplitude ratio of P- and S-waves of vertical component have been studies. The results show that amplitude ratio of foreshock sequences is a straight line through the origin, the ratio value remains stable and the first motion of P-wave is identical; For double event sequences, when the first motion of P-wave is identical after first main earthquake, the amplitude ratio of a group of waves form ( AP > As or As > AP ) still keeps a straight line; When the first motion shows two groups, the amplitude ratio which has same first motion is a stright line or the amplitude ratio consists two different stright lines or only one stright line; During the strong earthquake preparation the amplitude ratio of the main-after shock sequences is a stright line throngh the origin and others are scattered. The early-stage judgement capability as dynamical characteristics of seismic wave are 75%, 55%-73%, 90% respectively for three types of earthquake sequences.