大同—阳高震群多波分析及震群特征：—CDSN应用系列论文五

本文应用多波震相分析法,对1989年10月18日大同震群进行研究。使用模拟和数字台网资料,对主、余震群进行了多波分析处理。初步探讨了主震群的震源机制解及其与地质构造的关系;用sPn、P_M、S_M 等震相较准确的测定了震源深度及震群深度变化范围;通过震相、波形和振幅比的综合分析,清晰的显示大同-阳高震群具有两种震源类型特征,其中用(M)界面反射波 P_M、S_M 的振幅比,做出的大同-阳高地震序列时空域图象更为明显。本文初步研究表明,多波震相分析法,对较准确的测定主余震群的震源深度,推测震源延伸的走向,初步判断震源机制的变化及有可能为单台开展监测预报探索到一种新的途径。

THE MULTIWAVE ANALYSIS AND SEISMIC GROUP CHARACTER OF THE DATONG-YANGGAO SEISMIC GROUP

This article studied the Datong seismic group of October 18,1989;the mainshock and aftershocke were deal with by multiwave phase analysis using analogue and digital network data, we preliminarily studied the focal mechanisms of the mainshock group and their relationship with the geologic structure and accurately determined the depths of seismic focus and the range of depths of the seismic group; by using comprehensive analysis of phase waveforms and amplitude ratio of sPn, P_M, S_M etc;it was clearly shown that the Datong and Yanggao seismic group had two types of characters of seismic focus, among them, the time-space domain pattern of Datong-Yanggao seismic sequence obtained by using the amplitude ratio of P_M, S_M wave reflected at the Moho-discontinuity showed this distinctly.The preliminary study indicated that multiwave phase analysis proved to be a new method to determinate the focus depths of the mainshock and aftershock group acurately, to guess the strike of focus, to ascertain preliminarily the change of focal mechanism primarily and for the monitoring and prediction of earthquakes with a single station.