大同—阳高6.1级地震断层位移测量前兆异常特征

PRECURSORY ANOMALIES OF FAULT DISPLACEMENT MEASUREMENTS BEFORE THE DATONG-YANGGAO M_S6.1 EARTHQUAKE

大同—阳高6.1级地震前,1987年以来断层位移出现了趋势性的中期异常,1989年5月以后出现了短期异常。资料分析表明,断裂以水平活动为主。在空间上,远离震中的台点为较清晰的中期和短期异常,并具有相同的活动方式;近震中的台点显示为中期异常。文章最后还分析了断裂活动与应力状态的关系。

Before the Datong-Yanggao Ms 6.1 earthquake, the fault displacement measurements had shown a medium-term anomaly tendency since 1987, and a short-term anomaly appeared since May, 1989. The anomalies were dominated by horizontal fault activity. In spacial distribution, both med-term and short-term anomalies appeared clearly at measuring sites where fault moving in the same style and far from the epicenter, while only med-term anomaly, or, even no anomaly appeared at those sites close to the epicenter. These anomalous activities of faults might be related with the regional stress state.