华北地区跨断层形变中短期异常特征研究

较系统处理了华北地区跨断层形变资料 ,对 1975年以来华北地区发生的部分强震、中强震震前出现的跨断层形变异常特征进行了分析 ,着重研究了其中短期预报指标及区域特征。跨断层形变主要异常特征为 :(1)异常出现具有同步或准同步性 ;(2 )异常形态各异 ;有趋势异常、年畸变异常、突变异常 ;(3)异常相对变化幅度以水平变化量为大 ;(4 )异常出现时间、幅度与震中距有一定关系 ;(5)强震前异常多出现在震前半年以上 ;(6 )异常初期地面倾斜背向震中 ,地面倾向震中即预示着进入短临阶段。同时对中短期预报指标做了初步归纳。

STUDY ON ANOMALOUS CHARACTERISTICS OF SHORT-MEDIUM TERM OF CROSS FAULT DEFORMATION IN NORTH CHINA

Based on the cross fault deformation data of north China, the anomalous characteristics of cross fault deformation prior to a part of strong and moderate earthquakes in north China since 1975 are analysed. It is focus to be taken the short medium term prediction index and region characteristics. The main anomalous characteristics of cross fault deformation are (1) synchronism; (2) various morphology, like tendance anomaly, annual distortion one and abrupt change one; (3) horizontal component as main relative anomalous change amplitude; (4) the time, amplitude of anomalous appearance related to epicentre distance; (5) anomalous appearance often over half year before a strong earthquake; (6) at anomalous start, ground tilt departed from epicentre, at imminent short phas, one toward epicentre. The short medium prediction indes are reduced.