2008年10月5日乌恰6.9级地震短临异常研究

SHORT-TERM ABNORMITY BEFORE WUQIA M_S6.9 EARTHQUAKE ON OCT.5,2008

对2008年10月5日乌恰6.9级地震前短临异常特征进行了分析总结。强震前短临前兆特征为:①在空区内发生标志地震后围空区附近断裂发生预警地震;②与背景性条带相交出现前兆性小震条带;③地震波低值区出现高值回返;④地震活动异常增强—前兆性平静基础上出现短期增强及新疆大范围地震活动增强;⑤地磁垂直分量低值回返。

The short-term abnormities before Wuqia MS6.9 earthquake occurred on oct.5,2008 were analyzed.The short-term abnormal characteristics before strong earthquakes： the warning earthquake occurred on the fault near the seismic gap after the symbol earthquake occurred in the seismic gap;the precursor small earthquakes belt intersect the background belt;low value of the amplitude ratio return high value;seismic activity show short-term activity based on anomalous activity of seismic activity-precursor quietude and activity in Xinjiang region;change of speed and direction of ground tilt;vertical direction of geomagnetism return form low value.