2008年10月5日乌恰6．9级地震背景性异常

分析总结了2008年10月5日乌恰6．9级地震前背景性异常：1900～2008年新疆6．8级以上地震时空分布表明，于田7．4级地震发生后新疆仍缺少一次6．8级以上地震：2004年12月以来新疆3．5级以上地震累积频次持续低值；乌恰地区6级地震超常平静：2003年以来在乌恰地区形成4级地震空区；2006年以来新疆相继形成2条4级地震条带相交于乌恰地区：2006年1月至2008年7月乌恰台地震波振幅比大范围低值；2007年4月至2008年2月．沿卡兹特阿尔特断裂出现2次符合预报指标的异常增强现象：2008年2月以来喀什台地磁垂直分量拟合差值持续低值；2006年9月以来莎车台土层应力2道测值先后出现偏离正常年变现象．

Background Anomaly of Wuqia Ms6.9 Earthquake Occurred on Oct. 5, 2008

The background anomalies of Wuqia Ms6.9 earthquake occurred on Oct. 5, 2008 were analyzed in this paper, including： the space-time distribution of earthquakes with Ms ≥6.8 from 1900 to 2008 in Xinjiang shows that there is a lack of Ms6.8 earthquake after Yutian MsT.4 earthquake in Xinjiang; the accumulation frequency of earthquakes with Ms≥3.5 continued to be low; Ms6.0 earthquakes is anomaly quiescent in Wuqia region; Ms4.0 seismic gap has come into being in Wuqia region since 2003, while two Ms4.0 seismic belts in Xinjiang has come into being and intersecting in Wuqia region since 2006; the amplitude ratios of seismic wave of Wuqia seismic station show low values in a large range from Jan. 2006 to Jul. 2008; the abnormal phenomenon of seismic activity appeared two times in Kenzitearte fault; the error values of fitted line of vertical geomagnetic component of Kashi station show low values since Feb. 2008; the values of two channels of soil stress in Shache station have successively departed from the annual change value since Sep. 2006.