美国西部地区加卸载响应比的时空演化及地震活动性分析  

Study on the Tempo-spatial Evolution of LURR and Seismicity in Western America

作　　者：张浪平[1,2] 尹祥础[1,3] 梁乃刚[1] 

机构地区：[1]中国科学院力学研究所非线性力学国家重点实验室,北京100190 [2]中国科学院研究生院,北京100190 [3]中国地震局地震预测研究所,北京100036

出　　处：《地震》2008年第4期29-38,共10页Earthquake

基　　金：国家973项目(2004CB418406);国家自然科学基金项目(10721202,10572140)

摘　　要：美国西部地区位于环太平洋地震带,该地震带是地球上地震活动最为强烈的地带,为了研究该地区的地震活动性,对该地区进行了加卸载响应比的时空扫描,考察了该地区加卸载响应比异常区域的时空演化;并用2001—2006年的扫描结果与次年实际发生的5级以上地震进行对比,发现绝大部分的强震都发生在前一年的预测区域内。根据加卸载响应比的时空演化和该地区的最新扫描结果,对未来地震活动性进行了分析。The seismogenic process of a major earthquake is rather complicated.From the viewpoint of mechanics or physics,the essence of an earthquake is the damage,instability or failure of the focal media accompanied by a rapid release of energy.A new parameter-Load/Unload Response Ratio（LURR） has been proposed as a measure of this process.Using LURR as a precursor in earthquake prediction,retrospective examination of over hundred earthquake cases has been carried out,and more than 80% of the examined ones are well in agreement with that the peak of LURR,which appeared before the main shock and the peak value is much higher than 1.By the way,in the latest 4 years（2003—2006）,the earthquake prediction with LURR method is satisfied,which was conducted in Chinese mainland at the end of every year.The western United States lies on the Circum-Pacific zone,the most active seismic zone in the globe.In order to study the seismicity in western America,the spatial scanning of Load/Unload Response Ration in western America（30～50°N,100～125°W） has been conducted and the evolution of the LURR anomalous region has been investigated.The comparisons of the LURR anomalous regions in 2001—2006 with the actual M≥5.0 earthquakes are performed respectively,which shows that 18 earthquakes with M≥5.0 occurred in LURR anomalous regions while 19 earthquakes with M≥5.0 in LURR regions in total when the scanning radius R=100 km and 20 earthquakes in LURR anomalous regions while 21 earthquakes in LURR regions when R=200 km.The statistical results show that LURR is a good precursor in earthquake prediction.In order to analyze the seismicity in western America,the evolvement of the anomalous LURR regions is investigated.According to the evolution（figure 3 in the paper）,some analyses have been carried out as below：（1） In the rectangle zone of 45°N～49°N,120°W～124°W,anomaly appears in Figure 3a,and keeps increasing,stays in high value during（g） to（m）,decreases from（o） to（p）,while there is no ear

关 键 词：加卸载响应比(LURR) 时空扫描 地震活动性 美国西部地区 

分 类 号：P315.7[天文地球—地震学]