2008年汶川Ms8.0地震前定点形变高频异常特征的研究  

High-Frequency Anormaly Characteristics of Fixed-point Deformation before the 2008 Wenchuan M_S8.0 Earthquake

作　　者：武善艺 刘琦[2] 龚丽文 张治广[4] WU Shan-yi;LIU Qi;GONG Li-wen;ZHANG Zhi-guang(Earthquake Administration of Gansu Province, Lanzhou 730000, China;Institute of Earthquake Science, CEA, Beijing 100036, China;Earthquake Administration of Chongqing, Chongqing 401147, China;Earthquake Administration of Xinjiang Uygur Autonomous Region, Urumqi 830011, China)

机构地区：[1]甘肃省地震局,甘肃兰州730000 [2]中国地震局地震预测研究所,北京100036 [3]重庆市地震局,重庆401147 [4]新疆维吾尔自治区地震局,新疆乌鲁木齐830011

出　　处：《地震》2018年第2期145-156,共12页Earthquake

基　　金：甘肃省地震局科技发展基金(2016Y02); 中国地震局震情跟踪重点任务(2016030507);中国地震局震情跟踪青年任务(2017010226)

摘　　要：本文以中国大陆西部定点形变观测资料作为研究对象,采用S变换和超限率时频分析法对其进行了处理和分析。研究结果表明:在2008年汶川MS8.0地震前,距离震中600km范围内的定点形变个别台站观测到高频异常,异常持续时间较长;距离震中300km范围的个别台站临震高频异常非常显著;并且不同的定点形变观测手段对高频信号的响应不同,地倾斜测项临震前高频异常形态较地应变测项更为清晰灵敏。同时S变换和超限率两种方法处理结果具有较好的一致性,表明本文提取到的高频异常可信度较高。In this article,the fixed point deformation data of the west Chinese mainland had been analyzed by the analytical method of S transformation and overrun rate.The results show that abnormal signals with high frequency had been observed by some fixed-point deformation stations in the area of 600 km from the epicenter before the 2008 Wenchuan MS8.0 earthquake and had lasted a longer time.The short-term and impending highfrequency anomalies are obvious in the area 300 km from the epicenter.In addition,the responses to high-frequency signals are not the same for different fixed-point derformation approach.Usually,high-frequency anomaly patterns of ground tilt are more sensitive and clear than crustal strain.Meanwhile,the results of S transformation and overrun rate analyses have good consistency,which indicates the reliablity of the extracted high-frequency anomaly.

关 键 词：定点形变 高频异常 S变换 2008年汶川MS8.0地震 

分 类 号：P315.7[天文地球—地震学]