新疆和静5.6级地震前波速比异常震例分析

Case analysis of wave velocities ratio abnormity before Hejing M5. 6 earthquake in Xinjiang

摘要:

利用新疆天山中段数字化地震波资料,采用多台和达法,计算了2008年8月30日和静5.6级地震前后波速比资料的变化情况。得到如下结果:①空间分布上,和静5.6级地震前,形成一个椭圆形低值异常区,且椭圆长半轴约70km,短半轴约65km,椭圆走向NE,和静5.6级地震则发生在该椭圆区域的西偏北部边缘; ②时间进程上,和静5.6级地震前出现大约10个月的波速比低值异常,震前一个月出现明显的高值突跳点,波速比形成正常-降低-高值突跳-发震的模式。计算过程中,波速比误差控制在0.05之内,相关系数达99.0%以上。

Abstract:

The authors used digital wave data of earthquakes in the middle of Tianshan mountains，Xinjiang and Heda method of multi-stations to calculate changes of wave velocities ratio before and after the Hejing M5. 6 earthquake on August 30，2008． They obtained the result as follows: ①In space，it forms a low value area of ellipse before the Hejing earthquake with M5. 6． The half of the long axis is approximately 70km，while that of the short axis is approximately 65km． And the trend of the ellipse is NE． The Hejing M5. 6 earthquake occurred in northwest part of the ellipse． ②Temporarily，it appeared as low value abnormity of 10 months before the Hejing M5. 6 earthquake． Before this earthquake，the value was obviously high． It forms a model of normal-fall-high value-earthquake． In the calculation process，the error of wave velocities ratio is controlled in less than 0. 05， and the correlation coefficient reached above 99. 0%．