基于阿尔法导航系统记录分析2010年玉树M_(S)7.1地震异常

Anomaly analysis of Yushu M_(S)7.1 earthquake in 2010 based on the records of Alpha Navigation System

地震灾害是人类面临的重大考验,阿尔法导航系统在地震预报领域有着重要的科研及应用价值。以2010年4月13日23时49分(世界时)玉树M_(S)7.1地震为例,基于2010年4月6日—13日阿尔法导航系统超低频(VLF)电波场强和相位数据,使用滑动四分位法,分析该系统9条链路上的信号异常,结合地磁“低点位移”现象,综合分析此次地震前的异常变化。研究结果表明:在地磁活动平静时段,玉树M_(S)7.1震前3天及震前23 h,电波场强数据出现明显畸变,表现为持续1—6 h超阈值的异常扰动,最大扰动幅度超过阈值13.6μV/m,相位数据未出现明显异常。结合震前3天阿尔法导航系统主台—通海台、西副台—雅安台异常链路以及震前47天地磁“低点位移”分界线的重叠位置,可进一步精确临震预报时刻,并提高发震位置的预测精度。

Earthquake disaster is a major test for human beings all the time and the Alpha Navigation System plays an important role in scientific research and application value of earthquake prediction.Taking the Yushu M_(S)7.1 earthquake as an example,based on the field strength and phase of the VLF radio wave from April 6 to 13,2010,the signal anomalies on 9 links of the system are analyzed by using the sliding inter quartile range method,and the abnormal changes before the earthquake are comprehensively analyzed in combination with the geomagnetic low-point displacement.The results indicate that there is an obvious distortion in field strength 3 days before and 23 hours before the earthquake respectively during the quiet period of geomagnetic activities.The abnormal disturbance exceeds the threshold for 1-6 hours and the maximum amplitude of disturbance exceeds the threshold by 13.6μV/m,but the phase reflects no anomaly.Combined with the overlap among the two anomalies links 3 days before the earthquake and the boundary of geomagnetic low-point displacement 47 days before the earthquake,the prediction accuracy of time and location of impending earthquake prediction can be further improved.