与汶川地震可能相关的震磁效应——几个地磁站地磁Z分量小波变换后的“日变幅差”特征

Possible seismo-magnetic effect of the Wenchuan earthquake:Characteristics of “difference in daily amplitude ” derived from the wavelet transform for the Z-components in geomagnetic observatories

利用"日变幅差"方法,分析了汶川8.0级地震前泾阳、连云港、新沂地磁台地磁垂直分量小波变换后的"日变幅差"特征。结果表明,汶川8.0级地震前,泾阳与连云港和新沂台间的"日变幅差"ΔT_g(24)存在异常变化,异常出现时间都是震前150天和25天,新沂与连云港的"日变幅差"无异常。说明汶川8.0级的震磁效应,很可能在700 km内产生影响,但其影响范围尚无法达到1 500 km。表明小波分析可能是提取地震磁异常的一种有效方法。

In this paper,we use the geomagnetic analysis“The difference in daily amplitude”method to analyze the characteristics of“The difference in daily amplitude”based on the wavelet analysis of geomagnetic observatories in Jingyang,Lianyungang and Xinyi before the Wenchuan earthquake.The results show that there is anomalous variation of“The difference in daily amplitude”ΔTg(24)before the Wenchuan M8.0 earthquake and the time of the anomalous variation is 150 days and 25 days before the earthquake,although there is no such variation between Xinyi and Lianyungang.This indicates the Wenchuan 8.0 sesimo-magnetic effect is likely to have an effect within 700 km,but its suffering area is not able to reach 1 500 km.The results show that wavelet analysis is an effective method to extract seismic magnetic effect.