2013年3月3日洱源M_(S)5.5地震前地磁转换函数异常研究  

Geomagnetic transform function anomaly before the M_(S)5.5 Eryuan earthquake on March 3,2013

作　　者：杨杰 李琪[1] 袁伊人 Yang Jie;Li Qi;Yuan Yiren(Institute of Geophysics,China Earthquake Administration,Beijing 100081,China)

机构地区：[1]中国地震局地球物理研究所,中国北京100081

出　　处：《地震学报》2021年第2期215-226,I0002,共13页Acta Seismologica Sinica

基　　金：国家重点研发计划(2018YFC1503806);国家自然科学基金(41774085)联合资助。

摘　　要：利用有界影响估计地磁转换函数,分析了2013年3月3日云南洱源M_(S)5.5地震前后滇西北地磁台阵各测点的地磁转换函数及地磁实感应矢量变化特征。结果显示,震前1-2个月云龙测点和洱源测点多个周期的转换函数实部绝对值存在变大-转折-恢复的过程,异常变化幅值超过1倍标准差,其余震中距较大或距离余震区较远的测点震前转换函数无明显异常变化。该结果表明洱源M_(S)5.5地震前地磁转换函数异常范围小于50 km,可能与余震区空间分布有关。The geomagnetic transform function represents the lateral inhomogeneity which could be used to study the changes of the underground electricity structure during the seismogenic process.In this study,the geomagnetic transform function and variation characteristics of geomagnetic induction vector for each measuring point of the geomagnetic array in northwestern Yunnan Province before and after the Eryuan M_(S)5.5 earthquake on March 3,2013 are analyzed by using the bounded influence estimation geomagnetic transform function.The results show that the absolute values of the real part of the transform function for Yunlong station and Eryuan station undergo a process of increase,turn and recover in more than one period during1-2 months before the earthquake.The amplitude of the abnormal change is more than one time of the standard deviation.Before the earthquake,there is no obvious abnormal change in the transform function of the other measuring points which are far away from the epicenter or the aftershock area.The results show that the abnormal range of the geomagnetic transfer function before the Eryuan M_(S)5.5 earthquake is less than 50 km,which may be related to the spatial distribution of the aftershock area.

关 键 词：地磁转换函数 有界影响估计 地磁台阵 震例分析 

分 类 号：P315.721[天文地球—地震学]