文安地震前后的转换函数参数变化分析

Dependence of transfer function parameters on time before and after Wenan earthquake

为了提取地震前后的磁场异常变化,本文用转换函数方法分析了文安地震前后,距离震中分别为52km和298km的静海地磁台和泰安地磁台不同周期的转换函数参数随时间的变化过程,发现静海地磁台转换函数参数的数据异常点随着时间的向后推移从短周期向比较长的周期迁移,而泰安地磁台的转换函数参数没有出现类似现象。

In order to find the geomagnetic precursors before earthquakes, the dependence of transfer function parameters on time before and after Wenan earthquake is analyzed. The used geomagnetic data are recorded by Jinghai Observatory and Taian Observatory, which is 52 km and 298 km away from the epicenter of Wenan earthquake, respectively. The result derived from Jinghai Observatory shows that the anomalous values （especially the peak σz value） appeared first in variance of higher frequencies, and then in those of lower frequencies. However, the similar phenomenon has not been found from the result derived from Taian Observatory.