一、引言我们曾研究过短期地磁扰动△Z/△H在唐山地震和隆尧地震前后的异常变化。现在进一步研究包括菏泽5.9级地震在内的华北三次地震前后地磁短周期转换函数随时间变化情况,以便更广泛地考察不同地区和不同类型地震之前异常变化特征。地磁短周期是指磁暴急始、瞬时扰动及湾扰等,这些磁扰的幅度在三个分量Z、H、D之间有如下经验关系: I. INTRODUCTION We have studied the anomalous change of short-term geomagnetic disturbance △ Z / △ H before and after Tangshan earthquake and Longyao earthquake. We will now further study the temporal variation of the geomagnetic short-period transfer function before and after the three major earthquakes in North China, including the Heze M5.9 earthquake, in order to examine the characteristics of anomalous changes in different regions and before different types of earthquakes more extensively. Geomagnetic short cycle refers to the beginning of a geomagnetic storm, transient disturbance and bay disturbance, the magnitude of these magnetic interference in the three components Z, H, D have the following empirical relationship between: