RELATIONSHIP BETWEEN SHORT PERIOD VARIATION ANOMALIES OF GEOMAGNETISM AT JINGHAI STATION AND EARTHQUAKES OCCURRED NEAR IT

The research result in recent years show that the electric property structure changes of subsurface medium in seismogenic zone before earthquakes will result in anomalous variation of short period transfer characteristic of geomagnetism. This paper, by calculation of short period transtfer characteristic of geomagnetism at Jinghai station before and after the1991 Tangshan M5. 2 and M5. 6 earthquakes and by analysis of its result, has proposed a reliable short term and imminent seismic precursory information and determined the short term and imminent anomalous characteristics and index for the prediction of earthquakes of M≥5 in Tangshan region.