DISCUSSION ON THE "INDEX" OF EARTH RESISTIVITY METHOD FOR STRONG AND MODERATELY STRONG EARTHQUAKE PREDICTION
Wang Zhiliang Zhao Chengda Wang Guoqing(Center for Analysis and Prediction, State Seismological Bureau)
The differences of the earih resistivity anomaly prior to the seven strong earthquakes with M = 7 published nationwide and the four moderately strong seismicity periods after the Tangshan M7.8 earthquake in North China (32°-41°N, 111°-122°E), since the establishment of the earth resistivity stations 1967, have been analyzed in this paper. Results show that the earth resistivity prediction indexes used are different in predicting strong earthquakes-with M7 and moderately strong earthquakes. Strong earthquakes can be predicted using the regional variation of the anomalous resistivity radius 200-500 km, anomalous time 12-14 mpnths, amplitude (2.1-3.0) percent and so on; these features' of resistivity variations during moderately strong earthquakes are not clear and they are hardly recognized. Therefore, moderately strong earthquakes can be predicted only by combining closely the seismicity features and using some "sensitive points" of the earth resistivity.