THE SUDDEN CHANGE OF EARTH RESISTIVITY JUST PRIOR TO THE 1983 HEZE EARTHQUAKE OF M 5.9
Jin Anzhong Li Runxian Wu Longmao Wang Ruitian Li Yanzhu Jin Xiangqian (Seismological Bureau of Shandong Province)
The Heze Earthquake (Ms =5.9) occured in Shandong Province on November 7, 1983. Heze earth resistivity station situates at the distance of 14 km from the epicenter. It recorded the sudden increase of the resistivity just prior to the earthquake. The measuring system was carefully examined 2 days before and immediately after the earthquake, the data are believed to be right. The amplitude of the variation before the earthquake is about 2% and equals 6 times that of the square root error. The change of reading made immediately after the earthquake was 4%, it is 13 times over that for the square root error. The beginning of the sudden variation took place at 30 hours before the Heze earthquake. The reading basically recovered its normal value 3 hours later after the earthquake.The vibrating string earth strainmeter at Hui Xian, Henan Province which is about 153 km to the epicenter varies synchronistically in the same manner like the resistivity.