THE TIME AND SPACE DYNAMIC EVOLUTION OF THREE SEISMICITY PARAMETERS BEFORE AND AFTER THE HEZE M5.9 EARTHQUAKE

By computer scanning technique of two-dimensional space isogram of seismicity parameters (seismic frequency N, seismic energy E and b-value), we systematically traced the space dynamic evolution process of three seismicity parameters before and after the 1983 Heze M5.9 earthquake. The result shows that before the Heze M5.9 earthquake in the southern region of Hebei Plain fault and especially in Liaokao fault zone on its east boundary, the seismic activity exceedinyly increased, seismic frequency raised, seismic energy release accelerated and b-value decreased; the length of the region where seismic activity increased is more than 200km, the coming major earthquake occurred on the margin of theseismic activity increased region about one year after the earthquake, the seismic activity arround the epicenter turned to normal. The above variation of two-dimensional isogram of seismicity parameters clearly shows the whole space evolution process of the seismic activity around the epicenter before and after the 1983 Heze M5.9 earthquake, this contributes to extraction of near-field anomalous information during earthquake preparation and to dynamic monitoring and then can trace the source developing process of strong earthquakes.