ABSTRACT

The response to loading is different from that to unloading when the focal media is damaged since damage is an irreversible. The ratio of response rale during loading to that during unloading, called Load/Unload Response Ratio Y (LURR), could be a measure of the damage degree and closeness degree to instability and is used in a new approach to earthquake prediction. Retrospective examination of some hundred earthquake cases (from M4to M8.6) indicates that for more than 80% of the examined ones, the value of Y is much higher than 1 for a period before the mainshock, but the Y value always fluctuates slightly about 1 during two decades for seven stable regions, so that the parameter Y could indicate a dangerous degree of an impending earthquake. More than ten earthquakes occurring in the Chinese mainland in recent years as well as the Northridge Califonia,USA earthquake (Jaa 17, 1994, M w6.7) and Kanton earthquake (Japan,Sep. 11, 1996, Ms6.6) have been predicted beforehand with this method.