Seismic Risk Analysis Based on Strain Energy Accumulation in Focal Region

The object of this paper is to propose a stochastic method for evaluating the magnitude of future earthquakes taking account of nonstationarity in earthquake occurrence. For this purpose, the strain energy accumulation in the focal region was estimated by means of the earthquake data of the past 100 years in Japan. Furthermore, the distributions of maximum ground acceleration were derived by means of the attenuation law. As a result, we found that the distributions of maximum ground acceleration fit the type III extreme value distributions and that the expected values of those distributions depend on the strain energy accumulation significantly. Finally, it is pointed out that the nonstationarity in earthquake occurrence should be taken into consideration in order to evaluate the earthquake load in design.