Probability of earthquake occurrence in Greece with special reference to the VAN predictions

Abstract

The VAN earthquake predictions were made on the basis of seismic electric signals (SES), but the debate seems to be directed toward the statistical significance of the predictions from seismic data only. Accordingly, applying a logistic regression model to seismicity, we present our estimation of the probability of earthquake occurrence in Greece. The main purpose of our study is to examine whether or not we can find a specific seismicity pattern that can be used to considerably increase probability estimates. Our estimation of the probability of occurrence of an earthquake of Ms ≥ 5.0 is less than 0.25 in all the cases that we have examined. If we lower the threshold magnitude from 5.0 to 4.3, we can find cases in which the probability becomes as high as 0.75, comparable to the success rate of the VAN method estimated by Hamada [1993]. In these cases, however, such a high probability is due mostly to aftershocks, and if aftershocks are removed from the data set, the probability falls below 0.5.