A study of earthquake inter-occurrence times distribution models in Taiwan

Statistical studies on earthquake recurrence time probabilities have frequently been applied to seismic hazard analyses. In Taiwan, an instrumental catalog provides a good opportunity to examine statistical attributes of earthquakes around the study region, with the objective to evaluate the seismic risk and earthquake potential for hazard mitigation. With the completeness of recordings, seismic rates for small-to-moderate magnitudes can be obtained. An elimination of aftershocks was performed using a double-link cluster analysis method. The time intervals between a series of events (the inter-occurrence periods) are stationary with an identical temporal distribution. Based on the goodness-of-fit testing between a few models and observation, we suggested the use of the Gamma distribution in modeling this variable, earthquake inter-occurrence periods, for the study region. Accordingly, unified relationship was constructed, and statistical limitations of sparse sampling for devastating earthquakes (such as M ≥ 6.0 or 7.0) could be resolved. The empirical result evaluated by introducing the conditional probability indicates that the recurrence probability of a M ≥ 7.0 earthquake is 78.8 % within 10 years in Taiwan region.