Probability forecast of earthquake magnitude in Chinese mainland before A.D. 2005

Abstract

A probability forecast method of earthquake magnitude, based on the earthquake frequency-magnitude relation and the model of Bernoulli’s random independent trial, is applied to the earthquake risk assessment of seismic zones in mainland China before A. D. 2005 in the paper. The forecasting results indicate that the probabilities of earthquake occurrence with magnitude 5 in seismic zones before 2005 are estimated to be over 0.7 in common and 0.8 in most zones; and from 0.5 to 0.7 withM = 6; the maximum probability of earthquake occurrence with magnitude 7 is estimated at 0.858, which is also expected in Shanxi seismic zone. In west mainland China, earthquakes with magnitude 6 are expected to occur in most seismic zones with high probability (over 0.9 in general); the relatively high probabilities of earthquake occurrence (more than 0.7) with magnitude 7 are expected in the seismic zones surrounding the Qinghai-Tibet plateau and south Tianshan seismic zone. A discussion about the result confidence and the relationship between the estimated probability and the possible annual rate of earthquake occurrence is made in the last part of the paper.