Comprehensive index analyses on seismic activity parameters based on data mining for M_S≥5.0 earthquakes in northeast China and North China

According to the data characteristics of seismic activity parameters, taking the M_S5.3 Horqin, Inner Mongolia earthquake in 2013 for a typical case, the present paper introduces principal component analysis method and factor analysis method to reduce the dimension of parameter variables on the condition of information loss as little as possible, and extracts the comprehensive index. The result shows that the comprehensive index W had been changed significantly two years before the earthquake. Furthermore, by conducting factor analysis on Horqin earthquake, several single factor comprehensive indices with physical meanings are extracted, not only eliminating the inconsistency caused by the overlapping of information, but also achieving the refinement of the comprehensive index. In further research, the principal component analysis result about the eleven seismic activity parameters (N, b, η, A(b), M_f, AC, C, D, E, R_m, Y) of 29 earthquakes with M_S≥5.0 in northeast China and North China shows that comprehensive index W of principal component analysis had obvious precursor changes in 1-2 years before the earthquakes. This suggests that the index W can be taken as a precursory in earthquake prediction research.