Abstract: Based on the earthquake data around the epicenter before the Jiujiang earthquake with M_S5.7 occurred on Nov. 26, 2005 in Jiangxi province, the factor analysis method is applied to select the seismicity parameters of earthquake frequency N(M_L≥3.0), b-value, η-value, A(b)-value, Mf-value, Ac-value, C-value and D-value that reflect seismicity characteristics of time, space and magnitude in this paper. There is a certain correlation among these parameters. The variation of these parameters is different, and the anomaly of many parameters is not obvious before Jiujiang earthquake. The synthetic parameter W_fa-value reflected the seismicity characteristics of time, space and magnitude shows obvious anomaly. It shows that the synthetic parameter W_fa-value can reflect anomaly characteristics of seismicity. The other problems of the factor analysis method and conclusion are discussed in this paper.

Key words: Factor analysis, Eigenvector, Contribution rate, Seismicity.