Characteristics of Seismic Sequence and Early Tendency Judgment for Yutian M_S7. 3 Earthquake in 2014

The basic parameters,seismogenic structure and seismic sequences characteristic of Yutian MS7. 3 earthquake on Feb. 12,2014 are introduced,and are compared with Yutian MS7. 3 earthquake in 2008. The results showthat the MS5. 4 earthquake is regarded as an immediate foreshock of Yutian MS7. 3 main shock. The frequency of strong aftershock sequences was lowand the number of them declined quickly,the maximum aftershock is MS5. 7 earthquake. According to analyzing the historical earthquake sequence type,and parameter of hvalue,b-value and energy release ratio between main shock and sequence etc.,we got the preliminary conclusion which is the type of Yutian MS7. 3 earthquake sequence in 2014 belongs to foreshock-main shock-aftershock type.