Distribution and Temporal Evaluation Characteristic of Cangyuan M_S5.5 Earthquake Sequences in Yunnan in 2015

Using waveform data from seismic network of Yunnan province and their corresponding observation report,combined with the tectonic background and historical seismicity,we discussed seismogenic structure and the distribution and temporal evaluation variation of Cangyuan MS5. 5 earthquake sequence in Yunnan on M ar. 1,2015 from the activity characteristics and parameters of the sequence,the focal mechanism solutions of larger events as well as the accurate relocation of the sequence etc.. Referring to the focal mechanism solutions and the tectonics in epicenter area,we indicated that the seismogenic structure of Cangyuan earthquake is the west branch of Nantinghe Fault which appearred to be a right-lateral strike-slip faulting. It is showed that the seismicity of aftershock sequences remain low,decayed rapidly with time and appeared the obvious phased. The spatial distribution of the sequences which were relocated by the double-difference relocation algorithm showed that the main rupture area was a zonal area of NNEin approximately vertical direction. It seemed to be a unilateral rupture,furthermore,the distribution of the later aftershocks showed the scatter trend to the shallower and outer region of the epicenter.