RELOCATION OF THE EPICENTRE BEFORE AND AFTER WENCHUAN MS 8.0 EARTHQUAKE

The crustal thickness and velocity structure in both sides of Longmenshan fault zone are very different,so in the past using a single uniform velocity model was not appropriate positioning method,Hypo2000 locator epicenter located in different regions of the partition layer corresponds to come to non-uniform velocity model.In this paper,Hypo2000 locator for 187 seismic Network records before and after Wenchuan 8.0 earthquake 10 years are sorted and filtered.Draw the epicenter distribution shows the earthquake was not too much in the north of Longmenshan fault zone including the north of Beichuan before earthquakes,mainly still active in Yingxiu south area,and 8.0 magnitude earthquake happened in this region.After the earthquake Longmen mountains to the north along the fault zone to the north of Beichuan appeared more aftershocks.From the depth profile of aftershocks Longmen mountains,it shows that southern aftershocks belts has the characteristics of fault zone steep slowly shovel form fracture form,but in the north of the aftershocks belt,it has almost vertical steep loose broken structure,and the surface of the broken in both sides are corresponded to the aftershocks distribution.