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摘要
On August 8th, an M(s)7. 0 strong earthquake occurred in Jiuzhaigou, Sichuan province. We utilized the high precision relocation method, hypoRelocate, which has good constraints on both absolute location and relative location, to relocate 854 aftershocks that are larger than M(L)1. 5 and recorded before August 15th. In relocation, we used 6178 Pg travel times, 3363 Sg travel times, 16365 differential travel times and 74 SH coda cross-correlogram travel times of 34 events that are larger than M(L)3. 5. The relocation result indicates that the aftershocks are distributed along northwest with a length of 35 km and width of 12 km. The mainshock separates the aftershocks into northwestern crowd and southeastern crowd and the northwestern crowd spreads more widely than the southeastern. The seismogenic fault is nearly vertical that is consistent with the focal mechanism of the mainshock. The mainshock is relocated at the depth of 16 km and most of the aftershocks are between 5 km and 15 km. From the depth profile along the fault, we found that the seismicity near the main shock area is less active and this area extends to the surface. The phenomenon can be explained by that the area is the large slip area of the mainshock and the strain and stress are released adequately. Besides, we also found that the northwestern event crowd is shallower than the southeastern and the events' depths have temporal change that both the two event crowds move shallower after 60 hours after the main shock. After comparison and analysis, we found that the utilization of temporary stations caused the spatial and temporal evolution and that does not affect the main features of the distribution of the aftershocks.
- 出版日期2018-5
- 单位中国地震台网中心
