Source Rupture Process And Dynamic Coulomb Stress Triggering Of Strong Earthquakes, Xinjiang And Neighbouring Districts

We invert the rupture processes of5earthquakes of magnitude6.5or greater since2001, including the24February2003Bachu, Xinjiang, MS6.8earthquake, the8October2005Pakistan, MS7.8earthquake, the21March2008Yutian, Xinjiang, MS7.3earthquake, the5October2008Wuqia, Xinjiang, MS6.8earthquake, the30June2012Xinyuan-Hejing, Xinjiang, MS6.6earthquake, and make necessary analysis. We alsocollect the previous rupture processes results of the14November2001KunlunMountain MS8.1earthquake and the27September2003MS7.9earthquake. We studythe7earthquakes’ triggering effect on their aftershocks (especially the strongaftershocks), regional seismic activities, and the remote moderate strong earthquake.The aftershocks projection results on the main shock fault plane of the21March2008Yutian, Xinjiang, MS7.3earthquake and the30June2012Xinyuan-Hejing,Xinjiang, MS6.6earthquake show that aftershocks, especially strong aftershocks, occurat the area where the sliding displacement reduces rapidly and high gradient. In timeand space, the development of aftershocks does not have a spatial tendency over time.So we suspect that the accumulation and adjustment of stress due to the heterogeneityof fault medium strength in the source region may be the main reason for occurrence ofaftershocks. Other than140s the2001Kunlun Mountain MS8.1earthquake’s ruptureduration is, the6earthquakes’ rupture duration is between20s and40s. There are noobvious differences in various kinds of seismic faults’ main rupture duration. Strike-slip earthquake tend to have more subevents than the earthquakes of other nature anddifferent tectonic conditions may have impact on earthquakes’rupture processes. Thereis a positive correlation between magnitudes and faults’length.The results of Coulomb failure stress changes of7earthquakes of magnitude6.5or greater since2001in Xinjiang and neighbouring districts on the aftershocks nearbyshow that the aftershocks’ positions have good coherence with the Coulomb failurestress changes’ positive and negative region. The dynimic and static Coulomb failurestress changes both have triggering effect on most of aftershocks. The dynimicCoulomb failure stress changes are far greater than static Coulomb failure stresschanges and give a better explanation for the distribution of aftrshocks. In the remotefield, static Coulomb failure stress changes tend to be zero, but the dynimic Coulombfailure stress changes still could trigger earthquakes. The MS6.8Wuqia Earthquake maybe subjected to the triggering effect of dynamic Coulomb stresses induced by MS7.3Yutian Earthquake. The study of Bachu, Xinjiang, MS6.8earthquake,2001and Wuqia,Xinjiang, MS6.8earthquake,2008shows, parameters’changeof mainfault and receiverhave a significant effect on the results.