Precise Relocation Of Earthauqkes Before And After Wenchuan Ms8.0Earthquake

In this paper, the8.0magnitude earthquake of wenchuan before and after the precise location of the source, and the focal mechanism was studied.In accurate location, will the longmenshan fault zone region (29°N to34°N,100°N～106°N)8.0earthquake of wenchuan before and after10years (on January1,1999to July31,2011)187earthquake networks records are arranged in screening. With Hypo2000earthquake location methods to position precisely and analysis, from the output of more than30000more than2.0magnitude earthquake selected more than20000(8.0magnitude earthquake of wenchuan before7394greater than2.0magnitude earthquake, a2.0magnitude earthquake is greater than the20603earthquake) seismic phase reliable earthquake, reorientation. Through the Hypo2000positioning method and the uniform velocity model to positioning, we found that the results of the repositioning the improved to redefine the source depth after mainly distributed in the0to20km of the earth’s crust in between,25～40km crust also have a small amount of the earthquake, and the lower crust existence of the deformation of the brittle fracture activities corresponds.Positioning get when residual for±0.36s, the focal level distance error is±1.04km, depth error of±2.73km.In the study area focal mechanism, that’s in chengdu area199focal mechanism solution of the results. Which points before earthquakes calculated the time period from January1999to April3～5earthquake focal mechanism solution of30; After the earthquake in May2008to August2008of8.0magnitude8class wenchuan main shock and4～5magnitude aftershock focal mechanism solutions104; After an earthquake in September2008～2011June4～5magnitude aftershock focal mechanism solution of65. Finally the compiling comprehensive before earthquakes in small and medium-sized and strong earthquake focal mechanism comprehensive map and magnitude8.0the main shock and strong wenchuan aftershock focal mechanism comprehensive figure.Before the earthquake focal mechanism solution types to thrust is given priority to, after the earthquake of wenchuan earthquake sequence focal mechanism solution type has the obvious segmentation, from southwest to northeast along the main burst with direction, and there are fears aftershocks take to thrust south is given priority to, northern strike-slip primarily. Focal mechanism type3months after the quake appeared to a number of strike-slip faults, and thrust fault and strike-slip fault is the basic equal number, number is significantly more normal faults. Through a variety of focal mechanism kind of alternating transitional zone,08after September for change in the dextral slip to give priority to.