芦山Ms 7.0级地震震前及同震地表形变

对四川地区GNSS观测数据进行处理,获得如下结果:①汶川Ms8.0级地震之前龙门山断裂带及其以北近150km的范围内几乎不存在可分辨的右旋走滑活动和压性形变,四川盆地以西-鲜水河安宁河断裂带以东约100km的范围内几乎也不存在可辨的形变;②汶川Ms8.0级地震之后芦山Ms7.0级地震之前,龙门山断裂带中、北段存在约5mm/a右旋走滑活动,芦山震源及附近地区的三维形变一直处在闭锁状态,鲜水河安宁河断裂带及其以东的左旋形变有所增强;③芦山地震可变的同震形变场基本分布于以震源为中心的数十km范围内,大致以震中为界东侧呈右旋形变,西侧呈左旋形变;④距震中较近约12km的LS05震时"永久性"垂向位移量约7cm,水平向逆冲量约4cm,走滑量约5cm。

Pre-seismic and Co-seismic Deformation of Ms 7.0 Earthquake in Lushan

Based on the UNSS data processing results from the Sichuan area，following conclusions are obtained:①Before the Ms 8.0 earthquake in Wenchuan，there was almost no dextral strike-slip activity distinguished or compressional deformation on the Longmenshan fault zone and nearly 150 km north of it，and was deformation distinguished in the area of 100 kms west of Sichuan Basin-- the Xianshuihe Anninghe Fault.②Between the Ms 8. 0 earthquake in Wenchuan and Ms 7.0 earthquake in Lushan，there was about a 5 mm/a dextral strike-slip activity in the middle and northern sections of the Longmenshan fault zone，with no 3D deformation distinguished in and near the seismic source region. Meanwhile the sinistral deformation increased on the Xianshuihe Anninghe fault and east of the zone.③The co-seismic deformation field of the Lushan earthquake was basically distributed for 10 kilometers around the seismic source region，with an epicenter bounded，on the east side as a dextral deformation，on the west side with a sinistral deformation.④LS05 was about 12 km to the epicenter; the permanent vertical displacement momentum was around 7 cm，with a horizontal thrust momentum of about 4 cm，the horizontal strike-slip was about 5 cm from the station.