Dynamic Crustal Deformation Characteristics from GPS Data in the Southern Section of the Longmenshan Fault Belt after the 2008 Wenchuan Earthquake

Methods of Euler datum transformation and least square collocation for data interpolation and smoothing are used to process GPS displacement time series data in the southern section of the Longmenshan fault belt,and then we calculated some strain parameters in subareas by the model of rigid and elastic-plasticmotion.Combined analysis of displacement series and velocity and strain parameters revealed that influence of the 2008 Wenchuan earthquake in the southern fault zone enhanced from southeast to northwest and seismic risk along the way,causing deformation accelerating 5times the most and heightening the influence difference of concealed faults on its two sides.The comparison of seismic risk among subareas based on tectonic and earthquake background indicated that,the most dangerous area is on the southeast edge of the Longmenshan,and the amassed background strain accelerated by the Wenchuan earthquake advanced the happening of the 2013 Lushan earthquake and caused sinistral strike-slip on the rupture plane.The Wenchuan earthquake also caused slight strain release in southern Xianshuihe in the first two years,but far less than strain compression caused by the Sichuan-Yunnan block.