Primary study on seismic surface deformation and faulting behavior of Central Fault (Beichuan-Yingxiu Fault) is done by methods such as topographic analysis, field geological investigation, trench excavation, geological profile analysis and so on.

It is very important to analyze the co-seismic surface ruptures quantitatively for the comprehension of tectonic behavior of the great earthquake.

The characteristics of seismic rupture and seismically activity before and after Jiashi-Bachu M_S 6.8 earthquake in 24 Feb. 2003;

Dynamic displacement field caused by seismic rupture in a stratified medium using discrete-wavenumber method;

suppose a seismic rupture to be a strike-slip fault with bilateral rupture at a finite expanding speed,in the 1°×1° range of research,we calculate displacement time histories at 144 field points according to the theoretical displacement seismograms synthesized with discrete wave-number method.

The basic characteristics of near-fault ground motion,including the concentration of near-fault strong ground motions,the surface rupture and fling-step,the rupture directivity effect,the near fault large velocity pulse and the hanging wall effect,are discussed in this paper.

Field investigation on the surface ruptures of the MS8.

By laying emphasis on the geomorphic features of the surface ruptures of the huge earthquake in Longmen Mountains on the eastern margin of Qinghai-Tibet Plateau,this paper confirms the vertical and horizontal offsets of the Yingxiu-Beichuan fault and the Pengxian-Guanxian fault by detailed field geomorphic surveys.