A numerical solution to 2-D fault site model for incident SV waves was derived by using the explicit finite element combining transmitting boundary

and the distribution rules of site ground motion influenced by different fault characteristics

such as width and shear wave velocity of fault fracture zone

incidence angle of the seismic radiation

are discussed.The numerical simulation shows that transform waves can develop inside low-velocity-fault-zone（LVFZ）when struck by external incident seismic radiation

and trapped waves can develop obviously inside the LVFZ.This result implies that the invariance of energy

struck by external incident seismic radiation

is congregated at the LVFZ

and the convergence effect increases with the increasing of the width and the decreasing of the shear wave velocity of the LVFZ.The vertical LVFZ can obstruct the spread of oblique incidence seismic wave

and the isolation effect decreases with the increasing incidence angle.The study about the seismic response of a variety of LVFZ models with different width and velocity struck by external vertically incident seismic radiation implies that

the amplification characteristics of ground motion in near fault zone site are frequency dependent.The lower frequency components of seismic radiation are amplified obviously by the LVFZ sites with lower dominant frequency（these have wider width or lower shear wave velocity）

rather than vice versa.