关键词: 汶川地震, 位错模型, 断裂

Abstract: Basing on the fault dislocation model of Yoshimitsu Okada and Steketee and filed scientific investigation,we calculate theoretically space variation of the displacement fields,including vertical and horizontal displacements of the Wenchuan earthquake along the near zone(within 30km to the fault)of Yingxiu-Beichuan reverse fault.In the simulation,we interpret the space variation of the displacement field in the near zone of Yingxiu-Beichuan reverse fault in details.However,we can't describe the space variations in much detail by the field scientific investigation and limited data of GPS stations.Comparing with the results of field science investigation on surface rupture zone,our computational results show that the displacement fields have the same variation trend.At the same time,the displacement field declines drastically with distance to the outcrop of the fault,which agrees with the present research,and the velocity of this decline is much faster on the foot wall of fault than that on the hanging wall.By the simulation,we get the main conclusions:the vertical displacement of ground surface resulting from faulting in the earthquake shows the strong spatial inhomogeneity,and most large values of vertical displacement concentrate on the terminals of the fault,i.e.nearby Yingxiu and Beichuan.The displacement of the ground surface,including horizontal and vertical component,varies more drastically on both terminals of the fault than that of the middle section of the fault.The vertical displacement changes drastically along the direction of strike in the hanging wall of the fault than that of the foot wall.Except on the terminals of the fault,the horizontal displacement distributes homogenously in space.On the whole,except on the terminals of the fault,the amplitude of the displacement field on the hanging wall of the fault is larger than that of the foot wall.

Key words: M_S 8.0 Wenchuan earthquake, dislocation model, fault