????????????????????Ч??????

???????????λ???????USGS???????????????????о?????????????????????????????????????????PSGRN/PSCMP?????????????????????????????α???????仯??????????????????????????????Ч?????????????????????????λ???й??????????????????????????Ч????????????????????????????Ч?????????????????????????????????????10%~20%????????????????????30%?????г????????????????????????λ???γ??λ??????λ????????仯???????????18.4????18.0%??15.8%??16.2??????????40 km?????????????λ???γ??λ??????λ????????仯???????????4.6%??5.3%??3.8%??3.8%???????70 km??????????????3.5%??4.6%??3.0%??2.5%??

INFLUENCE OF CRUST LAYERING AND TICKNESS ON COSEISMIC EFFECTS OF WENCHUAN EARTHQUAKE

Using the PSGRN/PSCMP software and the fault model offered by USGS and on the basis of finite rectangular dislocation theory and the local layered wave velocity structures of the crust upper mantle, the influences of crust layering and thickness to coseismic gravity changes and deformation of Wenchuan earthquake have been simulated.The results indicate that: the influences have relation to the attitude of faults and the relative position between calculated points and fault. The difference distribution form of simulated results between the two models is similar to the distribution of coseismic effect. For the per centum distribution, it’s restricted by the zero line of the coseismic effects obviously. It’s positive far from the zero line. For the crust thickness, the effect is about 10%~20%. The negative and the effect over 30% focus around the zero line. The average influences of crust layering and thickness for the longitudinal deformation, latitudinal deformation, vertical deformation and gravity changes are 18.4％、18.0%、15.8% and 16.2％,respectively when the crust thickness is 40km, the average influences are 4.6%,5.3%,3.8% and 3.8%, while the crust thickness is 70 km, the average influences are 3.5%,\{ 4.6%\},3.0% and 2.5% respectively.