Influence of crustal layering and thickness on co-seismic effects of Wenchuan earthquake  

作　　者：Tan Hongbo Shen Chongyang Xuan Songbai Yang Guangliang 

机构地区：[1]Institute of Seismology, CEA, Wuhan 430071, China [2]Crustalal Movement Laborator , Wuhan 430071, China

出　　处：《Geodesy and Geodynamics》2011年第1期47-54,共8页大地测量与地球动力学（英文版）

基　　金：supported by the National Natural Science Foundation of China(40574012);the Earthquake Science Joint Foundation(A07030)

摘　　要：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 in- fluences of crustal layering and thickness on co-seismic gravity changes and deformation of Wenchuan earthquake have been simulated. The results indicate that： the influences have a relationship with the attitude of faults and the relative position between calculated points and fault. The difference distribution form of simula- ted results between the two models is similar to that of co-seismic effect. For the per centum distribution, it＇ s restricted by the zero line of the co-seismic effects obviously. Its positive is far away from the zero line. For the crustal thickness, the effect is about 10% -20%. The negative and the effect over 30% focus around the zero line. The average influences of crustal layering and thickness for the E-W displacement, N-S displacement, vertical displacement and gravity changes are 18.4 % , 18.0% , 15.8 % and 16.2% respectively, When the crustal thickness is 40 km, they are 4.6% ,5.3% ,3.8% and 3.8%. Then the crustal thickness is 70 kin, the average influences are 3.5%, 4. 6% ,3.0% and 2.5% respectively.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 in- fluences of crustal layering and thickness on co-seismic gravity changes and deformation of Wenchuan earthquake have been simulated. The results indicate that： the influences have a relationship with the attitude of faults and the relative position between calculated points and fault. The difference distribution form of simula- ted results between the two models is similar to that of co-seismic effect. For the per centum distribution, it＇ s restricted by the zero line of the co-seismic effects obviously. Its positive is far away from the zero line. For the crustal thickness, the effect is about 10% -20%. The negative and the effect over 30% focus around the zero line. The average influences of crustal layering and thickness for the E-W displacement, N-S displacement, vertical displacement and gravity changes are 18.4 % , 18.0% , 15.8 % and 16.2% respectively, When the crustal thickness is 40 km, they are 4.6% ,5.3% ,3.8% and 3.8%. Then the crustal thickness is 70 kin, the average influences are 3.5%, 4. 6% ,3.0% and 2.5% respectively.

关 键 词：Wenchuan earthquake co-seismic effects crustal layering crustal thickness finite rectangulardislocation theory 

分 类 号：P313.2[天文地球—固体地球物理学] P588.3[天文地球—地球物理学]