ABSTRACT
ABSTRACT: Dip angle of the Longmen Shan is quite important for disaster and seismic risk assessment of the 2008 Wenchuan earthquake. The stiff high Songpan-Ganzi plateau and the soft Sichuan Basin bring material differences along and across the Longmen Shan thrust belt. Three finite-element models were simulated using FEM method to compare the influence of dissimilar material, horizontal soft layers in the footwall, and tested the possible dip angle for the devastating earthquake. The dip angle played a decisive role in fault behavior and deformations, and the dissimilar material strongly influenced the results, but the soft layer’s effect on vertical deformations was very limited. High-angle faults caused longer interseismic interval and larger deformations, while low-angle faults with dissimilar material were also able to produce similar results. We suggest that the dip angle of the fault is no more than 50°, and the fault activity is strongly influenced by the material properties.
