Comparison of 2D and 3D valley topographic effect based on spectral element simulation

It is more realistic to use real source to study local topographic effect in larger scale real terrain areas. In this paper, 3D real topography model of Lushan area is established, and Lushan aftershock is simulated by spectral element method. At the same time, the 2D valley profile where the 51BXD rock station and the source located is also established, then the P-SV wave in the profile and the SH wave out of the profile are simulated respectively. Based on the Fourier spectral ratio calculated by the velocity time history of topography model and horizontal model, it shows that the spectral ratio of 2D simulation results is basically close to that of 3D simulation results, and the spectral ratio of components in the profile is greater than that out of the profile. The topographic effect of the peak and slope towards to source is significant, and the 51BXD rock station that located at the valley bottom also has significant topographic effect.