Diffraction of a two-dimensional (2D) semi-circular cavity in a half-space under incident SH-waves is studied using the classic
wave function expansion method with a new de-coupling technique. This so-called “improved cosine halfrange expansion” algorithm
exhibits an excellent performance in reducing displacement residual errors at two rim points of concern. The governing equations
are developed in a manner that minimizes the residues of the boundary conditions. Detailed derivation and analysis procedures
as well as truncation of infinite linear governing equations are presented. The semi-circular cavity model presented in this
paper, due to its simple profile, is expected to be used in seismic wave propagation studies as a benchmark for examining
the accuracies of various analytical or numerical methods for mixed-boundary wave propagation problems. 相似文献
The great Tancheng earthquake of M8? occurred in 1668 was the largest seismic event ever recorded in history in eastern China. This study determines the fault geometry of this earthquake by inverting seismological data of present-day moderate-small earthquakes in the focal area. We relocated those earthquakes with the double-difference method and found focal mechanism solutions using gird test method. The inversion results are as follows: the strike is 21.6°, the dip angle is 89.5°, the slip angle is 170°, the fault length is about 160 km, the lower-boundary depth is about 32 km and the buried depth of upper boundary is about 4 km. This shows that the seismic fault is a NNE-trending upright right-lateral strike-slip fault and has cut through the crust. Moreover, the surface seismic fault, intensity distribution of the earthquake, earthquake-depth distribution and seismic-wave velocity profile in the focal area all verified our study result.
A closed-form analytical solution of surface motion of a semi-elliptical cylindrical hill for incident plane SH waves is presented. Although some previous analytical work had already dealt with hill topography of semi-circular and shallow circular, our work aims at calculating surface motion of very prolate hill for high incident frequency, and explaining the special vibrating properties of very prolate hill. Accuracy of the solution is checked by boundary conditions, numerical results for surface motion of oblate and prolate hills are calculated, and some conclusions are obtained. 相似文献