In this paper, seismic response of the ground surface was presented in the presence of a subsurface elliptical inclusion subjected to propagating incident SH-waves. A numerical approach known as half-plane time-domain BEM that was able to focus the meshes only around the inclusion was used for analysing the problem. After implementing the method in a general algorithm and solving a verification example, a sensitivity analysis was successfully carried out to obtain the amplification pattern of the surface in the presence of a soft elliptical inclusion with considering some key parameters including the ratios of depth, location, shape, impedance and incident wave angle. Finally, by obtaining the maximum amplification of the surface and linear regression from them, the results were summarized in the form of tables and linear equations for engineering applications. The achievements showed that all these parameters were effective in forming different pattern of the ground surface. The results can be practically used in completing the existing seismic codes for heterogeneous domains with underground lenses.