Seismic wave simulation of a complex foothill belt

Abstract

Abstract Foothill belts ‘dual-complexity’ of the surface and underground structures hinders an accurate seismic imaging of complex geological structures. In this paper, the propagation law of the seismic wavefield in the foothill belt is studied through seismic forward modelling and its influences on the seismic data acquisition and imaging. A foothill belt with typical ‘dual-complexity’ characteristics is investigated. Single-shot records and their imaging effects simulated with different absorption coefficients and different near-surface structure models are analysed. The results suggest that strong surface waves and their scattered noise generated by the complex near surface in the foothill belt are the main reasons for the low signal-to-noise ratio and difficulties in the imaging process of seismic data. The viscoelastic-medium modelling method effectively suppresses the surface waves and their scattered noise, which improves the seismic data quality and imaging in the foothill belt, and thus is a suitable forward modelling method for the foothill belts.