Sensitivity analysis of fracture scattering

Abstract

We use 2D and 3D finite-difference modeling to numerically calculate the seismic response of a single finite fracture with a linear-slip boundary in a homogeneous elastic medium. We use a point explosive source and ignore the free surface effect, so the fracture scattered wavefield contains two parts: P-to-P scattering and P-to-S scattering. The elastic response of the fracture is described by the fracture compliance. We vary the incident angle and fracture compliance within a range considered appropriate for field observations and investigate the P-to-P and P-to-S scattering patterns of a single fracture. P-to-P and P-to-S fracture scattering patterns are sensitive to the ratio of normal to tangential fracture compliance and incident angle, whereas the scattering amplitude is proportional to the compliance, which agrees with the Born scattering analysis. We find that, for a vertical fracture, if the source is located at the surface, most of the energy scattered by the fracture propagates downwards. We also study the effect of fracture height on the scattering pattern and scattering amplitude.