Orthogonal Dual Polarization GPR Measurement for Detection of Buried Vertical Fault

This short letter proposes a ground-penetrating radar (GPR) measurement technique to better detect vertical fault that occurs in a base rock under a surface layer. The technique exploits polarization-dependent radar response of the linear feature of the fault end that appears on the featureless base rock surface. A set of GPR measurements of which polarizations are orthogonal to each other are carried out in a fashion that one polarization is parallel to the putative target fault line, while another is normal to it. Taking the difference of instantaneous power A-scope data of the measurements cancels contribution from the featureless base rock surface while the contribution from the fault fracture end is elicited, thanks to its strong polarization-dependent radar response. The technique was described by an analytic model, its feasibility was demonstrated by finite difference time domain (FDTD) simulation, and was verified by a field measurement experiment.