A theoretical note on scattering and diffraction of radar waves from a seismic disturbance propagating in the near-surface
Kristopher A. Innanen
A seismic disturbance alters the electrical properties of the Earth. This means, in principle, that within Earth volumes supporting both types of wave propagation, a radar wave field will tend to scatter from a seismic wave field. Given seismic disturbances with lengthscales on the order of that of the radar pulse, such interaction may be detectable as backscattering phenomena. Given seismic disturbances with length-scales much larger than that of the radar pulse, the interaction may be detectable as forward-scattering (e.g., anomalous traveltime) phenomena. Radar data with these characteristics would lend themselves readily to techniques of imaging-inversion, migration, and tomography, and would present the potential for providing "snapshot" images of a seismic wavefield during important stages of its evolution, e.g., as it propagates in poorly characterized and unconsolidated near surface structures. The relative magnitude of these effects as compared to other components of a GPR data set are likely very small. This work remains highly theoretical in that it is not clear whether they could be expected to rise above the noise level in realistic data sets.