Polarimetric borehole radar approach to subsurface fracture classification

In order to overcome the limitation of radar resolution, we proposed to use radar polarimetry in borehole radar. Even though the radar resolution is much less than the shape of the scattering object such as subsurface fracture, polarization status contains information about the scatterer. We applied the radar polarimetry to subsurface fracture measurement, and this information was used for classifying fractures. Due to the low resolution of the radar, accurate phase information was not easy to obtain. Therefore, we developed a technique to use power of the gated signal in the actual radar measurement. Using this parameter, we found that the polarimetric ratio of the gated power can be used for evaluation of the fracture. Polarization power ratio indicates that the fractures can be classified into clusters, and we think that this technique can be used for better understanding of each fracture structure.