Polarimetric Borehole Radar and Its Application

In order to overcome the poor resolution of the borehole radar, we have proposed a technique of radar polarimetry. Natural subsurface fractures have rough surface and include random media. These caused cross-polarized scattering. By measuring the full-polarimetric scattering from fractures, we can classify the subsurface fractures. This information can be used to evaluate the water permeable fractures, which is need in various engineering applications.

We have developed full-polarimetric borehole radar system. The maximum depth of measurement of the system is 1000m, which uses impulse radar system. Broad-band polarimetric borehole radar system can be operated up to 100m. There are a few types of the radar sonde. The thinnest sonde for polarimetric measurement is 45mm in diameter.

The radar system has been tested in many sites.

Kamaishi Field Test Site, Iwate, Japan

Mirror Lake site: New Hampshire, USA (Joint research with USGS)

Hirabayashi, Awaji Island, Japan (Joint research with the Institute of Natural Disaster and Prevention)