Ground-penetrating radar

Abstract

Introduction Ground-penetrating radar (GPR) is a geophysical method for subsurface investigation that utilises electromagnetic signals transmitted into the ground as pulses from an antenna. A receiver antenna picks up energy that is partially reflected as the signal passes through a dielectric boundary in the ground. Compared to other geophysical methods, GPR supplies data with very high vertical resolution, a potential high recording speed and real-time display of the acquired data. Commercial GPR systems have only been available since the mid 1970s and the first digitally controlled GPR system was introduced by Sensors & Software Inc. in the mid 1980s. Of early scientific applications of GPR, radar measurements in cold glacier ice are probably the most noteworthy and the technique became even more important within glaciology in the mid 1970s when technical development facilitated GPR applications also on temperate ice (see also Chapter 13). GPR was also applied early within permafrost studies (Annan and Davis 1976, Davis et al. 1976). GPR is today one of the standard methods for subsurface investigations, and the fundamentals of the method are provided in textbooks such as Daniels (1996) and Reynolds (1997). The range and number of GPR applications have in general risen sharply during the past 4–5 years. This rise is also noticeable within the fields of permafrost and periglacial research. However, despite the early promising results from GPR profiling in cold environments, the absolute number of applications is still rather limited.