Comparison of Frequency-domain and Time-domain Spectral Induced Polarization Methods at Field Scale

In this paper we present a comparison study of time-domain (TD) and frequency-domain (FD) spectral induced polarization (IP) methods in terms of field procedures, data quality, as well as spectral information retrieved from inversion. For this purpose we collected TDIP and FDIP surface measurements on three profiles with identical measurement setup at two field sites with different lithology. Both TD and FD data were processed and inverted using similar approaches. This comparison study shows that, given the right circumstances, both methods (TD and FD) can be readily applied on the field scale, thereby providing results that compare not only qualitatively, but also quantitatively. Furthermore, the surface inversions are in agreement with the boreholes’ inversions/lithology, proving the effectiveness of the surface imaging. However, due to the underlying technical constraints and with the instruments used in this comparison, TD measurements had a 10 fold speed advantage over the FD method, a wider spectral range and more flexibility in the array choice. Therefore we conclude that TD measurements are a suitable tool to recover spectral IP information in the field, provided that the measurement procedures are planned accordingly.