Optimization of time domain induced polarization data acquisition and spectral information content

Sammanfattning: The need for detailed subsurface information is increasing due to city expansion and infill projects as well as subsurface construction projects. One common method for acquiring this geo-information is the direct current resistivity and time domain induced polarization method (DCIP) that measures the electrical resistivity and chargeability of the subsurface. The work presented in this thesis demonstrates that the usefulness of the DCIP method can be improved. Field time and cost efficiency is increased by means of waveform optimization and investigations of the effect of different current pulse on-time duration. Furthermore, post processing efficiency is increased as a result of improved data quality and reliability. Additionally, the available spectral information from DCIP surveys is substantially increased by enabling extraction of the IP response closer to the pulse than was previously possible. In combination with more accurate removal of background drift potential, which improves data quality at late times, the spectral information is further increased. In total, these optimizations increase the usefulness of the resistivity and (spectral) time domain induced polarization method and can hopefully contribute to spreading and intensifying its use for acquiring qualified subsurface information.