Spectral Induced Polarization Detects Cracks and Distinguishes between Open- and Clay-filled Fractures

Abstract : Spectral induced polarisation (SIP) is applied to the detection and localization of fractures located in the roof of an abandoned quarry at Saint-Germain-la-Rivière (Gironde, southwest France). Two types of fracture are observed in the roof of the galleries: open (mostly clay-free) and clay-filled. The phase between current and voltage is used to detect the presence of these fractures and can differentiate those with or without clays. The amplitude and phase of complex conductivity can be analysed using a Cole-Cole model of relaxation times. Open fractures are characterized by very low chargeability and a high relaxation time in the order of 3 ms. Clay-filled fractures are characterized by high chargeability and a low relaxation time.