Fracture-induced resistivity changes in granite

Simultaneous electrical resistivity and elastic wave velocity measurements during triaxial deformation of granite under brine-saturated conditions

“…4), which agrees with the onset of dilatancy identified using strain measurements during triaxial deformation of the same material (Sawayama and Katayama 2016). A similar concavedown evolution of the electrical resistivity during the deformation of granite has been reported in previous experiments (Brace and Orange 1968;Tomecka-Suchon and Rummel 1992), even though different strain rates, confining pressures, and pore fluid pressures were employed. At higher effective pressures, the increase in resistivity during the early stage is larger due to the effective compaction, but the overall evolution of resistivity is similar among the experiments at different confining pressures.…”

“…The electrical resistivity and elastic wave velocity of rocks are sensitive to the presence of both cracks and fluids, such that these physical properties are frequently used to investigate structural changes in the crust (e.g., Scholz et al 1973;Nimiya et al 2017;Minami et al 2018). Laboratory experiments can monitor microcrack formation due to brittle deformation based on changes in electrical resistivity (e.g., Brace and Orange 1968;Tomecka-Suchon and Rummel 1992;Glover et al 2000) and elastic wave velocity (e.g., Hadley 1975;Lockner et al 1977;Schubnel et al 2003;Fortin et al 2011). However, simultaneous electrical resistivity and elastic wave velocity measurements are rarely obtained during the triaxial deformation of crystalline rocks.…”