Electrical conductivity of rocks under shock compression

The electrical conductivity of silicate rocks (quartzite, granite, and dry and wet tuffs) under single shock–wave loading is measured. It is shown that even at a shock–wave pressure of 20 GPa, the conductivity of rocks changes by several orders of magnitude compared to the initial value (10$^{-9}$ – 10$^{-12}$ $\Omega^{-1}$ $\cdot$ m$^{-1}$ for dry rocks) and reaches 0.01 $\Omega^{-1}$ $\cdot$ m$^{-1}$ for quartzite and granite and 0.1 – 1.0 $\Omega^{-1}$ $\cdot$ m$^{-1}$ for tuff. As the shock–wave amplitude increases from 20 to 60 GPa, the electrical conductivity increases by further one or two orders of magnitude. The experiments with rocks did not reveal a drastic change in electrical conductivity similar to the that observed for silicon dioxide (fused quartz) at a pressure of about 40 GPa.