Shock compression and isentropic release of rhyolite

A series of shock compression experiments have been conducted on rhyolite at pressure ranging from 6 to 33 GPa. A velocity interferometer (VISAR) was employed to monitor the particle velocity of an aluminum reflector with a diffused surface bonded to the rhyolite sample. In the forward ballistic experiments, a slow rise shock wave front is observed at 6 GPa. While in the forward experiments their release waves are smeared, in a reverse ballistic experiment, the particle velocity variation at the shock wave plateau and the isentropic release wave arrival have been clearly observed. Using Swegle’s mixed phase model, we simulated the experimental results with WONDY code. Like quartz and granite, the rhyolite data could be fit to a frozen release model which has some hysteric behavior. The Eulerian sound velocity at shock pressure 8.7 GPa has been determined to be 5.6 km/s.