Scaling in Pressure Stimulated Currents related with rock fracture

The application of uniaxial stress in rocks is accompanied by the production of an electric signal which described by the term Pressure Stimulated Current (PSC). Here we present a statistical analysis of PSC time series from rock fracture experiments obtained from samples of calcite and cement mortar materials. In all considered cases, the PSC waiting time distribution can be described by a unique scaling function. This can be well approximated by a gamma function implying a broad distribution of waiting times. A frequency-energy distribution similar with the well known in seismology Gutenberg-Richter law and a Benioff-type relationship are obtained. The resulting scaling functions are similar to that for earthquakes and acoustic emissions suggesting its general validity for fracture processes.