Generation of the low-frequency branch of acoustic emission in affected rocks

As follows from data analysis of physical modeling, the reaction of acoustic background oscillations to an external impact is well-defined under triaxial loading of a dry sandstone core in the low-frequency range (1–100 Hz). This phenomenon is explained by the generation of a low-frequency constituent of acoustic emission. A high correlation of oscillation dynamics (Klimontovich S entropy) is observed at frequencies of tens of hertz and tens of kilohertz in the absence of such a correlation in the intermediate frequency range; a synchronous increase in the oscillation level is also observed at low and high frequencies.