Acoustic Emission Events Clustering Parameters in Laboratory Rock Fracture Experiments

This paper verifies the compliance of the earthquake productivity law (Shebalin et al., 2020a) in laboratory experiments on rock destruction. Westerly granite and Benheim sandstone specimens were subjected to uniaxial loading under uniform compression. An acoustic-emission (AE) recording system made it possible to create catalogues of AE sources similar to earthquake catalogues. The data from experiments conducted at the Rock Friction Laboratory (USGS, Menlo Park, United States) and the Geomechanics and Rheology Laboratory (GFZ, Potsdam) were analyzed. It was found that the AE events in the considered samples are characterized by a unimodal distribution of the nearest-neighbor proximity function. The compliance of the productivity law for acoustic-emission events in laboratory experiments on the destruction of rock samples is shown, which gives grounds to speak about the similarity of grouping processes in real seismicity and in laboratory conditions.