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It is known that penetration of a liquid into a rock that gives rise to a pore pressure can play a key role in fracture of rocks [1, 2]. To explain this phenomenon, a dilatancy-diffusion (DD) model [1] based on laboratory experiments on deformation of rocks under high pressures was suggested in the 1970ies. Dilatancy is an increase in volume of a granular substance under deformation. The essence of the model is as follows. The microcracks formed in a rock under high pressures give rise to changes in the physical parameters of the rock, such as the P wave velocity [1, 3], volume, electrical resistance, etc. As water penetrates into cracks, the rock increases in volume and, as a result, the region saturated with water becomes larger, and the pore pressure in cracks arises. This can lead to a sample rupture (and to an earthquake at the large-scale level).