ABSTRACT
Presented are the results of seismic and deformation monitoring of a regional fault performed at the depth of 300 m from the free surface in one of the tunnels of an active mine recovering iron ore. Two different sources were used for seismic illumination of the fault: impacts of a sleeper over the tunnel wall and a delay-fired explosion in the mine. It is demonstrated that in the range of small strains 10−8–10−7 the normal stiffness of the discontinuity exhibits non-linearity—as the amplitude of disturbance increases by an order of magnitude, the normal stiffness of the fault decreases by more than an order of magnitude.
