EFFECT OF MECHANICAL VIBRATION ON SEISMICITY

Abstract

Weak vibration of constant amplitude has a significant effect on the deformation of a specimen under constant load and increases the rate of plastic deformation, but decreases the chance for abrupt deformations. But if there are distinct peaks, even small, in the amplitude of vibrations, then the smooth deformation process breaks down and an abrupt deformation occurs at the time when the peak appears. This result suggested that vibrational treatment could be used to relieve elastic stresses accumulating in a rock medium as a result of its deformation, and in particular that it would be possible to relieve the crustal stresses whose accumulation produces earthquakes. Both field and laboratory experiments indicate that vibrations have a major effect on the way in which accumulated elastic energy is liberated by stressed rock. Overall, these vibrations produce strong crack opening (and dilatation of the rock) and also increase the overall deformation rate. The vibrations increase the power expended on the plastic component of failure and concurrently decrease the importance of elastic seismic energy in failure.