SIMULATION OF TRIGGERED EARTHQUAKES IN THE LABORATORY

The experiments were conducted for the study of slick-slip at the cont act between two granite blocks. Three cases were studied under the fol lowing conditions: 1) the increase of load at a constant rate; 2) the additional application of sinusoidal oscillations in the frequency ran ge from 1 to 30 Hz; 3) subjection to the impulse in the kilohertz freq uency range. The imposition of sinusoidal oscillations with the amplit ude of 15% of the maximal load caused the reduction of time by 10% for the next stick-slip occurrence, as compared to that expected during t he gradual loading. This effect is discussed in terms of durability. T he high frequency impulse influence increased this effect and also cau sed essential changes in the amplitude of elastic oscillations generat ing during the stick-slip. The trigger phenomena should be integrated in prediction models of the time and magnitude of earthquakes.