Spectral Analysis of Microdeformations Caused by Natural and Artificial Disturbances of the Earth Crust

摘要

Characteristics of microdeformations caused by earthquakes and underground explosions were analyzed using the laser strainmeter measurements on the shore of the Japanese Sea. Packets of seismic waves from several earthquakes and from an artificial explosion were detected and analyzed with the help of Hilbert-Huang method for investigation of non-stationary and nonlinear processes. It was shown that the frequency (period) range of quasi harmonic seismic wave packets is very narrow and does not depend on their origin, but the length of the packets and of aftershocks is much shorter in the artificial explosion than in the natural ones. Physical interpretation is proposed for general and some specific features of the phenomena investigated.