Abstract:Frequency of micro-seismic signals is a very important characteristic parameter which may affect seismic data resolution. In this paper, frequency characteristics of micro-seismic signals are analyzed such as source rupture scale, viscoelastic effect of medium, and frequency bandwidth response of recorders in the signal propagation process. The following observations are obtained from our work: A. Signal frequency decreases with propagation distance increase. When the propagation distance increases to a certain degree, the signal frequency become unchanged; B. The dominant frequency does not change in full elastic medium, but it decreases with propagation distance increase in viscoelastic medium, and seismic energy decreases too with the propagation distance; C. The dominant frequency decreases gradually during signal propagation process, but it decreases suddenly when crossing an interface.
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