Recognizing of Microseismic Source Types Based on Small-Aperture Seismic Array Data

In this paper, we consider the problem of recording and processing the microseismic data with their subsequent interpretation and making the decisions concerning the probable threats associated with the violation of integrity of terrestrial environment due to mining activity. These decisions are made based on the detection of microseismic sources and recognition of their types by processing the multichannel seismograms from small-aperture seismic arrays. The procedures of seismogram processing include the algorithms for detecting the signals of microseismic sources in the noisy seismograms from the array sensors and the procedures for estimating various parameters of these sources. In this paper, we propose a new detection algorithm which is based on evaluating multiple coherence of the array seismograms and is capable of identifying the waves radiated from microseismic sources with complex focal mechanisms against the diffuse seismic noise. In contrast to the widely used STA/LTA array detector which is aimed at separating plane seismic waves, the proposed detector is intended for the recognition of waves from local seismic events in the complexly structured subsurface environment. Based on the numerical experiments with model and real seismic array data containing signals from the sources with complex focal mechanisms, it is shown that the types of microseismic sources can be recognized with the use of various algorithms of seismic array data analysis: with new algorithms for estimating the coordinates of microseismic sources and with traditional algorithms of space-time spectral analysis.