Location and source mechanism of a microseismic event in a mine using a single seismogram

摘要

Reliable location of microseismic events is an important objective for routine mine seismic monitoring.Reflections from the underground excavations result in complex recorded seismograms,and typically only the direct P-and S-wave arrivals are used to locate the source.We have developed an algorithm that uses the full waveform,including reflected arrivals,to locate a seismic event.The method uses a library of precomputed Green’s functions based on a 3D model of the mine tunnels and excavations.The library is used to quickly compute trial waveforms,which are cross-correlated with the recorded seismograms to produce an objective function.This function is maximized by a differential evolution algorithm to simultaneously yield the source location and six moment-tensor components.If the mine has many tunnels and excavations,which is typically the case,then this fully automatic method can use even a single triaxial or biaxial seismogram to reliably determine the source origin and mechanism.This result has useful consequences for mine seismic monitoring,and is demonstrated with recorded data from an Australian underground mine.