Controlled sources for shear-wave surveys in mines |
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| Authors: | Gordon M Holmes Stuart Crampin & R Paul Young |
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| Institution: | GeoScope Exploration Technologies, Inc., 715-5 Ave. S.W., Calgary, Alberta T2P 2X6, Canada. Formerly at;3 and British Geological Survey, Edinburgh, UK. E-mail: , Department of Geology and Geophysics, University of Edinburgh, Grant Institute, West Mains Road, Edinburgh EH9 3JW, UK. E-mail:;, Department of Earth Sciences, University of Liverpool, Liverpool, Merseyside L69 3BX, UK. Formerly at Department of Earth Sciences, Keele University, UK. |
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| Abstract: | The ability to analyse shear-wave anisotropy in a mine environment is greatly aided by using multiple source orientations of a reproducible, impulsive shear-wave source. The analysis of what is probably the first controlled source shear-wave experiment in a mine environment demonstrates clearly that shear-wave polarizations and time delays between split shear-wave arrivals are reliably measured because of the use of multiple source orientations rather than a single shear-wave source. Reliability is further aided by modelling the shear-wave source radiation pattern, which allows for the unequivocal discrimination between seismic raypaths where shear-wave splitting did and did not occur. The analysis also demonstrates the great importance of high reproducibility of the seismic source for the use of shear waves in time-lapse surveys to monitor changes in a rockmass. |
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