versão On-line ISSN 2411-9717
versão impressa ISSN 0038-223X
J. S. Afr. Inst. Min. Metall. vol.110 no.1 Johannesburg Jan. 2010
Mine seismicity: Prediction or forecasting?
Florida Park, Johannesburg, South Africa
Much as one hopes to predict whether damaging seismicity might occur somewhere in the next shift, this is not possible at present. Recently, an analysis of seismicity at two mines has shown that a small increase in seismicity occasionally occurs before both large and small events. This analysis is extended here to five mines, with the same results.
Earthquake seismologists forecast hazard in terms of the average incidence of earthquakes over the last 50 years, adjusted on an hourly basis according to the possibility of aftershocks of events that have happened.
The rate of seismicity in any area remains approximately constant when expressed as seismicity per area mined, or better still, per unit of elastic strain energy released. It is suggested that seismic hazard in mines be estimated using historical seismicity and forward modelling, adjusted according to the possibility of aftershocks.
In summary, medium-term forecasting of seismicity is viable; short-term prediction of large events is not.
“Full text available only in PDF format”
Durrheim, R.J., Cichowicz, A., Ebrahim-trollope, R., Essrich, F., Goldbach, O., Linzer, L., Spottiswoode, S.M., Stankiewicz, T., And Van Aswegen, G. Guidelines, Standards And Best Practice For Seismic Hazard Assessment And Rockburst Risk Management, Final Project Number: Sim 05 03 02 Output 3 (6 March 2007), Safety In Mines Research Advisory Committee. 2007. [ Links ]
Geller, R.J., Jackson D.D., Kagan, Y.Y., And Mulargia, F. Earthquakes Cannot be predicted, Science 14, March 1997, vol. 275. no. 5306, pp. 1616-0, DOI: 10.1126/science.275.5306.1616 (Enhanced version at: http://www.sciencemag.org/cgi/content/full/275/5306/1616). 1997. [ Links ]
Gerstenberger, M., Wiemer, S., And Jones, L. Real-time Forecasts Of Tomorrow's Earthquakes in California: a New Mapping Tool, USGS Open-File Report 2004-1390. 2004. [ Links ]
Jager, A.J. And Ryder, J.A. A Handbook On Rock Engineering Practice For Tabular hard rock mines, SIMRAC, Johannesburg. 1999. [ Links ]
Jordan, T.H. Earthquake Prediction: The Unsolved Problem, Keynote Lecture At the General Assembly of the International Association of Seismology and Physics of the Earth's Interior (IASPEI), 10-16 January 2009, Cape Town, South Africa. 2009. [ Links ]
Kgarume, T.E., Spottiswoode, S.M., And Durrheim, R.J. Statistical Properties Of mine tremor aftershocks, submitted to Pageoph special issue: Induced seismicity. 2009. [ Links ]
Mendecki, A.J. (ed.) MonitorSeismic ing In Mines. Chapman & Hall, London. 1997. [ Links ]
Mendecki, A.J. and van Aswegen, G. Seismic monitoring in mines: selected terms and definitions. Van Aswegen, G., Durrheim, R.J. and Ortlepp, W.D. (eds.) Rockbursts and Seismicity in Mines-RaSiM5, South African Institute of Mining and Metallurgy, Johannesburg, South Africa. 2001. [ Links ]
Mendecki, et al. Discussions at ISSI seminar, Stellenbosch, South Africa, 4 May 2009. [ Links ]
Richardson, E. And Jordan, T.J. Seismicity In Deep Gold Mines Of South Africa: Implications for tectonic earthquakes, Bull. Seism. Soc. Amer., 92, 2002. pp. 1766-1782. [ Links ]
Spottiswoode, S.M. Aftershocks And Foreshocks Of Mine Seismic Events. 3rd international workshop on the application of geophysics to rock and soil engineering, GeoEng2000, Melbourne Australia. 2000. [ Links ]
Spottiswoode, S.M., Linzer, L.M., And Majiet, S. Energy And Stiffness Of Mine models and seismicity, SHIRMS 2008 - Y. Potvin, J. Carter, A. Dyskin, R. Jeffrey (eds.) Australian Centre for Geomechanics, Perth, ISBN 978-0-9804185-5-2, vol. 1, 2008. pp. 693-707. [ Links ]
Spottiswoode, S.M. Is Mine Earthquake Prediction Possible? Rockbursts And Seismicity in Mines, Dalian, China. 2009. [ Links ]
Van Aswegen, G. Towards Best Practice For Routine Seismic Hazard Assessment in Mines. 30th International Conference of Safety in Mines Research Institutes, South African Institute of Mining and Metallurgy, Johannesburg, South Africa. 2003. [ Links ]
Van Aswegen, G. Routine Seismic Hazard Assessment In South African Mines. 6th Intl Symposium On Rockbursts And Seismicity In Mines, Perth, Australia, 2005. pp. 437-444. [ Links ]
Van Aswegen, G. Routine Seismic Hazard Assessment For Some S.a. Mines, unpublished ISSI document, Western Levels, September 2007. [ Links ]