Abstract
Although the U.K. is in an area of only low to moderate seismicity, the seismic hazard is sufficient to pose a threat to sensitive structures such as chemical plants and nuclear facilities. In quantifying the level of hazard by conventional probabilistic methodology, however, some problems arise in attempting to interpret earthquake data in terms of geological structure and faults. In the U.K., not only is it impossible to identify any demonstrably active faults, but also it is extremely difficult to discern any relationship between the pattern of seismicity and local or regional geological structure.
This study discusses the use of two zonation approaches which complement each other in such a way that the general character and trend of seismicity is preserved. In one approach, the zonation is informed by the structural geology, where possible; geological zonation is avoided if it produces sources with heterogeneous seismicity. In the other approach, the record of past earthquakes is divided up into very small zones around individual epicentres or groups of epicentres, the size of each zone usually being proportional to the uncertainty in the epicentral determination of the appropriate event. This zonation preserves an observed tendency of some British earthquakes to repeat themselves. It is suggested that, in intraplate areas such as the U.K., it is often inappropriate to attempt to model individual fault sources. No faults in the U.K. are provably active. Because an earthquake of moderate size can occur on a very short fault segment, it is impractical to restrict fault modelling to major features. Even the two largest U.K. faults, suspected to be active, pose problems in attributing historical seismicity to them as distinct features.
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References
Chadwick, R.A., Pharaoh, T.C., Williamson, J.P., and Musson, R.M.W.: 1996, Seismotectonics of the U.K., BGS Technical Report No. WA/96/3C.
Coppersmith, K.J. and Youngs, R.R.: 1986, Capturing uncertainty in probabilistic seismic hazard assessments within intraplate tectonic environments, Proc. Third U.S. Nat. Conf. Eq. Eng, Charleston, 1, 301-312.
Davenport, C.A., Ringrose, P.S., Becker, A., and Fenton, C.: 1989, Geological investigations of late and post glacial earthquake activity in Scotland, in: S. Gregerson and P. Basham (eds.), Earthquakes at North-Atlantic Passive Margins: Neotectonics and Postglacial Rebound, Proceedings of the NATO Advanced Research Workshop, Vordingborg, Denmark, 9-13 May 1988, Kluwer Acad. Publ., Dordrecht.
Davison, C.: 1924, A History of British Earthquakes, CUP, Cambridge.
Frankel, A.D., Perkins, D., Barnhard, T.P., and Mueller, C.S.: 1995, New Methodology for the USGS Seismic Hazard Maps, IUGG XXI General Assembly, Boulder 2-14 July 1995, Abstracts, p B343.
Gardner, J.K. and Knopoff, L.: 1974, Is the sequence of earthquakes in Southern California, with aftershocks removed, Poissonian?, Bull. Seis. Soc. Am. 64, 1363-1367.
Horne, J. and Hinxman, L.W.: 1914, The Geology of the Country Round Beauly and Inverness, Mem. Geol. Surv. Scotland, sheet 83, HMSO, Edinburgh.
Jacob, K., Armbruster, J., Barstow, N., and Horton, S.: 1994, Probabilistic Ground Motion Estimates for New York: Comparison with Design Ground Motions in National and Local Codes, Proc. Fifth U.S. Nat. Conf. on Eq. Eng., Chicago, 10-14 July 1994, pp. 119-128.
Johnston, A.C.: 1989, The seismicity of stable continental interiors, in S. Gregerson and P. Basham (eds.), Earthquakes at North-Atlantic Passive Margins: Neotectonics and Postglacial Rebound, Proceedings of the NATO Advanced Research Workshop, Vordingborg, Denmark, 9-13 May 1988, Kluwer Acad. Publ., Dordrecht, pp. 299-328.
Johnstone, G.S. and Mykura, W.: 1989, The Northern Highlands of Scotland, BGS Regional Geology Series, HMSO, London.
Muir Wood, R.: 1993, Ice Sheet Loading/Unloading and Sector Zoning Seismotectonics, Terra Abstracts, No. 5, suppl. 5, p. 11.
Musson, R M. W.: 1989, Seismicity of Cornwall and Devon, BGS Global Seismology Report No. WL/89/11.
Musson, R.M.W.: 1993, Comrie: a historical Scottish earthquake swarm and its place in the history of seismology, Terra Nova 5, 477-480.
Musson, R.M.W.: 1994, A Catalogue of British Earthquakes, BGS Global Seismology Report No. WL/94/04.
Musson, R.M.W.: 1996, The seismicity of the British Isles, Annali di Geofisica 39(3), 463-469.
Musson, R.M.W., Neilson, G., and Burton, P.W.: 1984,Macroseismic Reports on Historical British Earthquakes VII: North Scotland, BGS Global Seismology Report No. 232.
Musson, R.M.W., Neilson, G., and Burton, P.W.: 1986,Macroseismic Reports on Historical British Earthquakes X: The Great Glen, BGS Global Seismology Report No. 347.
Musson, R.M.W. and Winter, P.W.: 1993, Seismic Hazard Methodology for a Hazard Map of the U.K., AEA Tech. Cons. Serv. Report No. GNSR(DTI)P(93)149.
Musson, R.M.W. and Winter, P.W.: 1995, Seismic Hazard of the U.K., AEA Technology Report No. AEA/CS/16422000/ZJ745/005.
Musson, R.M.W. and Winter, P. W.: 1996/7, Seismic hazard maps of the U.K., Natural Hazards 14(2-3), 141-154.
Redmayne, D.W. and Musson, R.M.W.: 1987, The Dunoon Earthquake of 16 September 1985, BGS Global Seismology Report No 311.
Woo, G.: 1996, Kernel estimation methods for seismic hazard area source modelling, BSSA 86(2), 353-362.
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Musson, R.M.W. Seismic Hazard Studies in the U.K.: Source Specification Problems of Intraplate Seismicity. Natural Hazards 15, 105–119 (1997). https://doi.org/10.1023/A:1007970907854
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DOI: https://doi.org/10.1023/A:1007970907854