Authors / CoAuthors
Leonard, M. | Griffin, J. | Clark, D. | Darby, D. | Hu, G. | Featherstone, W.
Abstract
We compare GPS derived geodetic strain rates with estimates from seismic moment release for the Western Australian Seismic Zone. The geodetic strain rates were derived from occupations, in 2002 and 2006, of a 48 site regional network in the SW corner of Australia. The high precision nature of the experiment enabled us to identify 16 sites where antenna errors were the cause of the anomalous displacements. The cause of this is considered to be due to errors in the phase centre of three antennas. The ~1200 km2 study area is one of the most seismically active areas of mid-continental crust worldwide. The geodetic and seismic derived compressional strain-rates are 0.8±0.8 x10-9 yr-1 and 4.9 ±1.9 x10-9 yr-1 (±1) respectively. In effect, the geodetic strain rate would appear to be significantly less than the seismic rate which is amongst the highest of all mid-continental crust rates. With over 95% confidence we can exclude the geodetic and seismic strain rates being the same. This suggests that the contemporary seismic moment release it significantly higher than the long-term moment release. Thus the seismicity of this region is possibly not following the Poissonian behaviour normally observed for inter-plate earthquakes and may be episodic. Thus estimates of the long-term seismic hazard in this area based solely on the earthquake data are likely to be overestimates. Whether the geodetic stain rate reflects the Australian continental average or an intermediate value will require several repeat occupations.
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nonGeographicDataset
eCat Id
71152
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationScientific Journal Paper
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- earthquakes
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- geodynamics
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- seismology
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- geohazards
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2010-10-14T00:00:00
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