HR: 14:10h
AN: S23C-03    [Abstracts]
TI: Regional and Temporal Variations in the Diffusion of Triggered Earthquakes
AU: * McKernon, C
EM: conor.mckernon@glg.ed.ac.uk
AF: University of Edinburgh, School of GeoSciences, Kings Buildings, West Mains Road, Edinburgh, EH9 3JW United Kingdom
AU: Main, I G
EM: ian.main@glg.ed.ac.uk
AF: University of Edinburgh, School of GeoSciences, Kings Buildings, West Mains Road, Edinburgh, EH9 3JW United Kingdom
AB: Huc and Main (JGR Solid Earth, 2003) derived a method to examine earthquake triggering and how it varies in time. This method allows correlation lengths, {\it L}, and mean triggering distances, {\it $<$r$>$}, to be calculated. Using data from the CMT catalogue it was shown that these characteristic distances evolve slowly but surely over time. They can be fitted, to first order, to a power law of the form {\it r(t) $\sim$ t$^{H}$}, where {\it r} is distance and {\it t} is time. The exponent {\it H} tells us how the triggering signal diffuses in space and time after an earthquake. We have calculated diffusion exponents for different tectonic regimes, and global datasets, using events from the ISC catalogue. Our results show that there are distinct regional variations in {\it L} and {\it $<$r$>$}. However, to second order, we find that the exponent increases at times greater than 100 days, suggesting that different mechanisms influence earthquake triggering over different time scales. This acceleration has been seen previously in work by Marsan {\it et al} (JGR Solid Earth, 2003). Finally, we compare our results to other published values. The methods for determining diffusion of earthquake triggering parameters differ mainly in separation of background, tectonically driven seismicity, and temporally clustered triggered seismicity. We re-examine previous work by applying our method to data used in these studies, to allow the dependence of the results on the separation method to be determined.
DE: 7223 Seismic hazard assessment and prediction
DE: 7230 Seismicity and seismotectonics
DE: 7200 SEISMOLOGY
SC: Seismology [S]
MN: 2004 AGU Fall Meeting