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Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/6044

Authors: Malagnini, L.*
Nielsen, S.*
Mayeda, K.*
Boschi, E.*
Title: Energy radiation from intermediate to large magnitude earthquakes: implications for dynamic fault weakening
Title of journal: Journal of Geophysical Research
Series/Report no.: /115 (2010)
Publisher: American Geophysical Union
Issue Date: 1-Jun-2010
Keywords: earthquake radiation
coda
friction
self-similarity
dynamic weakening
Abstract: The amount of energy radiated from an earthquake can be measured using recent methods based on earthquake coda signals and spectral ratios. Such methods are not altered by either site or directivity effects, with the advantage of a greatly improved accuracy. Several studies of earthquake sequences based on the above measurements showed evidence of a breakdown in self-similarity in the moment to energy relation. Radiated energy can be also used as a gauge to estimate the average dynamic stress drop on the fault. Here we compute the dynamic stress drop, infer the co-seismic friction and estimate the co-seismic heating resulting from the frictional work during events from different main shock-aftershock earthquake sequences. We relate the dynamic friction to the maximum temperature rise estimated on the faults for each earthquake. Our results are strongly indicative that a thermally triggered dynamic frictional weakening is present, responsible for the breakdown in self-similarity. These observations from seismic data are compatible with recent laboratory evidence of thermal weakening in rock friction under seismic slip-rates, associated to various physical processes such as melting, decarbonation or dehydration.
Appears in Collections:04.06.03. Earthquake source and dynamics
Papers Published / Papers in press

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Malagnini_etAl_JGR_Final_Revised9.pdfMain article & figures8.77 MBAdobe PDFView/Open


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