Brantut, N;
Viesca, RC;
(2017)
The fracture energy of ruptures driven by flash heating.
Geophysical Research Letters
, 44
(13)
pp. 6718-6725.
10.1002/2017GL074110.
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Abstract
We present a model for dynamic weakening of faults based on local flash heating at microscopic asperity contacts coupled to bulk heating at macroscopic scale. We estimate the fracture energy G associated with that rheology and find that for constant slip rate histories G scales with slip δ as math formula at small slip, while math formula at large slip. This prediction is quantitatively consistent with data from laboratory experiments conducted on dry rocks at constant slip rate. We also estimate G for crack-like ruptures propagating at constant speed and find that math formula in the large slip limit. Quantitative estimates of G in that regime tend to be several orders of magnitude lower than seismologically inferred values of G. We conclude that while flash heating provides a consistent explanation for the observed dynamic weakening in laboratory experiments with kinematically imposed slip, its contribution to the energy dissipation during earthquakes becomes negligible for large events when considering the elastodynamic coupling between strength and slip evolution.
| Type: | Article |
|---|---|
| Title: | The fracture energy of ruptures driven by flash heating |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1002/2017GL074110 |
| Publisher version: | https://doi.org/10.1002/2017GL074110 |
| Additional information: | ©2017. The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Science & Technology, Physical Sciences, Geosciences, Multidisciplinary, Geology, Laboratory Earthquakes, Slip, Strength |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Earth Sciences |
| URI: | https://discovery-pp.ucl.ac.uk/id/eprint/1570288 |
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