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Fault friction during simulated seismic slip pulses
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  • Christopher Harbord,
  • Nicolas Brantut,
  • Elena Spagnuolo,
  • Giulio Di Toro
Christopher Harbord
University College London, University College London

Corresponding Author:[email protected]

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Nicolas Brantut
University College London, University College London
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Elena Spagnuolo
Istituto Nazionale di Geofisica e Vulcanologia, Istituto Nazionale di Geofisica e Vulcanologia
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Giulio Di Toro
Università degli Studi di Padova, Università degli Studi di Padova
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Theoretical studies predict that during earthquake rupture faults slide at non-constant slip velocity, however it is not clear which source time functions are compatible with the high velocity rheology of earthquake faults. Here we present results from high velocity friction experiments with non-constant velocity history, employing a well-known seismic source solution compatible with earthquake source kinematics. The evolution of friction in experiments shows a strong dependence on the applied slip history, and parameters relevant to the energetics of faulting scale with the impulsiveness of the applied slip function. When comparing constitutive models of strength against our experimental results we demonstrate that the evolution of fault strength is directly controlled by the temperature evolution on and off the fault. Flash heating predicts weakening behaviour at short timescales, but at larger timescales strength is better predicted by a viscous creep rheology. We use a steady-state slip pulse to test the compatibility of our strength measurements at imposed slip rate history with the stress predicted from elastodynamic equilibrium. Whilst some compatibility is observed, the strength evolution indicates that slip acceleration and deceleration might be more rapid than that imposed in our experiments.
Aug 2021Published in Journal of Geophysical Research: Solid Earth volume 126 issue 8. 10.1029/2021JB022149