The evolution of rock friction is more sensitive to slip than elapsed time, even at near-zero slip rates

Proceedings of the National Academy of Sciences
By: , and 

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Abstract

For many decades, frictional strength increase at low slip rates has been ascribed to time-dependent contact-area growth across the sliding interface. As a result, phenomenological models that correctly predict contact-area growth, as observed in laboratory experiments, have also been widely assumed to be appropriate descriptors of frictional strength evolution. We present experiments that impose more than 5-orders-of-magnitude slip-rate reductions on granite to show that frictional strength evolution in these rocks unequivocally refutes such models. Instead, the data suggest that, even at subnanometric slip rates, frictional strength dominantly evolves with accrued slip. This remarkable slip-sensitivity of friction requires changes of intrinsic strength of the interface with slip that are absent from popular conceptual models of friction at the microscopic contact scale.
Publication type Article
Publication Subtype Journal Article
Title The evolution of rock friction is more sensitive to slip than elapsed time, even at near-zero slip rates
Series title Proceedings of the National Academy of Sciences
DOI 10.1073/pnas.2119462119
Volume 119
Issue 30
Year Published 2022
Language English
Publisher PNAS
Contributing office(s) Earthquake Science Center
Description e2119462119, 11 p.
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