Violay, M. and Di Toro, G. and Nielsen, S. and Spagnuolo, E. and Burg, J.P. (2015) 'Thermo-mechanical pressurization of experimental faults in cohesive rocks during seismic slip.', Earth and planetary science letters., 429 . pp. 1-10.
Earthquakes occur because fault friction weakens with increasing slip and slip rates. Since the slipping zones of faults are often fluid-saturated, thermo-mechanical pressurization of pore fluids has been invoked as a mechanism responsible for frictional dynamic weakening, but experimental evidence is lacking. We performed friction experiments (normal stress 25 MPa, maximal slip-rate ∼3 ms−1) on cohesive basalt and marble under (1) room-humidity and (2) immersed in liquid water (drained and undrained) conditions. In both rock types and independently of the presence of fluids, up to 80% of frictional weakening was measured in the first 5 cm of slip. Modest pressurization-related weakening appears only at later stages of slip. Thermo-mechanical pressurization weakening of cohesive rocks can be negligible during earthquakes due to the triggering of more efficient fault lubrication mechanisms (flash heating, frictional melting, etc.).
|Keywords:||Friction, Earthquakes, Fluids, Thermo-mechanical pressurization, Basalt, Marble.|
|Full text:||(AM) Accepted Manuscript|
Available under License - Creative Commons Attribution Non-commercial No Derivatives.
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|Publisher Web site:||http://dx.doi.org/10.1016/j.epsl.2015.07.054|
|Publisher statement:||© 2015 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/|
|Date accepted:||24 July 2015|
|Date deposited:||29 September 2015|
|Date of first online publication:||07 August 2015|
|Date first made open access:||07 August 2016|
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