Title
Vaporization of fault water during seismic slip
Author
Chen, J.
Niemeijer, A.R.
Fokker, P.A.
Publication year
2017
Abstract
Laboratory and numerical studies, as well as field observations, indicate that phase transitions of pore water might be an important process in large earthquakes. We present a model of the thermo-hydro-chemo-mechanical processes, including a two-phase mixture model to incorporate the phase transitions of pore water, occurring during fast slip (i.e., a natural earthquake) in order to investigate the effects of vaporization on the coseismic slip. Using parameters from typical natural faults, our modeling shows that vaporization can indeed occur at the shallow depths of an earthquake, irrespective of the wide variability of the parameters involved (sliding velocity, friction coefficient, gouge permeability and porosity, and shear-induced dilatancy). Due to the fast kinetics, water vaporization can cause a rapid slip weakening even when the hydrological conditions of the fault zone are not favorable for thermal pressurization, e.g., when permeability is high. At the same time, the latent heat associated with the phase transition causes the temperature rise in the slip zone to be buffered. Our parametric analyses reveal that the amount of frictional work is the principal factor controlling the onset and activity of vaporization and that it can easily be achieved in earthquakes. Our study shows that coseismic pore fluid vaporization might have played important roles at shallow depths of large earthquakes by enhancing slip weakening and buffering the temperature rise. The combined effects may provide an alternative explanation for the fact that low-temperature anomalies were measured in the slip zones at shallow depths of large earthquakes.
Subject
ELSS - Earth, Life and Social Sciences
Geo
PG - Petroleum Geosciences
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http://resolver.tudelft.nl/uuid:edbdc1cc-728a-4298-96c3-28229c2dd9b9
DOI
https://doi.org/10.1002/2016jb013824
TNO identifier
868399
ISSN
2169-9313
Source
Journal of Geophysical Research : Solid Earth, 122 (122), 4237-4276
Document type
article