Friction properties and deformation mechanisms of halite(-mica) gouges from low to high sliding velocities

Friction properties and deformation mechanisms of halite(-mica) gouges from low to high sliding velocities

Buijze, L.
Niemeijer, A.R.
Han, R.
Shimamoto, T.
Spiers, C.J.

2017

The evolution of friction as a function of slip rate is important in understanding earthquake nucleation and propagation. Many laboratory experiments investigating friction of fault rocks are either conducted in the low velocity regime (10−8–10−4 ms−1) or in the high velocity regime (0.01–1 m s−1). Here, we report on the evolution of friction and corresponding operating deformation mechanisms in analog gouges deformed from low to high slip rates, bridging the gap between these low and high velocity regimes. We used halite and halite–muscovite gouges to simulate processes, governing friction, active in upper crustal quartzitic fault rocks, at conditions accessible in the laboratory. The gouges were deformed over a 7 orders of magnitude range of slip rate (10−7–1 m s−1) using a low-to-high velocity rotary shear apparatus, using a normal stress of 5 MPa and room-dry humidity. Microstructural analysis was conducted to study the deformation mechanisms. Four frictional regimes as a function of slip rate could be recognized from the mechanical data, showing a transitional regime and stable sliding (10−7–10−6 m s−1), unstable sliding and weakening (10−6–10−3 m s−1), hardening (10−2–10−1 m s−1) and strong weakening (10−1–1 m s−1). Each of the four regimes can be associated with a distinct microstructure, reflecting a transition from mainly brittle deformation accompanied by pressure solution healing to temperature activated deformation mechanisms. Additionally, the frictional response of a sliding gouge to a sudden acceleration of slip rate to seismic velocities was investigated. These showed an initial strengthening, the amount of which depended on the friction level at which the step was made, followed by strong slip weakening. © 2016 Elsevier B.V.

Geo
AG - Applied Geosciences
ELSS - Earth, Life and Social Sciences
Geological Survey Netherlands
Geosciences
2015 Energy
Halite
Low to high velocity friction
Rotary shear apparatus

http://resolver.tudelft.nl/uuid:e8c9c608-4627-442f-8f01-047e3ecf1775

https://doi.org/10.1016/j.epsl.2016.09.059

575381

Elsevier B.V.

0012-821X

Earth and Planetary Science Letters, 458, 107-119

article