Laboratory observations of time‐dependent frictional strengthening and stress relaxation in natural and synthetic fault gouges

Carpenter, B. M.; Ikari, Matt J.; Marone, Chris

doi:10.1002/2015jb012136

Cited by 93 publications

(153 citation statements)

References 141 publications

(299 reference statements)

Supporting

Mentioning

121

Contrasting

Order By: Relevance

“…In the laboratory, during the early part of the interseismic period, immediately after the stress drop, wave speed increases and reaches approximately the preslip value within a short time (Figures ). The increase in V p is consistent with log‐time growth, and/or stiffening, of grain contact junctions, consistent with frictional healing [e.g., Scuderi et al ., ; Carpenter et al ., ]. We note that similar observations have been made on natural faults [ Vidale and Li , ; Brenguier et al ., ; Taira et al ., ].…”

Section: Discussionsupporting

confidence: 87%

On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture

et al. 2016

Self Cite

View full text Add to dashboard Cite

The physical mechanisms governing slow earthquakes remain unknown, as does the relationship between slow and regular earthquakes. To investigate the mechanism(s) of slow earthquakes and related quasi‐dynamic modes of fault slip we performed laboratory experiments on simulated fault gouge in the double direct shear configuration. We reproduced the full spectrum of slip behavior, from slow to fast stick slip, by altering the elastic stiffness of the loading apparatus (k) to match the critical rheologic stiffness of fault gouge (kc). Our experiments show an evolution from stable sliding, when k > kc, to quasi‐dynamic transients when k ~ kc, to dynamic instabilities when k < kc. To evaluate the microphysical processes of fault weakening we monitored variations of elastic properties. We find systematic changes in P wave velocity (Vp) for laboratory seismic cycles. During the coseismic stress drop, seismic velocity drops abruptly, consistent with observations on natural faults. In the preparatory phase preceding failure, we find that accelerated fault creep causes a Vp reduction for the complete spectrum of slip behaviors. Our results suggest that the mechanics of slow and fast ruptures share key features and that they can occur on same faults, depending on frictional properties. In agreement with seismic surveys on tectonic faults our data show that their state of stress can be monitored by Vp changes during the seismic cycle. The observed reduction in Vp during the earthquake preparatory phase suggests that if similar mechanisms are confirmed in nature high‐resolution monitoring of fault zone properties may be a promising avenue for reliable detection of earthquake precursors.

show abstract

Section: Discussionsupporting

confidence: 87%

On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…[] and Carpenter et al . [] reported about 11 and 16% weight loss during drying, respectively. For wet experiments, a room dry sample was jacketed and placed in a pressure vessel with a small confining pressure.…”

Section: Methodsmentioning

confidence: 99%

Frictional strength of wet and dry montmorillonite

2017

View full text Add to dashboard Cite

Montmorillonite is a common mineral in fault zones, and its low strength relative to other common gouge minerals is important in many models of fault rheology. However, the coefficient of friction, μ, varies with degree of saturation and is not well constrained in the literature due to the difficulty of establishing fully drained or fully dried states in the laboratory. We measured μ of both saturated and oven‐dried montmorillonite at normal stresses up to 700 MPa. Care was taken to shear saturated samples slowly enough to avoid pore fluid overpressure. For saturated samples, μ increased from 0.10 to 0.28 with applied effective normal stress, while for dry samples μ decreased from 0.78 to 0.45. The steady state rate dependence of friction, (a − b), was positive, promoting stable sliding. The wide disparity in reported frictional strengths can be attributed to experimental procedures that promote differing degrees of partial saturation or overpressured pore fluid conditions.

show abstract

“…In recent decades, an increasing amount of data has become available from laboratory studies focusing on the frictional properties of natural fault rocks, or their simulated (crushed and sieved) equivalents, sampled from seismically active upper crustal terrains across the globe (Carpenter et al, , ; Chen et al, ; Collettini et al, ; Ikari et al, ; Niemeijer & Collettini, ; Scuderi et al, ; Tembe et al, ; Verberne et al, ; Zhang & He, ) and from hydrocarbon reservoir systems being considered for geological storage of CO 2 (Pluymakers et al, ; Samuelson & Spiers, ). These studies have shown that the frictional strength of such fault rocks and its slip rate dependence, hence potential for velocity weakening or unstable seismogenic slip in the rate and state friction (RSF) approach to fault mechanics (Dieterich, , ; Marone, ; Ruina, ; Scholz, , ), primarily depend on fault rock composition and true, in situ (pore) pressure and temperature conditions.…”

Section: Introductionmentioning

confidence: 99%

Frictional Properties of Simulated Fault Gouges from the Seismogenic Groningen Gas Field Under In Situ P–T ‐Chemical Conditions

2017

View full text Add to dashboard Cite

We investigated the frictional properties of simulated fault gouges derived from the main lithologies present in the seismogenic Groningen gas field (NE Netherlands), employing in situ P–T conditions and varying pore fluid salinity. Direct shear experiments were performed on gouges prepared from the Carboniferous shale/siltstone substrate, the Upper Rotliegend Slochteren sandstone reservoir, the overlying Ten Boer claystone, and the Basal Zechstein anhydrite–carbonate caprock, at 100°C, 40 MPa effective normal stress, and sliding velocities of 0.1–10 μm/s. As pore fluids, we used pure water, 0.5–6.2 M NaCl solutions, and a 6.9 M mixed chloride brine mimicking the formation fluid. Our results show a marked mechanical stratigraphy, with a maximum friction coefficient (μ) of ~0.66 for the Basal Zechstein, a minimum of ~0.37 for the Ten Boer claystone, ~0.6 for the reservoir sandstone, and ~0.5 for the Carboniferous. Mixed gouges showed intermediate μ values. Pore fluid salinity had no effect on frictional strength. Most gouges showed velocity‐strengthening behavior, with little systematic effect of pore fluid salinity or sliding velocity on (a–b). However, Basal Zechstein gouge showed velocity weakening at low salinities and/or sliding velocities, as did 50:50 mixtures with sandstone gouge, tested with the 6.9 M reservoir brine. From a rate and state friction viewpoint, our results imply that faults incorporating Basal Zechstein anhydrite–carbonate material at the top of the reservoir are the most prone to accelerating slip, that is, have the highest seismogenic potential. The results are equally relevant to other Rotliegend fields in the Netherlands and N. Sea region and to similar sequences globally.

show abstract

Laboratory observations of time‐dependent frictional strengthening and stress relaxation in natural and synthetic fault gouges

Cited by 93 publications

References 141 publications

On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture

On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture

Frictional strength of wet and dry montmorillonite

Frictional Properties of Simulated Fault Gouges from the Seismogenic Groningen Gas Field Under In Situ P–T ‐Chemical Conditions

Contact Info

Product

Resources

About