A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

Niemeijer, A. R.; Spiers, Christopher J.

doi:10.1029/2007jb005008

Cited by 177 publications

(283 citation statements)

References 69 publications

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“…These deformation mechanisms have similarly been identified in laboratory friction experiments performed under (seismogenic) conditions that favor pressure solution creep (Bos et al, 2000;Chen et al, 2015;Niemeijer & Spiers, 2006) and have been argued to govern velocity-weakening behavior and stick-slip instability nucleation (Chen & Spiers, 2016;Niemeijer & Spiers, 2007). Our simulations show that the interplay between dilatant granular flow and nondilatant pressure solution indeed generates stick-slips as reported by laboratory studies, as envisioned in microphysical models, and as supported by field observations.…”

Section: Implications and Concluding Remarkssupporting

confidence: 67%

“…Following Niemeijer and Spiers (2007) and Chen and Spiers (2016), we consider the interplay between dilatant granular flow and compaction by intergranular pressure solution, which has been proposed by these authors as a mechanism for velocity-weakening behavior, a requirement for stick-slip behavior (Gu et al, 1984;Ruina, 1983). By employing the implementation of pressure solution in DEM by Van den Ende, Marketos, et al (2018), we simulate unstable frictional sliding of fault gouges while systematically varying the kinetics of pressure solution, and we investigate the effect of these fluid-rock interactions on the frictional behavior of the gouge.…”

Section: Introductionmentioning

confidence: 99%

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Time-dependent compaction as a mechanism for regular stick-slips

Ende¹,

Niemeijer²

2018

Preprint

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Owing to their destructive potential, earthquakes receive considerable attention from laboratory studies. In friction experiments, stick-slips are studied as the laboratory equivalent of natural earthquakes, and numerous attempts have been made to simulate stick-slips numerically using the discrete element method (DEM). However, while laboratory stick-slips commonly exhibit regular stress drops and recurrence times, stick-slips generated in DEM simulations are highly irregular. This discrepancy highlights a gap in our understanding of stick-slip mechanics, which propagates into our understanding of earthquakes. In this work, we show that regular stick-slips emerge in DEM when time-dependent compaction by pressure solution is considered. We further show that the stress drop and recurrence time of stick-slips are directly controlled by the kinetics of pressure solution. Since compaction is known to operate in faults, this mechanism for frictional instabilities directly relates to natural seismicity. Plain Language SummaryEarthquakes have a big impact on the society and are therefore intensively studied in laboratory settings. The study of laboratory-scale earthquakes, the so-called stick-slips, generates new insights into the origin and behavior of earthquakes in nature. At present, computer simulations of stick-slips have not been able to reproduce prominent laboratory observations, which shows that the origin of stick-slips, and of natural earthquakes, is not yet fully understood. In this work, we present computer simulations that succeed to reproduce the laboratory observations, thereby revealing that time-dependent compaction is of great importance to stick-slips and natural earthquakes. These results help to further understand the complex behavior of earthquakes in nature.

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Section: Implications and Concluding Remarkssupporting

confidence: 67%

Section: Introductionmentioning

confidence: 99%

Time-dependent compaction as a mechanism for regular stick-slips

Ende¹,

Niemeijer²

2018

Preprint

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“…From laboratory experiments it is well known that the friction angle of the slipping portion of the fault is reduced upon slip initiation, resulting in more slip until a new balance is found for the stabilised stresses after slip and the reduced friction angle (e.g. Niemeijer & Spiers, 2007). Numerical inclusion of slip-weakening effects and/or rate and state friction effects during rupture events result in a less smooth build-up of seismic moment and can produce synthetic seismic catalogues with characteristics similar to actual catalogues (Baisch et al, 2010;Rutqvist et al, 2013;Wassing et al, 2014).…”

Section: Fault Slip and Rupturementioning

confidence: 99%

Geomechanical models for induced seismicity in the Netherlands: inferences from simplified analytical, finite element and rupture model approaches

Wees

Fokker

Thienen-Visser

et al. 2017

Netherlands Journal of Geosciences

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In the Netherlands, over 190 gas fields of varying size have been exploited, and 15% of these have shown seismicity. The prime cause for seismicity due to gas depletion is stress changes caused by pressure depletion and by differential compaction. The observed onset of induced seismicity due to gas depletion in the Netherlands occurs after a considerable pressure drop in the gas fields. Geomechanical studies show that both the delay in the onset of induced seismicity and the nonlinear increase in seismic moment observed for the induced seismicity in the Groningen field can be explained by a model of pressure depletion, if the faults causing the induced seismicity are not critically stressed at the onset of depletion. Our model shows concave patterns of log moment with time for individual faults. This suggests that the growth of future seismicity could well be more limited than would be inferred from extrapolation of the observed trend between production or compaction and seismicity. The geomechanical models predict that seismic moment increase should slow down significantly immediately after a production decrease, independently of the decay rate of the compaction model. These findings are in agreement with the observed reduced seismicity rates in the central area of the Groningen field immediately after production decrease on 17 January 2014. The geomechanical model findings therefore support scope for mitigating induced seismicity by adjusting rates of production and associated pressure change. These simplified models cannot serve as comprehensive models for predicting induced seismicity in any particular field. To this end, a more detailed field-specific study, taking into account the full complexity of reservoir geometry, depletion history and mechanical properties, is required.

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“…In order to reduce this error, in our inversions we begin with the measured stiffness of the apparatus based on the applied vertical load (that is, accounting for nonlinearity in stiffness at low loads) and then measure the stiffness for each velocity step and allow for minor changes that may arise from thinning of the layer and changes in porosity. Furthermore, while not the goal of this study, we note that there is a variety of "designer" friction laws that have been invoked to describe possible physical mechanisms underlying complex responses to velocity perturbations [e.g., Reinen et al, 1991;Kato and Tullis, 2001;Niemeijer and Spiers, 2007]. …”

Section: Friction Constitutive Propertiesmentioning

confidence: 99%

Frictional properties of the active San Andreas Fault at SAFOD: Implications for fault strength and slip behavior

2015

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We present results from a comprehensive laboratory study of the frictional strength and constitutive properties for all three active strands of the San Andreas Fault penetrated in the San Andreas Observatory at Depth (SAFOD). The SAFOD borehole penetrated the Southwest Deforming Zone (SDZ), the Central Deforming Zone (CDZ), both of which are actively creeping, and the Northeast Boundary Fault (NBF). Our results include measurements of the frictional properties of cuttings and core samples recovered at depths of ~2.7 km. We find that materials from the two actively creeping faults exhibit low frictional strengths (μ = ~0.1), velocity‐strengthening friction behavior, and near‐zero or negative rates of frictional healing. Our experimental data set shows that the center of the CDZ is the weakest section of the San Andreas Fault, with μ = ~0.10. Fault weakness is highly localized and likely caused by abundant magnesium‐rich clays. In contrast, serpentine from within the SDZ, and wall rock of both the SDZ and CDZ, exhibits velocity‐weakening friction behavior and positive healing rates, consistent with nearby repeating microearthquakes. Finally, we document higher friction coefficients (μ > 0.4) and complex rate‐dependent behavior for samples recovered across the NBF. In total, our data provide an integrated view of fault behavior for the three active fault strands encountered at SAFOD and offer a consistent explanation for observations of creep and microearthquakes along weak fault zones within a strong crust.

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A microphysical model for strong velocity weakening in phyllosilicate‐bearing fault gouges

Cited by 177 publications

References 69 publications

Time-dependent compaction as a mechanism for regular stick-slips

Time-dependent compaction as a mechanism for regular stick-slips

Geomechanical models for induced seismicity in the Netherlands: inferences from simplified analytical, finite element and rupture model approaches

Frictional properties of the active San Andreas Fault at SAFOD: Implications for fault strength and slip behavior

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