Y-B-P-R or S-C-C′? Suggestion for the nomenclature of experimental brittle fault fabric in phyllosilicate-granular mixtures

The Stability Transition From Stable to Unstable Frictional Slip With Finite Pore Pressure

“…The fault normal permeability decreases from 2.2 ∗ 10 −17 to 8.3 ∗ 10 −18 m 2 as a function of shear strain (see Figure S2 in Supporting Information ). We expect, highly anisotropic permeability within the gouge (Zhang et al., 1999) due to shear fabric mobilization (Niemeijer et al., 2009; Scuderi et al., 2017; Volpe et al., 2022). Given the K c increases with strain, we would expect that lower permeability would amplify any localized Pp effects—possibly influencing the frictional parameters.…”

Fluid Influx Promotes Local Strengthening of the Creeping Xianshuihe Fault, Eastern Tibet

“…As shown in studies of natural faults as well as low‐and high‐velocity friction experiments, some faults enriched in strong minerals (quartz, feldspar, olivine, pyroxene, calcite, and dolomite) typically have high frictional coefficients (0.6 < μ < 0.85) and Y‐B‐P‐R fabric, generally attesting to velocity‐weakening behavior (unstable slip) (Boulton et al., 2012; Byerlee, 1978; Volpe et al., 2022). By contrast, faults enriched in weak minerals (clays, talc, chlorite, muscovite, lizardite, and fibrous serpentine) are characterized by very low friction coefficient (0.1 < μ < 0.3) and S‐C‐C’ fabric with velocity‐strengthening behavior (stable slip) (Collettini et al., 2019; He et al., 2018; Moore & Rymer, 2007; Tesei et al., 2015; Volpe et al., 2022) (Table 3). The Qianning segment of the Xianshuihe fault has extensive stable‐slip (creeping) behavior based on geodetic and geological evidence (Figure 2), but the amount of strong minerals in the fault core of the Cunielongba exposure is 64%–87%, that is, much higher than that of weak minerals (12%–36%) (Table S1 in Supporting Information S1), and strong minerals in the PSZ gouge especially account for 71%–74% and clays for 27%.…”

“…The frictional stability of the fault is mainly related to the fault strength that depends on the mineral composition and heterogeneity of the fault rocks (Bedford et al., 2022; Ikari et al., 2011). As shown in studies of natural faults as well as low‐and high‐velocity friction experiments, some faults enriched in strong minerals (quartz, feldspar, olivine, pyroxene, calcite, and dolomite) typically have high frictional coefficients (0.6 < μ < 0.85) and Y‐B‐P‐R fabric, generally attesting to velocity‐weakening behavior (unstable slip) (Boulton et al., 2012; Byerlee, 1978; Volpe et al., 2022). By contrast, faults enriched in weak minerals (clays, talc, chlorite, muscovite, lizardite, and fibrous serpentine) are characterized by very low friction coefficient (0.1 < μ < 0.3) and S‐C‐C’ fabric with velocity‐strengthening behavior (stable slip) (Collettini et al., 2019; He et al., 2018; Moore & Rymer, 2007; Tesei et al., 2015; Volpe et al., 2022) (Table 3).…”

Strain Localization in Sandstone‐Derived Fault Gouges Under Conditions Relevant to Earthquake Nucleation

“…Laboratory friction experiments have shown that natural shear fabrics can be reproduced in experimental fault zones from subseismic ( V < 100 μm/s; e.g. Beeler et al., 1996; Bedford & Faulkner, 2021; Haines et al., 2013; Logan, 1979; Mercuri et al., 2018; Moore & Byerlee, 1991, 1992; Noël et al., 2023; Volpe et al., 2022; Wojatschke et al., 2016) to seismic rates ( V > 1 m/s; e.g. Kuo et al., 2014; S. A. F. Smith et al., 2013).…”