Experimental evidence for multiple controls on fault stability and rupture dynamics

Microphysical Modeling of Fault Slip and Stability Transition in Hydrothermal Conditions

“…Moreover, the value of (a − b) at 0.1-0.01 μm/s is a bit lower than that at 1-0.1 μm/s, implying that the load-point velocity can influence the friction rate parameter (a − b) and also the temperature range for stability transitions. The velocity-weakening behavior is enhanced by slow load-point velocities, which has been verified in some experiments (Chen et al, 2017;Mei et al, 2022;Niemeijer & Collettini, 2014;Okuda et al, 2023).…”

A Rate‐, State‐, and Temperature‐Dependent Friction Law With Competing Healing Mechanisms

“…The multiplicative form of Equation 4 is well posed for any range of sliding velocity, does not require additional regularization for vanishing slip speed, offers adequate prediction of velocity‐step experiments (Mei, Barbot, Jia, & Wu, 2021), and makes fault dynamics sensitive to absolute stress during seismic cycles (Barbot, 2019a, 2019b), as seen in some experiments (Karner & Marone, 2001). Using the real area of contact or the radius of curvature of micro‐asperities explicitly as a state variable allows direct comparison with experimental data for transparent materials (e.g., Bayart et al., 2018; Ben‐David & Fineberg, 2011; Dieterich & Kilgore, 1994, 1996; Gvirtzman & Fineberg, 2021; Kammer et al., 2018; Svetlizky et al., 2019, 2020), such that all aspects of the model are measurable quantities.…”

Laboratory Earthquake Ruptures Contained by Velocity Strengthening Fault Patches

“…For example, we find Ḋ max ∼ 4 μm/s at $$L/{h}^{\ast }$$ = 1.4 and ∼10 mm/s at $$L/{h}^{\ast }$$ = 2.8 (Figure 6b). For Transition 2, a bifurcation in slip behavior (e.g., alternation of slow and fast slips) has been reported (Mei et al., 2022; Veedu et al., 2020) under a narrow range of conditions. In addition to $$L/{h}^{\ast }$$, Luo and Ampuero (2018) found the relative strength parameter, α = ( b − a ) VW /( a − b ) VS , to be an important factor in determining slip behavior.…”

“…More commonly, lab experiments use a VW fault surface using rocks or plastic materials, surrounded by the free surfaces of the sample (i.e., L = total sample length). These experiments also reported fast and slow stick-slip events (Leeman et al, 2016;Mclaskey & Yamashita, 2017;Mei et al, 2021Mei et al, , 2022Yamashita et al, 2022). However, in this case, the free ends of the sample are more unstable than the interior of the sample, so the fault ends can act as asperities (Cebry et al, 2022), which does not correctly simulate natural seismic zones.…”