Estimating friction in normal fault systems of the Basin and Range province and examining its geological context

Abstract

The life cycle of a fault following initiation is governed in part by the reshear criterion, of which rock surface friction is the critical factor limiting the dip of a fault at its death. Using structural restorations where the initial and final dips of faults can be ascertained, the coefficient of rock surface friction is calculated for well-characterized extended locales (n=20) in the Basin and Range province, many with multiple fault generations (n=34). The calculated values exhibit a considerably wider range (0.19–1.33) than previously reported. The amount of tilting associated with each fault generation is compared with eight characteristics (mean slip magnitude, tilting per unit of slip, fault spacing, percentage extension, absence or presence and composition of magmatism, duration of extension, timing of extension and strain rate). No statistically strong correlation was found with any of the examined characteristics, although tentative linkages were noted with percentage extension, strain rate and mean slip magnitude from weighted regression analysis. These results are consistent with normal faults behaving as non-linear systems, with friction being an emergent property.

Accommodation of Plate Motion in an Incipient Strike‐Slip System: The Central Walker Lane

“…Whether we assume that the faults in the Mina Deflection initially formed at ϴ = ∼30° from the roughly north‐oriented σ 1 (e.g., Bellier & Zoback, 1995), based on Mohr Coulomb theory and Byerlee's law, or if they formed at ϴ = ∼45°, as Reidel shears perpendicular to the primary northwest oriented dextral faults (Wesnousky, 2005), their current 080°–085° orientation is close to the lockup angle, 2ϴ. At this stage of rotation, modeling and field studies show that a new set of faults may form (e.g., Olive & Behn, 2014; Richardson & Seedorff, 2017).…”

A minimal rupture model for earthquakeoccurrence with implications for the multiscaleanalysis of physical parameters from the lab tofault systems

“…There is indeed little evidence of static friction coefficients higher than µ s ≈ 0.2 at tectonic spatial scales at least along large fault systems, e.g., [78][79][80][81]. However, the possibility of macroscopically higher frictional coefficients cannot be excluded along strongly segmented and rough seismogenic sources in complex tectonic settings like rifts and locked fault segments, e.g., [82], observed at local scales with compatibility between laboratory friction and natural faults [83]. Moreover, friction coefficients are affected by the depth and temperature profiles, fluid pressure conditions.…”

Cenozoic structural evolution of the Catalina metamorphic core complex and reassembly of Laramide reverse faults, southeastern Arizona, USA

“…The means by which balance is achieved in the middle and lower crust is less certain; in certain locales this probably involves important three-dimensional components of crustal flow and magmatism (e.g., Gans, 1987;MacCready et al, 1997). A good first-order approximation of extensional deformation at shallow levels (e.g., <10 km), however, is brittle deformation characterized largely by rigid-body rotations (e.g., Proffett, 1977;Richardson and Seedorff, 2017) supplemented by flexure that probably is achieved by numerous, small-offset fractures (Thompson and Parsons, 2016).…”

“…Modern earthquakes in the Basin and Range province, as well as other actively extending areas of continental crust around the globe (e.g., Italy, Greece, and Turkey), rarely record offset on normal faults that dip at low angles (e.g., faults <30°; Jackson, 1987;Jackson and White, 1989;Collettini and Sibson, 2001). This suggests that normal faults in continental crust generally lock up and are no longer active after they rotate to 30-40° (though they vary in different cases; Richardson and Seedorff, 2017), and if extension is to continue, a new crosscutting fault set that originally dips at steep angles (~60°) would…”

“…When normal faults slip in the reconstruction, they rotate to lower angles, and faults with shallower dips typically have greater slip (e.g., Kusznir et al, 1991;Richardson and Seedorff, 2017;Thompson and Parsons, 2016). The edges of the section do not experience deformation and only move out laterally because, as slip progresses, the hanging wall flexes downward due to gravity and the footwall flexes upward due to isostatic unloading (Fig.…”