Strength evolution of simulated carbonate-bearing faults: The role of normal stress and slip velocity

• DOI: 10.1016/j.jsg.2017.12.017
• Publication Date: 2017-12-29T17:36:37Z
• Authors: Marco Mercuri; Marco Maria Scuderi; Telemaco Tesei; Eugenio Carminati; Cristiano Collettini
• Keywords: Calcite; Carbonate-bearing faults; Friction; Microstructures; 669; calcite; carbonate-bearing faults; friction; microstructures; geology; 01 natural sciences; 0105 earth and related environmental sciences

Abstract A great number of earthquakes occur within thick carbonate sequences in the shallow crust. At the same time, carbonate fault rocks exhumed from a depth 20 MPa) fault gouges undergo strain-weakening, that is more pronounced at slow slip velocities, and causes a significant reduction of frictional strength, from μ = 0.7 to μ = 0.47. Microstructural analysis show that fault gouge weakening is driven by deformation accommodated by cataclasis and pressure-insensitive deformation processes (pressure solution and granular plasticity) that become more efficient at slow slip velocity. The reduction in frictional strength caused by strain weakening behaviour promoted by the activation of pressure-insensitive deformation might play a significant role in carbonate-bearing faults mechanics.