Slow slip in subduction zones: Reconciling deformation fabrics with instrumental observations and laboratory results

Abstract Cataclasites are a characteristic rock type found in drill cores from active faults as well exposed fossil subduction faults. Here, cataclasites commonly associated with evidence for pervasive pressure solution and abundant hydrofracturing. They host the principal slip of regular earthquakes family so-called slow (episodic tremor, low to very frequency earthquakes, etc.). Slip velocities formation different types conditions controlling poorly constrained both direct observations nature experimental research. In this study, we explore sections their dominant microstructures. We use recently proposed constitutive laws estimate deformation rates, compare predicted rates instrumental zones. By identifying maximum strain using fault scaling relations constrain core thickness, find that shear identified “slow earthquakes” features range 10−3s−1 10−5s−1. These values agree estimated stress corrosion creep or brittle possibly cataclastic near failure threshold. Typically, pore-fluid pressures suggested be high zones triggering slip. However, seismic events causing local dilatancy may reduce fluid promoting pressure-solution (yielding <10−8 10−12s−1) during interseismic period agreement fabrics plate interface Our suggest cataclasis is controlled by driven fluctuations at near-lithostatic effective stresses close failure. posit flow physical mechanism governing transient episodes such (SSEs), accelerating preparatory before events, early afterslip seismogenic zone.