title: INDUCED SEISMICITY. Seismicity triggered by fluid injection-induced aseismic slip.
abstract: Anthropogenic fluid injections are known to induce earthquakes. The mechanisms involved are poorly understood, and our ability to assess the seismic hazard associated with geothermal energy or unconventional hydrocarbon production remains limited. We directly measure fault slip and seismicity induced by fluid injection into a natural fault. We observe highly dilatant and slow [~4 micrometers per second (μm/s)] aseismic slip associated with a 20-fold increase of permeability, which transitions to faster slip (~10 μm/s) associated with reduced dilatancy and micro-earthquakes. Most aseismic slip occurs within the fluid-pressurized zone and obeys a rate-strengthening friction law μ = 0.67 + 0.045ln(v/v₀) with v₀ = 0.1 μm/s. Fluid injection primarily triggers aseismic slip in this experiment, with micro-earthquakes being an indirect effect mediated by aseismic creep.
authors.affiliation: Centre de Recherche et d'Enseignement de Géosciences de l'Environnement (UMR7330), University of Aix-Marseille, CNRS, IRD, 13545 Aix-en-Provence, France. guglielmi@cerege.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Guglielmi
authors.affiliation: Géoazur (UMR 7329), University of Nice Sophia-Antipolis, CNRS, IRD, Côte d'Azur Observatory, 06560 Sophia-Antipolis, France. Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Cappa
authors.affiliation: Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Avouac
authors.affiliation: Centre de Recherche et d'Enseignement de Géosciences de l'Environnement (UMR7330), University of Aix-Marseille, CNRS, IRD, 13545 Aix-en-Provence, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Henry
authors.affiliation: Energy and Mineral Engineering and Geosciences, Earth and Mineral Sciences Energy Institute and G3 Center, Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Derek
authors.initials: D
authors.lastname: Elsworth