Citation

Guglielmi Y, Cappa F, Avouac JP, Henry P, Elsworth D. Science 2015; 348(6240): 1224-1226.

Affiliation

Energy and Mineral Engineering and Geosciences, Earth and Mineral Sciences Energy Institute and G3 Center, Pennsylvania State University, University Park, PA 16802, USA.

Comment In:

Science 2015;348(6240):1204-5.

Copyright

(Copyright © 2015, American Association for the Advancement of Science)

DOI

10.1126/science.aab0476

PMID

26068845

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.

Language: en