Citation

Kaproth BM, Marone C. Science 2013; 341(6151): 1229-1232.

Affiliation

Department of Geosciences, and Energy Institute Center for Geomechanics, Geofluids and Geohazards, Pennsylvania State University, University Park, PA, USA.

Copyright

(Copyright © 2013, American Association for the Advancement of Science)

DOI

10.1126/science.1239577

PMID

23950495

Abstract

Earthquakes normally occur as frictional stick-slip instabilities resulting in catastrophic failure and seismic rupture. Tectonic faults also fail in slow earthquakes with rupture durations of months or more, yet their origin is poorly understood. Here, we present laboratory observations of repetitive, slow stick-slip in serpentinite fault zones and mechanical evidence for their origin. We document a transition from unstable to stable frictional behavior with increasing slip velocity, providing a mechanism to limit the speed of slow earthquakes. We also document reduction of P-wave speed within the active shear zone prior to stick-slip events. If similar mechanisms operate in nature, our results suggest that higher-resolution studies of elastic properties in tectonic fault zones may aid in the search for reliable earthquake precursors.

Language: en