Earthquake nucleation on rough faults

Harbord, Christopher W.A.; Nielsen, Stefan B.; De Paola, Nicola; Holdsworth, Robert E.

doi:10.1130/g39181.1

Earthquake nucleation on rough faults

Harbord, Christopher W.A.; Nielsen, Stefan B.; De Paola, Nicola; Holdsworth, Robert E.

Authors

Christopher W.A. Harbord

Professor Stefan Nielsen stefan.nielsen@durham.ac.uk
Professor

Professor Nicola De Paola nicola.de-paola@durham.ac.uk
Professor

Professor Bob Holdsworth r.e.holdsworth@durham.ac.uk
Professor

Abstract

Earthquake nucleation is currently explained using rate and state stability analysis, which successfully models the behavior of laboratory simulated faults with constant thickness gouge layers. However, roughness is widely observed on natural faults and its influence on earthquake nucleation is little explored. Here we conduct frictional sliding experiments with different roughness on granite samples at upper crustal conditions (30–200 MPa). We observe a wide range of behaviors, from stable sliding to stick slip, depending on the combination of roughness parameters and normal stress. Stick slip is repeatedly observed in velocity-strengthening regimes, and increases in normal stress stabilize slip; these features are not fully predicted by current stability analysis. We derive a new instability criterion that matches our observations, based on fracture energy considerations and the size of weak patches created by fault roughness.

Citation

Harbord, C. W., Nielsen, S. B., De Paola, N., & Holdsworth, R. E. (2017). Earthquake nucleation on rough faults. Geology, 45(10), 931-934. https://doi.org/10.1130/g39181.1

Journal Article Type	Article
Acceptance Date	Jun 28, 2017
Online Publication Date	Aug 8, 2017
Publication Date	Oct 1, 2017
Deposit Date	Jun 28, 2017
Publicly Available Date	Jul 3, 2017
Journal	Geology
Print ISSN	0091-7613
Electronic ISSN	1943-2682
Publisher	Geological Society of America
Peer Reviewed	Peer Reviewed
Volume	45
Issue	10
Pages	931-934
DOI	https://doi.org/10.1130/g39181.1