Publication details for Mr Chris HarbordHarbord, Christopher W. A., Nielsen, Stefan B., De Paola, Nicola & Holdsworth, Robert E. (2017). Earthquake nucleation on rough faults. Geology
- Publication type: Journal Article
- ISSN/ISBN: 0091-7613, 1943-2682
- DOI: 10.1130/G39181.1
- Further publication details on publisher web site
- Durham Research Online (DRO) - may include full text
Author(s) from Durham
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.