The M_w 6.5 offshore Northern California earthquake of 10 January 2010: Ordinary stress drop on a high‐strength fault

Authors

Meng Wei, University of Rhode IslandFollow
Jeffrey J. McGuire

Document Type

Article

Date of Original Version

2014

Department

Oceanography

Abstract

The 10 January 2010 M_w 6.5 earthquake offshore Northern California is one of the first intraplate earthquakes in oceanic lithosphere to be well captured by a GPS network. It presents an opportunity to evaluate rupture mechanics on a high‐strength fault. Static inversion of the coseismic displacements shows that the slip peaks at the same depth as the expected strength envelope, where the differential stresses can be as high as 600 MPa. Laboratory experiments on peridotite predict dramatic dynamic weakening at these conditions. The observed ordinary stress drop, 2–20 MPa, may indicate that the lithosphere is much weaker than strength envelope predicts or that the failure mechanisms seen in the laboratory are not occurring during the rupture. The GPS observations show very little postseismic signal indicating that if a shear zone exists beneath the coseismic rupture, it operates at significantly greater stress levels than the coseismic stress change.

Citation/Publisher Attribution

Wei, M., and J. J. McGuire (2014), The M_w 6.5 offshore Northern California earthquake of 10 January 2010: Ordinary stress drop on a high‐strength fault, Geophys. Res. Lett., 41, 6367–6373, doi: 10.1002/2014GL061043.

Available at: https://doi.org/10.1002/2014GL061043