Exciting news! We're transitioning to the Statewide California Earthquake Center. Our new website is under construction, but we'll continue using this website for SCEC business in the meantime. We're also archiving the Southern Center site to preserve its rich history. A new and improved platform is coming soon!

Rupture history of 2014 Mw 6.0 South Napa earthquake inferred from near-fault strong motion data and its impact to the practice of ground strong motion prediction

Cedric Twardzik, Ralph J. Archuleta, & Chen Ji

Published April 14, 2015, SCEC Contribution #6108

The spatiotemporal rupture history of the 2014 South Napa earthquake is constrained using near-fault strong motion records. An aggressive source parameterization with 1372 subfaults is adopted to match the signals in the transverse components up to 4 Hz. The result reveals that the rupture of the Napa earthquake initiated at a depth of 9.84 km and propagated mainly to north-northwest (NNW) and updip on a 13 km long fault patch. A gradual increase in average rise time when the rupture propagates to shallower depth is observed. However, it is the rupture of a small (Mw 4.9), isolated, and high stress drop fault patch that excited the largest ground acceleration at stations south of the epicenter. Such fine-scale rupture heterogeneity shall be considered during seismic hazard analysis.

Key Words
2014 South Napa earthquake, aggressive source parameterization, 4 Hz seismic signals, variation of rise time, seismic hazard analysis

Citation
Twardzik, C., Archuleta, R. J., & Ji, C. (2015). Rupture history of 2014 Mw 6.0 South Napa earthquake inferred from near-fault strong motion data and its impact to the practice of ground strong motion prediction . Geophysical Research Letters, 42(7), 2149-2156. doi: 10.1002/2015GL063335. http://onlinelibrary.wiley.com/doi/10.1002/2015GL063335/full