Widespread Fault Creep in the Northern San Francisco Bay Area Revealed by Multistation Cluster Detection of Repeating Earthquakes
- Author(s): Shakibay Senobari, Nader
- Funning, Gareth J
- et al.
Published Web Locationhttps://doi.org/10.1029/2019gl082766
©2019. American Geophysical Union. All Rights Reserved. We search for repeating earthquakes (REs) in the northern San Francisco Bay Area in 1984–2016. By comparing over 670,000 waveforms from ∼75,000 events, we identify candidate clusters of events whose waveforms have high cross-correlation coefficients at multiple stations. A key difference with our approach is that these “multistation clusters” do not require each event in a family be recorded at multiple common stations. We validate these candidate REs by estimating precise relative relocations for the events in each cluster. We identify 59 RE families whose relocated hypocenters are separated by less than one source radius. These are distributed throughout the Maacama fault zone and along the northern Rodgers Creek and central Bartlett Springs faults, implying that widespread, pervasive creep occurs on those faults, at rates of 1–6 mm/year. At either end of the Maacama fault, the RE pattern highlights structural complexity, suggesting that multiple subparallel strands may be active and creeping.