We provide robust and reliable data products for Northern CA earthquakes.

Seismic Velocity Monitoring

Continuous seismic recording archived at the Northern California Earthquake Data Center have been routinely analyzed to monitor time-dependent deformation and hydrothermal fluid at faults and volcanoes. A method involves a cross-correlation of ambient seismic noise collected by pairs of two seismic stations. The resultant noise cross-correlation function (NCFs) will extract an empirical Green's function (or inter-station Earth's structure). By tracking temporal changes in NCFs, we explore changes in Earth's structure as seismic velocity changes that are related to earthquakes and volcanic eruptions.

Daily seismic velocity monitoring for South Napa from just after the August 2014 quake to the present

BSL scientist Taka'aki Taira's seismic velocity work highlighted on the SpringerOpen blog

Moment Tensor Solutions

The Berkeley Seismological Laboratory has been routinely estimating the seismic moment tensors of earthquakes in northern California since 1992. A seismic moment tensor is a mathematical description of the forces that drive earthquake rupture, and they can be interpreted in terms of the nature of the faulting. An automated moment tensor algorithms is used to attempt a preliminary (automatic) moment tensor solution within 6-9 minutes of an earthquake. Excellent solutions (variance reduction > 80%) are posted automatically to the web. All events with M>3.5 are reviewed by an analyst. If a solution is deemed acceptable, it is submitted to the database, disseminated via email and is posted to the web.

Read more about our moment tensor solutions.

Tremorscope Tremor Catalog

The TremorScope stations are designed to record recently discovered deep tremor along the San Andreas Fault in central California. Early studies of this deep tremor have led to dramatic revisions in our views about how faults behave at depth. They reveal fascinatingly complex faulting behavior in the deep crust that is surprisingly different from "normal" earthquakes in the upper crust. Tremorscope complements the existing monitoring activity at Parkfield to sharpen our ability to explore this unusual natural laboratory of active lower crustal faulting, improving our understanding of the nature of tremor signals and their implications for fault mechanics and earthquake hazard.

Read more about tremorscops and the BSL tremor catalog.

Finite Fault Solutions

Preliminary slip model computed at Berkeley for the 2014 Napa quake

2014 Napa quake

Finite-source slip model obtained for the August 24, 2014 Mw6.0 West Napa earthquake

Read the blog entry about this slip model.

2010 Gorda Plate quake

From our Annual Report: January 10, 2010 M 6.5 Gorda Plate Earthquake: Automated Finite-Source Modeling

2007 Alum Rock quake

From our Annual Report: Mapping the Rupture of the October 30, 2007 M 5.4 Alum Rock Earthquake