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Earthquake Early Warning

Earthquake Early Warning (EEW) systems attempt to provide seconds to tens of seconds of warning before the onset of damaging ground motions during an earthquake. The Real-Time Seismology group at the SED focuses its EEW efforts on the Virtual Seismologist (VS) algorithm, a Bayesian approach to regional, network-based EEW.

The VS algorithm (1) rapidly detects the initiation of an earthquake, (2) estimates magnitude and location, and (3) predicts the expected peak ground motion throughout the region. As a Bayesian approach, VS has the potential to use prior information such as the Gutenberg-Richter magnitude-frequency relationships, network topology, and various timescales of earthquake forecasts.

VS has been tested offline in Switzerland, and in real-time in California since July 2008.

VS is one of the three EEW algorithms (along with the ElarmS approach of UC Berkeley and the TauC/Pd approach of Caltech) contributing to the California Integrated Seismic Network (CISN) ShakeAlert system, a prototype, state-wide EEW system for California.

VS implementation efforts have been supported by the US Geological Survey (2009-2012) and by the SAFER (Seismic Early Warning for Europe) project (2006-2009).

Downloads

G. Cua, M. Fischer, M. Caprio, T. Heaton, J. Clinton, and the CISN Earthquake Early Warning Project Team (2010), Faster Alert Information Through Multiple Threshold Event Detection in the Virtual Seismologist (VS) Earthquake Early Warning Algorithm. American Geophysics Union Fall Meeting, San Francisco, California (download)

G. Cua, M. Fischer, T. Heaton, S. Wiemer (2009), Real-Time Performance of the Virtual Seismologist Earthquake Early Warning Algorithm in Southern California, Seism. Res. Lett. 80 (5), p740-747 doi:10.1785/gssrl.80.5.740 (download)

Cua, G. and the CISN EEW group (2009), CISN ShakeAlert: Three Years of Comparative Real-Time Earthquake Early Warning Testing in California. American Geophysics Union Fall Meeting, San Francisco, California (download)

ShakeMaps

Side links:
ShakeMaps @ USGS »
ShakeMaps @ SED »

ShakeMaps provide near-real-time maps of ground motion and shaking intensity following significant earthquakes.

The SED ShakeMaps are automatically generated within 6 minutes of an earthquake we use the ShakeMap codes distributed by the US Geological Survey, and configure these codes to conditions in Switzerland.

Downloads

Cua, G., P. Kaestli, M. Fischer, D. Faeh, S. Wiemer, D. Giardini (2008) Calibrating ShakeMaps in Switzerland, NERIES 3^rd Annual Meeting, Utrecht, Netherlands (download)

Ground Motion Characterization

Similar to standard seismic hazard analysis, earthquake early warning and ShakeMap systems require the use of ground motion prediction equations (GMPEs), intensity prediction equations (IPEs), ground motion – intensity prediction equations (GMICEs), and site amplification information.

Downloads

Cua, G., P. Kaesti, D. Faeh, S. Wiemer, J. Clinton, D. Giardini (2007). Deriving Vs30 Maps for Switzerland from Macroseismic Intenisty Data. American Geophysics Union Fall Meeting, San Francisco, California (download)

Cua, G., and T. Heaton (2008). New Ground Motion Prediction Equations Spanning Weak and Strong Motion Levels. American Geophysics Union Fall Meeting, San Francisco, California (download)