This summer, some people got an early warning of the 6.0 magnitude Napa earthquake. Can you tell us about that system?
We’re currently operating throughout California what we call the demonstration project of the CISN (California Integrated Seismic Network) ShakeAlert system. We can recognize earthquakes in progress, characterize them quickly and provide this information down the line to a user display. It’s not a prediction of earthquakes; it’s a very rapid estimation of the size and location of an earthquake that has definitely started. The network is made up of us at UC Berkeley, USGS Menlo Park, CalTech and USGS Pasadena.

Who’s getting the warnings?
We are currently providing warnings to scientists and to beta users who can provide information about how we can make early warning information more useful and how it could improve their ability to respond to an earthquake. The California Office of Emergency Services has ShakeAlert running in their operations center. The Bay Area Rapid Transit System is running it. Other beta testers are San Francisco, Google, Los Angeles, various fire departments in Southern California and Southern California Edison.
They’re receiving the same kind of information: there’s an earthquake, this is the size, the shaking at their location is going to start in X seconds, and it will be weak, moderate, strong, very strong, based on the magnitude of the estimated earthquake and the distance from the earthquake.

How much warning do you get?
You get different amounts of warning based on the distance you are from the earthquake. In Berkeley we would have gotten five seconds (for the Napa quake). The Bay Area Rapid Transit system got eight seconds because their operations center is farther away. The city of San Francisco got nine seconds. Google got about 20 seconds. Five seconds is more than enough time to drop, cover and hold on.
BART has an automated response, and they can stop the trains based on expected earthquake shaking. Every mile an hour less that the trains are going, that’s less of a hazard of derailing, and that means fewer injuries.

Are there plans to roll it out?
We want to have a public earthquake early warning system in California and along the West Coast. We have been working with our colleagues at the USGS, and we’ve put together an earthquake early warning implementation plan. The state of California has a law saying there will be an early warning system, and we are working with the Office of Emergency Services to design that system.