Scientists at UC Berkeley released a video showing an earthquake early-warning system that sent an alert before the magnitude-6.0 Napa earthquake Sunday morning.
Officials said the system provided an alert 10 seconds before the quake was felt.
California is working to complete a statewide system, which could be unveiled in the next few years.
Once fully developed, the system could give downtown Los Angeles 40 to 50 seconds of warning that the "Big One" was headed from the San Andreas fault, giving time for elevators to stop at the next floor and open up, firefighters to open up garage doors, high-speed trains to slow down to avoid derailment and surgeons to take the scalpel out of a patient.
A lack of funds, however, has slowed the system's progress.
The system works because while earthquakes travel at the speed of sound, sensors that initially detect the shaking near the epicenter of a quake can send a message faster -- at the speed of light -- to warn residents farther away that the quake is coming.
Rep. Adam Schiff (D-Burbank) said the successful test shows the need for the system.