How Useful Are Earthquake Early Warning Systems?

Mexico’s earthquake early warning system may have helped save lives in the Sept. 19 earthquake. Sirens in Mexico City sounded seconds before the earthquake struck the city, giving a brief window to shut down vital infrastructure and evacuate buildings. There was more warning, about 90 seconds, before the larger earthquake that occurred off the coast of Mexico Sept. 8.

ShakeAlert is an Earthquake Early Warning system for the US West Coast. It is being developed by the US Geological Survey and a consortium of universities.

A similar system has been tested for the U.S. West Coast including California and is expected to begin limited public operation in 2018.