A partnership of the U.S. Geological Survey (USGS), state agencies and universities has added satellite detection capability to its ShakeAlert earthquake early warning system. In addition to over 1,500 seismic sensors that monitor ground shaking, the network now also relies on sensors that detect earth-surface movement via satellite.

By receiving notifications faster, people in affected areas can quickly take protective actions. Combining seismic sensor information with data from real-time Global Navigation Satellite System (GNSS) sensors may more accurately determine the magnitude and the area of shaking from very large earthquakes. The seismic sensors measure how quickly the ground is shaking while the GNSS sensors measure how far the ground moves up, down or sideways during an earthquake.

At the completion of ShakeAlert seismic sensor installation in 2025, coverage will be provided for residents of California, Oregon and Washington by an array of over 2,000 ShakeAlert stations. Alert delivery will come by public and private means (internet, radio, television, cellular), including wireless emergency alerts delivered by the U.S. Federal Emergency Management Agency’s Integrated Public Alert and Warning System.