The U.S. Geological Survey and its partners have come out with a new capability designed to characterize large earthquakes quickly in hopes of helping warn the public about potentially damaging shaking headed their way.

The ShakeAlert System, currently available in California, Oregon and Washington, is tapping sensors to detect earth-surface movement via satellite, adding to capabilities from more than 1,500 seismic sensors that detect ground shaking.

The newly added ShakeAlert capability uses data from real-time Global Navigation Satellite System sensors to quickly and accurately determine the magnitude and the area of shaking from very large earthquakes. The GNSS data, which includes the U.S.-based Global Positioning System, will help measure how far the ground moves up, down or sideways during an earthquake.

The ShakeAlert System delivers alerts to cellphones and triggers automatic actions like slowing down trains to prevent derailments, opening firehouse doors so they don’t jam shut, and closing valves to protect water systems.

The ShakeAlert Earthquake system is managed by the USGS in partnership with state agencies and universities.

When the ShakeAlert seismic sensor buildout is completed at the end of 2025, it is anticipated there will be a network of more than 2,000 ShakeAlert stations in California, Oregon and Washington.