The Shake Alert System was first tested by the PNSN in 2015, and it was formally introduced in Washington State on May 4, 2021.

The technology will alert seismic stations monitored by the PNSN in real-time of any approaching earthquake movement close to the epicenter as the ground starts to tremble. This will give us more time to Drop, Cover, and Hold in the case of an earthquake.

Referring to the video: University of Washington