Entire West Coast now has access to earthquake early warning system Richard Vogel/AP FILE - In this Jan. 3, 2019, file photo, a mobile phone customer looks at an earthquake warning application on an iPhone in Los Angeles. (AP Photo/Richard Vogel, File) and last updated 2021-05-05 18:18:23-04 SEATTLE, Wash. â The entire West Coast now has access to ShakeAlert, an earthquake early warning system that allows messages to be sent to mobile phones once thereâs a tremor. The system debuted in Washington state Tuesday after it was introduced in Oregon in March and made available in California in 2019. The three states represent the most earthquake-prone region in the continental U.S.