alt Hacker NewsYou always need to act on it. Get an earthquake alert? Run outside. You can go back if it was a false alert.
In Mexico City the seismic alert gives like a minute (sensors are on the coast off Guerrero 350km away). Communities closer to the usual epicenter get almost no warning.
Before one can action one needs time to read and process whether the alert is for earthquake, tsunami, child abduction, etc