Not really sure if an "alert" about an earthquake that already happened was warranted. Sure, if a bridge was closed, subways were stopped, or power went out - these are things that require people to know and change their plans and require an alert. But telling people "there's an earthquake" but nothing else does not seem to be important.

Also, I live on the coast where earthquakes are common, we have that advanced warning system mentioned in the article - there have been more misfires than valid warnings so far.