The first AP item was Twitter-sized, and straight to the point: "Strong, long quake shakes Mexico City."
The center was about a hundred miles away from Acapulco, halfway between this popular resort-and-beaheadings town and the colonial city of Oaxaca. CBS News reports nine-foot waves at Acapulco beaches.
An informal scan of folks in Mexico whom I follow on Twitter suggests it was felt strongly in a wide area from the Guatemalan border to Mexico's capital city; structural damage seems limited so far; electricity mostly uninterrupted but cell and data service spotty. Aftershocks are causing jitters.
A statement from Mexican president Felipe Calderon: no serious damage reported.
* post updated to reflect new USGS data.