The earthquake, centered about 260 miles southwest of Tampa, was too small to trigger a tsunami or dangerous waves, the agency said. The USGS received almost 1,600 reports from people who felt the 10:56 a.m. temblor.
"This is a fairly unique event. There is no danger," said Don Blakeman, an analyst with the National Earthquake Information Center who said the quake was unusually strong. "I wouldn't expect any substantial damage, but it is possible there will be some minor damage."
Florida counties along the Gulf of Mexico called the state emergency operations center with reports of tremors, spokesman Mike Stone said. Gov. Jeb Bush was informed of the situation, Stone said.
The epicenter is an unusual location for earthquake activity, but scientists recorded a magnitude 5.2 temblor in the same location on Feb. 10.
"This kind of occurrence is unusual in that spot, especially for an earthquake of this size," Blakeman said.
The most prevalent vibration, which last for about 20 seconds, was felt on the gulf coast of Florida and in southern Georgia, Blakeman said. But residents in Alabama, Mississippi and Louisiana also called in reports.