Earthquake in Gulf of Mexico sends shock waves from La. to Fla.

TAMPA, Fla. -- The largest earthquake to strike the eastern Gulf of Mexico in the last 30 years sent shock waves from Louisiana to southwest Florida Sunday, but did little more than rattle residents.

The magnitude 6.0 earthquake, centered about 260 miles southwest of Tampa, was too small to trigger a tsunami or dangerous waves, the U.S. Geological Survey said.

The USGS received more than 2,800 reports from people who felt the 10:56 a.m. quake. Scientists said it was the largest and most widely felt of more than a dozen earthquakes recorded in the region in three decades.

"This is a fairly unique event," 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."

The most prevalent vibration, which lasted 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.

Florida counties along the Gulf of Mexico called the state emergency operations center with reports of tremors, but no damage was reported, spokesman Mike Stone said. Gov. Jeb Bush was informed of the situation, Stone said.

The earthquake likely did not have any effect on oil operations in the Gulf of Mexico, according to Ray Connolly, a spokesman for the American Petroleum Institute, the trade association for the U.S. oil and natural gas industry. Earthquakes are factored into the design of the industry's equipment both onshore and offshore, Connolly said.

The epicenter is an unusual location for earthquake activity, but scientists recorded a magnitude 5.2 temblor in the same location Feb. 10.

"This kind of occurrence is unusual in that spot, especially for an earthquake of this size," Blakeman said of Sunday's quake.

The temblor was unusual because it was not centered on a known fault line. The "midplate" earthquake, deep under the gulf, was probably the result of stresses generated by the interaction of tectonic plates in the earth's crust, the agency said.

Only one of Florida's rare earthquakes caused significant damage. In January 1879, St. Augustine residents reported heavy shaking that knocked plaster off the walls.

A more recent temblor, in November 1952, prompted a resident of Quincy to report the shaking "interfered with the writing of a parking ticket," the USGS said.