The blue square shows the epicenter of Sunday morning's 6.0 magnitude earthquake 260 miles west-southwest of Clearwater.
PINELLAS COUNTY - A magnitude 6.0 earthquake that originated in the Gulf of Mexico at 10:56 a.m. Sunday rattled windows of local residents, and tremors were felt as far north as Georgia and Alabama.
According to the U.S. Geological Survey, National Earthquake Information Center, the epicenter of the quake was in the Gulf of Mexico 260 miles west-southwest of Clearwater and about 6.2 miles below the surface.
A 6.0 earthquake on the Richter scale is classified as strong. According to Wikipedia, strong quakes can be destructive in areas up to about 100 miles across in populated regions. About 120 are reported a year.
More than 200 county residents reported feeling the effects of the quake to the U.S. Geological Survey, National Earthquake Information Center on Sunday morning. Local reports came in from Clearwater, Clearwater Beach, Largo, Pinellas Park, Seminole and St. Petersburg.
No major damage was reported. The USGS said there was no danger of a tsunami.
Florida is not known as a place where earthquakes are considered a hazard; however, history shows that the state has experienced several earthquakes or "tremors" over the years. Only one has ever caused "considerable damage," according to an USGS bulletin.
The earliest recorded earthquake occurred near St. Augustine in January 1878, according to the 1971 bulletin, and reportedly knocked plaster from wall and articles from shelves.
Floridians felt the effects of two strong earthquakes located in Cuba in January 1880, and were shaken by the Charleston, S.C. quake in August 1886.
Minor quakes, 3.0-3.9 on the Richter scale, were reported in Jacksonville in 1893 and 1900.
Quakes in more modern history include the one reported in Captiva on Captiva Island in November 1948. In 1952, a "slight tremor" was reported by residents of Quincy, a small town northwest of Tallahassee.
Before Sunday's quake, the most recent event was recorded Nov. 13, 1978, near Lake City. Authorities said the quake originated in the Atlantic Ocean.
No tremors were reported by the Gainesville seismographic station from 1978 to 1991.
According to information at www.dep.state.fl.us, Florida is located on the trailing (or passive) margin of the North American Plate while California is located on its active margin. The active margin is bounded by faults that generate earthquakes when there is movement along them.
"This is the fundamental reason that Florida has an extremely low incidence of earthquakes while California experiences many (mostly small) earthquakes," according to the Florida Geological Survey.
The FGS said because earthquakes are most often associated with faults, it has received numerous inquiries about the location of faults in the state.
" A number of faults have been proposed by various authors over the years based on various criteria," the USG said. "Because of the difficulties in defining faults in the state there is little agreement concerning the validity of those which have been proposed."
Florida's unique geology makes it difficult to define faults.
"The natural process that causes limestone to dissolve may obscure what was originally a faulted surface," the USG said. "Faults have been proposed based on unconventional criteria such as water quality changes ... None of the proposed features in Florida are known to have any seismicity associated with them. "