Even seasoned scientists were surprised by a rare 5.1-magnitude earthquake that struck Thursday afternoon off the northern coast of Cuba, rattling residents on both sides of the Florida Straits.
“There is no question that it is unusual where it hit,” said Timothy Dixon, a University of South Florida geophysics professor and earthquake expert. “I have no clue why this earthquake happened.”
Dixon said the earthquake — centered about 112 miles east of Havana in coastal waters — happened about 300 miles from a major fault line between southern Cuba and Hispaniola.
“Scientists are definitely going to be looking at this one,” he said. “Earthquakes happen periodically in Cuba, but in the south.”
The earthquake, which occurred at 3:58 p.m., was not strong enough to cause serious damage, but people reported feeling its effects across the Florida Keys and as far north as Cape Coral on Florida’s Gulf Coast.
“Unbelievable,” said Shelia Cullen, assistant retail manager at the Custom House Museum in Key West. “It scared the crap out of everyone on the third floor. We have stuff everywhere up here, and a huge decorative vase was rocking back and forth.”
Thursday’s earthquake was the sixth known earthquake between 3.0 and 5.6 magnitude recorded within 125 miles of the area in the past 75 years, according to the U.S. Geological Survey.
The epicenter was about 24 miles north of Corralillo, Cuba, in an area that the USGS said is generally “quiet seismically” but also close to several minor faults, collectively called the Nortecubana Fault system.
Cuba last experienced an earthquake in 2010, when a 5.6-magnitude earthquake hit in the waters off Oriente Province, according to the USGS.
The agency initially reported the quake as a magnitude of 5.0, and later upgraded it to 5.1.
The U.S. National Weather Service said there was no tsunami danger.
Still, nerves were rattled by the moving earth and swaying lamps.
In Bonita Springs on Florida’s west coast, resident Steve Dicarlo told the Naples Daily News he felt movement in his sixth-floor condo unit.
“I looked up and the blinds on my window were shaking back and forth,” he said. “The kitchen lamp, which is hanging on a chain, was swaying back and forth.”
Bill Winter, who lives in Marco Island, said the tremor lasted about 30 seconds in his 15th-floor condo.
"We heard noises in the kitchen, banging noises, and our hanging pots were clanging together," he said.
Winter said he didn't feel much but definitely heard noises and saw some of his light fixtures swaying.
"And no, we had not been drinking," he joked.
In Old Havana, the quake was felt clearly by workers in two six-floor buildings that were temporarily evacuated. It appeared to last around 30 seconds, according to the Associated Press.
Sandor Polo, a 31-year-old waiter, said he was delivering food to a third-floor office when boxes suddenly began to move and workers started yelling.
"I got dizzy," Polo said, adding that he's never felt anything like it in his life.
"Everything was moving," Nuria Oquendo, a 44-year-old office assistant who was on the sixth floor of a neighboring building, told the AP. "You could really feel it, very clear, very defined."
Like Polo, she had never been in an earthquake before. She called the experience unsettling, but said she wasn't scared.
"Not frightened, but a sensation that something strange is going on," Oquendo said.
Cuba is not as known for seismic activity as other parts of Latin America and the Caribbean. Just four years ago, for instance, Haiti was devastated by a 7.0 earthquake that killed more than 100,000 people.
But a number of significant quakes have hit Cuba over the years, including one in 1932 that killed eight people and damaged 80 percent of the buildings in the eastern city of Santiago, according to USGS records.
City of Key West spokeswoman Alyson Crean said the police station received "a few calls but no reports of any impacts."
Trice Denny, Naval Air Station Key West spokeswoman, she received a couple of calls from people who thought the shaking was the result of sonic booms.
“I got one from the city. As I was researching that, I happened to look at the USGS's website and realized it was an earthquake,’’ she said. “No, it was not the result of supersonic air-to-air combat training on our ranges."
Sean Kinney and Larry Kahn of Keynoter.com reported from the Keys.