A powerful magnitude 7.7 earthquake struck in the sea in the western Caribbean today, sending workers into the streets and triggering evacuations as buildings shook across the Cayman Islands, in Jamaica, and in downtown Miami.

The epicenter of the quake was between Jamaica, the Cayman Islands and Cuba, at a shallow depth of 10 km.

The region appeared to have avoided major damage and the International Tsunami Information Center said an earlier threat of a tsunami wave had largely passed. Minor sea level fluctuations up to 30cm were still possible, it said.

Angie Watler, a spokeswoman for police on Cayman Brac, the island nearest the epicenter of the quake, said members of the public had reported some damage to buildings and to a swimming pool at the Carib Sands resort on the south of the island.

Videos on social media, apparently from Jamaica and the Cayman Islands, showed water sloshing out of pools during the quake.

Watler said there were no reports so far of injuries but that authorities were still making checks on the area.

Buildings shook in downtown Miami in Florida, the Miami Herald reported. Office buildings were evacuated in the city, as well as in parts of Jamaica.

Officials across the region had no initial reports of major damage despite the size of the quake. A Cayman Islands official said there had been some reports of sinkholes following the quake.

The quake was also felt in several provinces across Cuba, the government said. It was not strongly felt in the capital of Havana, according to a Reuters witness.