"Based on all available data, there is no significant tsunami threat from this (6.1) natural disaster".
Citizens in Kingston, which is on the far side of the island from the epicenter, reported that they felt tremors for less than a minute. It was followed by more than a dozen aftershocks, the strongest of which registered at 6.1 magnitude. Some clips from the Cayman Islands and Jamaica captured damage to vehicles and gaping holes in the earth.
There was no immediate word on casualties or major damage.
Waves splash in a pool during an quake, seen in a still frame from social media video, in George Town, Grand Cayman, Cayman Islands.
The quake was at a depth of about 10 kilometres, according to the USGS.
The epicenter of the first quake was located 10 kilometers (6 miles) deep and 125 kilometers (77 miles) northwest of Lucea, Jamaica.
The statement from Hazard Management Cayman Islands reads: "A 7.7 magnitude natural disaster has occurred approximately 80 miles ESE of Cayman Brac and Little Cayman".
Floridians felt the effects in Southwest Miami-Dade where the Datran building in the Dadeland area started shaking, Fox 7 reported. And earlier this month, a significant quake hit Puerto Rico, causing injuries and serious property damage. Eastern, was felt in Miami and caused "very strong to severe shaking in far western Jamaica", The Weather Channel reports, citing the U.S. Geological Survey.