Update, 5:45 p.m. -- The Associated Press reports that the earthquake collapsed the roofs of a bank and a store in Roseau, and that minor injuries were reported on Dominica. So far, however, there are no reports of major damage in the vicinity.
(4 p.m.) -- A 7.4-magnitude earthquake shook Caribbean islands including Dominica and Martinique this afternoon at approximately 3 p.m. EST, the U.S. Geological Survey reports. The earthquake was centered 26 miles southeast of Dominica's capital, Roseau, and lasted for about 20 seconds, according to news outlets.
There is no threat of a tsunami at this time, because the quake occurred too deep within the earth to generate one, according to the Pacific Tsunami Warning Center.
So far there have been no reports of major damage. According to Reuters, earthquakes with a deep epicenter are less likely to cause damage -- though this one was felt hundreds of miles away, as far as Venezuela and Puerto Rico.
At this point, no itinerary changes have been announced; Dominica and Martinique are common stops on Southern and Eastern Caribbean itineraries. We'll keep you posted.