The other four quakes all registered greater than magnitude-5, the USGS said.
There were no immediate reports of injuries or damage.
The strongest earthquake, at a depth of 6.2 miles, was about 195 miles southeast of Stanley in the Falklands and 545 miles east of Ushauaia, Argentina.
Disney's 'Jessie' to feature network's first engagement
Rosie O'Donnell unveils nearly 50-pound weight loss