The quake struck at 8:36 pm (2336 GMT) about 210 kilometers (130 miles) east of the base at a depth of 10 kilometers (6 miles), Chile's National Emergency Office (Onemi) said, urging evacuation from "the beach area of the Antarctic" ahead of a possible tsunami.
The Chilean Air Force's base is the country's largest in Antarctica, and includes a village, hospital, school, bank, post office and chapel.
The maximum population in summer is 150 people, and the average population in winter is 80.
An unrelated 5.9-magnitude earthquake struck near Santiago on Saturday night, but Onemi said no significant damage or impact was reported.
Chile is one of the most seismically active countries in the world. A 8.8-magniture temblor in the city of Concepcion on February 27, 2010 left more than 500 dead.
The country suffered the most powerful earthquake ever recorded 60 years ago -- measuring 9.6 magnitude -- in the city of Valdivia.
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