Two strong earthquakes 40 minutes apart rocked the remote South Orkney Islands in Antarctica on Sunday, experts from the US Geological Survey said.
The epicenter of the first, a magnitude 6.6 temblor, was at a depth of 10 kilometers (six miles), some 539 kilometers (334 miles) west of Coronation Island, the USGS said. No destructive tsunami was created, according to a US-based warning center.
The first quake occurred at 1340 GMT. About 40 minutes later the region was struck by an aftershock measured at 6.2. A second 5.1-magnitude aftershock occurred at around 1640 GMT, USGS said later.
The South Orkney Islands form a remote archipelago in the Southern Ocean to the northeast of the Antarctic Peninsula.
An ownership dispute between Britain and Argentina was resolved by the 1959 Antarctic Treaty, which allowed for any of the 12 signatories to use the islands for non-military purposes.
The British Antarctic Survey staffs a small research station on Signy Island, while Argentina maintains a base on Laurie Island.
"There is the small possibility of a local or regional tsunami that could affect coasts located usually no more than a few hundreds kilometers from the earthquake epicenter," the Hawaii-based Pacific Tsunami Warning Center said.
The tsunami that struck Japan on March 11, 2011 caused waves that hit an ice shelf in Antarctica 13,000 kilometers (8,100 miles) away, smashing parts of it into huge icebergs.
The largest berg measured about 9.5 by 6.5 kilometers (5.9 by 4.0 miles), making it slightly bigger in surface area than Manhattan, according to the European Space Agency.
An early USGS alert Sunday put the depth of the first Antarctica quake at just one kilometer and located it closer to Coronation Island.
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