Two strong earthquakes 40 minutes apart this weekend rocked remote islands in Antarctica, the U.S. Geological Survey says. The USGS said the first, a 6.6-magnitude temblor, was at a depth of 6 miles about 334 miles west of Coronation Island in the South Shetland Islands and struck at 8:40 a.m. EST Sunday, CNN reported. About 40 minutes later an aftershock measuring 6.2 was felt, followed by a 5.1-magnitude aftershock about 2 hours later. The South Orkney Islands form a remote archipelago in the Southern Ocean to the northeast of the Antarctic Peninsula. \"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. Later the center released a statement saying there appeared to be no threat of \"destructive widespread tsunami\" because of the quake.