A major, preliminary magnitude 7.5 earthquake struck in the South Atlantic Ocean late Thursday, the United States Geological Survey reported, prompting Chilean authorities to issue an advisory for a potential tsunami along parts of Antarctica. There were no evacuation orders immediately declared for Chile or Argentina, the two countries closest to the quake. The temblor happened at 11:16 pm local time in Argentina about 710 kilometres southeast of Ushuaia, Argentina, in the Drake Passage, according to the U.S. Geological Survey. The earthquake had a preliminary depth of 10.8 kilometres. The Drake Passage connects the South Atlantic and South Pacific oceans between the southern tip of South America and the Antarctic Peninsula. Though less quake-prone than other stretches of Chile's coast, the Drake Passage straddles a highly active seismic and geological zone. The area is very remote and there were no immediate reports of damage or casualties.