A powerful earthquake with a preliminary magnitude of at least 6.9 hit in the Scotia Sea between South America and Antarctica, Japanese and US officials said Sunday. No tsunami alert was issued by the Hawaii-based Pacific Tsunami Warning Center, said Dale Grant, a geophysicist with the US Geological Survey's National Earthquake Information Center. The warning center monitors seismic activity in the Pacific area. The quake struck at 1:41 a.m. local time (0341 GMT) with a preliminary magnitude of 6.9, the USGS said. Japan's Meteorological Agency put the preliminary magnitude at 7.2. The USGS estimated the earthquake's depth at 10 kilometers (six miles). The quake was centered in the Scotia Sea, approximately 495 kilometers (305 miles) west-southwest of Bristol Island in the South Sandwich island group, the USGS said.