A 7.8-magnitude earthquake struck off the coast of Sumatra, an island in western Indonesia, according to the U.S. Geological Survey (USGS).
The quake happened at 7:49 p.m. local time on March 3 (7:49 a.m. ET on March 2), about 500 miles (800 kilometers) southwest of Sumatra. The temblor occurred as a result of two tectonic plates sliding against each other — what's known as strike-slip faulting — within the ocean lithosphere of the Indo-Australia plate, according to the USGS.
The earthquake's epicenter was located 500 miles southwest of the city at Padang, at a depth of about 15 miles (24 km), according to the USGS. Indonesian authorities issued a tsunami warning following the quake, but that notice has since been lifted, reported Bloomberg. Similarly, Australian officials canceled tsunami warnings for Cocos Island and Christmas Island in the Pacific Ocean, according to news reports.
"The plate boundary southwest of Sumatra is part of a long tectonic collision zone that extends over 8,000 km [4,970 miles] from Papua in the east to the Himalayan front in the west," USGS officials wrote in their preliminary report of the quake.
In 2004, a massive 9.1-magnitude undersea earthquake struck off the coast of Sumatra, triggering a deadly tsunami that killed more than 230,000 people and destroyed coastlines along the Indian Ocean.