The quake struck at 4.34 p.m. (local time) with the epicentre 85 km southwest of here in the Mandailing Natal region and with a depth of 96 km, a meteorological agency official told Xinhua news agency.
The US Geological Survey put the quake intensity at 6.1 on the Richter scale.
Indonesia lies on a vulnerable quake-hit zone called “the Pacific Ring of Fire”. (IANS)