A tectonic earthquake measuring 5. 1 on the Richter scale on Monday jolted Sipura Mentawai area in Indonesia's West Sumatra province, but there was no immediate report of casualty or damages, Xinhua reported.
The quake occurred at 2:50 a.m. local time when the local people were sound asleep, Antara news agency quoted the Meteorology and Geophysics Agency as saying.
The epicenter of the quake was located at between 1.84 degrees southern latitude and 99.32 degrees eastern longitude at a depth of 10 km below sea level, or some 55 kilometers northwest of Sipura Mentawai.
On Jan. 9, another tectonic earthquake measuring 5.0 on the Richter scale also rocked West Sumatra's area of Painan.
Indonesia, the world's largest archipelago, sits on the Pacific "Ring of Fire," the edge of a tectonic plate prone to seismic upheaval.