REPUBLIKA.CO.ID, PADANG -- The earthquake, which struck at 5:56 a.m. local time on Thursday, was centered 67 kilometers (42 miles) west of the village of Tapan, or some 145 kilometers (90 miles) south of Padang. It struck about 72 kilometers (44 miles) deep, making it an earthquake of intermediate depth.
Indonesian Agency for Meteorological, Climatological and Geophysics (BMKG) said no tsunami warnings had been issued, bnonews.com reported.
Strong shaking was felt across the region and woke up many people, according to residents, but there was no immediate word on damage or casualties. Some residents in Singapore, which is about 538 kilometers (334 miles) northeast of the epicenter, also reported feeling the earthquake.
Computer models from the United States Geological Survey estimated that some 15.6 million people would have felt the earthquake, including an estimated 236,000 people who may have experienced "moderate" to "strong" shaking.
Indonesia is on the so-called 'Pacific Ring of Fire', an arc of fault lines circling the Pacific Basin that is prone to frequent and large earthquakes.