The US Geological Survey said the undersea quake struck at 3:08 pm (0808 GMT) some 312 kilometres (194 miles) west-southwest of the North Sumatra capital Medan, at a depth of 34 kilometres.
Indonesia's meteorological agency, which put the magnitude of the quake at 6.6, said it struck 42 kilometres northwest of the town of Sinabang in Aceh province.
The Hawaii-based Pacific Tsunami Warning Centre issued a local watch bulletin, saying there was no threat of a "destructive widespread tsunami" but that a local tsunami could affect coastal areas within a 100-kilometre radius.
Indonesia sits on the Pacific "Ring of Fire" where continental plates meet, causing frequent seismic and volcanic activity.
The earthquake-triggered Asian tsunami in December 2004 killed some 168,000 people in Aceh, which is located at the northern tip of Sumatra. Indonesia was the nation worst hit by the tsunami.
Güncelleme Tarihi: 20 Şubat 2008, 16:39