Indonesia's Meteorology and Geophysics Agency said the quake was centered about 110 miles (178 kilometers) southeast of Tahuna island and six miles (10 kilometers) beneath the Maluku Sea.
The agency said it was magnitude 6.9, while the US Geological Survey put the magnitude at 6.2.
It strongly shook the North Sulawesi provincial town of Manado, said Arif, an agency official who uses a single name. Witnesses said many residents woke up and ran out in panic.
Indonesia has frequent earthquakes due to its location on the Pacific "Ring of Fire," an arc of volcanos and fault lines encircling the Pacific Basin.