The quake hit at 03:34 am (local time), at a depth of 103 kilometres, according to a revised report by the US Geological Survey (USGS).
The epicentre was 110 kilometres north-northwest of Ternate in the Moluccas and 260 kilometres east of Manado on Sulawesi.
The Hawaii-based Pacific Tsunami Warning Center did not release a tsunami warning.
Indonesia sits on the Pacific "Ring of Fire," where the meeting of continental plates causes high volcanic and seismic activity.
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