The quake struck off Halmahera island in North Maluku province at 0948 GMT at a depth of about 35 kilometres (22 miles), the USGS said.
There were no immediate reports of damage or injuries after the earthquake.
The Pacific Tsunami Warning Centre said there was "no tsunami threat" from the quake in the Molucca Sea.
But Indonesia's geophysics agency (BMKG) advised residents in nearby areas of possible aftershocks.
Indonesia, a vast archipelago nation, experiences frequent earthquakes due to its position on the Pacific "Ring of Fire", an arc of intense seismic activity where tectonic plates collide that stretches from Japan through Southeast Asia and across the Pacific basin.
A magnitude-6.2 quake that shook Sulawesi island in January 2021 killed more than 100 people and left thousands homeless.
In 2018, a magnitude-7.5 quake and subsequent tsunami in Palu on Sulawesi killed more than 2,200 people.
And in 2004, a magnitude-9.1 quake struck Aceh province, causing a tsunami and killing more than 170,000 people in Indonesia.
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