Four consecutive quakes in four hours ranging from 5.2 to 5.7 in magnitude hit off the western coast of northern Sumatra, the US Geological Survey reported.
The strongest, 6.6-magnitude tremor rocked Papua region on the western tip of the island of New Guinea at 01:16 GMT on Saturday.
It was followed ten minutes later by a 5.6-magnitude quake in the same location.
Panicked residents escaped shaking houses and stores, in the town of Manokwan in Papua, closest to the epicenter.
In the town of Ransiki in the west of the region, students attending morning classes ran from school buildings that shook for around a minute.