Two moderate quakes of 5.5 magnitude struck western and eastern Indonesia on Sunday, but there was no threat of a tsunami and no immediate reports of damage, meteorologists said.
The first earthquake, which hit at 0906 IST, occurred at sea about 147 kilometers southeast of the city of Gunungsitoli on Nias island, off the west coast of Sumatra island, at a depth of 60 kilometers.
The second undersea tremor hit about an hour later in the eastern province of Maluku about 340 kilometers southeast of the provincial capital Ambon, at a depth of 125 kilometers.
Both shakers had no potential for a tsunami, the meteorology and geophysics agency said in a statement.
An 8.7-magnitude quake struck in March 2005, killing hundreds of people on Nias.
The Indonesian archipelago sits on the Pacific Ring of Fire, where continental plates meet and cause frequent seismic and volcanic activity.