A 6.4-magnitude undersea earthquake struck western Indonesia on Tuesday, the U.S. Geological Survey said, but there was no tsunami alert and no immediate reports of casualties or damage.
The quake hit at a depth of 37 kilometers at 5:37 pm (local time) close to Pulau Siberut, part of the Mentawai Islands, off the west coast of vast Sumatra island, said the USGS.
A huge undersea quake in 2004 triggered a tsunami that killed more than 170,000 people in Aceh province, on western Sumatra island, and tens of thousands more in other countries with coasts on the Indian Ocean.