An earthquake measuring 6.4 magnitude struck off the Indonesian island of Sumatra on Tuesday, the US Geological Survey said.
There was no immediate word on damage or casualties.
The quake was 23 miles deep and centred 114 miles (183 km) west of the town of Padang.
Indonesia, badly hit by the Indian Ocean tsunami in 2004, straddles the so-called "Pacific Ring of Fire", a highly seismically active zone where different plates on the earth's crust meet and create a large number of earthquakes and volcanoes.
© Thomson Reuters 2015