" Twelve minutes after the first 8.1-magnitude earthquake, a minor quake of 3.1 magnitude was…
A powerful and shallow earthquake of magnitude 7.9 struck off the west coast of the Indonesian island of Sumatra on Wednesday, the US Geological Survey said.
The epicentre was 808 km (502 miles) southwest of Padang, USGS said. It was 10 km (six miles) deep.
There were no immediate reports of damage or casualties but the shallower a quake, the more likely it is to cause damage. USGS originally put the magnitude at 7.9.
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.
A tsunami warning for West Sumatra, North Sumatra and Aceh has been issued following the quake.