( BBC ) A powerful earthquake and several aftershocks have struck off the western Indonesian island of Sumatra, sparking fears of a tsunami.
Tsunami alerts were issued for several nations in the Indian Ocean, though some have now been lifted.
Buildings collapsed on the west coast of Sumatra. Hospitals are on alert in case there are significant casualties.
A massive undersea earthquake sparked a tsunami that killed more than 220,000 people in December 2004.
The Pacific Tsunami Warning Centre issued an alert for the entire Indian Ocean region following Wednesday's main quake, which the US Geological Survey said measured 8.4.