By the CNN Wire Staff
updated 6:46 AM EDT, Wed April 11, 2012
Jakarta, Indonesia (CNN) -- A massive earthquake struck off the coast of the Indonesian island of Sumatra on Wednesday afternoon, triggering a tsunami alert for the Indian Ocean.
The quake struck about 434 kilometers (270 miles) southwest of Banda Aceh, the capital of Indonesia's Aceh province, and had a magnitude of 8.6, the U.S. Geological Survey said. It took place at a depth of 23 kilometers (14 miles).
The tremor revived fearful memories of the catastrophic earthquake and tsunami in the region in 2004 that killed tens of thousands of people.
The Pacific Tsunami Warning Center said Wednesday that it had issued a tsunami watch for the entire Indian Ocean, and the Indonesian Meteorology, Climatology and Geophysics Agency said it had put up a tsunami warning.