© Reuters/U.S. Geological Survey/Handout/Combination
A major earthquake of magnitude 7.8 shook the Indonesian island of Sumatra, the U.S. Geological Survey said Tuesday.
A major earthquake of 7.8 magnitude shook the northwestern coast of the Indonesian island of Sumatra, the U.S. Geological Survey said on Tuesday.

A local tsunami watch was in effect for Indonesia, the Pacific Tsunami Warning Center said.

"A destructive widespread tsunami threat does not exist based on historical earthquake and tsunami data," the center said.

But it added "there is the possibility of a local tsunami that could affect coasts" no more than 100 km (62 miles) from the epicenter of the quake.

The quake was centered 127 miles west-northwest of Sibolga and was at a depth of 28.6 miles, the USGS said. It initially reported the quake's magnitude at 7.6.

In December 2004, a magnitude 9.15 quake off the coast of Sumatra's Aceh province triggered an Indian Ocean tsunami that killed about 226,000 people in Indonesia, Sri Lanka, India, Thailand and nine other countries.

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