Indonesia has issued a tsunami warning after a quake with a preliminary magnitude of 8.7 hit waters off westernmost Aceh province.
The U.S. Geological Survey said on Wednesday that the quake was centered 20 miles (33 kilometers) beneath the ocean floor, around 308 miles (495 kilometers) from the provincial capital of Banda Aceh.
Said, an official at Indonesia's Meteorology and Geophysics Agency who goes by only one name, said a tsunami warning has been issued.
Indonesia straddles a series of fault lines that makes the vast island nation prone to volcanic and seismic activity.
A giant 9.1-magnitude quake off the country on Dec. 26, 2004, triggered a tsunami in the Indian Ocean that killed 230,000 people, nearly three quarter of them in Aceh.