A powerful 6.0-magnitude earthquake struck off Indonesia's western Sumatra island Monday, the US Geological Survey said, but no tsunami warning was issued and there were no reports of casualties or damage.
The undersea tremor hit at 4.05pm at a depth of 10 kilometres, 215 kilometres south of Bengkulu, and almost 500 kilometres west of the capital Jakarta, said the USGS.
Fadli Yusuf, an official from Indonesia's meteorology, climate and geophysics agency, said the quake was felt moderately in parts of Sumatra but there were no immediate reports of damage or casualties.
Indonesia sits on the Pacific "ring of fire" where continental plates collide, causing frequent seismic and volcanic activity.
A huge undersea quake in 2004 triggered a tsunami that killed more than 170,000 people in Aceh province on Sumatra, and tens of thousands more in other countries with coasts on the Indian Ocean.