Jakarta - An undersea earthquake registering 6.0 on the Richter scale struck the western coast of the Indonesian island of Sumatra Friday afternoon, but there were no reports of injuries or damage, the Indonesian seismologist agency said.

The quake struck at 1:37 pm (0637 GMT) and was centred in the Indian Ocean, 140 kilometres south-east of Mentawai island, off the western coast of Sumatra, Indonesia's National Meteorology and Geophysics Agency said.

While it occurred only 10 kilometres beneath the seabed, the quake did not trigger a tsunami, the agency said.

On September last year, a powerful 8.4-magnitude earthquake hit the western coast of Sumatra, killing more than 20 people and injuring scores of others.

Indonesia, the world's largest archipelago nation, sits atop the Pacific Ocean's Ring of Fire, where the meeting of continental plates causes high volcanic and seismic activity.

On Thursday, a 6.6 strong earthquake struck eastern Indonesian Sumbawa Island, which destroyed or damaged more than 1,000 homes and other buildings but claimed no lives. (dpa)