AUTHORITIES IN INDONESIA have issued a tsunami warning after an earthquake measuring 7.5 on the Richter scale struck off the west coast of the Indonesian island of Sumatra – the area devastated by the Christmas Day tsunami of 2004.

Reuters reports that the Pacific Tsunami Warning Centre (PTWC) said a local tsunami watch was in effect, but a wider tsunami threat was not seen.

The US Geological Survey reports that the quake struck at 3:42pm Irish time, about 33km below sea level, with the epicentre about 175 miles away from Padang (population 750,000).

The PTWC said, however, that “a destructive, widespread tsunami threat does not exist” based on historical earthquake data, with only coastlines within 100 miles of the epicentre likely to see any unusual tidal activity.

Indonesia’s earthquake agency also issued a tsunami warning, though it said that the quake hit 78km northwest off South Pagai, one of the Mentawai islands, at a depth of 10 km. The agency measured the quake at 7.2.

The contradictory reports could indicate that the region – known as the ‘Pacific ring of fire’ due to regularity of seismic activity – may have been struck by more than one quake simultaneously.

Sumatra was devastated by a 9.1-magnitude quake off the coast which a tsunami in the Indian Ocean at Christmas 2004, which killed 250,000 in 13 countries including Indonesia, Sri Lanka, India and Thailand.