Four people were injured, one critically, when houses collapsed near the epicentre of the quake at Sinabang, on Simeulue Island off the northwestern coast of Sumatra, officials said.

The quake hit Aceh province at the northern tip of Sumatra, an area devastated by the massive Asian tsunami of 2004, and set off wave alerts for waters off Sumatra and Thailand.

Residents of Banda Aceh, the provincial capital, said they felt the earth shudder with frightening intensity for about a minute at around 5:15 am (2215 GMT April 6). Many fled their homes or piled onto motorcycles to head inland in fear of destructive waves, but a tsunami warning issued by the Indonesian government was lifted about two hours later.

The quake occured at a depth of 46km, according to the US Geological Survey. Indonesian geologists said the epicentre was 60 kilometres southeast of Sinabang.

Electricity was down in Banda Aceh.

The people of Aceh are still traumatized by memories of December 26, 2004, when the Indian Ocean surged over the northern tip of Sumatra after a 9.3-magnitude quake split the seabed to the island's west.

AFP