Bangkok - The 2004 tsunami that devastated northern Indonesia and Thailand's Andaman coast had at least one likely precedent about 600 years ago, Nature Magazine said Wednesday.

Two groups of scientists have found sedimentary evidence for possible predecessors to the 2004 catastrophe on Phra Thong Island, Thailand and in Aceh, Indonesia, suggesting that a similar-sized tsunami occurred in 1400 AD, predating any historical records.

The December 26, 2004 tsunami, triggered by a 9.2 magnitude earthquake off the coast of Sumatra, took the region by surprise, leaving an estimated 226,000 people dead and missing from 11 countries rimming the Indian Ocean.

The disaster raised questions about the lack of tsunami preparedness in the region, especially in Thailand where more than half of the victims were foreign tourists vacationing in popular Andaman Sea resorts such as Phuket, Phang Nga and Phi Phi.

To conduct sedimentary research, the Thai team headed by Brian Atwater had to travel to Phra Thong Island, 150 kilometres north of Phuket Island.

"The problem we faced in Phuket and parts of Phang Nga was the extensive mining and tourism in the area which had obliterated any evidence we could find," said Kruawun Jankaew, a geologist from Chulalongkorn University who was one of three Thais on the research team.

By drilling in marshy swales inland of the beach on Phra Thong, where the tsunami reached 20 metres high, the team was able to discover similar sediments and sand patterns dating back 550 to 700 years.

Similar sediments that were carbon-dated to about 600 years ago were discovered on beaches in Aceh, North Sumatra, which was hardest hit by the 2004 tsunami.

Aceh suffered several other major tsunamis, such as one recorded in 1907, that apparently did not make it up to southern Thailand, according to Nature.

The data suggests that recurring intervals of such destructive tsunamis in the Sumatra-Andaman Island region can span centuries, with the 2004 event separated from its most recent predecessor by roughly 600 years.

But the scientists said more research will be needed to pinpoint the dates of the previous tsunamis.

"There were two more possible tsunami in the past, but unfortunately we haven't been able to find radio-carbon samples to determine them precisely," Kruawun said.

"We are hoping that after this paper comes out in Nature we can get more funding to look at new locations and get better samples for radio-carbon testing," she said in an interview with Deutsche Presse-Agentur