The evidence comes from deposits of sand washed inland by colossal waves and preserved under layers of coastal peat, according to studies published in Thursday's issue of Nature, the London-based science journal.

The December 2004 tsunami was triggered by an earthquake of 9.2 magnitude that ripped open the Sunda Trench - the fault that zigzags up the eastern side of the Indian Ocean - along 1,500 kilometers(950 miles).

Around 220,000 people were killed in a dozen countries.

The two teams pored over coastal areas in Indonesia and Thailand, seeking sheets of sand that had been deposited in past tsunamis but had been left undisturbed by wind, rivers, storms, animals or humans.

The age of the sand sheets was derived from carbon-dating organic debris collected just below the deposit.

The Sumatra sand sheet was dated to 1290-1400 AD, and its apparent counterpart in Thailand to 1300-1450 AD. The clear proximity in dating suggests both deposits were left by the last big forerunner to the 2004 tsunami.

Norwegian geologist Stein Bondevik said it was vital to confirm what these studies indicated - that it may take some 600 years for stress to build on the Sunda Trench to the point that a 2004-style quake is unleashed.