Researchers in Thailand and Indonesia wrote in two articles in Nature magazine that the tsunami hit around 1400, long before historical records of earthquakes in the region began.

A person drives past a tsunami hit building at Peraliya in Hikkaduwa, December 23, 2007.
"Tsunamis are something we never experienced before and after 2004, people thought it was something we would never experience again," Kruawun Jankaew of Thailand's Chulalongkorn University told Reuters by telephone.