An earthquake centred just off Sumatra caused huge tidal waves over large parts of South and South East Asia, from India to Indonesia. Thousands are reported dead, and thousands more missing.

Benjamin Gilmour reports from Thailand

"As an Australian medic I, along with two other medical students who witnessed the tsunami were taken to the Ko Lanta hospital where we have worked since midday. I was involved in 2 unsuccessful resuscitations of drowning victims, and treated over sixty foreign holidaymakers with injuries, mainly multiple fractures, some severe such as skull factures and suspected spinal fractures.

There have been 3 confirmed dead on Ko Lanta with a number of missing local children. One family from Sweden with 10 children were swept from their longboat and sustained multiple abrasions and fractures but survived. We have evacuated 25 patents by military helicopter to the mainland. People are awaiting another wave and most are camping out on hilltops, not that any accommodation at beach level remains."

What about ships? There are very busy shipping lanes with oil tankers, container ships etc as well as fishing boats