To find the story for this Naked Science show for National Geographic US, we went to the US to talk to scientists about what a tsunami is and why they are so dangerous.  

Then I met the actual scientist in Hawaii who was the first person to see the data on the earthquake which caused the Asian Tsunami - it registered 9.1 on the Richter Scale, larger than the 8.1 San Francisco quake of 1906 which flattened the whole city. The whole cataclysmic event was reduced to a squiggly line on a computer screen he showed me and you can watch that in the clip.  

Inconsequential-looking on his computer screen, the shock produced a new shelf in the Indian Ocean 800 miles long and 120 feet high in places…in a few seconds. It was as if someone had shaken the ocean like a carpet right down the coast of Indonesia.  

The wave went round the world twice before finally petering out.  

Filming for the show also took us to the island of Simileu, which was the closest inhabited landfall to the very centre of the quake, 40 miles from their coast. The tiny island tilted almost ten feet as the earth’s surface heaved below. In ten seconds, 100 feet of coral coastline emerged from below the waterline and the coral began to bleach and die.  

We filmed as the exposed coral was sliced in two with a water-cooled six foot chainsaw by a team overseen by geologist Kerry Sieh, one of the world’s leading experts in the field who is licensed to carry out this sort of research, to literally count its rings and determine if this had happened to the coral before.  

This would indicate other earthquake, and therefore probably, tsunami activity. And he found what he was looking for.  

The night before we left the island, there was a 4.5 quake which gently rocked the rickety building where we were sleeping. Three weeks later it was demolished by a much bigger shock.  

The southern half of the Sunda Trench fault line running south of Indonesian capital Jakarta and into Java is still under the same stress as the northern half and hasn’t shifted in the same way which caused the notorious tsunami…yet but there have been a series of mid-sized shocks across Sumatra and Java since.

To watch video click here.