Tsunami quake second largest on record

The Sumatra earthquake that triggered the devastating Indian Ocean tsunami was the second largest on record, it was revealed today.

New measurements show that the earthquake was significantly more powerful than scientists had originally thought.

The new findings, from two American geologists, may explain why the tsunami, which killed more than 200,000 people, was so destructive.

Professors Seth Stein and Emile Okal, from Northwestern University in Chicago, found that the earthquake’s magnitude measured 9.3, not nine as was earlier estimated.

This made it the second largest earthquake seismically recorded after a 9.5 magnitude quake that hit Chile on May 22, 1960.

Prof. Stein said: “The rupture zone was much larger than previously thought. The initial calculations that it was a 9.0 earthquake did not take into account what we call slow slip, where the fault, delineated by aftershocks, shifted more slowly. The additional energy released by slow slip along the 1,200-kilometre long fault played a key role in generating the devastating tsunami.”

One piece of good news from the new analysis is that the chances of another large tsunami occurring in the same area are reduced.