Any place having tectonic plate stresses can experience mega-quakes

March 10th, 2008 - 2:26 pm ICT by admin  

Washington, March 10 (ANI): A new research has suggested that it is not just certain high-risk subduction zones that experience mega-quakes, but any place where one tectonic plate is being actively shoved under another can experience a catastrophic magnitude 9 earthquake as well.

The new research also suggested that on an average, three catastrophic, magnitude 9 or greater earthquakes around the world could be expected each century.

According to a report in Discovery News, the research was conducted by seismologist Dr Robert McCaffrey of New Zealand’s government research agency GNS Science.

Though the estimate may sound strange as there have been five such quakes in the past half century, a cluster that includes the deadly 2004 rupture offshore of northern Sumatra, the good news is that the new estimate is lower than previous ones.

But there is a dark side to the new study that removes certain limits on where such quakes can occur.

Now it looks like any place where one tectonic plate is being actively shoved under another, at a subduction zone, can experience a catastrophic magnitude 9 earthquake.

Previously, different subduction zones were thought to pose greater or lesser risks of magnitude 9 quakes, depending on the speeds at which the plates were colliding, and their stiffness and age.

McCaffrey decided to re-examine the risks of the largest earthquakes without biasing his simulation with the known recent history of giant earthquakes or with the failed theory that was supposed to predict the danger of any given subduction zone.

When he ran his simulation, it popped out the three-per-century figure, as well as the new possibility that any subduction zone posed a danger for these mega-uakes, albeit not a very frequent danger.

According to Professor Seth Stein of Northwestern University, “What that means is when you think of giant ocean tsunamis, you can’t count on where they will come from.”

In other words, McCaffrey’s paper is bad news for tsunami emergency planners because it increases the number of disaster possibilities, he added. (ANI)

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