Are We in an Age of Great Earthquakes?
Baku, April 22 (AZERTAC). A number of devastating quakes have struck across the globe in recent years — from Japan to Chile to Haiti — sparking fears that our planet is due to experience even more catastrophic temblors in the near future.
Three research teams have now combed through 110 years` worth of global seismic records to see if we might be caught in a global trend of giant earthquakes.
One pair of researchers found clusters of what they called “megaquakes,” earthquakes of magnitude 9.0 or greater.
One cluster involved three such quakes between 1952 and 1964, including the magnitude 9.5 Chile quake of 1960, the largest earthquake ever recorded on Earth. Another, larger, cluster of magnitude 8.6 and higher temblors happened between 1950 to 1965, said Charles Bufe and David Perkins, seismologists with the U.S. Geological Survey in Golden, Colo. They speculate that the magnitude 8.4 Peru quake in 2001 could mark the beginning of a new global sequence of major quakes that we are currently experiencing.
“This isn`t doomsday — I don`t think large earthquakes will occur over a long period of time — but we`re saying there seems to be a cluster right now with a higher than normal probability for large quakes," Bufe told OurAmazingPlanet.
“Bufe suggested that by sending seismic waves traveling around and around the planet`s surface, very large earthquakes might weaken fault zones that are already very close to failure.
On the other hand, this apparent recent spike in large quakes could just reflect random fluctuations in global patterns of seismic activity. A statistical study from U.S. Geological Survey researcher Andrew Michael at Menlo Park, suggests this seeming cluster pattern disappeared once local aftershocks of the large earthquakes are taken into account.
Seismologist Richard Aster at the New Mexico Institute of Mining and Technology and his colleagues looked at historical catalogs of earthquakes along with more recent findings to create a long-term record of the cumulative size of earthquakes around the world.
They suggest there were relatively low rates of big earthquakes during the periods 1907 to 1950 and 1967 to 2004. However, they found the rate of large earthquakes increased substantially during the period 1950 to 1967 and appears to be on the rise again since 2004, since the devastating magnitude 9.1 to 9.3 earthquake that struck Indonesia and generated a massive tsunami late that year. Still, this finding “is not statistically differentiable from randomness,” Aster told OurAmazingPlanet.
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