Earthquakes in one area can trigger quakes worldwide, says study


Global triggering is a theory that's been around for 20 years. The theory states that a big earthquake can trigger other earthquakes, not aftershocks in the immediate area, but quakes all around the world.

The group of seismologists that led the analysis in the journal Nature also point out that in the 12 days leading up to the April quake, the number of earthquakes around the globe had dropped significantly.

Earthquake expert Dr. Susan Hough, a seismologist for the U.S. Geological Survey based at Caltech, says don't lose any sleep over that finding.

"It's not a huge effect. It's not a 10.5 apocalyptic cascade of events," said Hough.

The USGS seismologist debates a possible link between the Indian Ocean earthquake and a large increase in quakes. She says the quakes that may have been triggered by the East Indian Ocean quake were a sprinkling of relatively insignificant temblors.

"The triggering, if it happens, is at such a low level that if you looked at the statistical increase of an event, it's tiny," said Hough.

Hough worries that the new study was based on limited data and says before any concrete conclusions can be made about global triggering, more huge earthquakes have to be thoroughly examined.

The problem is 8.5-magnitude quakes are incredibly rare, so scientists don't have enough of them to study.

As for those who live in Southern California, Hough says be prepared, but don't freak out when a big quake hits on the other side of the planet.

"Any day is fair game for a big one. As far as we know, the odds don't change significantly based on what's happening around the world," said Hough.

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