Monster earthquakes like the 9.0-magnitude event that occurred off Japan on March 11 are unlikely to trigger a large quake in distant regions of the world, according to a study published on Sunday.
The research — coincidentally published in the wake of the tsunami-generating killer — counters a novel theory that an exceptional quake in one continent can unleash a temblor in another.
Tom Parsons of the US Geological Survey (USGS) and Aaron Velasco of the University of Texas at El Paso cast their net in 30 years of data.
They looked at all earthquakes around the world that were 7.0 magnitude or above and were followed by quakes greater than magnitude 5.0.
Their trawl came up with 205 main shocks, and more than 20,000 hypothetical secondary shocks.
There was a "significant increase" in seismic activity in adjoining areas of the fault, they found.
This confirms beliefs that a big quake places stress on a nearby section of the same fault, which then ruptures, rather like buttons on a shirt that pop off one by one.
Read the rest of the story: AFP: No long-distance risks from mega-quakes: study.