New, Unpublished Research: Recent Quakes Unlikely To Set Off Big One Here

If you wondered what the earthquakes around the world meant for San Fran, you weren't the only one.

​With major earthquakes striking Haiti, Chile, and Turkey this year, it's hard not to wonder in San Francisco if we might next. And when one considers that big earthquakes are known to trigger smaller earthquakes around the world, the situation seems all the more precarious.

That's why we wanted to know -- can these devastating earthquakes trigger the next big one in San Francisco? According to U.S. Geological Survey geophysicist Tom Parsons of Menlo Park -- who researched that question for the last six months -- it's unlikely.

"Seismic waves travel all around the earth," Parsons explained, "which can jostle and trigger small earthquakes around the world." In 2004, for example, a 9.3 quake in Sumatra set off numerous smaller quakes as far away as Alaska.

So Parsons and his colleagues wondered: If a large quake can set off a small one, is it possible for a large quake to trigger another massive temblor? 

Parsons and his research partner, Aaron Velasco of the University of Texas at El Paso, pored through years of data for patterns to suggest that vibrations from large earthquakes might set off other large earthquakes. But after months of research they found nothing of statistical significance. They've submitted a resultant paper for publication and are awaiting comments.

All that said, Parsons recommends that San Franciscans continue to take the earthquake threat here seriously. "They should be concerned," he said. But these other earthquakes need not elevate that concern. If we're all about to be shaken down, it has little to do with what's going on elsewhere.

As scientists are fond of noting, chances arethe Bay Area's next Big One will strike in the next 30 years.