Berkeley Earthquakes Prompt Investigation

Berkeley got accustomed to feeling the dizzying uncertainty of shaky ground last October, when a "swarm" of earthquakes emanated from the city.

The temblors were unnerving enough to prompt residents to , and even spark an Internet rumor about the imminence of the "Big One." Self-professed "quake predictor" Luke Thomas claimed that blockages in electromagnetic radiation proved that a quake of magnitude 6.0 or more was ready to strike. Experts from the U.S. Geological Survey (USGS) disagreed, stating that .

But even if the Hayward Fault was just letting off steam, the Berkeley quakes left a lot for seismologists to ponder. Jack Boatwright, who leads the USGS's Northern California earthquake hazards investigations, is one of the experts looking for clues about how the fault is moving by analysing the data from Berkeley.

In an interview with the Wall Street Journal, Boatright explained that swarms of earthquakes are common on the Hayward Fault, usually with temblors up to a magnitude of 4.0. Despite the relative normality of quake swarms, Hayward is a "high anxiety" fault, according to Boatright, not only because of the urban setting that causes lots of people feel the shaking — but also because the Hayward Fault is the most likely in the Bay Area to have a magnitude 7 earthquake. A 7 on the Richter Scale is considered a "major" earthquake, likely to cause serious damage over large areas.

But that hasn't happened in 143 years, not since "The Great San Francisco Earthquake" in 1868. Are we overdue? Boatright says the recurrance interval for such a seismic event is about 140 years. So, the short answer is "yes."

But the recent quake cluster doesn't necessarily indicate disaster. According to UC Berkeley researchers, a section of Berkeley is "slipping" — but isn't building up stress. Therefore, "this swarm is probably not a foreshock of something larger on the Hayward Fault," said Boatright.

However, the science is still scarily inadequate when it comes to predicting a major shaker.

"We just don't have anything resembling a silver bullet that tells us whether an earthquake is about to occur," Boatright concluded.

Are you prepared for a major earthquake? How? Let us know in the comments.

Create your family disaster plan online on the Berkeley Public Health website.