USGS: Bay Area Major Earthquake Odds Rise to 74% by 2055

The probability of a major earthquake striking the San Francisco Bay Area within the next 30 years has risen to 74 percent, according to a new assessment from the U.S. Geological Survey. The updated forecast, released this week, represents a 2 percentage point increase from the previous estimate calculated more than a decade ago. Scientists attribute the heightened risk to the continued accumulation of tectonic stress along the region's active faults, as no major rupture has occurred since the last assessment. The new calculations, part of the third Uniform California Earthquake Rupture Forecast, estimate a 74.1 percent chance of at least one magnitude 6.7 or stronger earthquake hitting the region by 2055. The increase is a direct result of time passing without a significant release of built-up pressure on the fault systems. "Things seem to be pretty locked and loaded," said Ned Field, a seismologist with the USGS. "We'd be wise to be ready." While the overall regional risk has increased, the probability varies among individual fault lines.