In news that is sure to remind everyone to check their earthquake kit (you have one of those, right?), the Chronicle reports that the odds of a major quake happening in the Bay Area some time during the next 30 years have jumped to a frightening 72 percent. Experts last year predicted the chances of a 6.7 magnitude or higher quake hitting the region at 63 percent — a number that seems almost comforting by comparison.
The 1989 Loma Prieta quake's magnitude was 6.9.
The estimate comes from the appropriately named Working Group on California Earthquake Probabilities, which released a report last week detailing what its authors say is a better understanding of quakes gleaned from improved fault mapping and updated models.
David Schwartz, a geologist who works with the U.S. Geological Survey, told the paper that info from 32 faults like the Wright Way, Collayami, and Monterey Bay-Tularcitos faults helped researchers come to their most recent conclusion. Apparently multiple small faults can rupture simultaneously leading to larger earthquakes — an unpleasant fact, to say the least.
This sounds much like the idea put forth last year that San Andreas might in fact be a "zipper fault." The idea is that smaller faults, when colliding, merge instead of passing each other by.
Meanwhile, small earthquakes — such as the 3.5 magnitude quake that struck near Piedmont early Tuesday morning — will continue to hit of course. And the Hayward Fault is the one that's most overdue for a big one.