There are a few things on which every seismologist agrees. First, there’s almost certainly a “Big One” in our future — a super shake-up destined to deliver disaster-movie perils. With local seismic activity running some 300 years behind schedule, it’s safe to say we’re living on borrowed time. A second point of agreement: It’s anybody’s guess when the sword of Damocles will lose its grip, send the valley trembling, and compel us to drop, cover, and hold on for dear life.















