If you're a Californian living in fear of the inevitable next "Big One" to hit the San Francisco Bay Area, well, we're not sure if you'll find this comforting or not: A new study from USGS scientists finds that the next "Big One" is more likely to be a cluster of pretty big earthquakes, as opposed to one really big earthquake, the San Jose Mercury News reports. "Everybody is still thinking about a repeat of the 1906 quake," says the geologist who co-authored the study, referring to the 7.8-magnitude earthquake that hit the city that year. "But what happens if every five years we get a magnitude 6.8 or 7.2? That's not outside the realm of possibility."
The scientists found that, between 1690 and 1776, at least six earthquakes ranging in magnitude from 6.3 to 7.7 shook the Bay Area. Those quakes, taken together, released about as much stress on the area's major faults as did the 1906 quake, Phys.org explains. We've gotten "through the next 110 years in relative quiet"—in fact, abnormally so, says the co-author; but that stress has been re-accumulating all the while, and something's gotta give. And, while the accumulated energy could be released in "the Big One," researchers say a cluster is more likely because of all the faults in the region. (Read more earthquake stories.)