One of the many chilling parts of Kathryn Schulz's OMG-inducing New Yorker longread on the likelihood of a major earthquake and tsunami hitting the Pacific Northwest was this detail about the magnitude-9.0 Tohoku earthquake that struck Japan in 2011:
The shaking earlier in the week turned out to be the foreshocks of the largest earthquake in the nation's recorded history. Not to get all fearmongery, but given that we were woken up by last night's quake, this is, well, on our minds. CBS quotes a research geophysicist from the US Geological Survey who expects the Hayward Fault—the same one that jiggled at 2:41 a.m.—to produce a much bigger quake "any day now."
The Hayward Fault spans from San Pablo Bay in the north to Fremont in the south and cuts through Berkeley, Oakland, Hayward, and Fremont. According to the USGS, the last major seismic event on the fault was a 6.8-magnitude quake in 1868, which killed 30 (population then wasn't what it is today). Until 1906 came along, it was known as the "Great San Francisco Earthquake." Today the population in the East Bay is about 100 times greater.
CBS notes that a report from 2008 placed the likelihood of a 6.7-magnitude or larger earthquake on the fault system in the next 30 years at 31 percent, but the geophysicist they spoke to, Tom Brocher, pointed out that the fault's recurrence interval is about 140 years. "[N]ow we're 147 years from that 1868 earthquake, so we definitely feel that could happen any time," he told CBS.
Brocher added that this morning's quake isn't likely to affect the chances of a major earthquake on the Hayward Fault (phew).
Even if danger is not imminent—after all, recurrence intervals are just averages, not foolproof or predictive, really—now would be a good time to amass an earthquake kit. If it helps, take a precautionary trip to the wine aisle (and don't forget the corkscrew).
· OMG, You Guys [Curbed SF]
· The Really Big One [The New Yorker]
· Major Quake On Hayward Fault Expected 'Any Day Now' [CBS]
· Hoard This, Not That [SF Mag]