A team of seismologists on the west coast have found a troubling pattern in the geological record over the last few thousand years: Megathrust earthquakes along the Cascadia subduction zone off the coasts of northern California, Oregon, and Washington state were followed by strike-slip temblors along the northern stretch of the San Andreas fault, the Los Angeles Times reports.
Followed very closely. “It could have even been minutes, but we can’t nail it down,” said the study’s lead author, Chris Goldfinger, an Oregon State University paleoseismologist and a professor emeritus of marine geology about the aftermath of the cataclysmic January 1700 quake off the coast of Washington that sent a massive tsunami across the Pacific that devastated Japan.
The upshot is that a Cascade quake at a 9.0 magnitude – sending a monster tsunami into the Pacific northwest’s coastal regions killing tens of thousands – would then quite likely within hours prompt a massive break in the San Andreas fault running from Cape Mendocino down as far as south of San Francisco. Just “one of these big events will draw down the resources of the whole country trying to respond to it. So if you have two of those, you double up on that,” said Goldfinger and everyone just fucking pray that if this has to happen then for it to at least happen after January 2029.