Two of the West Coast’s most dangerous fault lines might be more in sync than scientists have realized. A new study found that the two sleeping giants, the Cascadia subduction zone and the northern San Andreas fault, have been moving in rhythm for millennia, shaking within hours of each other in a geological “dance” that can rattle the coastline from Oregon to California.
A team led by Oregon State University geologist Chris Goldfinger published its findings on Sept. 29 in the scientific journal Geosphere, demonstrating the first evidence that the two faults have interacted repeatedly over thousands of years.
Washington, up to southern British Columbia. The famous San Andreas fault runs along the California coast straight through San Francisco.
By examining deep-sea sediment cores from the Cascadia megathrust — the deep undersea fault where the oceanic plate dives beneath North America — researchers found signs that major quakes on one fault may have helped trigger ruptures in the other.