Research Suggests Cascadia and San Andreas Faults Could Trigger Linked Earthquakes

Sun, 03 May 2026 04:26:00 +0200

New research from Oregon State University indicates that two major West Coast fault systems—the Cascadia subduction zone and the San Andreas fault—may be more closely linked than previously understood. By analyzing sediment cores from the ocean floor, scientists discovered patterns in turbidite layers that suggest earthquakes on one fault could potentially trigger activity on the other. The study identifies at least three instances in the past 1,500 years, including the 1700 Cascadia earthquake, where events on both faults may have occurred within minutes to hours of each other. This partial synchronization could exacerbate the impact of a major earthquake, potentially overwhelming emergency response systems across multiple cities, including San Francisco, Portland, Seattle, and Vancouver. The research was sparked by an accidental discovery during a 1999 oceanographic survey near Cape Mendocino, where unusual sediment layering pointed to closely timed seismic events, referred to by the