Study Reveals Cascadia, San Andreas Faults May Trigger Each Other

SAN FRANCISCO — A new study has found evidence that two of the best-known earthquake fault lines on the West Coast of the United States are synchronized. Researchers from Oregon State University focused on the San Andreas Fault and the Cascadia Subduction Zone. Their findings suggest that earthquakes on one fault could set off the other, potentially leading to a major disaster.

The study analyzed sediment samples taken from the ocean floor. It revealed that seismic activity on the Cascadia fault, located off the coast of Oregon and Washington, could trigger earthquakes on the San Andreas Fault, which stretches from Northern to Southern California. This connection raises concerns, as two large earthquakes occurring in succession could create widespread emergencies.

Chris Goldfinger, a marine geologist and lead author of the study, emphasized the urgent need for emergency planners to prepare for this scenario. “We could expect that an earthquake on one of the faults alone would draw down the resources of the whole country to respond to it,” Goldfinger stated. “And if they both went off together, then you’d have potentially San Francisco, Portland, Seattle, and Vancouver all in an emergency situation in a compressed timeframe.”

The researchers discovered that in some sediment layers, earthquakes on the Cascadia fault and the San Andreas fault occurred very close together in time, sometimes within minutes or hours. This connection means that a significant event on either fault could lead to another major quake, increasing the risk of disaster across the region.

Previous major earthquakes in history have shown the potential power of these faults. Goldfinger explained that a magnitude 9+ event on the Cascadia Subduction Zone could trigger devastating results, including tsunamis and landslides, compounding the destruction.

While major earthquakes on either fault are rare, the potential for them to occur in tandem poses questions about preparedness for such disasters. Emergency management officials are urged to consider this likelihood in their response plans.

Goldfinger concluded by advising individuals to prepare for any emergencies: “Get a kit, make a plan, and be informed.”