Key Insights for Washington State Commercial Property Owners on Earthquake Risks

As a property owner in Washington, it’s essential to stay informed about the Cascadia Subduction Zone (CSZ), a significant fault line that stretches 700 miles from Northern California to British Columbia. This fault, where two tectonic plates meet, is one of the most powerful in North America. While it has been relatively quiet for the last 300 years, recent research is enhancing our understanding of the associated risks.

New Insights on the Cascadia Fault

In 2021, scientists embarked on a marine research expedition that mapped nearly the entire CSZ from Oregon to British Columbia using advanced imaging techniques. Their findings, published in Science Advances, provide a clearer picture of the fault and reveal distinct segments with varying characteristics that could influence earthquake risk in the region.

One notable discovery is that the segment off Washington state has a shallow angle, creating a large fault surface. Scientists suggest that if this segment were to rupture, it could release significant seismic energy. The limited activity on this fault over time means that pressure has built up, potentially leading to stronger ground shaking that could affect areas like Seattle and Tacoma. This segment can be compared to a “loaded spring,” with the potential to produce an earthquake similar to the one in 1700, which caused tsunamis and left behind “ghost forests” — dead trees along the coast that were submerged by seawater.

What This Means for Your Property

These new findings indicate that the earthquake risk for many property owners in Washington may be higher than previously estimated. Earlier models relied on data from the 1980s, but this recent study offers a more nuanced understanding of how different fault segments might behave. For example, some segments in Oregon are rougher and more fragmented, which may limit the spread of seismic waves. In contrast, the Washington segment’s smoother characteristics and larger area of overlap raise concerns about potential physical impacts.

The key takeaway is that while the timing of a significant earthquake remains unpredictable, understanding these fault characteristics equips scientists with better tools to model potential impacts, enhance preparedness, and inform building standards.

Steps to Protect Your Property

While scientists cannot predict when the CSZ will rupture, there are proactive steps property owners can take to prepare for potential risks:

1. Review Earthquake Insurance Options: Standard insurance policies typically exclude earthquake damage, so consider adding earthquake insurance. This can provide financial protection for structural and personal property losses in the event of a earthquake. Contact your agent to learn more about ICAT's Earthquake Insurance options.
2. Consider Seismic Retrofitting: If your property was built before modern seismic standards, retrofitting can significantly improve its resilience to earthquakes. This process may include anchoring the foundation, strengthening walls, and securing heavy appliances or furniture.
3. Stay Informed and Prepare: Familiarize yourself with local emergency resources and educational materials. Develop a safety and business interruption plan and ensure that your tenants know what to do when an earthquake occurs.

By taking these steps, you can help safeguard your property and be better prepared for the future.