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Cascadia Subduction Zone Earthquake

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The Cascadia Threat

A Cascadia event is based on the threat of a catastrophic magnitude 9.0 Subduction Zone earthquake and resultant tsunami. Coastal counties will experience a devastating tsunami on top of severe ground shaking (up to five minutes). Shaking intensity will be less in the I-5 Corridor and Southern, Central, and Eastern Oregon, but older buildings may incur extended damage.

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Expected Impacts

  • Ground shaking for 4-6 minutes causing massive critical infrastructure damage

  • Liquefaction and landslides causing disruption of transportation routes

  • Tsunami inundation to coastal areas with as little as 15 minutes warning

  • Up to 25,000 fatalities resulting from combined effects of earthquakes and tsunami

  • Tens of thousands of buildings and structures destroyed or damaged

  • Tens of thousands of people in need of shelter because of destroyed or damaged households

  • $30+ billion in economic loss

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