Thousands of emergency responders, community leaders and soldiers will be practicing how to respond to the aftermath of a Cascadia subduction zone megaquake and tsunami this week.
Called “Cascadia Rising,” the exercise will provide those responders scenarios of damage that could stem from an event on the 600-mile-long subduction fault that runs along the coasts of Washington, Oregon, California and British Columbia.
Based on the studies some of the Pacific Northwest’s top minds have assembled, we know the fault produces magnitude 9.0 quakes every 200 to 700 years. The last was on Jan. 26, 1700. We know this thanks to tribal lore, Japanese records and a cedar forest petrified by the tsunami.
Models help locals be prepared
Home to the Washington Geological Survey, DNR has spent decades studying the state’s major faults and investigating the damage major seismic activity could inflict on our communities. Those studies are compiled in our interactive Seismic Scenario Catalog.
The catalog is a compilation of results from 20 scenario models run using FEMA’s Hazards United States (HAZUS)software program and is based on reasonable estimates of the most serious earthquake hazards to Washington State.
Each scenario includes a shaking intensity map to convey how widely felt the particular seismic event is projected to be, and many additional data layers, detailing the demographics of affected regions and impacts to infrastructure (for example, damage to hospitals and schools).
The Seismic Scenario Catalog represents a multi-agency collaboration, including DNR, EMD, Western Washington University (WWU), Huxley College of the Environment, Federal Emergency Management Agency (FEMA), US Geological Survey (USGS) and URS Corporation. We are working to keep the catalog updated and improved over time.
Tsunami, Inundation dangers also mapped
In addition to earthquake hazards, DNR has also mapped geologic hazards that could come alongside a Cascadia quake.
Our geologists have produced studies of how a quake might produce landslides and soil liquefaction in coastal communities and what areas could be inundated by tsunamis.
Alongside all of this, DNR’s Division of Geology and Earth Resources has compiled information about emergency preparedness on a web page.
All this is geared toward making sure you, your families and your neighbors are as informed as possible about the geologic hazards that have formed Washington’s stunning and special landscape. Look it over and be prepared, not scared.