New, interactive maps pinpointing how and where a tsunami might flood the Oregon and Washington coastlines – and the closest uphill evacuation spots – are online now at NANOOS, the Northwest Association of Networked Ocean Observing Systems.
The new Tsunami Evacuation Zone portal is a joint project of the Oregon Department of Geology and Mineral Industries, Washington Department of Natural Resources, and the NANOOS Visualization System team.
The new maps allow users to enter an address, or click on the map, and see if their location is in a danger zone. Users can create multiple places, and if they sign up for a free myNANOOS account, save their own personalized maps for future use.
The maps show areas projected to be at risk of flooding by close and distant tsunamis, and the approximate time residents would have to evacuate those areas before the waves arrive. They also show nearby areas of high ground where residents and visitors can expect to be out of the reach of the incoming water.
All low-lying coastal areas, harbors, streams, and rivers in Oregon are vulnerable to tsunami inundation. While the waves from distant earthquakes like the one that struck Japan in March 2011 can take several hours to arrive, a sea-floor earthquake in the seismically active Cascadia Subduction Zone, just off the coast, could generate devastating waves in a matter of minutes. Undersea landslides can also generate powerful, localized tsunamis.
Recent research suggests that powerful near-shore quakes have occurred off the Oregon coast at relatively regular intervals; scientists now put the chance of a magnitude 8-9 earthquake striking the region at 37% within the next 50 years.
The new NANOOS site is tied to NOAA’s West Coast and Alaska Tsunami Warning Center, and displays earthquake and tsunami alerts in real time. It also contains printable PDF versions of local tsunami evacuation brochures for specific coastal communities in Oregon and Washington. The brochures are also widely available in printed form at visitor centers, motels and other locations on the coast.
A powerful nearshore earthquake could disrupt communications, including Internet service, on the coast. The site emphasizes preparing in advance: Developing family and workplace evacuation plans, obtaining or printing out evacuation brochures, walking local evacuation routes, and figuring out how you will reconnect with family members once the immediate danger has passed.
For more information about tsunami preparedness, visit Oregon Sea Grant’s Coastal Natural Hazards page.