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Special Paper 51, Columbia River tsunami modeling: toward improved maritime planning response, by Jonathan C. Allan, Joseph Zhang, Fletcher E. O'Brien, and Laura L. Gabel.


Report (77 p., 24.7 MB PDF)


Related publication:
DOGAMI Maritime Tsunami Response Guidance (MTRG) - Port of Astoria, Clatsop County, Oregon and Lower Columbia River Estuary
Guidance for operators of small watercraft and commercial fishing vessels in the event of a distant tsunami.


Recent tsunamis affecting the West Coast of the United States have resulted in significant damage to ports and harbors, as well as to recreational and commercial vessels attempting to escape the tsunami. This study evaluates new tsunami modeling results completed for both distant and local tsunamis in the Columbia River system. The overall goal is to examine the interaction of tsunamis with dynamic tides (as opposed to modeling using a fixed tidal elevation such as mean higher high water), different riverine flow regimes, and friction to provide an improved understanding of tsunami effects on maritime traffic operating offshore the mouth of the Columbia River and within the estuary, as well as upriver toward the ports of Longview, Vancouver, and Portland. This was accomplished by evaluating a suite of tsunami simulations (35 in total) for the Columbia River focused on two distant earthquake scenarios: the 1964 Anchorage, Alaska (AK64) earthquake and a maximum considered eastern Aleutian Island (AKMax) earthquake, and two local Cascadia subduction zone (CSZ) scenarios: Large1 (L1) and Extra-extra-large1 (XXL1).
The Alaska 1964 scenario provides an excellent reference point for the potential maritime effects of the most extreme distant event to strike the Oregon coast in the past century. Our model simulations reveal the following:

For the maximum considered AKMax distant tsunami, our analyses indicate:

With respect to maritime evacuation for a maximum considered distant tsunami, we note the following:

Results from modeling a maximum considered locally generated CSZ tsunami revealed the following:

With respect to maritime evacuation for a maximum considered CSZ tsunami, we note the following:

Modeling undertaken using dynamic tides and varying river flows has yielded some useful insights, when compared with static models undertaken at MHHW and with no flows. These include: