Some Historic Tsunamis Affecting the Pacific Northwest
Last updated June 23, 2021
Recent as well as historical tsunamis have directly affected the Pacific Northwest. Learn about some of these individual tsunamis below. For a general introduction to tsunami risk in the Pacific Northwest, read the 2015 New Yorker article, "The Really Big One: An earthquake will destroy a sizable portion of the coastal Northwest. The question is when."
Local (from a Cascadia Subduction Zone earthquake)
Distant (from an earthquake anywhere on the Pacific Rim of Fire except the Cascadia Subduction Zone)
Cascadia 1700 Earthquake and Tsunami
On January 27, 1700, a tsunami struck the coasts of Japan without warning? no one in Japan felt the earthquake that must have caused it. A very large earthquake?perhaps as large as 9.2 magnitude, comparable to the Great Alaska Earthquake of 1964?had ruptured the earth along the entire length of the 1,000 km (600 mi) long fault of the Cascadia Subduction Zone. This NOAA/NWS/Pacific Tsunami Warning Center animation models tsunami wave speed, wavelength, and amplitude through 24 hours of simulated motion and as the waves race around the globe from the Cascadia Subduction Zone earthquake.
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Tohoku, Japan 2011 Earthquake and Tsunami
On March 11, 2011, a 9.0 moment magnitude earthquake struck near the coastline of Honshu, Japan. The tsunami caused the greatest devastation and over 17,000 deaths in Japan, where waves reached over 40 m or 130 ft. high. After traveling across the Pacific, the tsunami rose to more than 5 m or 16 ft. in Hawaii and more than 2 m or 6.5 ft in California and Oregon. This NOAA/NWS/Pacific Tsunami Warning Center animation models tsunami wave speed, wavelength, and amplitude through 36 hours of simulated motion and as the waves race around the globe from the Japan earthquake.
Oregon is a geologic mirror-image of northern Japan. In both places, the Pacific Ocean floor is sliding beneath adjacent continents along giant faults called subduction zones. (Source:
Oregon Resilience Plan: Reducing Risk and Improving Recovery for the Next Cascadia Earthquake and Tsunami.)
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Alaska 1964 Earthquake and Tsunami
On March 27, 1964, the largest earthquake ever measured in North America, and the second-largest recorded anywhere, struck 40 miles west of Valdez, Alaska in Prince William Sound with a moment magnitude we now know to be 9.2. The earthquake generated a tsunami that killed 124 people (5 in Oregon) and caused about $2.3 billion (2016 dollars) in property loss all along the Pacific coast of North America from Alaska to southern California and in Hawaii. The greatest wave heights were in Alaska at over 220 feet. Waves as high as 12 ft. struck Oregon.
Today, more than 50 years since the Great Alaska Earthquake, the Real-Time Forecasting of Tsunamis (RIFT) forecast model takes earthquake information as input and calculates how the waves move through the world?s oceans, predicting their speed, wavelength, and amplitude. This animation shows these values through the simulated motion of the waves and as they travel through the world's oceans.
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Aleutian Islands 1946 Earthquake and Tsunami
On April 1, 1946, an 8.6 moment magnitude earthquake struck off the coast of Unimak Island in Alaska?s Aleutian Islands, generating a tsunami that caused the greatest damage and number of deaths in Hawaii?s history, leading to the creation of the United States? first tsunami warning system. Tsunami waves reached as high as about 138 ft. on Unimak Island, destroying its lighthouse and killing the five people there. Elsewhere this tsunami caused the greatest damage and number of deaths on inhabited Pacific islands. In Hawaii the waves reached about 55 ft. high and killed 158 people, most in the town of Hilo. In North America the highest waves were in California at over 2 m or over 8 ft. and killed one person there.Coos Bay, Oregon, reported a 10-ft. wave.
A tsunami warning system did not exist in 1946 and no one had any warning of the approaching dangerous waves. In response to this event the United States government set up its first tsunami warning operation in Hawaii in 1948 to mitigate tsunami hazards in Hawaii. This facility would later be renamed the Pacific Tsunami Warning Center (PTWC) and expand its mission to include the rest of the Pacific Ocean and the Caribbean Sea.
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