TSUNAMI HAZARD MITIGATION FOR ALASKA

Coastal Alaska communities live with the most serious tsunami risk in the United States. Historically, tsunamis generated by earthquakes in Alaska have caused damage and loss of life along the West Coast and across the Pacific. Here in Alaska, though, tsunamis generated by nearby earthquakes represent “near-field” hazards. This means people may have minutes rather than hours to reach safety.

The Earthquake Center works to make our coastal communities safer by providing state and local officials with the best possible information for addressing the tsunami hazards faced by their communities. We tackle community safety through the following projects:

Inundation Mapping Project

In partnership with the Alaska Division of Geological and Geophysical Surveys and the Alaska Division of Homeland Security and Emergency Management, we evaluate and map potential inundation using numerical modeling of tsunami wave dynamics. The maps incorporate the best tsunami science available at the time of publication.
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Click on the map to explore our Tsunami Hazard Map Tool. Zoom to your area of interest by selecting a community and map type. You can also toggle between map and satellite views at the top right. At present, the interactive map includes flow depths and inundation boundaries for 26 at-risk communities, and hazard extent for an additional 27 communities.
Frequently Asked Questions about the Tsunami Hazard Map Tool

Click to enter the Tsunami Hazard Map Tool

 

Maritime Response Guidance Documents

These documents provide response guidance in the event of tsunamis for small vessels such as recreational sailing and motor vessels, and commercial fishing vessels.
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Pedestrian Travel Time Maps

For communities that have well-defined tsunami scenarios, it is possible to estimate the amount of time required to evacuate to high ground by foot.
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Tsunami News

Tsunamis caused by submarine (below water) and subaerial (above the water) landslides are a serious hazard in bays and fjords of coastal Alaska, particularly in Southeast and South-central Alaska. This region has a long history of tsunami waves generated by submarine and subaerial landslides, avalanches, and rockfalls. These have produced some of the largest tsunami waves recorded and, unlike earthquake-induced tsunamis, they can strike with no warning.

Submarine landslide-induced tsunamis

The most common trigger of submarine landslides is slope over-steepening due to high rates of sediments being deposited on already steep slopes. Other triggering factors include earthquakes, large tidal ranges that can expose unstable sediments and weaken their hold on the slope, construction activities in coastal areas, or some combination of these. The animation below shows how an underwater landslide causes the water above it to be pulled down. When the water rebounds back up towards the surface, it produces a local tsunami. Water can be displaced in front of or behind (as in the animation) the moving landslide.