About Tsunami Hazard Maps

The Alaska Earthquake Center, in partnership with the Alaska Division of Geological and Geophysical Surveys and the Alaska Division of Homeland Security and Emergency Management, evaluates and maps potential tsunami inundation of coastal communities using numerical modeling of tsunami wave dynamics. This project is a component of the National Tsunami Hazard Mitigation Program that provides guidance to at-risk populations with tsunami hazard assessment, evacuation planning and public education. 

Learn more about our other tsunami hazard mitigation projects for Alaska

How to use the tsunami map tool 

  • Select a community from the menu on the right. The tool will zoom to the community map and show you the list of available data.
  • Select the data by clicking on the boxes. Zoom in and out to adjust the view. 
  • Find more about the data types by hovering over the information button.
  • To change transparency of the water depth layer, use the slider icon in the menu bar at the top right.
  • Under the community name, there is a Disclaimer and a link to the publicaiton if the report for this community has been published. 
  • All menu items can be turned off by clicking the appropriate buttons in the menu bar at the top.
  • Map settings (zoom, transparency, etc.) can be saved or shared by copy-pasting or bookmarking the URL. 
  • Clicking on the "+" in the menu bar will bring up a printer icon that can be used to scale the map to 8.5"x11" for easy printing. To exit and return to the full map press the print icon again. 

For more information on how to use the tsunami map tool please see this instructional video.

How to interpret the map

The red line is the maximum calculated extent of flooding caused by tsunamis. This line is NOT the evacuation line. Please contact your local emergency officials to find out where evacuation routes and tsunami shelters are in your community. 

The tsunami water depth is represented by three colors: yellow for depths less that 1 foot (below knee), orange for depths between 1 and 6 feet (an average person's height), and red for depths above 6 feet. Based on evidence from previous tsunamis, the tsunami flow depths represented by orange and red colors are not survivable. 

 

Frequently Asked Questions:

  • What is the inundation line? 

This is the maximum calculated extent of flooding caused by tsunamis.

  • Will all tsunamis flood all of the inundation zone?

No. The inundaiton zone displayed on the map encompasses the maximum extent of flooding based on model simulation of all credible scenarios. Some tsunami events may result in a smaller flooded area.

  • How do scientists estimate the inundation zone and the maximum water depth?

For each community, we develop a set of tsunami scenarios based on potential earthquakes and submarine landslides. Then we perform model simulations for each of these scenarios. We compare the results with historical tsunami observations, if such data exist. Finally, we develop the inundation line that encompasses the maximum extent of flooding based on model simulation of all credible source scenarios and historical observations. Similarly, the water depth over previously dry land represents the maximum value of water depth derived from all calcualted tsunami scenarios. 

  • What should I do if my house is in the tsunami zone?

Contact your local emergency managers to find information about evacuation routes and tsunami shelters in your community. Develop your family emergency plan. 

  • How do you select communities for tsunami mapping? 

Communities are selected with consideration to their tsunami hazard exposure, location, infrastructure, availability of data, and willingness to incorporate the results in a comprehensive mitigation plan. 

  • Why do the maps shown here differ from those used in the ASCE 7 building code?

ASCE 7 maps were developed using a generic methodology across the Pacific and are not tailored for the specifics of Alaska. Though ASCE 7 does include some sources in the North Pacific, it does not properly account for the tectonophysics and geometry of specific segments of the Alaska subduction zone. It is not verified against known seismic history of Alaska (i.e., paleoseismology), nor does it include the probabilistic effects of tsunamis caused by submarine landslides. The ASCE 7 product was calculated in a uniform manner across the West Coast of the U.S. and Hawaii using lower-resolution models that may reflect the irregular Alaska coastline with less accuracy. The maps used at tsunami.alaska.edu, and published by the Alaska Division of Geological and Geophysical Surveys, attempt to develop tsunami inundation according to the maximum credible tsunamis. The maps are not the probabilistic assesment and may have some limitations [link to disclaimer text]. However, they are the only tsunami product created start-to-finish with the sole purpose of serving Alaska and Alaskans.

  • Where can I find more information about living safely with tsunamis?

Alaska Earthquake and Tsunami Preparedness

National Tsunami Warning Center

International Tsunami Information Center

  • What if I have other questions?

All additional questions or issues with the map tool can be sent to uaf_aec@alaska.edu.