Large ocean wave

Tsunami

A Tsunami is a wave or series of waves generated by an Earthquake, Landslide, volcanic eruption, or even a large meteor hitting the ocean and causing a rise or mounding of water at the ocean surface. A Tsunami can travel across open ocean at about 500 mph and slow down to about 30 mph as it approaches land, causing it to grow significantly in height.

In the National Risk Index, a Tsunami Risk Index score and rating represent a community's relative risk for Tsunamis when compared to the rest of the United States. A Tsunami Expected Annual Loss score and rating represent a community's relative level of expected building and population loss each year due to Tsunamis when compared to the rest of the United States.

A map of the United States colored by Tsunami Risk Index ratings. Tsunami risk is only a concern along the West Coast, Hawaii, and Alaska. For full results, see the National Risk Index Map webpage.

Tsunami Exposure

A Tsunami exposure value represents a community's building value (in dollars) and population (in both people and population equivalence) exposed to Tsunamis.

Tsunami Annualized Frequency

A Tsunami annualized frequency value represents the average number of recorded Tsunami hazard occurrences (events) per year over the period of record (218.96 years).

Tsunami Historic Loss Ratio

A Tsunami historic loss ratio is the representative percentage of the exposed consequence type value (building or population) expected to be lost due to a Tsunami hazard occurrence.

Tsunami Processing Methodology

For comprehensive details about the Tsunami processing methodology, see the National Risk Index Technical Documentation.