Tsunami Warnings

Logo: Tsunami Evacuation Sign

What Is A Tsunami?

Tsunami: a Japanese word that means harbor wave; a sea wave of local or distant origin that results from large-scale seafloor displacements associated with large earthquakes, major submarine slides, or exploding volcanic islands. Typically generated by seismic or volcanic activity or by underwater landslides, a tsunami consists of a series of high-energy waves that radiate outward like pond ripples from the area in which the generating event occurred.

Not all earthquakes produce tsunamis. To generate a tsunami, an earthquake must occur underneath or near the ocean, be very large (approximately Richter magnitude 7 or greater), and create vertical movement of the sea floor. However, recent studies regarding the potential for a great Cascadia Subduction zone earthquake off the Washington, Oregon, and Northern California coastlines indicate the local tsunami waves may reach nearby coastal communities within minutes of the earthquake thereby giving little or no time to issue warnings.

How will I know if a Tsunami is coming?

The West Coast/Alaska Tsunami Warning Center (WC/ATWC) is responsible for tsunami warnings for California, Oregon, Washington, British Columbia and Alaska.


Tsunami Messages issued in the past 7 days

The Pacific Tsunami Warning Center (PTWC) provides warnings to international authorities, Hawaii, and U.S. Territories within the Pacific Basin.