Tsunami Information

A tsunami threat to the City of Laguna Beach is considered low to moderate.

Tsunamis (pronounced soo-nah-mee) are an infrequent, yet serious hazard in the Pacific. A tsunami is a series of traveling ocean waves of great length and long period, generate by disturbances associated with earthquakes in oceanic and coastal regions. As the tsunami crosses the deep ocean, its length from crest to crest may be hundred miles or more, its height from trough to crest only a few feet. It cannot be felt aboard ships in deep water and cannot be seen from the air. But in deep water, tsunami waves reach speeds exceeding 600 miles per hour.

As the tsunami enters the shoaling water of coastlines in its path, the velocity of its waves diminishes and wave height increases. It is in these shallow waters that tsunamis are a threat to life and property, for they can crest to heights more than 10 feet and strike with deviating force.

Tsuami Ready National Weather Service

Tsunami Web Site California Department of Conservation

Tsunami Education Videos California Deparment of Conservation

Tsunami Inundation Maps California Department of Conservation

Google Maps Interface Inudation Maps for Emergency Planning


The tsunami warning system in the United States is a function of the National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service. Development of the tsunami warning system was impelled by the disastrous waves generated in Alaska in April 1946, which surprised Hawaii and the West Coast, taking a heavy toll in life and property. The Pacific Tsunami Warning Center was established in Hawaii in 1948. A 1964 Alaskan earthquake triggered a tsunami which hit Crescent City in Northern California resulted in the Alaska Tsunami Warning Center in Palmer, Alaska. This facility is the nerve center for an elaborate telemetry network of remote seismic stations in Alaska, Washington, Colorado, California and other location. Tide data from Canada, ‘Washington, Oregon and California are available via telephone, teletype and computer readout.


When a large earthquake occurs near the coast in the North Pacific, seismologists at the Alaska Tsunami Warning Center determine its location (epicenter) and magnitude. If the earthquake is considered great enough to generate a tsunami, the Center will issue a immediate Tsunami Warning for the area near the epicenter. This warning is issued and immediate Tsunami Warning for the area near the epicenter. This warning is issued through state emergency service offices, Coast Guard, military, FAA, National Weather Service and other agencies. A Tsunami Watch is issued to the rest of Alaska, Canada and West Coast states alerting the public to the possible threat of a tsunami. If a tsunami is detected by tide stations near the epicenter, the warning is expanded to the entire coastline. If no wave is generated, the warning will be cancelled.


Tsunamis can be categorized as local and Pacific-wide. Typically a Pacific-wide tsunami is generated by major, vertical, ocean bottom movement in off-shore deep trenches. A local tsunami can be component of the Pacific-wide tsunami in the area of the earthquake or a wave that is confined to the area of generation within a bay or harbor and caused by movement of the bay itself or landslides. The local tsunami may be the most serious threat because of the lack of warning time before reaching shore.

Therefore, it is imperative that those people near shore who feel a strong earthquake should move to higher ground immediately. A strong quake is one that last 30 seconds or longer and causes difficulty in standing. The Alaska Tsunami Warning Center will begin issuing its warning to the West Coast in approximately 25 minutes, but that is not quick enough for a local tsunami, so when in doubt, areas should be evacuated.

A tsunami threat to the City of Laguna Beach is considered low to moderate.