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Eureka, California
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Earthquakes

     Northwest California is one of the most scenic areas in all of the United States, however this beauty comes at a price. The rugged terrain found throughout the area is a result of active seismic activity. One of the most active earthquake regions in the entire U.S. is just off our coast, near Cape Mendocino. The numerous earthquakes found here and around the entire Pacific Rim not only leads to frequent shaking, but also the potential for tsunami or harbor waves. View an image of tectonic plates and subduction zones in Northern California

     
Earthquakes are not a meteorological phenomena, but the Eureka NWS will use its communication capabilities to disseminate information on earthquakes felt in this area via NOAAWeather Radio.

    Interesting Northwest California Earthquake Facts

  • California's North Coast, particularly in the vicinity of Cape Mendocino is one of the most seismically active areasof the United States.
  • About 25% of California's annual release of seismic energy comes in this region.
  • Since 1980, there have been five earthquakes close to magnitude 7.0.
  • Since 1980, there have been six earthquakes of magnitude 6.0 or larger.

   The United States Geological Survey, in Menlo Park California, provides up to the minute Earthquake Information. The latest reports are computer-generated messages and are therefore preliminary until reviewed by a seismologist.


Tsunami

     A Tsunami is a series of sea waves most commonly caused by earthquakes beneath the sea floor. In the open ocean tsunami waves travel at speeds up to 600 MPH. As these waves enter shallow waters they may rise to several feet or in rare cases, tens of feet. It is in these rare cases when life and property are in jeopardy as the large waves wash ashore.

The National Weather Service in Eureka is responsible for disseminating Tsunami Watches/Warnings issued the Alaska Tsunami Warning Center (ATWC) in Palmer, Alaska. When a watch or warning is issued, the message is immediately transmitted via NOAAWeather Radio. There may also be instances when a large earthquake materializes right offshore. This could a produce a tsunami in such a rapid manner, that the AWTC would not have time to issue a warning. Our office will then issue our own Tsunami Statement and disseminate it via NOAA Weather Radio. If there is a tsunami warning issued for a strong and long-lasting earthquake just off our shore you should follow these rules.

  1. Protect yourself during the earthquake. Duck, cover and hold if inside and watch for falling objects if outside until the earthquake is over.
  2. Move to higher ground immediately. Gather your family members and evacuate quickly. Leave everything else behind. A tsunami may be coming in a matter of minutes. Go by foot if at all possible. If there is no high ground, move inland and away from the coastline.
  3. Stay away from the coast. A later wave may be higher than the first! Damaging waves may continue to arrive even hours later.
  4. Listen to NOAA Weather Radio, commercial radio or television. Wait for some sort of "all clear" message before returning to low-lying areas.

Tsunami Links


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Eureka Weather Forecast Office
300 Startare Drive
Eureka, California 95501

Tel: (707) 443-6484

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