Tsunamis... You Can't Surf These Waves!

Did you know that tsunamis are a possible threat here in California?  Whether you live, work, or play near the California coast, it's important to know what to do if a tsunami occurs or if a tsunami watch or warning is issued.  The following article, brought to you by the County of Los Angeles and The California Governor's Office of Emergency Services, provides helpful information about tsunamis and what to do to prepare. It's great information... something we should all keep on file!

  

Contrary to popular belief, a tsunami isn't one giant wave.  It's a series of waves that build up momentum.  They can travel at speeds up to 500 miles per hour in the open sea and reach heights of up to 100 feet in shallow coastal waters.  Usually, however, tsunamis that reach California average 10 feet in height and peak in the 20-40 foot range.  The first tsunami wave is seldom the highest or last.  Waves will continue to arrive for several hours, spaced minutes to hours apart.  In fact, hundreds and perhaps thousands of people died in the catastrophic 2004 tsunami when they went to the ocean to see the impacts of the first waves.  They were swept to their deaths when subsequent waves struck.

The time it takes for tsunami waves to reach the coast can vary.  Tsunami waves are typically generated by giant earthquakes below the ocean floor or as a result of underwater landslides.  If a tsunami is caused by an earthquake a few miles off the coast, the resulting waves will arrive within minutes of the quake.  If it happens 200 miles away, the waves could arrive within 30-60 minutes.  There is no exact way to measure this, but your local news should be able to provide up to date information as the event unfolds.

So what is the our threat here in California?

 More than a dozen tsunamis with waves three feet high or more have struck California since 1812.  Some have caused significant damage:

• The tsunami generated by the 1964 Alaska earthquake killed a dozen Crescent City residents and caused more than $34 million in damage. 
• Three tsunamis flooded Santa Barbara during the 1800s
• A tsunami resulting from a Chilean earthquake damaged a pier in San Diego Harbor in 1960
• One foot waves resulting from the 1992 Cape Mendocino earthquake were detected near Santa Barbara

Historically, tsunamis have caused greater casualties and damage in Northern California.  But Southern California residents are still at risk because our coastal population is higher.

So what can we do to prepare?

Before The Next Tsunami or Tsunami Warning:

• Determine the elevation of your home and how far it is from the coast.  Know whether you live in a tsunami danger zone.
• If you live within a couple of miles of the coast, identify a location to go to if a tsunami strikes.  The location should be at least two miles inland or 100 feet above sea level.
• Learn the signs of an approaching tsunami.  If the tide rises or recedes rapidly, move immediately inland to higher ground.
• Ask local emergency officials or your planning department what areas are susceptible to the tsunami flooding
• Locate refuge areas and learn evacuation routes.  If you live in San Diego like we do, you can obtain information here: http://www.sandiego.gov/ohs/index.shtml
• Develop or update your family's emergency plan.  If you don't have a plan or need help revising your existing plan, Servpro of Point Loma can help!  We provide free emergency plan assistance!
• Assemble an emergency supply kit that includes a portable radio
• Identify a friend or relative living in another state that can serve as a family point of contact
• Learn first aid techniques such as CPR to assist neighbors who may be injured
• Teach family members how and when to turn off the utilities
• Start of join a Community Emergency Response Team.  Servpro of Point Loma is a member of Ready San Diego.   It's a great safety tool for San Diego residents! http://www.sdcounty.ca.gov/oes/ready/  

During or After The Next Tsunami or Tsunami Warning:

• If you feel an earthquake, DROP, COVER, AND HOLD ON until the shaking stops.  Estimate how long the shaking lasted.  If severe shaking lasted 20 seconds or more, immediately evacuate to height ground as a tsunami might have been generated by the earthquake.
• Move inland two miles or to land that is at least 100 feet above sea level immediately.  Don't wait for officials to issue a warning.  Walk quickly, rather than drive, to avoid traffic, debris, and other hazards.
• Stay away from coastal or low-laying areas until an "all clear" notice has been issued by local emergency officials.  Waves might continue to arrive for several hours.
• Use common sense.  Do not go to the coast to see a tsunami.  Tsunamis are not like regular waves.  They are much faster, higher, and are filled with debris.
• Obey evacuation notices.  Listen to the radio or watch television for emergency information and instructions from local officials about re-entry.
• Contact your local office of emergency services for more information about preparing for tsunamis.

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This information was extracted and adapted from "Tsunami!  How to Survive This Hazard on California's North Coast," Humblodt Earthquake Education Center, Humboldt State University, Arcata, CA;  other sources included the FEMA publication "Are You Ready?  Your guide to disaster preparedness," and from information provided by the Governor's Office of Emergency Services, Earthquake and Tsunami Program and The city of Los Angeles publications.

*** Servpro of Point Loma is a Ready San Diego Business Alliance Member. Feel free to contact us anytime for safety tips!