Information sourced from the California Department of Conservation, California Office of Emergency Services & The National Oceanic and Atmospheric Administration
Millions of people enjoy California’s wonderful coastline. Whether you live, work, or visit, it is important to be aware that the coastal region is vulnerable to tsunamis. California’s large active offshore faults and unstable submarine slopes can cause tsunami activity along the coast.
Strong ground shaking from an earthquake is the natural warning that a tsunami might be coming. If you are on the beach or in a harbor and feel an earthquake, immediately move inland or go to high ground. If strong shaking lasts for 20 seconds or more, everyone within the tsunami evacuation area should evacuate as soon as it is safe to do so. Other natural warnings include seeing the ocean quickly recede to expose the ocean bottom, or hearing an unusually loud roar coming from the ocean. A tsunami can arrive within minutes and may last for several hours.
For tsunamis coming from across the ocean, local communities use a variety of communication methods to broadcast emergency information. Be informed on what signals, sirens, and public services will be employed for your area. Practice tsunami evacuation drills.
- January 26, 1700 – A magnitude 9 earthquake along California’s north coast generated a major tsunami. Oral histories of Native Americans in this region incorporate recollections from this event.
- December 21, 1812 – A local earthquake triggered a tsunami near Santa Barbara. Residents in coastal villages were so alarmed that they retreated several miles inland to the nearby Santa Barbara Mission.
- November 4, 1927 – A magnitude 7.1 earthquake off the coast of northern Santa Barbara County caused a six-foot-high tsunami along portions of the central coast.
First, find out if you live, work or play in a tsunami hazard area:
- Use the links listed below to find out where tsunami hazard zones occur.
- Information from these websites can help you identify the tsunami hazard area in your community and help you prepare. Check out the county web pages on the CGS website for evacuation plans for your community. If you are located just outside of a tsunami hazard area, you may consider working with your community to see what kind of assistance you might be able to provide for those that are in a tsunami hazard area and will need to relocate.
- Identify if there is an evacuation plan in place for your site. Contact your building manager, school district, city or county offices to find out the recommended procedures. Additionally, the California Geological Survey Tsunami website provides many links to local, regional, state, and national information sources.
- If there is no evacuation plan in place, learn what the recommended tsunami evacuation routes are in your city, county and region. Some cities and counties have this information available online. Identify safety zone(s) near you, and plan your primary and secondary evacuation routes.
- Identify what your evacuation destination will be (school, church, parking lot).
- Prior to an evacuation drill, walk your evacuation route. Make sure there are no potential hazards that may prevent your staff/students/family from using this evacuation route safely.
- Coordinate in advance to have volunteer groups (from non evacuation areas) serve refreshments to evacuation drill participants. After the drill, have a safety fair planned: invite local emergency response groups, learn emergency preparedness skills, distribute tsunami and earthquake preparedness information.
- For school evacuation drills, plan for interactive educational tsunami activities at the relocation area (for ideas see CGS tsunami education link). Provide a snack. Have a guest speaker.
Know the warning signs
- An earthquake in your area is one of nature’s tsunami warning signals. Do not stay in low-lying coastal areas after a strong earthquake has been felt.
- Tsunamis are sometimes preceded by a noticeable receding of sea level as the ocean retreats seaward exposing the seafloor. A roar like an oncoming train may sometimes be heard as the tsunami wave rushes toward the shore. These are also nature’s tsunami warning signals.
- A tsunami is not a single wave, but a series of waves. Stay out of danger areas until an “all-clear” is issued by competent authority.
Understand how your community will broadcast official tsunami emergency information
- Tsunami warnings may be by radio, television, telephone, text message, door-to-door contact, NOAA weather radios, outdoor sirens.
- During a tsunami emergency, your local civil defense, police, and other emergency organizations will try to save your life. Give them your fullest cooperation.
- All warnings to the public must be taken very seriously, even if some are for non-destructive events. The tsunami of May 1960 killed 61 people in Hilo, Hawaii because some thought it was just another false alarm.
- Look for the blue and white tsunami evacuation signs along the coast.
- Assemble a small evacuation kit (essential documents, medications, flashlight, portable NOAA weather radio and batteries, water, snack, warm clothes, silver “space blanket).
- Make a reunification plan with your family. Decide when and where you will meet if you are separated. Designate an out of state relative or friend for the individuals in your family to call if it is not possible to meet at your reunification spot.
- Make plans for how to address any needs or disabilities you might have.
Contact other Emergency Response Groups in Your Area
- Consider joining your Community Emergency Response Team: www.csc.ca.gov/cc/cert.asp
- Find out if other organizations, agencies, or schools in your area are participating in a tsunami drill. Even if you are in an area that does not require evacuation, volunteer to work at relocation sites, comfort stations, or animal care facilities in your area. Learn what the potential needs of your community might be.
- Share ideas and coordinate resources. For example, your elementary school may need to evacuate to another school, church, or business; coordinate with them to work out details such as how to enter the site and where to assemble.
Important Online Resources
Official State Tsunami Hazard Zones:
CalEMA MyHazards http://myhazards.calema.ca.gov/
NOAA Tsunami Warning Center http://wcatwc.arh.noaa.gov/
Preparing for earthquakes:
The Great California ShakeOut http://www.shakeout.org/
Red Cross http://www.redcross.org/
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