Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. Out in the depths of the ocean, tsunami waves do not dramatically increase in height, but as the waves travel inland, they build up to higher and higher heights as the depth of the ocean decreases. The speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. While tsunamis are often referred to as tidal waves, this name is discouraged by oceanographers because tides have little to do with these giant waves.
Updated 2021 Tsunami Hazard Maps
Los Angeles County updated its Tsunami Hazard Maps to now include a 1,000-year event. View the presentation given to the community on April 13, 2021. For more information, visit the State of California Conservation webpage or the California Office of Emergency Services My Hazards Map.
Tsunami PREPAREDNESS Week 2021
Although Tsunami Preparedness Week 2021, which took place from March 22-26, has passed, it's never too late to go over your family evacuation plan and update your disaster supply kits. Although Malibu doesn't face the same risk from a tsunami as from other disasters, it is important to always be prepared as a tsunami can strike any coast, at any time.
How to Find Out If a Tsunami is Approaching
Strong ground shaking, a loud ocean roar, or the water receding unusually far and exposing the sea floor are all nature’s warnings that a tsunami may be coming. Immediately go to higher ground or inland. A tsunami may arrive within minutes and may last for eight hours or more. Stay away from coastal areas until officials announce that it is safe to return.
Tsunami Warnings may come via radio, television, telephone, text message, door-to-door contact by emergency responders, or NOAA weather radios. Move away from the beach and seek more information. Follow all directions from emergency personnel, and use your phone only for life-threatening emergencies.
When Should I Evacuate?
Evacuation should not be automatic. Before evacuating, you should determine if you are in a hazard zone and consider possible hazards that may exist along your evacuation route.
- GO ON FOOT. Roads may be damaged. Remember what PCH looks like on a Saturday in July - the last place you want to be when a tsunami strikes the coast is trapped in gridlocked traffic.
- Move at least 90 feet above sea level. If this is not possible, move as far inland as you can.
- If you are outside of a tsunami hazard zone, take no action. You are safer staying where you are.
Recommended Evacuation Routes
- Topanga Cyn Blvd
- Malibu Cyn Rd
- Kanan Dume Rd
- Mullholland Hwy
Following a tsunami, even those who live outside the tsunami hazard zone could find themselves in a dire situation. PCH is vulnerable to tsunami damage, and many neighborhoods depend on PCH as their only means of egress. In other words, you might live, work, or go to school well out of the reach of even the largest tsunami, but your main transportation route may not be.
As with any disaster, preparation is the key to survival. You should always keep on hand enough food and water to provide for you, your family, and your pets for at least seven to 10 days following a disaster. Remember, in a wide-scale event, Malibu may not be the first priority for outside help. Each Malibu resident should be prepared to maintain their own livelihoods until help arrives.
For more information, visit The Tsunami Zone California website or download the National Tsunami Hazard Mitigation Program (NTHMP) Tsunami Information Guide offered by the National Weather Service.