Although California is unlikely to be hit with a large tsunami, Marina del Rey is the most vulnerable area in Los Angeles County for high waves and flooding.
“Tsunamis are rare in California, but Marina del Rey could see higher than usual waves because the area sits on low-lying ground,” said Bill Butler, assistant administrator for the Los Angeles County Office of Emergency Management.
Tsunami is a Japanese word combining the Japanese words for harbor (tsu) and wave (nami).
A tsunami is most commonly generated by underwater earthquakes but also by underwater landslides and volcanic eruptions.
When the massive force abruptly shifts the ocean floor, water is displaced and forms a series of waves that move outward in all directions across entire ocean basins.
Tsunami waves differ from ordinary ocean waves and tidal waves in that they reach speeds of 500 miles per hour and heights of 45 feet.
As the tsunami moves closer to the coastline, its speed diminishes but its height increases greatly, possibly up to 100 feet.
Waves will continue to pound the coastline, separated by minutes or hours.
“You don’t want to surf these waves,” said California Governor’s Office of Emergency Services officials.
Los Angeles County and the Cities of Los Angeles and Santa Monica prepare for tsunamis as part of their earthquake survival programs.
California is located on the Pacific Ocean “Ring of Fire,” a rim known for numerous geological activities under water and on ground.
With federal funding, California has completed mapping of tsunami hazard areas for counties south of San Francisco.
The state is expected to finish mapping northern counties in March.
IN THE MARINA — Marina del Rey is not expected to be hit with tsunami waves higher than three feet.
Area residents would most likely experience widespread flooding one mile or more inland and need to be evacuated.
“It is the job of local law enforcement to have evacuation plans,” Butler said.
“The Marina del Rey Sheriff’s Station does very well. They have experience with high water,” he said.
The City of Los Angeles characterizes tsunamis as a “low risk hazard” and has ongoing mitigation measures for warning residents and controlling floods and storm water pollution.
IN SANTA MONICA — The City of Santa Monica considers tsunamis to be a “potential threat.”
“Tsunamis, like earthquakes and severe storms, are one among a number of potential threats that Santa Monica faces,” said Santa Monica Emergency Services Office officials.
“But the chance of a significant tsunami impacting our coastline is remote because of the underlying geology in the Southern California region,” the Santa Monica officials added.
Santa Monica recommends that its residents and businesses keep a three-day supply of food, water, medicine and other essential items handy at all times for “whatever events we may encounter.”
STATE OFFICIALS SAY —State officials warn people to stay away from the coastline after an earthquake. The threat of a tsunami may last for several hours.
People may want to go to the beach to see unusually high waves but this is dangerous because tsunami waves are smaller at first before a much taller wall of water crashes down minutes later, state officials said.
One indication to move inland is when the water rapidly moves back into the ocean because this means a tsunami is forming in the distance.
“If severe earthquake shaking lasts 20 seconds or more, a tsunami might follow,” state officials said.
“Stay away from coastal or low-lying areas. Waves travel several times faster than you can walk, run or drive.”
ASIAN DISASTER — A series of Indian Ocean tsunamis killed more than 60,000 people in Indonesia, Sri Lanka, India, Thailand and seven other countries in the region Sunday, December 26th.
A 9.0-magnitude underwater earthquake off the coast of Sumatra, Indonesia triggered the 20-feet high waves.
Impoverished countries that surround the Indian Ocean basin did not have a communications system or emergency services to warn heavily populated coastlines that destructive waves were approaching.
U.S. WARNING SYSTEM — A multi-million dollar warning system for the United States West Coast and Hawaii has been in place since 1996.
The National Oceanic and Atmospheric Administration (NOAA) monitors changes in Pacific Ocean waves by getting signals from six high technology buoys floating in the ocean.
Within a few seconds, NOAA is aware of tsunami waves and alerts state officials who in turn alert local officials.
NOAA has two warning centers for Pacific Ocean tsunamis.
The Alaska/West Coast Tsunami Warning Center alerts California, Alaska, Washington and Oregon.
The Pacific Tsunami Warning Center alerts Hawaii and foreign nations on the Pacific Ocean “Ring of Fire.”
Since 1812, more than a dozen tsunamis three feet or higher have struck California.
The most recent was a one-foot tsunami near Santa Barbara in 1992.
In 1964, a tsunami triggered by an earthquake in Alaska struck Crescent City in Northern California.
Twelve people were killed and damage was estimated at $34 million.
In Marina del Rey, the Alaska Earthquake tsunami brought huge waves inside the Marina.
The “surge” of large waves coming into the Marina from Santa Monica Bay led to the building of a breakwater at the Marina entrance.
NOAA, state and local officials say they will review and possibly upgrade their tsunami emergency systems in light of this week’s events in South Asia.