Tsunami warning signs are posted along the Santa Monica Pier. They tell the public to flee to higher ground if large waves approach the shoreline. (Daniel Archuleta daniela@smdp.com)

Tsunami warning signs are posted along the Santa Monica Pier. They tell the public to flee to higher ground if large waves approach the shoreline. (Daniel Archuleta daniela@smdp.com)

CITYWIDE — What would happen if a tsunami hit Santa Monica?

Not much thanks to natural protection.

Experts say the city sits above sea level with a large swath of beach and bluffs acting as natural barriers protecting residents, but cautioned people to stay prepared in case of a tsunami, or a series of ocean waves generated by changes in the sea floor, most likely because of a major earthquake.

In a study released earlier this month by the U.S. Geological Survey, researchers looked at what effects a tsunami would have on the Californian coastline by simulating a 9.1 magnitude earthquake off the coast of Alaska. The study was a partnership between federal, state, academic, and private organizations to develop a statewide tsunami scenario.

For Southern California, the scenario could cause major flooding in parts of Long Beach and Orange County.

Rick Wilson, senior engineering geologist at the California Geological Survey, who was involved in the study, said the cliffs that are around Santa Monica Bay help protect a lot of the inland areas.

“We can’t predict when something like this will happen, but if we look at the patterns in historically large earthquakes around the Pacific, this has a chance of happening every couple hundred years,”  Wilson said. “If you think about it like a 0.5 percent chance, which is really low, per year, but it could happen any time. It’s important we plan for the worst and hope for the best.”

Despite a natural barrier against high waves, a downside is it doesn’t take much of a tsunami to flood the beach, said Wilson. That means bad news for visitors.

On any given day at the Santa Monica State Beach there can be thousands of people enjoying the sun and surf. On holidays, those numbers tend to double or triple.

“That’s a really high population to evacuate in a short amount of time,” Wilson said.

The study examined tsunami heights or surges that could reach 7 to 8 feet above high tide conditions along Santa Monica’s coast, Wilson said. High tide is usually about 3 feet high.

There could be inundation for some of the areas to the south of Santa Monica, where there are no bluffs, Wilson said, based on the scenarios on the state tsunami inundation maps.

The tsunami in the scenario is unlikely to overtop the historic Santa Monica Pier, officials said.

 “It’s not clear what kind of damage might occur to the piles and foundation of the pier from this scenario or other future tsunamis,” Wilson said. “However, it is likely the local emergency managers would call for an evacuation of the pier during the tsunami until inspections are completed after the tsunami.

Lucy Jones, lead scientist for the study, said a lot of the piers in California are “high up.” She did caution there would be “really strong currents,” which the pier would be fine against, but half of the floating docks in California would be destroyed.

Santa Monica was designated as “TsunamiReady” and “StormReady” in June from the National Oceanic and Atmospheric Administration’s National Weather Service.

That means Santa Monica meets certain criteria including having an alert system in place and a functioning emergency operation center, said Paul Weinberg, emergency service coordinator in City Hall’s Office of Emergency Management.

Tsunami hazard zone signs are posted along the beach and its parking lots. The blue and white evacuation route signs designate that visitors north of the pier should head for the bluff. If visitors are south of the pier, in an abundance of caution, they are directed to head east of Fourth Street.

Weinberg said there are two types of tsunamis. A distance tsunami is like the simulated tsunami in the study, which would give officials several hours to implement the evacuation. The second type of tsunami is local, or when a strong earthquake takes place in Santa Monica or nearby. In that case the earthquake will be the warning, Weinberg said.

“The city won’t have a capability to send out an alert,” Weinberg said. “If you feel strong shaking, get to higher ground.”

Officials said residents should consult the tsunami pamphlet on the Office of Emergency Management website on how to survive a disaster and live through the aftermath.

“[You’re] making sure where to go to be safe and making sure you have communications with your family,” Wilson said.

Folks should also have a kit and emergency numbers jotted down among family members, said Lt. Robert Almada, emergency services manager for the Office of Emergency Management.

Residents and employees are also encouraged to sign up for SM Alerts, which can notify them of an emergency and provide important information, such as road closures or where to receive medical treatment.

On Oct. 14 at the RAND Corp. headquarters in the Civic Center the Office of Emergency Management and other partners, including the Santa Monica Chamber of Commerce, are hosting a free workshop to prepare employers for a tsunami, active shooter or earthquake, Weinberg said.

Depending on the business, they have different levels of compliance on what they do, Weinberg said. For example, the hotels along the beach are almost “a small city responsible for a number of residents for that night and work closely with us.”

When Santa Monica’s tsunami plan was approved, the office took pamphlets to all the hotels and did a presentation, Weinberg said.

For more information on how to prepare for a tsunami or to register for the workshop, visit smgov.net/departments/oem.

 

ameera@smdp.com