Is Los Angeles ready for a massive tsunami? How about Honolulu or Seattle?
In Chile, more than a million people evacuated their homes in the wake of an 8.3-magnitude earthquake and tsunami alert on Wednesday night, keeping the casualty count below a dozen.
Compare that to 2010, when an 8.8-magnitude temblor caused more than 500 deaths, many of them due to a massive tsunami. Back then, the government failed to issue an early tsunami alert, resulting in criminal charges against several officials and prompting new evacuation drills and emergency response procedures.
Evacuating a million people and having only a few deaths is “phenomenal,” Costas Synolakis, director of the University of Southern California’s Tsunami Research Center, told NBC News.
“It’s a positive message for us,” he said. “If the Chileans can evacuate a million people in 15 or 20 minutes, we should be able to do it as well.”
But there is no guarantee that Americans are as prepared as people in Chile.
Tsunami danger zones
It’s possible that a tsunami could hit the East Coast. But it’s cities along the Pacific Ocean’s “Ring of Fire” that are most at risk.
Hawaii is constantly threatened by tsunamis that originate far away. Those big waves can be deadly for some swimmers and boaters, but overall they’re not the stuff of natural disaster nightmares.
More dangerous are local or “near-field” tsunamis triggered by powerful nearby quakes. Think of the deadly Indian Ocean tsunami in 2004 that contributed to more than 230,000 deaths. Coastal towns in Washington and Oregon run the highest risk of encountering these disasters. California and Alaska are also at risk.
Last month, a study found that an earthquake off the coast of Southern California could send a 23-foot-high wave more than a mile inland into the cities of Ventura and Oxnard.
Escaping a tsunami
With distant tsunamis, people have hours to react, which makes it easier for local governments to warn people away from the coast. Some U.S. cities — including many in Washington state and Hawaii — use sirens that go off when a tsunami is coming.
Others, like those in Los Angeles County, use opt-in emergency alerts to contact people with text messages, emails and pre-recorded phone messages. Beaches will often have law enforcement and lifeguards warn people away and use bullhorns to get the attention of swimmers and sunbathers, according to Nathan Wood, a research geographer with the U.S. Geological Survey.
There is no federal standard — each local government decides for itself how to warn people of a tsunami.
Near-field tsunamis are the real danger. They can sometimes hit within 10 to 15 minutes, too quickly for local governments to do much but give emergency responders a heads-up.
These tsunamis do, however, come with natural warnings.
“In Chile, they actually teach in school: If the shaking is strong enough to throw you to the ground, the minute you can get up, run for high ground,” Lucy Jones, a USGS seismologist, told NBC Nightly News.
In most areas of the United States, according to Synolakis, able-bodied people should be able to walk to a safe area within 10 minutes.
The problem? Not everyone knows where those areas are.
Evacuating Los Angeles
So what would happen if a tsunami hit American’s second-biggest city? Unlike in “San Andreas,” L.A. residents can’t count on Dwayne “the Rock” Johnson to save them.
There isn’t a big risk of a local tsunami in L.A., but it could happen, possibly due to an underwater landslide near the city of Palos Verdes. More likely is a distant tsunami originating from a massive earthquake in Alaska. Overall, there are 43,000 people in L.A. County living in tsunami induction zones, plus an additional 38,000 in nearby Huntington Beach, according to the USGS.
If a distant tsunami was headed toward L.A., traffic might be worse for a few hours, but people would be able to get away. A local tsunami would be far more dangerous.
“I think the emergency services would know what to do, but a lot of people would not,” Synolakis said.
L.A. has signs that warn people that they are in a tsunami induction zone and when they are clear of one. But in a city filled with parking and street signs, they are pretty easy to ignore. (There are maps of danger zones across the country available online).
Many cities — including Los Angeles — focus on teaching local community leaders and schools what do in case of tsunami.
“We don’t have to train every person to run to high ground,” Wood said. “We have to train enough people to get a critical mass of people moving.”
L.A. County, along with sending out emergency alerts, provides information through its 211 hotline and by holding tsunami preparedness events. Still, in Los Angeles, there are a lot of people who don’t speak English and a plenty of transient residents moving in and out of beach communities.
Overall, Synolakis feels that people in L.A. aren’t prepared enough for a tsunami — something the city shares with many other U.S. communities.
In Chile, the government has made sure people know exactly what to do when a tsunami hits, partly thanks to evacuation drills. Those drills would be the best thing U.S. cities could do to protect their residents from a tsunami, Synolakis said.
But even that might not be enough. Even if locals know to run for high ground after an earthquake, tourists could still be in danger.
“We ask why people in Iowa should get tsunami education,” he said. “Well, where do they go on vacation? California and Hawaii. Tsunami education should be a national effort.”