Better education about tsunamis for coastal residents is urged

The nation’s ability to detect tsunamis has improved in the last few years, but the government remains ill-prepared to warn coastal communities of fast-approaching waves like those that ravaged Southeast Asia in 2004, according to a report issued to Congress on Friday.

In a near-the-shore tsunami that arrives less than an hour after a seismic event — such as an earthquake, landslide or volcanic eruption — most people along the coast would receive no warning or orders to evacuate, according to the 266-page study by the National Research Council.

“If the source were so close to shore that only minutes were available before the tsunami reached the coast, the public would need to recognize natural cues — mainly, ground shaking from the tsunami-triggering earthquake — and know to evacuate even without official warnings,” the report says.

In the tsunami that devastated Samoa, American Samoa and Tonga last fall, killing nearly 200 people, an alert wasn’t issued until 16 minutes after an earthquake was detected, giving only eight minutes’ warning to residents of American Samoa and 28 minutes to people in Samoa, the report notes.

“This is a major concern that can’t simply be dealt with by increasing our technical capabilities,” said John Orcutt, a seismologist at the Scripps Institution of Oceanography and head of the committee that wrote the report.

Congress requested the study to review the nation’s tsunami preparedness after the catastrophic 2004 Indian Ocean event that killed more than 230,000 people. That disaster inspired a number of laws to strengthen tsunami detection, warning and education efforts in the United States, an expanded network of deep-ocean sensors and improved maps in several states showing vulnerable coastline and evacuation routes.

Unlike such natural disasters as hurricanes, tornadoes and earthquakes, tsunamis happen so rarely that many people who live in low-lying coastal areas don’t know the signs or how to react. And yet, efforts have lagged when it comes to making sure people know what to do when they have only a few minutes’ notice, according to the study.

Orcutt said the recent tsunamis originating near American Samoa and Chile underscored the room for improvement in informing coastal residents to take swift action if they feel an earthquake.

“There were a large number of people that didn’t understand and there were lives that were lost because people simply didn’t take the action to get away from the shore when they felt this huge earthquake,” he said. “People have to understand the signs of a tsunami and head to higher ground.”

Costas Synolakis, director of the USC Tsunami Research Center and an author of the study, said the United States has a long way to go before it has a timely and effective response system, including more tsunami sensors near the shoreline and better training for first responders in low-lying areas.

After the February earthquake in Chile, for instance, the response to a potential tsunami at the Port of Los Angeles was hampered by fire officials’ misunderstanding of how tsunamis work, Synolakis said.

“Everybody thought that the tsunami was a single wave, and once the expected landfall time came and left, they thought it was over,” he said. “In fact, tsunamis are a series of waves that can last for three to four hours.”

The report pointed out several other shortcomings. Dual warning centers — one in Hawaii and one in Alaska — sometimes broadcast conflicting information and about one-third of detection buoys are inoperable at any given time.

tony.barboza@latimes.com