SALEM, Ore. — When a tsunami watch went out overnight Tuesday via text messages, phone calls and on the radio to residents of the Oregon Coast, most were asleep and oblivious of the potential danger.

That worries emergency managers, who said the 7.9 magnitude earthquake off the coast of Alaska that triggered the alert is a wake-up call. Any tsunami generated by the temblor that struck at 12:32 a.m. would have hit the Oregon Coast hours later, authorities said. No tidal wave materialized because the quake moved more horizontally instead of up and down, pushing up less water.

“It’s a real reminder that these kinds of events can happen at any time,” said Althea Rizzo, a tsunami and earthquake specialist with the Oregon Office of Emergency Management.

In the daytime, people on the Oregon Coast would have had hours to monitor the situation and flee to higher ground if the tsunami watch was escalated. But at night it’s easy to sleep through warnings, as many did Tuesday. By the time they became aware of the situation, the all-clear had been given.

It is important for people to sign up for tsunami alerts, and to keep their phones nearby when they go to bed so they can hear them, Rizzo said. Alerts can also be received on radios that sell for around $30.

Seaside, about 60 miles (100 kilometers) northwest of Portland, is considered the most vulnerable Oregon coastal town because so many people live in the inundation zone, far from high ground. Some residents were fatalistic about a tsunami, not worrying about signing up to receive alerts.

But Sheila Roley, the school district superintendent, said it was a learning experience for her. Overnight, she blocks incoming calls and texts except for people close to her and her leadership team. On Tuesday, she discovered she needed to add the tsunami alerts to her unblocked numbers.

“I met with the leadership team this morning,” Roley said in a telephone interview. “Some slept through (the tsunami watch), and by the time people got up at 5 or 6, it had already been canceled.”

Seaside is taking the risk of a tsunami so seriously that voters approved a $100 million bond measure in the November 2016 election to move three schools out of the inundation zone.

A distant earthquake is a risk — a 1964 earthquake off Alaska triggered a tsunami three-stories high that hit Oregon, killing several people. But an earthquake along the nearby Cascadia subduction zone is even more dangerous, expected to generate a much bigger tsunami with people in inundation zones having only minutes — not hours — to get to high ground. Coastal residents and visitors can go to http://nvs.nanoos.org/TsunamiEvac to input an address and see if it is in a hazard area.

Jenny Demaris, emergency manager for Lincoln County, which encompasses several coastal population centers including Lincoln City and Newport, said people can sign up for emergency alerts through the county’s web page.

“We live, work and play here,” Demaris said. “It’s important that we’re aware of our environment and hazards, and sign up for warnings.”

Rizzo said the state doesn’t have a tsunami siren system because it would be so expensive and not every coastal area would need to be evacuated in the event of an incoming tsunami. Plus they would often be hard to hear on the stormy coast, she said.

Coincidentally, a large yellow buoy used by the National Weather Service to detect large tsunami waves was discovered Monday on a beach near Yachats.

The National Weather Service in Portland said on Twitter Tuesday that the DART buoy is probably one that broke from its mooring 230 miles (370 kilometers) west of Astoria on Oct. 4.


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