Earthquake-Generated Tsunami Could Reach Seattle In 3 Minutes: Study

SEATTLE — A major earthquake on the Seattle Fault could create a tsunami that reaches Seattle in minutes.

It might sound like the plot of the next summer Hollywood blockbuster, but it actually could happen, according to a new study by Washington State Department of Natural Resources.

The study, published Thursday, modeled the impact of a magnitude 7.5 earthquake on the Seattle Fault. Tsunami waves, the researchers found, could reach the greater Seattle area within three minutes.

"According to our geologists’ findings, tsunami waves could be as high as 42 feet at the Seattle Great Wheel and will reach inland as far as Lumen Field and T-Mobile Park," the agency wrote in a Facebook post.

And while residents might try to take solace in the fact that the last earthquake on the Seattle Fault happened 1,100 years ago, the geologic record shows a history of smaller, more frequent earthquakes roughly every 700 years. That places Seattle "well within the window for a seismic event," state officials said.

Hilary Franz, the state's public land commissioner, told reporters Thursday the waters of Washington state are beautiful — but dangerous.

"Every once in a while we get a glimpse of an orca and the beauty these waters hold, but underneath these beautiful waters behind me lurks a hidden threat that will inevitably impact this region," Franz said.

She said it's a matter of when — "not if" — the quake strikes the Seattle Fault. The fault zone runs across the Puget Sound and through Seattle, the state's largest population center.

Scientists estimate there's about a 5% to 7% chance of an earthquake happening along the Seattle fault in the next 50 years.

"When it does, it will have a drastic impact on Seattle and our region," she said.

While many people know low-lying, coastal communities are devastated by tsunamis, the geologic record shows tsunami deposits from the last major Seattle Fault earthquake on Whidbey Island, as well as in Everett and West Point. That quake and ensuing tsunami redefined the region's shorelines.

"It is capable of doing it again," Franz said.

A magnitude 7.5 earthquake would bury parts of the region under 10 feet of water. Harbor Island would be buried under up to 40 feet of water, with tsunami waters reaching as far inland as Lumen Field, home of the Seahawks, and T-Mobile Park, home of the Mariners.

Franz said efforts are underway to prepare and take precautions to mitigate a looming, unavoidable disaster. This includes updating construction and emergency response planning.

She also reminded residents living near the Puget Sound to stock or resupply earthquake emergency kits with enough supplies for several days. This includes a gallon of water for each person, per day, as well as enough non-perishable food to feed each family member for every meal for several days. A battery- or crank-operated radio and flashlight with extra batteries are also recommended.

"We sometimes get too comfortable when the earth isn't shaking. We think it won't happen in our lifetimes. But the fact is it could happen any day," she said.

Monisha Harrell, Seattle's senior deputy mayor, told reporters peoples' first instinct will likely be to protect themselves from the shaking. But they'll also want to know how close they are to the Puget Sound and Lake Washington.

"You're going to want to come in, and you're going to want to go upwards. And you'll have about 3-5 minutes ... after the shaking stops," Harrell said.