Seattle’s shores could be buried under 20 feet of water in a future tsunami or earthquake

A future major earthquake centered beneath Seattle’s Puget Sound could trigger a tsunami that would bury waterfronts in 20 feet of water for hours, according to a new study released Thursday by the State Department of Natural Resources. Washington.

The study shows the potential consequences of a 7.5 magnitude earthquake-triggered tsunami along the Seattle Fault Zone, which runs east and west through Puget Sound and midtown. city ​​of Seattle.

Scientists say those along seafronts in the Seattle area and islands across the strait would only have about three minutes after the quake before the tsunami arrived. Waves could reach up to 42ft along Seattle’s downtown waterfront near the Great Wheel, with floodwaters several feet deep eventually flooding Lumen Field and T-Mobile Park, home to the Seahawks and Seattle Mariners, respectively.

The flood would last up to three hours and could keep waters as deep as 20 feet, according to the study. Floodwaters would spread along the Inland Sea, inundating Tacoma – 30 miles to the south – in 6 feet of water up to three miles inland.

Experts say the last known earthquake to occur in the Seattle Fault occurred around 1,100 years ago. Geological evidence shows it was powerful enough to push the beach at Restoration Point on Bainbridge Island up 23 feet, while dropping land at Seattle’s West Point by three feet, according to the DNR. If another earthquake occurs, the study suggests that ground level changes could create entirely new shoreline in many places near the Seattle Fault Zone.

Despite the significant time gap since the last earthquake, scientists say another earthquake is still possible. Geological evidence shows that there have been five additional earthquakes averaging magnitude 6.5 in the Seattle Fault area over the past 3,500 years.

« While the odds of this happening in our lifetime are small, it’s important for families to prepare now, » said Maximilian Dixon, risk and awareness program supervisor for the Division of Emergency Management. Washington, in a press release announcing the study. « The earthquake will be your warning that a tsunami could be on the way. Make sure you know where the nearest high ground is and the quickest route to get there. Sign up for tsunami alerts and local.

Seattle Mayor Bruce Harrell said studies like this are an essential tool for the city to understand the risks and prepare for future emergencies.

But emergency officials acknowledge that the study results « can be frightening », but point out that the study used a « maximum event considered », meaning it has a low probability of occurring.

“It sounds legitimately terrifying. We understood. This earthquake could happen before an alert reaches your phone,” officials from the Washington Department of Emergency Management said. “If you feel an earthquake, drop down, cover up and hold on, then evacuate to higher ground and get as far inland as quickly as possible.”