The Alaskan Way Viaduct in Seattle may have been the place where a lot of us liked to be during a sunset drive. But the aging, elevated highway shouldn’t have been anyone’s top choice for favorite spot to ride out a big earthquake.
Now just days before the storied section of SR 99 along the city’s waterfront closes for good, the Washington State Department of Transportation has released a new video in which experts discuss why the city’s new 2-mile tunnel is the safest place to be in the event of a major earthquake.
The video is illustrated with dramatic images from the 1989 Loma Prieta earthquake which struck the San Francisco Bay Area. Oakland’s Cypress Street Viaduct — a structure very similar in age and design to Alaskan Way — collapsed and killed 42 people.
In 2001, the magnitude 6.8 Nisqually earthquake hit Washington and the viaduct was damaged. Although repaired, the calls began to replace the structure before disaster struck again. Video simulations in 2009 showing what a collapse along Seattle’s waterfront would look like did plenty to scare people over the past decade.
“The viaduct was built in the 1950s and seismic design is now light years ahead of what we knew back then,” said David Sowers, deputy administrator of the Alaskan Way Viaduct Replacement Program. “Ultimately, replacing the viaduct is all about keeping people safe and this new tunnel meets the gold standard for safety.”
The video discusses how earthquake waves do more damage the closer they get to the surface, and why tunnels are able to move underground with those waves. The new tunnel is designed to withstand a 2,500 year quake — roughly a magnitude 9 off the coast of Washington state, WSDOT said.
WSDOT previously touted the technology that will make the tunnel one of the “smartest ever built” while also keeping drivers safe.