New sensors show how quake rattled Seattle viaduct

SEATTLE — A 4.5 magnitude quake that rattled the Puget Sound region on Jan. 30 caused no damage to Seattle’s Alaskan Way Viaduct.

But new sensors on the elevated highway showed the top deck shook 10 times harder than nearby ground.

The head of the University of Washington Seismology Lab, John Vidale, told The Seattle Times the measurements confirm the structure and the fill dirt it’s built on amplify earthquakes.

Officials fear the 56-year-old viaduct could collapse in a stronger quake.

Transportation officials are working on a plan to replace the mile-long section of Highway 99 along the Seattle waterfront.