Seattle historian speculates on what’s blocking Bertha’s path

Something is blocking Bertha’s path. The boring machine is the largest in the world and should be able to get through just about anything, except for whatever is beneath the surface of Seattle’s streets.

The massive drilling machine has been stopped since hitting an obstruction about 60 feet below South Jackson Street and South Main Street. Bertha had just passed the 1,000 foot mark last Friday and was close to crossing under the existing Alaskan Way Viaduct when it ran into resistance.

Seattle historian Feliks Banel says he hopes the obstruction is some bizarre ancient artifact that no one has even begun to consider. And he’s glad whatever it is – has brought Bertha to a screeching halt.

According to Banel, before the present-day Seattle skyline was erected, the waterfront was actually a big river delta. The Duwamish River flowed into what is now Elliott Bay and there was mud everywhere. In the 1850s settlers of the area started to fill in the area with dirt, and by 1853, they were filling it in with sawdust from Henry Yesler’s saw mill.

But Bertha could cut through dirt and saw dust. So what is it below Seattle’s streets?

“It’s probably bad to say this, but I’m glad Bertha has struck something like this because it gives us a chance to talk about Seattle – which is a very young city. For the size of Seattle and the scope of it 150 years, that’s not much to have gotten as far as we’ve come,” says Banel.

Just below the city streets, beneath six inches of asphalt there are cobble stones. Banel says you often see it when crews are out repaving.

A little deeper below the surface is the basement level of Pioneer Square, it used to be the ground level, but the fire of 1889 gave Seattleites the opportunity to build on top of the existing neighborhood.

Even farther down was a discovery crews made while digging another tunnel – one used for Metro Transit and the Sound Transit Link Lightrail near the Paramount Theater.

“Forty feet down they found about a 40 foot stretch of wooden sidewalk that had been built in the 1890s,” said Banel. “It’s anaerobic, there’s no oxygen down there, so it didn’t rot.”

Aside from the neighborhood below what’s now Pioneer Square, Banel said that what you’ll find in the rest of the city is mostly trash. That’s in part due to a lack of regulations when crews first started the regrade projects.

“One of the great things about the Denny Regrade, or all the regrades, they were essentially regarding the land making flat for commerce and for economic growth. There was no environmental impact statement required,” says Banel. “It was a much more freewheeling time.”

Some of the speculation as to what’s stopping Bertha in her tracks: How about a discarded locomotive? Or a giant old submarine? Or even a meteorite?

If it is an ancient artifact, the tunnel project could run into some legal battles. But then again, it could be something we’ve been looking for all along. Said Banel, “It could be D.B. Cooper, you never know.”