WSDOT says Bertha is safe, despite sinkhole

SEATTLE - Some people are questioning the safety of the Highway 99 tunnel machine, after a large sinkhole opened up in downtown Seattle.

When the world’s largest tunneling machine starts digging beneath a major city, there are bound to be issues.  Early Thursday morning, a seven foot deep sinkhole opened up on King Street.

“This was not out of the realm of expectation,” says Matt Preedy, Deputy Program Administrator for the Washington State Department of Transportation.

The sinkhole was immediately filled in, and Bertha kept digging.

Today, WSDOT tried to reassure people working and living downtown that the project is going as planned. They say right now, the soil they’re moving through is loose fill. Until they get down to more compact soil around Jackson Street, sinkholes are a possibility. But they say they’re prepared for that.

“We have a variety of monitoring equipment on all the utilities. We have a variety of monitoring equipment on the surface street itself,” says Preedy.

That doesn’t make downtown resident Matthew Hall feel better.

“I live right there, my office is right there, who knows what else is going to happen?” he says. “If it happened down here, what if it happens under one of the big office buildings or whatever?”

WSDOT says Bertha will be much farther underground by the time it reaches the viaduct early next year.

“What has happened down here is not able to happen there,” says Preedy.

But they’re still planning on closing the viaduct at that point, to be safe.

Shelli Park, who’s getting ready to open a new business downtown, is hoping WSDOT’s safety plan will work.

“I think I trust just enough that there’s been forethought and the buildings aren’t going to be in any danger,” she says.

Bertha started digging on July 30. She's traveled about 460 feet since then.