You are off a bit. It isn’t drilling under Elliot Bay. It is drilling under some of the regrade in old low land areas of Seattle and under First Hill and Denny.
I wish they’d tunnel under the damn Sound and sell all the damn ferry boats. We on the Peninsula are held as mobility hostages. It costs either 15.00 to cross the Sound in your car and driver or 5.50 toll over a bridge to Tacoma! A tunnel makes more sense even in an earth quake zone. We can engineer it to be safe.
“We can engineer it to be safe.”
I was reading (or perhaps it was a talk?) about tunnels in EQ zones. It was amazing. Had photos of tunnels where the tunnel was damaged where the fault had occurred - a big crack in the tunnel wall and a few feet of offset due to the fault movement. But on either side of the fault everything was intact!