"What you see on the surface is about a 4 by 4, but underneath it could be about a 10 by 10," Gary Welling, Santa Clara's director of water and sewer utilities, said. "A lot of soil eroded. Once we excavate the top of the pavement, we'll see a much larger hole underneath."
Crews plated over the open sinkhole. It was caused by a 42-inch sewer line collapse. Officials insist Lafayette Street is stable.
"We're checking all of the lines and the lines look good," Welling said.
A timeline for the sinkhole repair process has not been solidified.
VIDEO: Car stuck in sinkhole in Castro Valley