Officials trying to determine cause of sinking Silver Line parking garage under construction

Construction of a Silver Line parking garage is at a standstill because portions of the $52 million project have sunk into the ground by as much as four inches.

The problem is at the Innovation Center Metro station in Herndon, as first reported by the Washington Post, and officials aren't sure what caused it.

"The forensic aspect of how and why did this happen is something that we will get to, but we're not prepared to speculate on that yet," Fairfax County Director of Building Design and Construction Carey Needham said at a public hearing Tuesday night.

He added that the parking garage has been stabilized and is no longer sinking.

Officials were first notified of the problem in July. The contractor stopped working on the project shortly thereafter, and Fairfax County has hired an outside expert to help figure out what happened.

The garage is still scheduled to open in April or May of 2019, Needham said - something many people who live and work nearby are counting on.

"I am waiting on this, definitely," Adolphus Tarty said. "It's going to make it easier on me because, right now, I go to Wheeler station and take the Metro from there and it's a hassle. It's like an hour and 30 minutes to get back home."

Another reason developments are being watched closely - the Innovation Center Metro stop is closest to one of the locations being offered for Amazon's second headquarters.