A stretch of Interstate 80 in Morris County, New Jersey, that’s been plagued by sinkholes in recent months will be closed for at least “several weeks,” an official said, as crews investigate up to 90 “voids” lurking below the surface.

A sinkhole that has closed all eastbound lanes of Interstate-80 through a stretch of New Jersey since last week will take an additional three weeks to assess and repair, an official said Monday.

The eastbound lanes of Route 80 are expected to remain closed for at least another three weeks to get to the root cause of two sinkholes that have opened up in the past two months.