Police and Yokohama city officials say a sinkhole was confirmed shortly after 5 a.m. on May 8 on a narrow road in a busy area near the west exit of JR Yokohama Station.

The cave-in initially covered an area of about 4 meters and was roughly 15 centimeters deep but expanded in both size and depth the following day.

Private construction work was being carried out near this road.

Officials believe a retaining board, which was intended to prevent soil from flowing out from the road, tilted and allowed the soil beneath the road to wash away, causing the collapse.

They said no impact on nearby buildings or water pipes has been confirmed, but traffic restrictions were placed on the road.

There were no immediate prospects for restoration.