Chichibu Geopark

Basic points

This is one of the Hino faults, which have formed on the border between the Chichibu Mountains and Chichibu Basin. The cave was created as a result of water washing away the portion of the rock that had crumbled due to a shift in the fault. It is called a “fault cave.”

There is a place called Kagamihada (slickenside) that had been polished when the faults shifted and rubbed against each other, and you can also see linear scratches. It is rare to find a place where you can directly observe a fault plane.