The basalt complex that rose from underground and pierced the thick pumice layer that had accumulated around Shuzenji Spa is known as the Asahidaki Falls Basalt.
The lava that penetrated the pumice layer contracted upon cooling and created columnar shapes, or “columnar joints.”
Asahidaki offers the visitors a view of cross-section of the hexagonal columnar joints on the surface of the waterfall. The shapes of these rocks are so symmetrical that they appear like a man-made wall.
The location is about 10 minutes by car from Shuzenji Station of Izuhakone Railway.