The Kanahama Fault cuts the sedimentary strata of Older Unzen Volcano (500,000-300,000 years ago) with a gap of 150-200 meters. If you look at the valley from the national road, you will find the sediments of Older Unzen Volcano distributed on the right (south) side and the sediments of Middle Unzen Volcano (300,000-150,000 years ago) on the left (north) side of the fault. As the Unzen Graben continues to subside with volcanic eruptions, the sediments of Middle Unzen Volcano cannot be seen on the southern side of the fault.