Abstract
Many debris barriers were constructed in the Chichibu Mountains and the distribution of these dams is closely related to geology; tectonic line, rocks and crustal movement. Dams were constructed on the Kannon yama-Tomoe gawa tectonic line which runs from northwest corner to southeast in the Tertiary System of the Chichibu basin. Almost of all dams were distributed in the crystalline schist area of the Toya upheaval mountain block, especially along the Jushi-Kunigami and the Zogahana-Asahine tectonic lines of the outsides of this block, and the drainage of the river Toki. In the Chichibu paleozoic complex they were built on schalstein and black slate along faults.
