shows a geological map(TCA, 2006) of the damaged
area. Mt.Kurikoma at the focal point of the earthquake is a
Quaternary active volcano; it is part of the Quaternary
volcano front in Northern Japan. The basement rock of this
volcano consists of Tertiary to Quaternary pyroclastic rock,
such as sedimentary and welded tuffs. Details of the stratigraphy of the volcanic materials are shown in the lite rature
(Fujinawa etal.,2001). A massive lava distribution covers the
basement tuff directly in the source part of the debris flow at
such sites as the Dozouand the Ubusume Rivers near the top of Mt.Kurikoma.