16:15 〜 16:45
[HGM03-02] 火山体の侵食比の変動と侵食力の推定
★招待講演
キーワード：侵食比、湖沼－流域系、堆積物情報
Changes in erosion ratio were observed in several of stratovolcanoes in Japan (Suzuki, 1969). Main forces for the changes are assumed to be erosional ones based on rainfall intensity. Estimation of erosional force is roughly estimated with lake-catchment studies in Japan. Earth surface processes and changes in the systems are generally printed in lacustrine sediments, which are of great use for considering erosional forces. Two time-intervals are introduced for discussion of the forces; one is the short interval during the past 10 years (instrumental observation period) for a small system, and the other is the long one during the past some 10-100 thousand years for large systems. The erosional force can be expressed as mathematical equations using dominant periods in sedimentation rate both for the short and long intervals in the systems. Erosion ratio for volcanic mountain dissection is discussed for the long interval using mathematical equations with the erosional force estimated from sedimentation rate in Lake Biwa. The calculated results for the dissection and evolution show that the establishment of the erosional force in the equations is of value for understanding the temporal changes.