Abstract
The changes of disaster topography and vegetation in northern Kitakami mountains area were investigated by aerial photograph on six periods during 1970 to 2001. The hard sedimentary rocks considered in homogeneous conditions are distributed in this area. The climate conditions of this area were constant from 1970 to 2001. The geomorphometric study was performed using detailed digital elevation model that was obtained by aerial laser measurement at late autumn in 2000.
As the results of these investigations, it is explained that both of geomorphological conditions and vegetation changes influence the generation and the reduction of disaster topography. For example, the number of collapse increases, as the average value of slope angle in drainage basin becomes large. In proportion to decrease of the distribution area of Quercus serrata/chestnut/deciduous broadleaf forest community, the number of collapse increases. However, if the average of slope angle in the drainage basin is small, the basin has no slope collapse even after the deforestation. When the average of slope angle and the ratio of surface area to drainage basin area in the basin become large, many disaster topographies occur in the basin. Therefore, it is assumed that we can assess the possibility of disaster topography developments by the numerical value of vegetation and geomorphology.
