抄録
On a landslide caused by the 2009 Chugoku and Northern Kyushu Heavy Rainfall at Iizuka City, Fukuoka Pref., we developed a unique topographic measuring method by using TruPulse200: a ground-based laser rangefinder, carried out the measuring and discussed the results obtained from the calculated DEM.
In this study, we measured a horizontal distance between observation points, two horizontal distances from the two observation points to a measuring point and a vertical distance from an observation point to the measuring point by using the laser rangefinder. In addition, we measured an azimuth of a line joining the two observation points by using a geological compass. We reported that the coordinates (x, y, z) for the measuring points can be calculated by Excel from these measured values, and DEM can be interpolated from the coordinates of all points on the landslide by GIS.
In this measuring, the invisible problem yielded by woods or topographic relief can be solved by lowering the observed position and raising the reflector. The DEM of more realistic surface model can be acquired when we try to set the lines with the same interval and the measuring points almost evenly while giving priority to the intersection of a measuring line and break line.
By the DEM made by the measuring method, we can present the realistic landform model, estimate the process of the slope failure easy and calculate the approximate volume of it by analysis on geomorphic and geologic conditions.
