Vol.52-4 CONTENTS

Hiroshi P. SATO and Tatsuo SEKIGUCHI

Detailed understanding of landslide susceptibility mapping is important if effective measures against landslides are to be taken. The Kuchisakamoto area in Shizuoka City, central Japan, has suffered from frequent landslides. Conventional techniques can only measure the detailed terrain in vegetated areas with difficulty. Airborne light detection and ranging (LIDAR) is a promising tool to precisely and directly measure a digital terrain model (DTM). Using a five-meter-grid DTM we attempted to map landslide susceptibility. In advance, we prepared a landslide inventory map, and cells were separated into landslide and non-landslide cells. First, we calculated the terrain slope and upstream drainage area of each cell. These are the important factors inducing landslides in Japan. Secondly, these parameters were classified into 48 sections, and the landslide density, which is the number of landslide cells divided by the total number of cells, was calculated for each section. The landslide density was classified into four categories, such as very low (0-1 % in the density), low (1-5 %), high (5-10 %), very high (>10 %), and finally, landslide susceptibility was mapped based on the four categories. The obtained landslide susceptibility is believed to be able to predict the severity of disaster in the study area.

1. Introduction
2. Study area
3. Airborne LIDAR-measurement
  3.1 Airborne LIDAR
  3.2 First and last pulses
  3.3 Measurement precision
  3.4 Topography measured by airborne LIDAR
4. Landslide susceptibility mapping
  4.1 Terrain slope and upstream drainage area
    4.1.1 Hatano’s contour map based method
    4.1.2 Grid DTM based method
  4.2 Method of landslide susceptibility classification
5. Results and discussion
6. Conclusion
Acknowledgements
References