Results of forty-six years monitoring of landslides in Nakatsu River basin in Tanzawa mountains [Japan]
2005
Ohkawa, W.(Nihon Univ., Fujisawa, Kanagawa (Japan). Coll. of Bioresource Sciences) | Masutani, T. | Ishigaki, I.
To analyze long-term changes of shallow landslides over a wide area as basic data for soil and water conservation, we used aerial photographs to analyze the distribution, area and number of landslides in 1947,1959, 1978 and 1993. The study area was the Nakatsu River basin (3,544.0ha) in the Tanzawa Mountains of Kanagawa Prefecture, Japan. We prepared orthophotographs from these four years, then created database using GIS analyze to them. As a result, the number of landslides was 1,801 (sum area 700.6ha) in 1947, 1,544 (571.9ha) in 1959, 369 (70.8ha) in 1978 and 178 (39.2ha) in 1993. The long-term distribution tended to concentrate in the high elevation area. At least 90% of landslide area in the latter three years had already existed in 1947, and there were few new ones. The number of landslides extending over the 46-year period was 126, but the area affected by landslides decreased from 179.4ha in 1947 to 36.3ha in 1993. We shall focus on long-term remaining landslides and analyze geographical factors of areas where the vegetation did not recover in the short term.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by Agriculture, Forestry and Fisheries Research Information Technology Center