Abstract
Ever since men began to try to exploit nature in order to multpily productivity, landslides have occurred to cause damage and disaster.
The surface of the earth has kept on complex changes in its shape. Namely, the so-called land-forms have been caused from the earliest geological ages by various natural phenomena such as river flows, glaciers, waves, weathering, erosion, crastal movement, land flows and so on. Landslides may be one of the processes in the geological cycle.
Among the landslides in the agricultural land in the Kobe Group, we have made a study of the land-form and the characteristics of land use at the west Sudare district, Ozo-cho, Kita-ku, Kobe City. This study has yielded the following conclusions:
1) Terraced farms, small in area and like honey-comb, occurs in the drainage area from the banks of the Ozo River to the Hilgelland. Most of the gentle slope of the Hugelland consists of such terraced paddies and roughly distributes in the shape of a bow. Such a distribution is a common characteristic of the landslides which have occurred in land belonging to the Tertiary Period.
2) The surface shows uneven patterns of transformation like upheaval, depression, crack, collapse and flow.
3) The terraced farms on the slopes are narrow, and the space between the contour lines is cramped. These are the ruins of the second series of collapsed cliffs.
4) As a result of surface transformations, some sections of the roads and waterways are damaged to do unable to function.
5) The landslides have given a great damage to houses, two of which have collapsed and lain buried under more than 1.5 meters of the earth and sand.
6) A surface slope from 0° to 13° holds 70% of the whole area. The average slope is quite gentle, being 10°30'. The phenomenon of land movements is one of the characteristics of landslides in the agricultural land of the Kobe Group.
7) J udging from the cross-sectional leveling of the terraced farms, the average slope is 7°, which is much gentler than the average of the whole area.
8) The west side of the Hugelland is one block of a landslide. It is moving toward the Ozo River.
9) Arable land forms 57% of the whole area and 73% of that is paddy field. Consequently, this area may be called the Paddy Field Zone.
10) There are 749 paddy fields, the average area of which is quite small, being 188m2.
11) The levees compose about 20% of the arable land. This is inevitable in the case of fields cultivated on a terraced slope; the rate of land use efficiency is quite low.
12) The damage inflicted on the agricultural land by landslides appears to be the result of transformations, subdivisions, conversion of land categories and abandonment of farms.
13) The levees are damaged and have collapsed in 91 places, corresponding to about 12% of the area of the levees.
14) The landslides are recorded in 1913, 1914, 1921, 1938, 1940 and 1945, and have occurred ever since 1955.
