Shuji Yamada

A flexible print circuit(FPC) was printed on a spring steel strip to make a strain probe with a sufficient number of sections to measure the shearing displacement of soil, because current strain probes cannot detect shearing displacement. In addition, a two-gauge method was adopted with a pair of strain gauges attached to both sides of a section of the steel strip. We fashioned an FPC type strain probe 48 cm in length with 12 sections (i.e., each section length 4 cm). Shearing deformation tests (shearing thickness 2, 4 and 6 cm) were conducted on the FPC type probe and the current probe (section length 10 cm). The current type could not detect any shearing displacement, whereas the FPC type could detect that of a 4- and 6-cm shear-layer thickness with a 100% success ratio. In contrast, the FPC probe could detect only 33.3% of the shearing 2 cm in thickness. These results indicate that the FPC probe can detect shearing displacement when a section length is equivalent to or smaller than the shear layer thickness; in addition, it can detect shear displacement fairly accurately, but it overestimates the shearing layer thickness due to propagation of strain in the probe.

This study classified Japanese mountains based on mountain ordering using 1 : 500000 topographic maps, and examined the relationships of relief, relative relief and perimeter fractal dimension for the classified mountains. Mountain order was defined in terms of closed contour lines on the topographic map. A set of closed, concentric contour lines defines a first-order mountain. Higher-order mountains can be defined as a set of closed contour lines that contain lower-order mountains and that have only one closed contour line for each elevation. Relief, relative relief and fractal dimension were measured for ordered mountains using personal computer, and were defined as follows : relief E = H/A^1/2, where H and A are the height and area of each ordered mountain, respectively; relative relief R= ∑ h_i/H, where h_i is the height of the enclosed, lower-order mountains, and represents the degree of vertical roughness of the ordered mountain; fractal dimension was measured for perimeter contour line by the pixel dilation method, and represents the degree of horizontal roughness of the ordered mountain. Japanese mountains were classified into 74 third order mountains and 11 fourth order mountains. The area of a third order mountain varies from 50 to 4712 km², and that of a fourth order mountain is 2498 to 15563 km². A significant relationship was found among relief E, relative relief R, and fractal dimension D for the ordered mountains (r=0.91, n=85), and can be defined by the expression : <BR>LogE=-aD-bLogR-c<BR>This relationship shows that Japanese mountains have the following morphological characteristics : a high relief mountain has low vertical and horizontal roughness, and a low relief mountain has high vertical and horizontal roughness. These characteristics suggest that slope angle of Japanese mountains converges within a certain range.

The topographic parameters of mountains modified as residential land and golf courses are measured, and a new parameter, topographic naturalness, which describes the differences between natural and anthropogenic landforms are defined. Three topographic parameters, relief (E), relative relief (R) (degree of vertical roughness), and contour fractal dimension (D) (degree of horizontal roughness), of mountains in and around Tokyo, Nagoya, and Osaka are measured on topographic maps (1: 25, 000) published before and after modification of the sites. The three topographic parameters before modification showed a significant correlation (r=0.79, n=69, p<0.0001), and the regression plane was expressed as LogE=-0.31D-0.58 LogR-0.56. From this equation and actual D and R values, calculated LogE (LogE_cal) was obtained, and topographic naturalness, T, was defined as the difference between actual LogE (LogE_act), and LogE_cal: T=LogE_act-LogE_cal. The topographic naturalness of the mountains before modification was nearly 0: the mean was 0 and standard deviation was 0.15. After modification, the hills had low T values: the mean of residential land and golf courses was -0.20 and -0.05, respectively. These results show that topographic naturalness is a useful parameter for evaluating anthropogenic landforms.

The maximum glacial extent and depression of equilibrium line altitudes (ELAs) in the Hiunchuli massif of West Nepal were reconstructed by air photograph interpretation. The present glaciers are characterized by either of the following two types: steep valley or valley sided type. On the other hand former glaciers were large plateau glaciers with many radial outlets. During the maximum glacial extent, the lowest ELA lay at an altitude of 4, 100m, about 1, 000m below the present ELA and the area of the maximum glacial extent was 200 km2, some 200 times as large as the present one.