Showing papers in "Geographical reports of Tokyo Metropolitan University in 1980"

Land characteristics of the hills and their modification by man : with special reference to a few cases in the Tama Hills, West of Tokyo

Abstract: Most of the Japanese cities have been characteristically located. in the lowlands and lower uplands, which mostly correspond to fluvial or marine plains of Holocene age and late Pleistocene age, respectively, although the respective landsurfaces cover only about 15% and lO% of the total land area of Japan. Urban expansion had been practiced almost within the area of the two types of landsurfaces during the long times before the most recent economic growth of Japan. Saito (1965) estimates that more than95% of the total built-up area of Japan was located in the lowlands and uplands in 1960, which immediately precedes the turning point of locational trend of built-up areas in Japan (Tamura, 1976). Since around the year, large-scale residential developments have been carried out in the hills also, though they had been proceeding since the 1950's in the uplands and lowlands in major metropolitan areas (Fig. l). Recently about two-thirds of major residential-development districts having broader areas than 300ha are located in the hills which cover abovt lWo of the total land area (Fig. 2). One of the most conspicuous examples of urban expansion to the hills is given in the Sendai area, Northeastern Japan. It is well demonstrated in the changes of arealproportion of the hills, uplands and lowlands in respective built-up areas of three metropolitan areas where the hills occupied about the same proportion in 1960 and subsequent urban expansion has been active alike (Fig. 3). In the Tokyo metropolitan area relatively broad upland zone surrounding the central city, particularly the Musashino Upland in the westem suburbs, had been exploited for major residential districts since the industrial revolution of Japanin the late 19th century. It is in the early or mid-1960's that residential development was set about in the hills outside the western upland zone (Fig.4; see Watanabe et al., 1980, also). Recently the Tama Hills lying to the southwest of the Musashino Upland are most intensely exploited for residential districts (Fig. 5). Generally the hills, being dominated by slopes of not so high relief and mostly composed of semiconsolidated rocks, suffer more intense artificial landform modification than the uplands and lowlands which are extensively flat, for putting many house sites side by side, and are more easily modified than the mountains which are steeper and higher and mostly composed of resistant rocks. The intense hilllandform modification for residential development brings intricate distribution of artificial cut zones and fill zones and is followed by