中心都市からの距離と人口変化 : 広島湾岸地域の場合
On the Character of Population Change with the Distance from Central City : A Case in the Area of Hiroshima Bay
The regional changes of many phenomena in the urbanized society generally occur in accordance with the distance from the central city of each region. This is, so called, the urban circular structure within a city region. This study intends to reexamine this urban ciruclar structure under the example of the area surrounding Hiroshima Bay through many indices especially concerning population structure. The staistics of these were used mainly from the National Population Cansus on 1985 and eight administrative districts which were considered within the influence of Hiroshima City were selected as the units of regional change (four districts weswards from Hiroshima City, i.e., successively Itsukaichi-cho, Hatsukaichi-shi Ono-cho, Otake-shi and to the direction of east Fuchu-cho, Kaita-cho, Saka-cho, Kure-shi).
The following results were gained through this study.
1. The changes of indices related to the population such as the number of population, the composition ratio of population by age group, the population increase, the migrants, the commuters and school attendants to and from the Hiroshima City and others fundamentally accroded with the distance from this city. That is, the numbers and ratios decreased or increased with the enlargement of the distance. But these simple relationships were partially disturbed by the regional characterstics.
2. The regional changes of indices relating to the employment such as the rate of the daytime population to the residents, the rate of the workers (not working outside of the region) to the residents, the component ratio of the population by industrial group were very contract between the regions westwars and the ones eastwards from the Hiroshima City. These occur mainly by the cause of the character of suburb. Namely, the westward suburb is developing as the area of residence, whereas eastward one strengthen the character of working place.
3. The reaction to the distance was quite diffrent between the commuters and the school attendants. In the case of commuting and attending school to the Hiroshima city, the component ratio of the commuters went down with the increase of the distance from this city, while the ratio of school attendants went up.
4. Although the degree of the dependence of the commuting and attending school from the surrounding area to and from the Hiroshima City was going high, the rate of the migrants to and from this city declined. From this fact, it may be said that the cyclical movement of the population not altering the place of residence advances.