Journal of Geography (Chigaku Zasshi)
Online ISSN : 1884-0884
Print ISSN : 0022-135X
ISSN-L : 0022-135X
Volume 84 , Issue 5
Showing 1-7 articles out of 7 articles from the selected issue
  • Hirotaro ISEKI
    1975 Volume 84 Issue 5 Pages 247-264
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    Alluvial plains in the coastal regions of Japan are considered to have developed according to the following processes : during the last glacial stage when the sea level was lowered, rivers dissected their valleys downward to that level. After then, in consequence of the postglacial rise of the sea level, these valleys were drowned and were filled up with Flandrian deposits.
    The bottom floors of such buried valleys are mostly found at 30-80 meters below the present sea level. These bottom floors in many cases are covered with fluvial gravel beds about 10-20 meters thick. Such gravel beds are mostly overlaid with sediments of finer materials which deposited in the shallow sea during the late and post glacial transgression. They are called “Basal Gravel Beds” of the Recent deposits by the present author. They have probably been formed when the lowering of the sea level reached the limit during the last glacial stage. The huge accumulation of gravels as the Basal Gravel Beds might have been brought on by the overloaded streams which carried much detritus as the production of the strong physical weathering under glacial or periglacial conditions during the Ice Age. The author found that some of the Japanese alluvial fans of a large scale are formed by Recent Basal Gravel Beds.
    The maximum accumulation of the ice during the last glacial stage should be enough to cause a lowering of the sea level of about 80-15 meters below that of the present. In order to get a acceptable figure regarding the lowering of the sea level or the lowest sea level during the last glacial stage, the author, presuming the figures-100 and-140 meters as the postulated low sea level stand, examined the depth of these floors of buried valleys, respectively.
    Based on the results of borings which were carried out with 21 major buried valleys in Japan, the depth from the surface of present-day alluvial plain to the upper face of Basal Gravel Bed which covered bottom floor of buried valley was measured in each alluvial plain and then the relation between the depth of the deepest bore hole and the distance from the mouth of the old valley to that bore hole site was investigated (Fig. 3 and 4). The correlation coefficient between the depth and distance was also calculated.
    Fig. 3 indicates the case in which the sea level was presumed to be 100 meters below that of the present and Fig. 4 in the cases of-140 meters, respectively. Is is obvious from these two charts that the depth of the deepest bore hole negatively correlates with the distance from the mouth of buried valley to that bore hole site. So far as the correlation coefficients are concerned, being-0.870 and-0.890, respectively, the presumed figure of the latter seems to be more acceptable than that of the former. Therefore, judging from the depth of buried valley floors, the author is of the opinion that the figure-140 meters as the lowest sea level during the last glacial stage should be more acceptable than that of-100 meters.
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  • Hideo SUZUKI
    1975 Volume 84 Issue 5 Pages 265-276
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    A small group of Kirisitan (Christian) has miraculously survived in Japan despite the severe oppression in Tokugawa Period. While the majority of Japanese used a lunar calendar, only these Kirisitan fishers knew Gregorian Calendar introduced by Portugese missionaries. During the oppression time their christianity has transformed into a polytheistic religion. Even so they have kept and used their calendar until today for their services with a day's delay from the Gregorian Calendar.
    Through this solar calendar, they have experienced that on their Christmas Eve, 23 rd of December, heavy storms often began, followed by calm days on 26th and 27th. These storms are confirmed by Fig. 1 to be the winter monsoon from Siberia and the calm days to be the result of the weakening of the Siberian High (Fig. 2).
    A problem arises whether these Kirisitans have discovered this “Christmas Storm” by themselves or they have learnt it from Portugese missionaries four hundred years ago. For it is possible that the Portugese missionaries knew something about the Portugese weather on these days of which equivalent is known in Germany as Wheinachtstauwetter (Christmas Bad Weather).
    Such a oversea spread of weather knowledge seems to be possible through a case study on the west coat of South America, where fishers know Viento de San Juan (Wind of St. John) etc which are not supported by the local meteorogical observations. In this case a spread from Spain seems to be probable.
    On the other hand, some of Japanese fishers have used a lunar calendar even until today with several knowledges on lunar singularities such as “8 th's Storm” etc. Against my working hypothesis that such knowledges reflect local weather differences, the distributions of lunar weather knowledges are almost uniform throughout Japan except “Daishiko Storm” and “Daishiko Calm” on 23rd of XI Month (Fig. 3 and 4).
    This uniformity may indicate that a spreading played more important role in the aquirment of weather knowledges than discovery. Since some similarities in lunar weather knowledges are found in Korea and Taiwan a spread from the mainland of China is possible.
    By such considerations a spread of “Christmas Storm” from Portugal still remains a possible guess. Informations from Portugal are most welcomed.
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  • Shigehiko DOI
    1975 Volume 84 Issue 5 Pages 277-285
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The purpose of the present paper is to design the ordering system for complex road networks in a region. The system design is based on fundamental spatial patterns of central settlements as traffic generators, and traffic flows. The ordering algorithm in detail is as follows : (1) given road networks ; (2) identification of central settlements and construction of the hierarchy ; (3) division of given networks into central settlement-road networks ; (4) transformation of circuited networks to trees ; (5) linkage ordering ; (6) superimposition of ordered linkages and output finally ordered road networks in a region.
    An application of the system was made for road networks in the western part of Shizuoka Prefecture in Central Japan. And their flow properties on ordered road networks in Aratama area and Fukude area in this region were investigated. As the results, it has become clear that the order was closely conformed with flow properties : that is, compared with low order networks, high order networks have the properties that traffic volume is more, trip-length is longer, speed is higher, essential traffic means are not walk nor bicycle but motor vehicle, and trip-purpose is limited to business and work. This system is applicable to the case of road networks which are bundled centralized flows, and is useful to categorize local and regional road networks which lack flow data.
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  • Shiro MAEDA, Nobuo YAMAGIWA, Tateharu KITAMURA, Leonardo BRANISA, Mari ...
    1975 Volume 84 Issue 5 Pages 286-293
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
    The Copacabana group distributed between the two ranges of the Andes Oriental and the Andes Occidental in the central part of Bolivia represents one of the standard stratigraphic sequences of the upper Palaeozoic sediments in Central Andes. In 1973 the writers carried out the geological reconnaissance at the Colquencha area, Altiplano, paying special attention to that group. The Palaeozoic formations in this area consist of Silurian, Devonian, Carboniferous and Permian systems, the last of which is called as the Copacabana group. The group estimated about 300 m in thickness is well exposed at the northeastern foot of mountainland near Colquencha. It lies conformably on the Carboniferous system consisting of the alternation of sandstone and shale. The group is mainly composed of fine-to coarsegrained reddish sandstone, black or dark grey shale and dark or reddish limestone. Its lower part is dominated by massive sandstone, and the upper part by the alternation of sandstone, shale and limestone. The limestone contains such fossils as Brachiopods, Gastropods, Fusulinids, Corals, Crinoids, Bryozoans and so forth with calcareous or siliceous angulated nodules.
    The writers found Pseudoschwarina, Schwagerina, “Rugosofusulina” and other fusulinaceans from the upper-most horizon of the group in this area. Judging from these fossil evidences, it is thought that the upper-most horizon of the group assigns to the Lower Permian. The geological structure of the Palaeozoic strata is characterized by a syncline with axis running NNE-SSW and by the faults of NW-SE. The deformation of the Palaeozoic strata might had been completed before the Tertiary sediments were deposited.
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  • Takeo OKANO
    1975 Volume 84 Issue 5 Pages 294-301
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1975 Volume 84 Issue 5 Pages 302-303
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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  • [in Japanese]
    1975 Volume 84 Issue 5 Pages Plate1-Plate2
    Published: October 25, 1975
    Released: November 12, 2009
    JOURNALS FREE ACCESS
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