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Volume 75 (1966)
- Issue 6 Pages 307-
- Issue 5 Pages 257-
- Issue 4 Pages 185-
- Issue 3 Pages 123-
- Issue 2 Pages 61-
- Issue 1 Pages 1-
Volume 75, Issue 3
Displaying 1-13 of 13 articles from this issue
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Kazuo KURODA1966 Volume 75 Issue 3 Pages 123-135
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSTo find out the geological characteristics of the landslide provinces distributed as narrow belts or areas which include many landslide-units, the author considered the relation between topographical distribution of landslide provinces and erosional or weathering properties of each rocks and formations which are represented by geomorphological or photogeologic characteristics. As the map showing subdivisions of surface geology had already been made by the author, the consideration was practiced on the points clarifying the cause of peculiar erosional or weathering landforms which are called as the landslide topography.
The causes of landslide are generally summarized into the following three essential points : namely
1. Denudation and lateral erosion are observed topographically, for example deep and narrow valley accompanying river terraces and coast terraces with high and steep slopes towards the sea.
2. Underground water, which occurs the sliding movements, is poured into the area from the background which is composed of porous rocks such as gravel, permeable lavas and pyroclastics, at the time of downpours or snowbreaks.
3. Clay-seams, which are considered to cause landslide movements, are produced at or below the surface of the earth. Likewise, along the places which joint sets develop densely in the rocks and formations, or fresh joints or cracks are successively generated, inside the rocks and formations, landslide provinces occur.
The following types of ground are preferred as geological conditions that cause landslides.
a. Rocks which are altered into clayey weathering products : The surface of sliding is uncertain below the surface of the ground.
b. Rocks which include closely developed joint sets : Rotational slide occur in general cases, and slub slide rarely.
c. The sheared belt of bedrocks which have many joint sets and cracks originated by crustal deformations : Rotational slide occur.
d. Monoclinal formations composed of alternations of mudstone, sandstone and tuff : Slub slide occur.
e. Intensely folded formations composed of rocks which produce sliding clay : Rotational slide occurs along the folded zones.
f. Clayey basement rocks, which underlies thick talus deposits :
g. Talus deposits that includes clayey fragments of rocks in the matrixes :
In conclusion, the author subdivided the types of landslides based on above-mentioned conditions as follows ;
1. Unconsolidated debris deposits type
2. Volcanic altered areas type
3. Tectonic type (see the following table)View full abstractDownload PDF (2178K) -
Nobuo KURATA1966 Volume 75 Issue 3 Pages 136-141
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSWe have hydrogeological maps introducing the groundwater condition on the different parts of Japan. They are published as follows.View full abstractDownload PDF (944K) -
[in Japanese]1966 Volume 75 Issue 3 Pages 142-160
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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Mutsumi HOYANAGI1966 Volume 75 Issue 3 Pages 155-165
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
JOURNAL FREE ACCESSRecent geographical research in China has, as are exemplified by many articles in Acta Geographica Sinica of recent years, been carried out placing the emphasis upon the studies of natural environment, particularly of climatic factors, of the China's land and of its applied problems. This makes a remarkable contrast with researches before the war, when the majority of topics were concentrated on the problems of historical geography of the land. This change has been probably brought about in many cases in accordance with the national needs of China after “liberation”. Several major problems in which many Chinese geographers are interested can be drawn out from recent articles and publications of geographical research and among them are the glacial problems, past and present.
1) Glacial problems of China were originally discussed mainly by European geographers and geologists concerning the mountainous region of western China and several distinguished views were presented. However, after the war the situation of research has changed. The summary of geographic achievements and the present situation of European geographers and geologists are well expressed by H. von Wissmann in his illustration (Fig. 1) and the following statement.
“In Europa und Nordamerika kann man vielleicht zu Recht von einer pleistozanen ' oder eiszeitlichen ' Schneegrenzdepression sprechen. In Hoch-und Ostasien muss man die letzteiszeitliche Schneegrenzdepression streng von den Schneegrenzdepressionen älterer Eiszeiten auseinanderhalten. Für diese älteren Eiszeiten erscheinen die Unterlagen für eine Zusammenschau noch durchaus nicht zu genügen, zumal wir seit 1949 zu meinem grossen Leidwesen von der chinesischen Wissenschaft noch stärker geschieden sind als von der russischen.” (Die heutige Vergletscherung und Schneegrenze in Hochasien. 1959, s. 227)
2) There appeared several articles in Acta Geographica Sinica and Geologica Sinica of recent years dealing with the problems of glaciation and glacial ages of western China. By tracing remnants of glaciation in the Himalaya (around Mt. Everest), the Tien-Shan and the Chilien Mountains and the Tibetan Plateau, some different views are expressed concerning the ice ages of the past. For instance, some claim the existence of 4 ages, others 3 ages, still others 2 ages, and the last one seems to be the safest conclusion in the present condition of evidences.
Discussions have been concentrated on the relationship between climatic changes during the Pleistocene and the recent crustal movement continued in the mountain zones of western China. The conclusion common to many articles is that the combined effect has contributed much to the development of ice ages and extent of ice-cover. While many geographers agree that the younger the ice ages, the smaller the extent of glacial development (Fig. 2), despite the continual upheaval of mountain lands and that it proves the continual weakening of the invasion of oceanic influences from the Indian Ocean.
3) Remarkable theories were suggested concerning the depression of snowline of the past. A great depression, far greater than estimated by European geographers is assumed (Fig. 3), but the ice age in which such a depression occurred is still obscure. Some hold that it occurred during Qii period -the greatest ice age of the past-, while the other suggests the probability during the last the age.
As to the extent of ice-cover, two opposing views are presented, the one suggests a large extension which covered almost all the land higher than 4, 200 m, while the other claims the different degree of extension according to the patterns of ice-cover, which were determined by both topographical and climatic conditions of the region (Fig. 4).View full abstractDownload PDF (1858K) -
[in Japanese]1966 Volume 75 Issue 3 Pages 166-167
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 168-172
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 173
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 173a-174
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 175-176
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 176
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 176a-177
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages 177-178
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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[in Japanese]1966 Volume 75 Issue 3 Pages Plate1-Plate2
Published: June 25, 1966
Released on J-STAGE: November 12, 2009
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