Earth Science (Chikyu Kagaku)
Online ISSN : 2189-7212
Print ISSN : 0366-6611
Volume 73 , Issue 1
Showing 1-9 articles out of 9 articles from the selected issue
Research Article
Short Report
  • Hikaru SATO, Yoshinori MIYACHI, Sadao HIRAKOSO, Research Group for Geo ...
    Type: short report
    2019 Volume 73 Issue 1 Pages 15-20
    Published: January 25, 2019
    Released: June 04, 2020

    Unconsolidated sand with the maximum thickness of 40 m was found in the D4 unit of the Plio-Pleistocene upper Dainenji Formation in southern Minamisoma City, Fukushima Prefecture, Japan. The thickness of this sand is unique because the D4 unit is mainly composed of mudstone with thin-sandstone. This sand is mainly composed of coarse to fine grains. Mudstone blocks are found at the bottom of this sand, and the sand is overlain by upper mudstone. The lower part of the sand shows slump structure. This sand shows fining-upward succession, which indicates that deposition had progressed during reducing period of current energy. The boundary between the sand and the underlying mudstone shows that the sand buries a channel extending from WSW to ENE with 4.5 km of length and 1 km of width. It was also presumed that the sand occurs above SF γ, a tephra bed of the D4 unit. The thickness, facies and stratigraphic position of the sand are similar to those of “medium-grain sandstone” at the site of Fukushima Daiichi Nuclear Power Station (FDNPS). Therefore, a channel buried by thick and unconsolidated sand is likely to exist even at the FDNPS site.

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Special issue: The culture geology of Hokkaido(1)
  • Hirokazu KATO
    Type: review
    2019 Volume 73 Issue 1 Pages 23-33
    Published: January 25, 2019
    Released: June 04, 2020

    MIYAZAWA Kenji (1896-1933) is one of the most popular literary men (poet and the writer of fairy tales) in Japan. He was born in Hanamaki City, Iwate Prefecture, northeast Japan. He was educated in the Department of Geology and Soil Science, the Imperial College of Agriculture and Forestry, located in Morioka City, which lies to the north of Hanamaki City, in the same prefecture. He enrolled in a master’s course in same college. Therefore, many geological terms and concepts that he learned from textbooks could be appeared in his literary works. Also his experiences of geological field excursions gave a unique and positive influence to his literary works. Therefore, his works are the quite right target for culture geology. He travelled Hokkaido three times, which is the northern main island of Japanese archipelago. During his second travel to Hokkaido, he visited furthermore in Karafuto (Sakhalin), the island north of Hokkaido. In this time, he created many eminent poems, which were printed in the first anthology published in 1924. The present writer tries to interpret those works viewed from culture geology in this text.

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  • The folklore of Mt. Optateske and volcanic disaster
    Tsutomu CHITOKU
    Type: research-article
    2019 Volume 73 Issue 1 Pages 35-45
    Published: January 25, 2019
    Released: June 04, 2020

    The author assays the geologic phenomenon on the basis of oral traditions of the Ainu who are indigenous people of Hokkaido. Many volcanoes are distributed over in Hokkaido. However, because "Wajin (the Japanese without Ainu peoples)" did not stay habitually before the Edo era except a part of Southern Hokkaido, there are no documents about the eruption of volcanoes. Nevertheless, Ainu has a lot of dynamic folklores concerning with the volcanic activity in each place. Some of Ainu folklores can give us a hint of past volcanic eruptions. On a topographic map of the Geospatial Information Authority of Japan (GSI), the Mt. Optateske is shown. But there are no established explanations about the meaning Optateske of Ainu language, and the geographic locality of Mt. Optateske in Ainu folklores remains an open question. On this article, the author considers the name and the locality of legendary Mt. Optateske, and deduces its place and the time of volcanic mud flow disaster

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