Journal of Japan Association for Earthquake Engineering
Online ISSN : 1884-6246
ISSN-L : 1884-6246
Volume 18, Issue 3
The English Issue
Displaying 1-10 of 10 articles from this issue
Technical Papers
Technical Reports
  • - REPORT ON FIELD INVESTIGATIONS IN HOKKAIDO -
    Takuya EGAWA, Takahiro YAMANASHI, Koichi TOMISAWA
    2018 Volume 18 Issue 3 Pages 3_104-3_118
    Published: 2018
    Released on J-STAGE: June 28, 2018
    JOURNAL FREE ACCESS

    In the conventional design method, there is no particular method to judge the liquefaction phenomenon of the unusual soil such as volcanic ash soil. This study, in order to clarify and evaluate the liquefaction characteristics of volcanic ash soil, field investigations and a series of soil laboratory tests of volcanic ash ground were carried out. The field investigations and sampling were conducted in the areas where ground liquefaction occurred due to the 1993 Hokkaido-nansei-oki and the 2013 Tokachi-oki earthquakes. According to the results, the liquefaction strength ratio (RL) was underestimated when using the formulation of the conventional design method. Moreover, it was found that the estimated formulation RL need to be modified for evaluating the liquefaction phenomenon in volcanic ash soil.

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  • Michihiro OHORI, Yuta ASAKA, Hiroki AZUMA, Shigeki ADACHI, Masaki ITO, ...
    2018 Volume 18 Issue 3 Pages 3_119-3_130
    Published: 2018
    Released on J-STAGE: June 28, 2018
    JOURNAL FREE ACCESS

    The eighth meeting of the Microtremor Research Camp (MRC) was held in Ohno City, Fukui Prefecture from September 30th to October 2nd in 2016, and MRC carried out microtremor measurements in the Katsuyama Basin, which is constituted by deposits of the Kuzuryu River. These measurements consist of microarray measurements at 25 sites and single-point measurements at 67 sites. This paper reports the outline of these measurements and presents the distribution of predominant frequencies in the basin obtained by the analysis of horizontal-to-vertical spectrum ratio at single-point measurement sites. As a result, the large differences in the distribution of predominant frequencies and peak spectral amplitudes between the Quaternary terrace deposits and alluvial deposits are clarified.

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