論文

査読有り
2018年2月1日

Resuspension of ash after the 2014 phreatic eruption at Ontake volcano, Japan

Journal of Volcanology and Geothermal Research
  • Takahiro Miwa
  • ,
  • Masashi Nagai
  • ,
  • Ryohei Kawaguchi

351
開始ページ
105
終了ページ
114
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1016/j.jvolgeores.2018.01.003
出版者・発行元
Elsevier B.V.

We determined the resuspension process of an ash deposit after the phreatic eruption of September 27th, 2014 at Ontake volcano, Japan, by analyzing the time series data of particle concentrations obtained using an optical particle counter and the characteristics of an ash sample. The time series of particle concentration was obtained by an optical particle counter installed 11 km from the volcano from September 21st to October 19th, 2014. The time series contains counts of dust particles (ash and soil), pollen, and water drops, and was corrected to calculate the concentration of dust particles based on a polarization factor reflecting the optical anisotropy of particles. The dust concentration was compared with the time series of wind velocity. The dust concentration was high and the correlation coefficient with wind velocity was positive from September 28th to October 2nd. Grain-size analysis of an ash sample confirmed that the ash deposit contains abundant very fine particles (&lt
30 μm). Simple theoretical calculations revealed that the daily peaks of the moderate wind (a few m/s at 10 m above the ground surface) were comparable with the threshold wind velocity for resuspension of an unconsolidated deposit with a wide range of particle densities. These results demonstrate that moderate wind drove the resuspension of an ash deposit containing abundant fine particles produced by the phreatic eruption.

リンク情報
DOI
https://doi.org/10.1016/j.jvolgeores.2018.01.003

エクスポート
BibTeX RIS