Japan Geoscience Union Meeting 2015

Presentation information

International Session (Oral)

Symbol S (Solid Earth Sciences) » S-VC Volcanology

[S-VC12] Multidisciplinary volcano monitoring

Tue. May 26, 2015 2:15 PM - 4:00 PM 304 (3F)

Convener:*Yosuke Aoki(Earthquake Research Institute, University of Tokyo), Maurizio Ripepe(Dipartimento Scienze della Terra, Universita di Firenze), Mie Ichihara(Earthquake Research Institute, University of Tokyo), Chair:Mie Ichihara(Earthquake Research Institute, University of Tokyo), Yosuke Aoki(Earthquake Research Institute, University of Tokyo)

2:45 PM - 3:00 PM

[SVC12-03] Temporal variation of the ash component of the 2014-15 Aso Nakadake eruption

*Nobuo GESHI1, Yasuo MIYABUCHI2, Isoji MIYAGI1, Takahiro MIWA3 (1.IEVG Geological Survey of Japann, AIST, 2.Kumamoto University, 3.NIED)

Keywords:eruption, volcanic ash, magma, Aso

The eruption of Aso Nakadake volcano started in the end of November 2014 and keeps continuous emission of volcanic ash. Most of the volcanic products distributing outside of the crater consist of volcanic ash, though some scoriaceous volcanic bombs are landed on the crater rim.
We trace the temporal change of the grain components of the volcanic ash. The volcanic ash erupted from the onset of the eruption in November till December 10 contains dark-colored opaque glassy grain and cryptocrystalline black grains. Since middle of December, pale-brownish glassy grains occupy the major part of the products. These glassy grains are subdivided into i) blocky grain, with fractured surface, lower vesicle contents, ii) sponge-like grain, with higher vesicle contents surrounded by fractured surface, iii) elongated grain, with smooth surface and elongated bubbles. Some elongated grains show Pele′s hair shape. The volcanic ash erupted in December 15-16, 25-27, January 13-16 contains elongated glassy grains.