Air-Fall Ash from the Main Crater of Asama Volcano on August 7, 2019, and its Water-Soluble Components
Muga Yaguchi*,, Akihiko Terada**, and Yasuo Ogawa**
*Volcanology Research Department, Meteorological Research Institute, Japan Meteorological Agency
1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
**Volcanic Fluid Research Center, School of Science, Tokyo Institute of Technology, Tokyo, Japan
We collected volcanic ash immediately following the eruption of Mt. Asama on August 7, 2019, observed the characteristics of ash particles, and analyzed the water-soluble components. The volcanic ash consisted mostly of altered fragments, and no clear evidence of essential materials was found. The volcanic ash contained large amounts of water-soluble components, Cl and SO4 at concentrations of 8,710 mg/kg and 49,100 mg/kg, respectively. These results indicate that this eruption was caused by the phreatic explosion and that part of the volcanic edifice of Mt. Asama was fractured and emitted.
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