JpGU-AGU Joint Meeting 2020

Presentation information

[J] Oral

S (Solid Earth Sciences ) » S-VC Volcanology

[S-VC47] Volcanic and igneous activities, and these long-term forecasting

convener:Teruki Oikawa(GSJ, National Institute of Advanced Industrial Science and Technology ), Takeshi Hasegawa(Department of Earth Sciences, College of Science, Ibaraki University), Daisuke MIURA(Department of Physical Science, Graduate School of Science, Osaka Prefecture University), Nobuo Geshi(Geological Survey of Japan, The National Institute of Advanced Industrial Science and Technology)

[SVC47-02] The 1649 AD pyroclastic fall deposits of Nikko-Shirane Volcano

*Yuki Kusano1, Teruki Oikawa1, Yoshihiro Ishizuka1 (1.Geological Survey of Japan, AIST)

Keywords:Nikko-Shirane Volcano, 1649 calAD, pyroclastic fall deposit, Volume

Nikko-Shirane Volcano is an active volcano on the border between Gunma and Tochigi prefectures. The largest eruption on historic record occurred in 1649 AD. Eruption products of the 1649 AD eruption are correlated with a muddy-pyroclastic fall deposit below the surface soil at the foot of Nikko-Shirane Volcano (Okuno, 1993; Suzuki et al., 1994). Recently, we conducted six trench surveys around the summit of Nikko-Shirane Volcano and detected the 1649 AD eruption product (Kusano and Ishizuka, 2020). Based on the stratigraphy, thickness, grain size and composition of pyroclastic fall deposit, we will present the summary the eruption products and volume of the 1649 eruption. According to three estimation methods of the eruption volume by Geshi et al. (2010), Hayakawa (1985) and Fierstein and Nathenson (1992), evaluated volume of this eruption is at least 2–3 × 107 m3 which is one digit larger than the estimation before (Okuno, 1993).