open access

https://hdl.handle.net/2115/87276

Eruptive Volume and Age of Large-Scale Pumice Eruptions of the Asama-Maekake Volcano, Central Japan, as Revealed by Detailed Trench Surveys : Implications for Future Volcanic Hazards

英語

volcanic hazard

2022-10

富士技術出版(Fuji Technology Press)

Journal of Disaster Research

17(6)

1080-1089

The eruptive volumes and ages of the large-scale pumice eruptions of the Asama-Maekake volcano were obtained from extensive trench-based surveys. The calibrated radiocarbon age unit (CRAU) was adopted instead of each calibrated radiocarbon age. From the high-resolution tephro-stratigraphy of large-scale pumice eruptions and CRAU dating, the eruptive history of the Asama-Maekake volcano is divided into three active and two moderately active stages as fol-lows: active stage I (9430 to 7260 ycalBP), moderately active stage 1 (7261 to 6446 ycalBP), active stage II (6447 to 3160 ycalBP), moderately active stage 2 (3161 to 1819 ycalBP), and active stage III (1820 ycalBP to present). The eruptions of the Asama-Maekake volcano consists of small-scale (phreatic to phreato-magmatic), intermediate-scale (Vulcanian), and large-scale pumice eruptions (sub-Plinian). The active stages were characterized by the occurrence of large-scale pumice eruptions. In the moderately active stages, pumice producing eruptions were lacking but instead Vulcanian eruptions dominated. A step dia-gram showing the relationship between eruption vol-umes (DRE) and ages (CRAU) is proposed, which in-dicates that active stage III is not time-predictable but is volume-predictable; if the large-scale pumice erup-tion occurs in 2022 AD, the forecasted eruptive volume is approximately 0.21 km3. The eruption rate is not constant and changes in each stage, and the average eruption rate of active stage III (0.0011 km3/year) is larger than those of active stage I (0.00006 km3/year) and II (0.0001 km3/year).

学術雑誌論文

Version of Record

1881-2473