Temporal variations in volumetric magma eruption rates of Quaternary volcanoes in Japan

Abstract

Long-term evaluations of hazard and risk related to volcanoes rely on extrapolations from volcano histories, including the uniformity of their eruption rates. We calculated volumetric magma eruption rates, compiled from quantitative eruption histories of 29 Japanese Quaternary volcanoes, and analyzed them with respect to durations spanning 10 1 -10 5 years. Calculated eruption rates vary greatly (10 1 -10 −4 km 3 dense-rock equivalent/1000 years) between individual volcanoes. Although large basaltic stratovolcanoes tend to have high eruption rates and relatively constant repose intervals, these cases are not representative of the various types of volcanoes in Japan. At many Japanese volcanoes, eruption rates are not constant through time, but increase, decrease, or fluctuate. Therefore, it is important to predict whether eruption rates will increase or decrease for long-term risk assessment. Several temporal co-variations of eruption rate and magmatic evolution suggest that there are connections between them. In some cases, magma supply rates increased in response to changing magma-generation processes. On the other hand, stable plumbing systems without marked changes in magma composition show decreasing eruption rates through time.

Experimental Constraints on Magma Storage Conditions of Two Caldera‐Forming Eruptions at Towada Volcano, Japan

“…The bulk rock major element compositions of the episode N and L eruptive products reported in Yamamoto et al. (2018) and Kudo et al. (2019) are shown in Figure 3.…”

“…The bulk rock major element compositions of the episode N and L eruptive products reported in Yamamoto et al (2018) and Kudo et al (2019) are shown in Figure 3. The normalized contents were used for the whole-rock major element compositions in this study.…”

“…Solid symbols denote the silicic endmember pumices used in our experiment (No‐1 from Yamamoto et al. (2018); Lh‐13 from this study). Open symbols correspond to the other data from Kudo et al.…”

“…Solid symbols denote the silicic endmember pumices used in our experiment (No-1 from Yamamoto et al (2018); Lh-13 from this study). Open symbols correspond to the other data fromKudo et al (2019) andYamamoto et al (2018). The boundaries for the low-K and medium-K series and tholeiitic and calc-alkaline series are after LeMaitre (1989) andMiyashiro (1974), respectively.…”

Isotopic Characteristics of Neogene‐Quaternary Tephra From IODP Site U1438: A Record of Explosive Volcanic Activity in the Kyushu‐Ryukyu Arc

“…Large caldera‐forming eruptions are regional and global hazards and may act as an important control on short‐ and long‐term climate change (e.g., Self, ). This is particularly the case in Japan where the historical and geological records shows periods of intense volcanism associated with caldera‐forming, explosive rhyolitic eruptions (e.g., Machida, , ; Yamamoto et al, ). The historical tephra record is thus of fundamental importance in any effort to build a comprehensive representation of the explosive volcanic activity through time of particular arc segments in order to better mitigate potential volcanic hazards (e.g., Self, ) and constrain the long‐ and short‐term tectonic, mantle and subduction control on timescales of magma production and volcanism (e.g., DeCelles et al, ; Ducea et al, ; Kimura et al, ).…”