Progressive mixed-magma recharging of Izu-Oshima volcano, Japan: A guide to magma chamber volume

Magma Plumbing System at Izu-Oshima Volcano, Japan: Constraints From Petrological and Geochemical Analyses

“…Fujii et al (1988) showed that the Mg/Fe ratios of the eruptive products of YOG generally tend to decrease over time, and suggested that primary magma has not been supplied from the source mantle to the crustal magmatic system FIGURE 1 | An index map showing the location of the Izu-Oshima volcano, and a geological map of the volcano (after Kawanabe, 1998). The location of the Izu-Tobu volcanoes is from Ishizuka et al (2015). The distributions of the products of the S1, N2, Y6, Y1Ca, 1876Y6, Y1Ca, -1877Y6, Y1Ca, , and 1912Y6, Y1Ca, -1914 eruptions are not shown because those of S1, N2, and Y6 mainly occur as scoria fall deposits, those of Y1Ca are entirely covered by those of Y1Cb, and those of the 1876-1877 and 1912-1914 eruptions were mainly ejected inside the summit crater of Mt.…”

“…Hamada (2016) attributed the higher-and lower-Al/Si trends to crystallization differentiation of magmas at the 8-10 km depth and ∼4 km depth magma chambers, respectively, which was controlled by the stability of plagioclase relative to mafic minerals. Recently, Ishizuka et al (2015) reported geochemical data for the Izu-Oshima volcano and the adjacent Izu-Tobu volcanoes located at the rear-arc side of Izu-Oshima (Figure 1). Their results showed that the Izu-Tobu magmas were involved in the magma plumbing system at the Izu-Oshima volcano, in particular, before ∼5 ka.…”

“…Notably, the data for the 1950-51 and 1986-87a products do not lie on the trend formed by the data of the 1986-87b products. Kawanabe (1991Kawanabe ( , 1998, and Ishizuka et al (2015), and they are shown in gray.…”

“…The Izu-Oshima volcano, located on the volcanic front of the Izu arc (Figure 1), is one of the most active volcanoes in Japan, and younger volcanism (<∼1.5 ka) has produced mainly basaltic magmas with minor basaltic andesitic magmas. Relatively largescale eruptions, in the order of 10 5 -10 6 m 3 of eruption volume, have occurred every 30-40 years for the past 200 years (1876-77, 1912-14, 1950-51, and 1986-87), and eruptions are expected to occur in the near future; therefore, many petrological and geochemical studies have been conducted to understand the magma plumbing system beneath the volcano (e.g., Fujii et al, 1988;Kawanabe, 1991;Nakano and Yamamoto, 1991;Hamada et al, 2011Hamada et al, , 2014Ishizuka et al, 2015). Our knowledge of magmatic processes has greatly advanced as a result of these studies, and there is now a consensus that basaltic magmas and basaltic andesitic magmas are stored in a main magma chamber located at 8-10 km depth and small magma bodies located at 4-5 km depth, respectively, and new magmas have been intermittently supplied to the main 8-10 km-deep magma chamber from a deeper magma chamber (Meteorological Agency, 2008;Hamada, 2016).…”

Large‐volume lateral magma transport from the Mull volcano: An insight to magma chamber processes

“…Long‐distance magma transport within the Earth's crust is an important process that shapes the structure of volcanic edifices and is a significant, yet unseen, contributor to crustal growth. This lateral transport has been recognized in various volcanic settings including large igneous provinces [e.g., Ernst and Buchan , ; Magee et al ., , , ], hot spot volcanoes [e.g., Ryan , ; Klugel et al ., ], mid‐oceanic ridges [ Dziak et al ., ; Sinton et al ., ], and island arc volcanoes [e.g., Hildreth and Fierstein , ; Geshi et al ., ; Ishizuka et al ., ]. There is increasing evidence from active volcanic systems for lateral magma movement based on the migration of seismic swarms [e.g., Einarsson and Brandsdottir , ; Toda et al ., ; Peltier et al ., ; Aloisi et al ., ], ground deformation [e.g., Nishimura et al ., ; Aloisi et al ., ; Peltier et al ., ], emanation of volcanic gases [e.g., González et al ., ], and the formation of eruption fissures [e.g., Nakamura , ].…”