Reevaluation of the pre-1640 A.D. eruptive history of Hokkaido-Komagatake volcano, northern Japan

Abstract

We propose a new thousand year-old eruption history of Hokkaido-Komagatake volcano, northern Japan, from new field observations, radiocarbon dating of charcoal woods and whole-rock chemistry of juvenile materials. In previous studies, eight distinct

Size–distance relationships for hummocks on volcanic rockslide-debris avalanche deposits in Japan

“…3c), with a present altitude of 1131 m, consists of lava and pyroclastics of pyroxene andesite. The Plinian eruption of 1640 produced the Kurumizaka debris avalanche (Katsui et al, 1989;Yoshimoto and Ui, 1998;Yoshimoto et al, 2003), which was divided into the Shikabe Lobe extending to the eastern flank of volcano and the Onuma Lobe. The Onuma Lobe ran down the southern flank of the volcano and formed a landscape of lakes and islands (Yoshimoto and Ui, 1998).…”

“…1.0 km, ca. 11 km and 0.3 km 3 , respectively (Table 1; Yoshimoto and Ui, 1998). The equivalent coefficient of friction is calculated to be 0.091.…”

Eruption history, conduit migration, and steady discharge of magma for the past 50,000 yr at Esan volcanic complex, northern Japan

“…3). In addition to the overlying Ko-g ash-fall deposit derived from Hokkaido-Komagatake volcano at 6.8 ka (Yoshimoto et al, 2008), this relationship indicates that the Mi dome was erupted shortly after Ed dome formation (Figs. 3 and 5) or that the Mi and Ed domes might have erupted almost concurrently.…”

“…Three active volcanoes are found in the vicinity of the Esan volcanic complex: Hokkaido-Komagatake to the northwest, Osorezan to the south, and Oshima-Oshima to the west (Japan Meteorological Agency [JMA], 2005). Many ash-fall units have been erupted from Hokkaido-Komagatake volcano in the past 30,000 yr, and four of these units are present in the immediate area of the Esan volcanic complex (Okuno et al, 1999;Yoshimoto et al, 2008). These units are chronostratigraphic markers that constrain the chronology of eruption units from the Esan volcanic complex.…”

Magnitude of the sediment transport event due to the Late Pleistocene sector collapse of Asama volcano, central Japan

“…A sector collapse is considered to happen at least once during the growth history of steep volcanoes (Moriya, 1983). Such events have attracted much attention, especially since the violent and devastating destruction of Mount St. Helens, USA in 1980 (Voight et al, 1981(Voight et al, , 1983Crandell et al, 1984;Stoopes and Sheridan, 1992;Lopez and Williams, 1993;Vallance et al, 1995;Yoshimoto and Ui, 1998;Vries et al, 2000;Macias, 2000, 2002;Tibaldi, 2001;Waythomas and Wallace, 2002;Concha-Dimas et al, 2005), and has been considered in many volcanic hazard assessments. Traces of volcanic sector collapses have been identified from topographic features such as a horseshoe caldera reminiscent of an amphitheater (Voight et al, 1981;Ui et al, 1986).…”