Degassing activity from Iwodake rhyolitic cone, Satsuma-Iwojima volcano, Japan: Formation of a new degassing vent, 1990–1999

• DOI: 10.1186/bf03353017
• Publication Date: 2014-08-15T03:28:10Z
• Authors: Hiroshi Shinohara; Kohei Kazahaya; Genji Saito; Nobuo Matsushima; Yoshihisa Kawanabe
• Keywords: Caldera; Fumarole; Magma chamber

Large changes in the surface manifestation of degassing activity were observed from 1990 to 1999 at summit crater Iwodake cone Satsuma-Iwojima volcano. During this period, a new high-temperature fumarolic area formed center floor and became vent with diameter 40 m. Altered volcanic rocks ejected during course formation. Although glass fragments ash, comes altered rhyolite that covers floor. The highest temperature equilibrium temperatures gases had maximum about 900°C beginning flux SO2, measured by COSPEC, varied 300 700 ton/day correlated directly fumarole temperature. open fractures along southern rim almost contemporaneously formation nature discharges. continuous intense is likely caused volatile transport deep magma chamber through convecting column. An increase convection rate might have these large manifestations, including SO2 temperatures, ground deformation,