Stratigraphy and mineralogy of phreatic eruptions from Kurikoma volcano

Abstract

This research was aimed to report tephra stratigraphy of northern slope of Kurikoma volcano and also to estimate the originated depth, temperature and chemical composition of subsurface hydrothermal fluid related to the phreatic eruption. The ash derived from 1994 Showako eruption was analyzed. I concluded that the eruption derived from c. 1.5km subsurface hydrothermal system which fluid chemical composition is acid to neutral and maximum temperature is over 230 °C to 300 °C.