The 2022 Activity of Ebeko Volcano: The Mechanism and Ejecta

This paper provides information on the 2022 eruptive activity of Ebeko Volcano. Phreatic explosions had been occurring in the crater lake from January 22 to June 13 due to water seepage through a plug in the upper part of the magma conduit with subsequent boiling. Vulcanian type explosions started since June 14 and dried the lake. The ash particle-size distribution changed toward smaller sizes. Petrographic, mineralogical, and geochemical studies of the tephra define this period as a phreatomagmatic eruption based on the presence of fresh juvenile material. Interaction between magma and waters of the Ebeko hydrothermal system results in its depletion in alkali and enrichment in silica. We hypothesize that the formation of amorphous water-bearing silica in the form of numerous segregations and its subsequent dehydration can favor the volcano’s explosive activity.