Relationship between volcanic activity and chemical composition of volcanic gases—A case study on the Sakurajima Volcano

Abstract

Concentrations of chlorine and sulfur bearing species in volcanic gases from the Sakurajima Volcano have been continuously measured by a variety of collection techniques and analytical methods. The results of analyses on water-soluble components in volcanic ashes, gases absorbed into alkaline solutions, and gases diffused into the atmosphere revealed that HCl/SO2 ratio increased prior to any surface activity such as frequency of explosions. It is suggested that HCl/SO2 ratio can be one of the useful precursory indicators for volcanic activity. © 1982, GEOCHEMICAL SOCIETY OF JAPAN. All rights reserved.