The release of various gases at volcanoes is complex and dependent on a large number of variables. Most studies have used only a few techniques of measuring and sampling. This research will increase the number of techniques used at a few active volcanoes where a background of other data exist. Long-range goals of this project are to: 1) Test and perfect forecasting tools based on gas studies, 2) Evaluate and improve constraints on the conditions prevailing in shallow magma bodies which lead to eruptions, and 3) Make a better assesment of volatiles and particles released to the atmosphere by volcanoes. This is a continuing project, but in the next two years emphasis will be on the development of a thermodynamic model which includes hundreds of trace species in volcanic gases. Both homogeneous and heterogeneous equilibrium modelling will be done, and applied to field data of both the PIs and other workers. Results are expected to clarify the speciation of trace components in gases and the reaction processes in gas plumes and at fumarolic vents, as well as what variables control the concentrations of trace components volatilizing from magmas. Collection, analysis and geologic interpretation will be done by Rose and collegues at Michigan Tech. Modelling will be done primarily by Reed and collegues at Oregon. Results are expected to have applicability beyond the immediate geologic concerns.
