Active basaltic magma systems are rich in olivine, and the same system can simultaneously produce both aphyric and picritic lavas, indicating that magmatic fluids and a crystal mush occupy the same magma system. Petrologic studies constrain depths and pressure evolution, geodetic studies constrain pressure and system geometry, and seismic imaging constrains the geometry, structure, and variations in fluid and solid content. All studies profit from the assumption of a relatively simple mixture of basaltic liquid, olivine crystals, supercritical carbon dioxide gas at depth. The similarities in structure and melt content between active systems such as in Iceland, Hawaii, Etna, and the Canary Islands, as well as along spreading ridges, are likely to be more profound than their differences. We invite researchers in petrology, geodesy, and seismology who are working together on models of basaltic systems to discuss similarities between systems in many areas of the world.

• G - Geodesy
• MR - Mineral and Rock Physics
• S - Seismology
• T - Tectonophysics