Partially miscible interfaces are central to the evolution of subsurface systems, including underground hydrogen storage, CO₂ sequestration, groundwater oxygenation, and methanogenesis in sediments. The physics may involve multiple coupled processes such as evaporation, condensation, Ostwald ripening, bubble/crystal nucleation via reactions, biogenesis, or pressure-induced exsolution. A unifying feature of these systems is the formation and dissolution of fluid-fluid or fluid-solid interfaces in a surrounding fluid, whose kinetics depend not only on temperature, pressure, and fluid composition but also on interfacial energy. The resulting gradients in chemical potential can drive mass transfer, sometimes in the “uphill” direction, redistributing fluid/solid phases, thereby altering macroscale flow properties such as relative permeability. In fluid–solid interfaces, crystallization can even induce mechanical stresses strong enough to fracture a porous matrix. We invite experimental, computational, and theoretical contributions that advance our understanding of partially miscible interfaces and how they evolve from the pore to the continuum scale.

• MR - Mineral and Rock Physics
• NG - Nonlinear Geophysics
• V - Volcanology, Geochemistry and Petrology