Two models of magma storage beneath Yellowstone.
Models of magma storage. Part (A) depicts the standard model of magma storage—a single, large body of crystal-poor melt, surrounded by crystalline mush. Although this is the standard 'mush' model, geophysical studies fail to find evidence of this type of magma storage at many active systems. The diagram in (B) shows the updated model for magma storage in large volcanic systems. This model involves a network of interconnected and/or isolated melt pockets which are tapped sequentially through the course of an eruption.