Right now, the earthquake swarm at Mt. Hood is centeredjust to the south of the main edifice (see below) and most of the earthquakes are between 3 and 5 kilometers below the surface. This is likely the zone where magma is being staged as it ascends from its source. Research by Adam Kent and others (including myself) has found that the magmatic system beneath Hood is likely dominated by a big pile of high silica crystals and magma (the crystal mush) that then interacts with new, hotter and less silica-rich magma that intrudes, producing a hybrid magma that compositionally is in between the two. These earthquakes may be a sign of new magma rising and stalling in that “crystal mush”—but very little of the time is the system in a state that it can erupt.