Structural geologic evidence in the vicinity of the Inyo Domes indicates that the youngest extrusive products were erupted from a silicic dike that divided into at least three segments which underwent up to 30¿ of clockwise rotation as they neared the surface. The geometry of ground cracks, explosion craters, and surface structures on they domes suggest that the dike may have propagated laterally from a source beneath Mammoth Mountain, with both the overall dike and the individual segments rising as they moved northward. Structural evidence and tephrochronology also imply that the actual vents may have migrated northward along individual dike segments as the activity evolved from explosive eruptions to the more quiet emplacement of lavas. Monitoring of changing patterns of ground cracks and faults may assist in predicting the sites and timing of future eruptions.