Schematic cross-section of the crust beneath the Yellowstone
Caldera based on Hildreth (1981) and Husen et al.
(2004). Red dots represent earthquake epicenters. The silicic magma
reservoir is responsible for most of the volcanism over the past 2.1 million
years and overlies a middle and lower crust invaded by mantlederived
basalt. The silicic magma is a hybrid of crustal melts and residual
liquid formed as mafic magma cools and crystallizes. Magma rises