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The Laguna del Maule Volcanic Field includes an unusually large and recent concentration of silicic eruptions across a 23x17 km lake basin atop the southern Andes. We present findings that allow us to link currently observed deformation with a geological record of surface change spanning the Holocene. Since 2007 the crust here has been inflating at more than 20 cm/y. Geological, petrological, and geophysical findings have led to the hypothesis that the silicic vents have tapped an extensive, but ephemeral, layer of crystal-poor rhyolitic melt that began to form atop a mush zone that was established by~ 20 ka, with a renewed phase of rhyolite eruptions concentrated around the southern flank of the basin during the Holocene (Singer et al., 2014). One of the earliest rhyolites, the 1 km3 Espejos coulée, 40Ar/39Ar-dated at 19 ka, dammed the northern outlet of Laguna del Maule raising the lake level~ 200 m to form …