 Many vents cluster in an area known as the Altiplano-Puna volcanic complex which occupies a surface of about approximately north of Galán, and which includes the large calderas of La Pacana, Cerro Guacha, Pastos Grandes and Cerro Panizos as well as more recent geothermal systems.This volcanism appears to be a surface expression of a pluton, and at depths of beneath the Altiplano-Puna volcanic complex electrical, gravity and seismic tomography data have localized a structure of partially molten rock called the "Altiplano Puna Magma Body".Volcanism in this "back" region may not be directly related to subduction processes despite the region itself being close to a subducting margin.