The caldera was at first considered to be in width with a centre around , coinciding with the Vilama depression. Vents were localized on the eastern margin beneath the Cerro Caucani, Cerro Solterío, Campanario and Coyaguayma volcanoes, which in turn make up the Abra Granada volcanic complex. One nested caldera associated with the Bonanza ignimbrite was identified as well, the Coruto caldera which is situated southwest of the redefined extent of the Vilama caldera.