Very little is known about eruptions before the
Holocene epoch. This is explained by the great extent of the
Patagonian Ice Sheet that covered most of the southern Andes and caught volcanic material such as ash and pyroclast. Glaciers of the ice sheet also reworked previously deposited layers. Some 10,300 years ago Choshuenco produced the
Neltume Pumice during a
plinian eruption. The earliest historical accounts of eruptions from the Mocho-Choshuenco complex may be those in
Alonso de Ovalle's map
Tabula Geographica Regni Chile from 1646. Here Mocho-Choshuenco may be one of the mountains drawn as erupting volcanoes east of
Valdivia. In
Juan Ignacio Molina's map from 1795 Mocho-choshuenco appears erupting under the name of
Volcán de Valdivia, but eruption shown in this map is probably that of 1759. On November 1, of 1864 the Chaiquemahuida cinder cone erupted, the eruption eventually ended 1–3 days later. This explosive eruption originated from a vent on the southwestern flank of Mocho's edifice and produced pyroclastic flows. According to a missionary from
Quinchilca, who was interviewed by
Vidal Gormaz in 1869, a strong noise followed by an earthquake was felt during one of the first days of November 1864. The last reported eruption, is supposed to have occurred on June 16, 1936. Little is known about this event apart from the occurrence of
mudflows and
lahars, this have led volcanologists to consider this eruption report as a false report just like in the case of the supposed 1906
Lanín eruption. == Glaciers ==