 Geologically, Quetrupillán is located in a tectonic basement block between the main traces of Liquiñe-Ofqui Fault (to the west) and Reigolil-Pirihueico Fault (to the east).The volcano consists of one stratovolcano with a summit caldera, and is constructed within a field of smaller centres and a larger caldera.It was active during the late Pleistocene; some large eruptions occurred during the Holocene as well.