Potassium-argon dating indicates that the dome last erupted 119.8±5.4 ka ago.
[2] The dome is located on the northwestern side of Cerro del Azufre.
The flanks of the dome are steep and talus and lava blocks lie at its feet.
[1] Cerro Chanka has a SiO2 content of 66% and is of calc-alkaline origin.
The lavas are potassium-rich dacitic and rhyolitic save for an andesitic mafic component, and rich in crystals.