It consists of two volcanic cones, the older Lokon and the younger Empung.

The active crater of Tompaluan is situated in the saddle between the two cones.

Lokon formed during a period of andesitic volcanism on ring fractures resulting from the Tondano caldera's Late Miocene or Early Pliocene collapse.

[1] Tompaluan is a 150 x 250 m wide double crater situated in the saddle between the two peaks, historical eruptions have been reported from the crater since the mid-19th century.

[1] Historical eruptions have been reported since 1375 (give or take 25 years).