The Auckland Domain volcano, Pukekawa, is one of the oldest in the Auckland volcanic field, and consists of a large explosion crater surrounded by a tuff ring with a small scoria cone (Pukekaroro) in the centre of the crater. Its tuff ring, created by many explosive eruptions, is made of a mixture of volcanic ash, lapilli and fragmented sandstone country rock. Its eruption followed soon (in geological terms) after the neighbouring Grafton Volcano was created, destroying that volcano's eastern parts and burying the rest.