Schematic cross section of an underground region 3 km deep and 2 km wide. A red dike stretches across the bottom, and a pipe containing some xenoliths runs from the dike to the surface, varying from red at the bottom to orange-yellow at the top. The pipe's root, at its bottom, is about 1 km long, and its diatreme, above the root, is about 1.5 km long. The pipe's top is a crater, rimmed by a tuff ring and containing washed-back ejecta. The erosion level is almost zero for Orapa, about 1 km for Jagersfontein, and about 1.4 km for Kimberley.