Mt Richmond/Otahuhu Volcano

One of the 53 volcanoes in the Auckland Volcanic Field, all of which erupted in the last 200,000 years.
Mt Richmond Domain contains the partly quarried remains of several small scoria cones formed by fire-fountaining from a number of vents. The cones sit in the middle of an 800-m diameter explosion crater surrounded by a tuff ring, with its lowest rim to the west. The flat floor of the crater (partly used as playing fields) is like the moat around a castle (the scoria cones).
On the slopes of the cones are the sites of four scoria quarries that have significantly altered the original shape of these volcanic landforms. There are two small natural circular craters in the middle of the scoria cone complex. A lot of the northern part of the tuff ring has been flattened for industrial subdivision located outside the domain.
The scoria cones are strategically situated next to a major canoe portage between the Manukau and Waitemata (Tamaki Estuary) harbours and their slopes have been extensively modified with earthworks to create a defensive pre-European pa.

Both carparks are on the edge of the "moat" - the flat floor of the explosion crater. Can you trace the moat around the scoria cones?
Why do you think the floor of the crater is so flat?
Can you make out the crest of the tuff ring around the northeast to southern side of the crater?
Explore the scoria cones - can you work out which of the slopes are natural, which of the pits are natural circular craters, which are kumara pits dug by pre-European Maori, and which of the pits are European scoria quarries?
Look around and see if you can find lumps of basalt lava that are full of holes and almost as light as pumice - how did these lumps of rock form like this?