Geologically, the Southern Alps lie along a plate boundary,
part of the Pacific Ring of Fire. The Alpine Fault developed
25-30 million years ago, with the Indo-Australian Plate in
the west pushing northwestward, the Pacific Plate to the
east being subducted beneath it. The mountains that form
the Alps continue to be uplifted by tectonic pressure,
causing earthquakes on the Alpine Fault, but they are
eroded at approximately the same rate.

According to Ngai Tahu legend, Aoraki and his three
brothers were on a sea voyage when their canoe
overturned on a reef. When the brothers climbed on top of
their canoe, the freezing south wind turned them to stone.
Aoraki and his brothers became the peaks of the Southern
Alps, while their canoe became the South Island.