The range’s story: two names, an ancestor and a fault line
The official name is Southern Alps / Kā Tiritiri o te Moana. A LINZ place-names map says the Māori name recalls Māui mistaking the white-tipped peaks for a mirage of the ocean. The English name is usually credited to James Cook in 1770. “New Zealand Alps” has never been official. It is an old descriptive name, as in G. E. Mannering’s 1891 climbing bookWith Axe and Rope in the New Zealand Alps.
To Ngāi Tahu, Aoraki is the most sacred of ancestors. In their tradition, Aoraki and his brothers turned to stone on their upturned waka and became the main peaks of the range. “Cloud Piercer” is a popular translation of the name, not the meaning Ngāi Tahu give it. Under the Ngāi Tahu Claims Settlement Act 1998, the Crown returned Aoraki to Te Rūnanga o Ngāi Tahu, which gifted it back to the nation, and the mountain was renamed Aoraki / Mount Cook.
The rock itself is still rising. The range sits on the boundary of the Pacific and Australian plates, and the Alpine Fault runs for hundreds of kilometres along its western edge. Uplift near Aoraki reaches about a centimetre a year, roughly as fast as erosion wears the peaks down, and it comes in jumps of several metres during big earthquakes. GNS Science puts the fault’s rhythm at a quake of about magnitude 8 every 300 years or so; the last big one was in 1717.