Editing Cook Strait (section)

== Geography ==
[[File:BrothersFromKoamaru.JPG|thumb|left|View from Cape Koamaru of the Brothers Islands with Wellington west coast on the horizon]]
Approximately 18,000 years ago during the [[Last Glacial Maximum]] when sea levels were over {{convert|100|m|abbr=off}} lower than present day levels, Cook Strait was a deep harbour of the Pacific Ocean, disconnected from the Tasman Sea by the vast coastal plains which formed at the [[South Taranaki Bight]] which connected the North and South islands. Sea levels began to rise 7,000 years ago, eventually separating the islands and linking Cook Strait to the Tasman Sea.<ref name="Niwa">{{Cite web |title=Estuary origins |url=https://niwa.co.nz/te-kuwaha/tools-and-resources/ng%C4%81-waihotanga-iho-the-estuary-monitoring-toolkit-for-iwi/estuary-origins |access-date=3 November 2021 |publisher=[[National Institute of Water and Atmospheric Research]]}}</ref>

The strait runs in a general NW-SE direction, with the South Island on the west side and North Island on the east. At its narrowest point, {{convert|22|km|mi}} separate [[Cape Terawhiti]] in the North Island from [[Perano Head]] on [[Arapaoa Island]] in the Marlborough Sounds.<ref name="McLintock" /> Perano Head is actually further north than Cape Terawhiti. In good weather one can see clearly across the strait.

The west (South Island) coast runs {{convert|30|km|mi}} along [[Cloudy Bay]] and past the islands and entrances to the Marlborough Sounds. The east (North Island) coast runs {{convert|40|km|mi}} along [[Palliser Bay]], crosses the entrance to [[Wellington harbour|Wellington Harbour]], past some Wellington suburbs and continues another {{convert|15|km|mi}} to [[Mākara Beach]].

[[The Brothers (islands), New Zealand|The Brothers]] is a group of tiny islands in Cook Strait off the east coast of Arapaoa Island. North Brother island in this small chain is a sanctuary for the rare [[Brothers Island tuatara]], while the largest of the islands is the site of the Brothers Island Lighthouse.[[File:Coast of Wellington Region from Cook Strait.jpg|thumb|right|Wellington's  coast, seen from Cook Strait]]The shores of Cook Strait on both sides are mostly composed of steep cliffs. The beaches of Cloudy Bay, [[Clifford Bay, New Zealand|Clifford Bay]], and Palliser Bay shoal gently down to {{convert|140|m|ft}}, where there is a more or less extensive submarine plateau. The rest of the bottom topography is complex. To the east is the Cook Strait Canyon with steep walls descending eastwards into the [[bathyal]] depths of the [[Hikurangi Trough]]. To the north-west lies the Narrows Basin, where water is {{convert|300|and|400|m|ft}} deep. Fisherman's Rock in the north end of the Narrows Basin rises to within a few metres of low tide, and is marked by waves breaking in rough weather. A relatively shallow submarine valley lies across the northern end of the Marlborough Sounds. The bottom topography is particularly irregular around the coast of the South Island where the presence of islands, underwater rocks, and the entrances to the sounds, create violent eddies.<ref name="McLintock" /> The strait has an average depth of {{convert|128|m|ft}}.{{cn|date=August 2024}}

In 1855 a [[1855 Wairarapa earthquake|severe earthquake]] occurred on both sides of Cook Strait.{{Citation needed|date=January 2025}} In 2013 two large earthquakes measuring [[2013 Seddon earthquake|6.5]] and [[2013 Lake Grassmere earthquake|6.6]] on the Richter Scale struck Cook Strait, causing significant damage in the town of [[Seddon, New Zealand|Seddon]], with minor to moderate damage in Wellington.{{Citation needed|date=January 2025}}