New Zealand () is an island country located in the southwestern Pacific Ocean, near the centre of the water hemisphere. It consists of a large number of islands, estimated around 700, mainly remnants of a larger landmass now beneath the sea. The land masses by size are the South Island () and the North Island (), separated by the Cook Strait. The third-largest is Stewart Island (), located off the tip of the South Island across Foveaux Strait. Other islands are significantly smaller in area. The three largest islands stretch across latitudes 35° to 47° south. New Zealand is the sixth-largest island country in the world, with a land size of .
New Zealand's landscapes range from the fiord-like sounds of the southwest to the sandy beaches of the subtropical Far North. The South Island is dominated by the Southern Alps while a volcanic plateau covers much of the central North Island. Temperatures commonly fall below and rise above then conditions vary from wet and cold on the South Island's west coast to dry and continental a short distance away across the mountains and to the temperate oceanic climate in coastal Southland.
About two-thirds of the land is economically useful, with the remainder being mountainous. The North Island is the most populous island in New Zealand with over 4 million residents and South Island is the second-most populated home to over 1.2 million residents.
New Zealand is situated on the boundary of the Pacific and Australian tectonic plates, making it one of the most active earthquake and volcanic regions in the world. The country has experienced several devastating earthquakes throughout its history.
The New Zealand mainland is about east of the Australian mainland across the Tasman Sea, the closest foreign neighbour to its main islands being Norfolk Island (Australia) about to the north west. Other island groups to the north are New Caledonia, Tonga and Fiji. It is the southernmost nation in Oceania. The relative close proximity of New Zealand to Antarctica has made the South Island a major gateway for scientific expeditions to the continent.
Physical geography
Overview
New Zealand is located in the South Pacific Ocean at , near the centre of the water hemisphere. It is a long and narrow country, extending along its north-north-east axis with a maximum width of . The land size of makes it the sixth-largest island country. New Zealand consists of a large number of islands, estimated around 600. The islands give it of coastline and extensive marine resources. New Zealand claims the ninth largest exclusive economic zone in the world, covering , more than 15 times its land area.Ministry for the Environment. 2005. Offshore Options: Managing Environmental Effects in New Zealand's Exclusive Economic Zone. Introduction
The South Island is the largest land mass of New Zealand, and is the 12th-largest island in the world. The island is divided along its length by the Southern Alps. The east side of the island has the Canterbury Plains while the West Coast is famous for its rough coastlines, high rainfall, very high proportion of native bush (forest), and glaciers.
The North Island is the second-largest island, and the 14th-largest in the world. It is separated from the South Island by the Cook Strait, with the shortest distance being . The North Island is less mountainous than the South Island, although a series of narrow mountain ranges form a roughly north-east belt that rises up to . Much of the surviving forest is located in this belt, and in other mountain areas and rolling hills. The North Island has many isolated volcanic peaks.
Besides the North and South Islands, the five largest inhabited islands are Stewart Island ( due south of the South Island), Chatham Island (Wharekauri in Māori or Rēkohu in Moriori) (some east of the South Island), Great Barrier Island (in the Hauraki Gulf), Rangitoto ki te Tonga / D'Urville Island (in the Marlborough Sounds) and Waiheke Island (about from central Auckland).
Extreme points
The phrase "From Cape Reinga to The Bluff" is frequently used within New Zealand to refer to the extent of the whole country. Cape Reinga / Te Rerenga Wairua is the northwesternmost tip of the Aupōuri Peninsula, at the northern end of the North Island. Bluff is Invercargill's port, located near the southern tip of the South Island, below the 46th parallel south. However, the extreme points of New Zealand are in fact located in several outlying islands.
The points that are farther north, south, east or west than any other location in New Zealand are as follows:
The northernmost point is in Nugent Island in the Kermadec Islands (). The southernmost point is Jacquemart Island in the Campbell Island group (). The easternmost point is situated in a group of islands within the Chatham Islands called the Forty-Fours (). The westernmost point is Cape Lovitt on Auckland Island ().
Antipodes
New Zealand is largely antipodal to the Iberian Peninsula of Europe. The northern half of the South Island corresponds to Galicia and northern Portugal. Most of the North Island corresponds to central and southern Spain, from Valladolid (opposite the southern point of the North Island, Cape Palliser), through Madrid and Toledo to Cordoba (directly antipodal to Hamilton), Lorca (opposite East Cape), Málaga (Cape Colville), and Gibraltar. Parts of the Northland Peninsula oppose Morocco, with Whangārei nearly coincident with Tangiers. The antipodes of the Chatham Islands lie in France, just north of the city of Montpellier. The Antipodes Islands were named for their supposed antipodal position to Britain; although they are the closest land to the true antipodes of Britain, their location 49°41′S 178°48′E is directly antipodal to a point a few kilometres to the east of Cherbourg on the north coast of France.
In Europe the term "Antipodes" is often used to refer to New Zealand and Australia (and sometimes other South Pacific areas), and "Antipodeans" to their inhabitants.
Geology
New Zealand is part of Zealandia, a microcontinent nearly half the size of Australia that gradually submerged after breaking away from the Gondwana supercontinent. Zealandia extends a significant distance east into the Pacific Ocean and south towards Antarctica. It also extends towards Australia in the north-west. This submerged continent is dotted with topographic highs that sometimes form islands. Some of these, such as the main islands (North and South), Stewart Island, New Caledonia, and the Chatham Islands, are settled. Other smaller islands are eco-sanctuaries with carefully controlled access.
The New Zealand land mass has been uplifted due to transpressional tectonics between the Indo-Australian plate and Pacific plates (these two plates are grinding together with one riding up and over the other). This is the cause of New Zealand's numerous earthquakes. To the east of the North Island the Pacific plate is forced under the Indo-Australian plate. The North Island of New Zealand has widespread back-arc volcanism as a result of this subduction. There are many large volcanoes with relatively frequent eruptions. There are also several very large calderas, with the most obvious forming Lake Taupō. Taupō has a history of incredibly powerful eruptions, with the Oruanui eruption 26,500 years ago ejecting of material and causing the downward collapse of several hundred square kilometres to form the lake. The most recent eruption occurred and ejected at least of material, and has been correlated with red skies seen at the time in Rome and China. The associated geothermal energy from this volcanic area is used in numerous hydrothermal power plants.Hall, Matthew (2004) Existing and Potential Geothermal Resource for Electricity Generation. Ministry for Economic Development. . Some volcanic places are also famous tourist destinations, such as the Rotorua geysers.
The subduction direction is reversed through the South Island, with the Indo-Australian plate forced under the Pacific plate. The transition between these two different styles of continental collision occurs through the top of the South Island. This area has significant uplift and many active faults; large earthquakes are frequent occurrences here. The most powerful in recent history, the M8.3 Wairarapa earthquake, occurred in 1855. This earthquake generated more than of vertical uplift in places, and caused a localised tsunami. Fortunately casualties were low due to the sparse settlement of the region. In 2013, the area was rattled by the M6.5 Seddon earthquake, but this caused little damage and no injuries. New Zealand's capital city, Wellington is situated in the centre of this region.
The subduction of the Indo-Australian plate drives rapid uplift in the centre of the South Island (approx. per year). This uplift forms the Southern Alps. These roughly divide the island, with a narrow wet strip to the west and wide and dry plains to the east. The resulting orographic rainfall enables the hydroelectric generation of most of the electricity in New Zealand. A significant amount of the movement between the two plates is accommodated by lateral sliding of the Indo-Australian plate north relative to the Pacific plate. The plate boundary forms the nearly long Alpine Fault. This fault has an estimated rupture reoccurrence interval of ~330 years, and last ruptured in 1717 along of its length. It passes directly under many settlements on the West Coast of the South Island and shaking from a rupture would likely affect many cities and towns throughout the country.
The rapid uplift and high erosion rates within the Southern Alps combine to expose high grade greenschist to amphibolite facies rocks, including the gemstone pounamu. Geologists visiting the West Coast can easily access high-grade metamorphic rocks and mylonites associated with the Alpine Fault, and in certain places can stand astride the fault trace of an active plate boundary. The South Island also has two major goldfields in Otago and the West Coast.
To the south of New Zealand the Indo-Australian plate is subducting under the Pacific plate, and this is beginning to result in back-arc volcanism. The youngest (geologically speaking) volcanism in the South Island occurred in this region, forming the Solander Islands (<2 million years old). This region is dominated by the rugged and relatively untouched Fiordland, an area of flooded glacially carved valleys with little human settlement.
Mountains, volcanoes and glaciers
The South Island is much more mountainous than the North, but shows fewer manifestations of recent volcanic activity. There are 18 peaks of more than in the Southern Alps, which stretch for down the South Island. The closest mountains surpassing it in elevation are found not in Australia, but in New Guinea and Antarctica. As well as the towering peaks, the Southern Alps include huge glaciers such as Franz Josef and Fox. The country's highest mountain is Aoraki / Mount Cook; its height since 2014 is listed as (down from before December 1991, due to a rockslide and subsequent erosion). The second highest peak is Mount Tasman, with a height of . The North Island Volcanic Plateau covers much of central North Island with volcanoes, lava plateaus, and crater lakes. The three highest volcanoes are Mount Ruapehu (), Mount Taranaki () and Mount Ngauruhoe (). Ruapehu's major eruptions have historically been about 50 years apart, in 1895, 1945 and 1995–1996. The 1886 eruption of Mount Tarawera, located near Rotorua, was New Zealand's largest and deadliest eruption in the last 200 years, killing over 100 people. Another long chain of mountains runs through the North Island, from Wellington to East Cape. The ranges include Tararua and Kaimanawa.
The lower mountain slopes are covered in native forest. Above this are shrubs, and then tussock grasses. Alpine tundra consists of cushion plants and herbfields; many of these plants have white and yellow flowers.