Geography of New Zealand
42°S 174°E / 42°S 174°E / -42; 174
3,724 m (12,218 ft)
−2 m
425 km (264 mi)
3,487 km2 (1,346 sq mi)
New Zealand (Māori: Aotearoa) 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 (or Te Waipounamu) and the North Island (or Te Ika-a-Māui), separated by the Cook Strait. The third-largest is Stewart Island / Rakiura, located 30 kilometres (19 miles) off the tip of the South Island across Foveaux Strait. Other islands are significantly smaller in area. The three largest islands stretch 1,600 kilometres (990 miles) across latitudes 35° to 47° south.[2] New Zealand is the sixth-largest island country in the world, with a land size of 268,680 km2 (103,740 sq mi).[3]
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 0 °C (32 °F) and rise above 30 °C (86 °F) 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 tundra like climate in the Deep South of Southland.
About two-thirds of the land is economically useful, with the remainder being mountainous. The North Island is the most populous island with 4 million residents, and Auckland being by far the largest metropolitan area in the country by population and urban area. The South Island is the second-most populated island, with over 1.18 million people, but is geographically larger than the North.
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 2,000 kilometres (1,200 miles) east of the Australian mainland across the Tasman Sea, the closest foreign neighbour to its main islands being Norfolk Island (Australia) about 750 kilometres (470 miles) 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 41°S 174°E / 41°S 174°E / -41; 174, near the centre of the water hemisphere.[4] It is a long and narrow country, extending 1,600 kilometres (990 mi) along its north-north-east axis with a maximum width of 400 kilometres (250 mi).[5] The land size of 268,680 km2 (103,740 sq mi) makes it the sixth-largest island country.[3] New Zealand consists of a large number of islands, estimated around 600.[6] The islands give it 15,134 km (9,404 mi) of coastline and extensive marine resources. New Zealand claims the ninth largest exclusive economic zone in the world, covering 4,083,744 km2 (1,576,742 sq mi), more than 15 times its land area.[7]
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.[8]
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 23 kilometres (14 mi).[9][10] The North Island is less mountainous than the South Island,[8] although a series of narrow mountain ranges form a roughly north-east belt that rises up to 1,700 metres (5,600 ft). Much of the surviving forest is located in this belt, and in other mountain areas and rolling hills.[11] The North Island has many isolated volcanic peaks.
Besides the North and South Islands, the five largest inhabited islands are Stewart Island / Rakiura (30 kilometres (19 mi) due south of the South Island), Chatham Island (Wharekauri in Māori or Rēkohu in Moriori) (some 800 kilometres (500 mi) east of the South Island),[12] Great Barrier Island (in the Hauraki Gulf),[13] Rangitoto ki te Tonga / D'Urville Island (in the Marlborough Sounds)[14] and Waiheke Island (about 22 km (14 mi) from central Auckland).[15]
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.[16] 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.[17]
The points that are farther north, south, east or west than any other location in New Zealand are as follows:[17]
- The northernmost point is in Nugent Island in the Kermadec Islands (29°13′54″S 177°52′09″W / 29.231667°S 177.869167°W / -29.231667; -177.869167).
- The southernmost point is Jacquemart Island in the Campbell Island group (52°37′10″S 169°07′33″E / 52.619444°S 169.125833°E / -52.619444; 169.125833).
- The easternmost point is situated in a group of islands within the Chatham Islands called the Forty-Fours (43°57′48″S 175°49′53″W / 43.963306°S 175.831410°W / -43.963306; -175.831410).
- The westernmost point is Cape Lovitt on Auckland Island (50°47′59″S 165°52′12″E / 50.799838°S 165.870128°E / -50.799838; 165.870128).
Antipodes
New Zealand is largely antipodal to the Iberian Peninsula of Europe.[18] The northern half of the South Island corresponds to Galicia and northern Portugal.[18][better source needed] 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.[18] 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.[19]
In Europe the term "Antipodes" is often used to refer to New Zealand and Australia (and sometimes other South Pacific areas),[20] 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.[21] 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).[22] This is the cause of New Zealand's numerous earthquakes.[23]
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 approx. 26,500 years ago ejecting 1,170 cubic kilometres (280 cubic miles) of material and causing the downward collapse of several hundred square kilometres to form the lake.[24] The most recent eruption occurred c. 180 CE and ejected at least 100 cubic kilometres (24 cubic miles) of material, and has been correlated with red skies seen at the time in Rome and China.[25] The associated geothermal energy from this volcanic area is used in numerous hydrothermal power plants.[26] Some volcanic places are also famous tourist destinations, such as the Rotorua geysers.[27]
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 6 metres (20 ft) 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.[28] New Zealand's capital city, Wellington is situated in the centre of this region.[29]
The subduction of the Indo-Australian Plate drives rapid uplift in the centre of the South Island (approx. 10 millimetres (0.39 in) 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.[30] 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 800 kilometres (500 mi) long Alpine Fault. This fault has an estimated rupture reoccurrence interval of ~330 years, and last ruptured in 1717 along 400 kilometres (250 mi) 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.[31]
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.[32] The South Island also has two major goldfields in Otago and the West Coast.[33]
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).[34] This region is dominated by the rugged and relatively untouched Fiordland, an area of flooded glacially carved valleys with little human settlement.[35]
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 3,000 metres (9,800 feet) in the Southern Alps, which stretch for 500 kilometres (310 mi) down the South Island.[36] 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.[37] The country's highest mountain is Aoraki / Mount Cook; its height since 2014 is listed as 3,724 metres (12,218 feet) (down from 3,764 m (12,349 ft) before December 1991, due to a rockslide and subsequent erosion).[38] The second highest peak is Mount Tasman, with a height of 3,497 metres (11,473 ft).[39]
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 (2,797 metres (9,177 ft)), Mount Taranaki (2,518 metres (8,261 ft)) and Mount Ngauruhoe (2,287 metres (7,503 ft)). Ruapehu's major eruptions have historically been about 50 years apart,[40] 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.[41] Another long chain of mountains runs through the North Island, from Wellington to East Cape. The ranges include Tararua and Kaimanawa.[42]
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.[43]
Caves
New Zealand's cave systems have three main origins, the chemical weathering of limestone by water (karst), lava caves and erosion by waves (sea caves). Therefore, the distribution of limestone, marble (metamorphosed limestone) and volcanoes defines the location of caves in inland New Zealand.[44] The main regions of karst topography are the Waitomo District[45] and Takaka Hill in the Tasman District. Other notable locations are on the West Coast (Punakaiki), Hawke's Bay and Fiordland.[46]
Lava caves (lava tubes) usually form in pāhoehoe lava flows, which are less viscous and typical formed from basalt. When an eruption occurs the outer layer of the lava flow hardens, while the interior remains liquid. The liquid lava flows out as it is insulated by the hardened crust above. These caves are found where there are relatively recent basaltic volcanoes in New Zealand, such as the Auckland volcanic field particularly on Rangitoto, Mount Eden and Matukutūruru.[47]
The distribution of sea caves is more sporadic, with their location and orientation being controlled by weakness in the underlying rock. As cave systems take many thousands of years to develop they can now be isolated from the water that formed them, whether through change in sea level or groundwater flow.[48] If as a cave grows it breaks through to the surface somewhere else it becomes a natural arch, like the Ōpārara Basin Arches near Karamea.[49]
Rivers and lakes
The proportion of New Zealand's area (excluding estuaries) covered by rivers, lakes and ponds, based on figures from the New Zealand Land Cover Database, is (357526 + 81936) / (26821559 – 92499–26033 – 19216) = 1.6%.[50] If estuarine open water, mangroves, and herbaceous saline vegetation are included, the figure is 2.2%.[50]
The mountainous areas of the North Island are cut by many rivers, many of which are swift and unnavigable. The east of the South Island is marked by wide braided rivers, such as the Wairau, Waimakariri and Rangitata; formed from glaciers, they fan out into many strands on gravel plains. The total length of the country's rivers is over 180,000 kilometres (110,000 mi). The Waikato, flowing through the North Island, is the longest, with a length of 425 km (264 mi).[51] New Zealand's rivers feature hundreds of waterfalls; the most visited set of waterfalls are the Huka Falls that drain Lake Taupō.[52]
Lake Taupō, located near the centre of the North Island, is the largest lake by surface area in the country. It lies in a caldera created by the Oruanui eruption, the largest eruption in the world in the past 70,000 years. There are 3,820 lakes with a surface area larger than one hectare.[53] Many lakes have been used as reservoirs for hydroelectric projects.[30]
Coastal wetlands
Wetlands support the greatest concentration of wildlife out of any other habitat. New Zealand has six sites covering almost 551 square kilometres (213 sq mi) that are included in the List of Wetlands of International Importance (Ramsar sites), including the Whangamarino Wetland.[54]
A recent global remote sensing analysis suggested that there were 1,191 square kilometres (460 sq mi) of tidal flats in New Zealand, making it the 29th ranked country in terms of tidal flat area.[55]
Climate
The main geographic factors that influence New Zealand's climate are the temperate latitude, with prevailing westerly winds; the oceanic environment; and the mountains, especially the Southern Alps. The climate is mostly temperate with mean temperatures ranging from 8 °C (46 °F) in the South Island to 16 °C (61 °F) in the North Island.[56] January and February are the warmest months, July the coldest. New Zealand does not have a large temperature range, apart from central Otago, but the weather can change rapidly and unexpectedly. Near subtropical conditions are experienced in Northland.[57]
Most settled, lowland areas of the country have between 600 and 1,600 mm (24 and 63 in) of rainfall, with the most rain along the west coast of the South Island and the least on the east coast of the South Island and interior basins, predominantly on the Canterbury Plains and the Central Otago Basin (about 350 mm (14 in) PA). Christchurch is the driest city, receiving about 640 mm (25 in) of rain PA, while Hamilton is the wettest, receiving more than twice that amount at 1,325 mm (52.2 in) PA, followed closely by Auckland. The wettest area by far is the rugged Fiordland region, in the south-west of the South Island, which has between 5,000 and 8,000 mm (200 and 310 in) of rain PA, with up to 15,000 mm in isolated valleys, amongst the highest recorded rainfalls in the world.[58]
The UV index can be very high and extreme in the hottest times of the year in the north of the North Island. This is partly due to the country's relatively little air pollution compared to many other countries and the high sunshine hours. New Zealand has very high sunshine hours with most areas receiving over 2000 hours per year. The sunniest areas are Nelson/Marlborough and the Bay of Plenty with 2,400 hours per year.[59]
The table below lists climate normals for the warmest and coldest months in New Zealand's six largest cities. North Island cities are generally warmest in February. South Island cities are warmest in January.
| Location | Jan/Feb (°C) | Jan/Feb (°F) | July (°C) | July (°F) |
|---|---|---|---|---|
| Auckland | 23/16 | 74/60 | 14/7 | 58/45 |
| Wellington | 20/13 | 68/56 | 11/6 | 52/42 |
| Christchurch | 22/12 | 72/53 | 10/0 | 51/33 |
| Hamilton | 24/13 | 75/56 | 14/4 | 57/39 |
| Tauranga | 24/15 | 75/59 | 14/6 | 58/42 |
| Dunedin | 19/11 | 66/53 | 10/3 | 50/37 |
The combined effects of climate change in New Zealand will result in a multitude of irreversible impacts; by the end of this century New Zealand will experience higher rainfalls, more frequent extreme weather events and higher temperatures.[61] In 2021, the Ministry for the Environment estimated that New Zealand's gross emissions were 0.17% of the world's total gross greenhouse gas emissions. However, on a per capita basis, New Zealand is a significant emitter, the sixth highest within the Annex I countries, whereas on absolute gross emissions New Zealand is ranked as the 24th highest emitter.[62][63]
Human geography
Tasman SeaSouth Pacific Ocean
North Island / Te Ika-a-Māui
South Island / Te Waipounamu
Stewart Island / Rakiura
