Puysegur Trench

The 6,300-metre (20,700 ft) deep[1] Puysegur Trench is a deep cleft in the floor of the south Tasman Sea formed by the subduction of the Indo-Australian Plate under the Pacific Plate to the south of New Zealand. Immediately to its east lies a ridge, a northern extension of the Macquarie Ridge, which separates the Puysegur Trench from the Solander Trough. To the west is the expanse of the Tasman Basin, which stretches most of the distance to Australia. To the north of the trench lies the Fiordland Basin, which can be considered an extension of the trench. The Puysegur Trench mirrors the Kermadec Trench and Tonga Trench north of New Zealand.

The Puysegur Trench stretches for over 800 kilometres south from the southwesternmost point of the South Island's coast, its southernmost extent being 400 kilometres due west of the Auckland Islands. It is named after Puysegur Point.

Zealandia-Continent map en
The Puysegur Trench and Macquarie Ridge are marked by the line extending south from the southwestern South Island.

Earthquakes

The area around the Puysegur Trench is highly seismically active, with the Alpine Fault starting at the trench's northern end. In July 2009, New Zealand's third-largest recorded earthquake (magnitude 7.8) struck close to the northern end of the trench off the coast of Fiordland. A magnitude 7.2 quake hit the trench itself in November 2004.

References

  1. ^ Stern, Robert J. (2004). Subduction initiation: spontaneous and induced, Earth and Planetary Science Letters 226, 275–292. doi:10.1016/j.epsl.2004.08.007.

External links

Australian Plate

The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately 100 million years ago when India broke away and began moving north. Australia and Antarctica began rifting 85 million years ago and completely separated roughly 45 million years ago. The Australian plate later fused with the adjacent Indian Plate beneath the Indian Ocean to form a single Indo-Australian Plate. However, recent studies suggest that the two plates have once again split apart and have been separate plates for at least 3 million years and likely longer. The Australian plate includes the continent of Australia, including Tasmania, as well portions of New Guinea, New Zealand, and the Indian Ocean basin.

Banc Capel

Banc Capel is a guyot, or flat-topped underwater volcano, in the Coral Sea.

Bounty Trough

The Bounty Trough is a major submerged feature, a bathymetric depression, of the oceanography of the southwest Pacific Ocean. It is located off the east coast of New Zealand's South Island. It is named after the Bounty Islands near the Eastern end of the trough. The islands in turn, named after HMS Bounty.

Challenger Plateau

The Challenger Plateau is a large submarine plateau west of New Zealand and south of the Lord Howe Rise. It has an approximate diameter of 500 km (310 mi) and an area of about 280,000 km2 (110,000 sq mi). The water depth over the plateau varies between 500 m (1,600 ft) to 1,500 m (4,900 ft) and is covered by up to 3,500 m (11,500 ft) of sedimentary rocks of Upper Cretaceous to recent in age. The plateau originated in the Gondwanan breakup and is one of the five major submerged parts of Zealandia, a largely submerged continent.

Chatham Rise

The Chatham Rise is an area of ocean floor to the east of New Zealand, forming part of the Zealandia continent. It stretches for some 1,000 kilometres (620 mi) from near the South Island in the west, to the Chatham Islands in the east. It is New Zealand's most productive and important fishing ground, as well as important habitat for whales.Relative to the rest of the Pacific Ocean waters around New Zealand, the Chatham Rise is relatively shallow, no more than 1,000 metres (3,300 ft) deep at any point. This shallowness is made more remarkable by the depth of the ocean immediately to the north and south. To the northeast, the Hikurangi Trench, an extension of the much deeper Kermadec Trench, drops to below 3,000 m (9,800 ft) close to the New Zealand coast, and further from the coast the Rise borders on the Hikurangi Plateau. To the south, similar depths are achieved in the Bounty Trough. Past the eastern end of the rise, the sea floor drops away to the abyssal plain.

Graveyard Seamounts

The Graveyard Seamounts is the informal name for the Graveyard Knolls. These are a series of 28 small seamounts (underwater volcanoes) and edifices located on the Chatham Rise, east of New Zealand. They cover about 140 km2 (54 sq mi) and stand out from the surrounding oceanic plateau that measures several hundred kilometers. They are named after various morose figures following the naming of the largest of the knolls as "the Graveyard" as it was a graveyard of fishing gear that became stuck on it. The most prominent among the group of knolls are Ghoul, Diabolical, Voodoo, Scroll, Hartless, Pyre, Gothic, Zombie, Mummy, Headstone, Morgue and Graveyard (ordered roughly by increasing size).

Great South Basin

The Great South Basin is an area of mainly sea to the south of the South Island of New Zealand.

Starting in the 1960s, the area was explored and drilled for oil deposits by various, mostly international minerals companies — including Hunt Oil — but by 1984 all of these companies had left empty-handed.With advances in seismic surveying and drilling technology, hopes have been raised once again for a potential oil strike. Since 2006, new tenders for drilling rights have been issued.In 2010, Exxon Mobil and Todd Energy relinquished their exploration rights, citing technical difficulties and the harshness of the environment. Royal Dutch Shell subsequently purchased a stake in a joint venture headed by OMV New Zealand, with drilling announced at the start of 2014.Anadarko Petroleum Corporation made a test drilling in the area in early 2014, without success. Schlumberger subsequently made a drilling attempt in the same areas later in the year.

Healy (volcano)

Healy is a submarine volcano located among New Zealand's Kermadec Islands. Its last major eruption took place around 1360, creating a large caldera.

The volcano's name originates from the British-Australian explorer and navigator Captain Jake Healy who first wrote about the volcano in his journal after noticing Volcanic glass in the water whilst fishing.

Hikurangi Plateau

The Hikurangi Plateau is an oceanic plateau in the South Pacific Ocean east of the North Island of New Zealand. It is part of a large igneous province (LIP) together with Manihiki and Ontong Java, now located 3,000 km (1,900 mi) and 3,500 km (2,200 mi) north of Hikurangi respectively. Mount Hikurangi, in Māori mythology the first part of North Island to emerge from the ocean, gave its name to the plateau.

Hikurangi Trench

The Hikurangi Trench, also called the Hikurangi Trough, is an oceanic trench in the bed of the Pacific Ocean off the east coast of the North Island of New Zealand, lying between the southern end of the Cook Strait and the Chatham Rise. It is the southward continuation of the much deeper Kermadec Trench. It lies in the Hikurangi Margin subduction zone, which is the southern extension of the Kermadec-Tonga subduction zone. The Hikurangi Margin is the subduction zone where the thick oceanic Hikurangi Plateau is subducting beneath continental crust of the Indo-Australian Plate. By contrast, the Kermadec and Tonga trenches represent the parts of the subduction zone where oceanic crust of the Pacific Plate is subducting beneath oceanic crust of the Indo-Australian Plate.

Although shallower than the trenches north of it, the Hikurangi Trench reaches depths of 3,000 metres as close as 80 kilometres from shore. Its maximum depth is about 3,750 metres (12,300 ft).At the southern end of the trench, off the coast of the Marlborough region, the seabed rises sharply, and because of the prevailing winds and tides in this area, many deep water species are found close to the shore. This food source attracts the whales for which the town of Kaikoura is famous.

The plate boundary continues inland along the Marlborough Fault System, linking through to the Alpine Fault. Here the plates converge much more obliquely, exhibiting transpression instead of subduction.

Kenn Plateau

The Kenn Plateau is a large piece of submerged continental crust off northeastern Australia that rifted from northeastern Australia about 63-52 mya, along with other nearby parts of the Zealandia continent.

List of earthquakes in New Zealand

This is a list of large earthquakes that have occurred in New Zealand. Only earthquakes with a magnitude of 6.0 or greater are listed, except for a few that had a moderate impact. Aftershocks are not included, unless they were of great significance or contributed to a death toll, such as the M 6.3 2011 Christchurch earthquake and the M 7.3 aftershock to the 1931 Hawke's Bay earthquake.

Earthquakes occur frequently in New Zealand as the country is situated in the collision zone between the Indo-Australian and Pacific tectonic plates, part of the Pacific Basin Ring of Fire, where many earthquakes and volcanoes occur. Most events occur along the main ranges running from Fiordland in the southwest to East Cape in the northeast. This axis follows the boundary between the Indo-Australian and Pacific plates. Large earthquakes are less common along the central Alpine Fault, where the plates are not subducting and the forces are accommodated in different ways.

The largest city within the highest-risk zone is the nation's capital, Wellington, followed by Hastings then Napier. All these cities have experienced severe earthquakes since European settlement. About 14,000 earthquakes occur in and around the country each year, of which between 150 and 200 are big enough to be felt. As a result, New Zealand has very stringent building regulations.

Quite early on, European settlers were faced with the reality of earthquakes in their new home. On 26 May 1840, the new settlement at Port Nicholson was struck by the first of a number of earthquakes and tremors. Early settlers learned fairly quickly the importance of using appropriate building methods in an earthquake-prone country. The 1848 earthquake, centred in Marlborough, caused great damage to the brick and masonry buildings in Wellington, and the city was rebuilt mainly in wood; consequently it suffered comparatively little damage in the 8.2 magnitude earthquake of 1855, which lifted the land 2–3m. Many buildings in Hastings and Napier were damaged in the 1931 Hawke's Bay earthquake. New building regulations meant that any new buildings constructed afterwards attempted to take earthquake shaking into account in building design.

Maari oil field

The Maari oilfield is an oil reservoir located 80 kilometres (50 mi) off the coast of South Taranaki, New Zealand. Maari is the second largest crude oil field in New Zealand with total reserves of 49 million barrels (7.8×10^6 m3). Production of oil began in February 2009, and the field is expected to have a productive life of 10 to 15 years. The lead partner for the field is OMV New Zealand (69%), with other parties Horizon Oil (26%) and Cue Taranaki (5%).

Macquarie Fault Zone

The Macquarie Fault Zone is a major right lateral-moving transform fault along the seafloor of the south Pacific Ocean which runs from New Zealand southwestward to the Macquarie Triple Junction. It is also the tectonic plate boundary between the Indo-Australian Plate to the northwest and the Pacific Plate to the southeast.

The Macquarie Fault Zone includes a component of convergence which increases as it approaches the South Island of New Zealand. Many researchers conclude that the fault zone here is an incipient subduction zone, with oblique motion corresponding to the transition from lateral (strike-slip) motion. In the area known as the Puysegur Trench, the Indo-Australian Plate appears to be starting to sink beneath the Pacific Plate, the reverse of what is occurring off of New Zealand's North Island (see Kermadec-Tonga Subduction Zone).

A major geographic feature which runs along the Macquarie Fault Zone is known as the Macquarie Ridge. This ridge represents both the different relative heights of the abutting plates as well as the component of compression between the plates. The namesake Macquarie Island, named after Lachlan Macquarie lies atop a segment of the Macquarie Ridge.

The Macquarie Fault Zone merges into the Alpine Fault which cuts across the continental crust of New Zealand's South Island.

Norfolk Ridge

The Norfolk Ridge is a long submarine ridge running between New Caledonia and New Zealand, about 1300 km off the east-coast of Australia.

It is part of a complex region of ridges between the crust of the Pacific Basin and the continental crust of Australia. Little is known about the Norfolk Ridge; however, it generally lies about 2000 m below sea level and consists of Late Cretaceous continental crust. It is part of Zealandia, a submerged continent that sank 60-85 million years ago.

Pacific Plate

The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At 103 million square kilometres (40,000,000 sq mi), it is the largest tectonic plate.The Pacific Plate contains an interior hot spot forming the Hawaiian Islands.Hillis and Müller are reported to consider the Bird's Head Plate to be moving in unison with the Pacific Plate. Bird considers them to be unconnected.

Pohokura field

The Pohokura field is an oil and gas field located 4 km offshore of north Taranaki in New Zealand, in approximately 30 m of water. The field was discovered in 2000 by Fletcher Challenge and has ultimate recoverable reserves (1P) of 1,227 Bcf (1435 PJ) of gas and 61 mmbbls of oil and condensate.The field has 6 offshore and 3 onshore wells, with the production station located on shore, adjacent to the Motunui methanol plant. The production station is unmanned, and is operated from a control room in New Plymouth. The first commercial production was in September 2006.

In 2009, Pohokura was the largest gas-producing field in New Zealand, producing 42% of total production.Pohokura is owned by OMV (74%) and Todd Energy (26%), and is operated by OMV.

Puységur

Puységur or Puysegur may refer to:

PlacesPuységur, Gers is a French commune in the département of Gers

Puysegur Point, South Island, New Zealand

Puysegur Trench, an ocean trench off the New Zealand coastPeopleLouis Pierre de Chastenet de Puységur (1727-1807), French soldier

Jean Auguste de Chastenet de Puységur (1740-1815), French bishop

Armand Marie Jacques de Chastenet de Puységur (1751-1825), artillery officer, theoretician on animal magnetism

Edmond Puységur, 20th century French writer

Tui oil field

The Tui oil field is an oil reservoir located 50 kilometres (31 mi) off the west coast of Taranaki, New Zealand. Tui is the sixth largest crude oil field in New Zealand with total reserves of 41 million barrels (6.5×10^6 m3). Remaining reserves as at January 2018 was 1 million barrels (160×10^3 m3). Oil is produced from the Tui, Amokura and Pateke wellheads on the seabed in approximately 120m of water. These wells are connected to the Umuroa, a floating production storage and offloading vessel.The reservoir was discovered in 2003 by a joint venture between Australian Worldwide Exploration and New Zealand Overseas Petroleum. The nearby Amokura and Pateke oil reserves were discovered in 2004. In 2016, Tamarind purchased AWE's 57.5% interests in the field.

In 2019, permits were granted for drilling of side track wells to extend the production life of the field.

Major divisions
Plateaux, ridges, and rises
Troughs and trenches
Oceanic basins
Seamounts
Other

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