The Pacific Ocean evolved in the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

from the Panthalassic Ocean, which had formed when

Rodinia Rodinia (from the Russian родина, ''rodina'', meaning "motherland, birthplace") was a Mesoproterozoic and Neoproterozoic supercontinent that assembled 1.26–0.90 billion years ago and broke up 750–633 million years ago. were probably ...

rifted apart around 750 Ma. The first ocean floor which is part of the current Pacific Plate began 160 Ma to the west of the central Pacific and subsequently developed into the largest oceanic plate on Earth. The

East Pacific Rise The East Pacific Rise is a mid-ocean rise (termed an oceanic rise and not a mid-ocean ridge due to its higher rate of spreading that results in less elevation increase and more regular terrain), a divergent tectonic plate boundary located along ...

near

Easter Island Easter Island ( rap, Rapa Nui; es, Isla de Pascua) is an island and special territory of Chile in the southeastern Pacific Ocean, at the southeasternmost point of the Polynesian Triangle in Oceania. The island is most famous for its nearl ...

is the fastest spreading

mid-ocean ridge A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a diverge ...

, with a spreading rate of over 15 cm/yr. The Pacific Plate moves generally towards the northwest at between 7 and 11 cm/yr while the Juan De Fuca Plate has an east-northeasterly movement of some 4 cm/yr. Most subduction zones around the rim of the Pacific are directed away from a large area in the southern Pacific. At the

core–mantle boundary The core–mantle boundary (CMB) of Earth lies between the planet's silicate mantle and its liquid iron-nickel outer core. This boundary is located at approximately 2,891 km (1,796 miles) depth beneath Earth's surface. The boundary is observed ...

below this area there is a large low-shear velocity province (LLSVP). Most of Pacific

hotspots Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tra ...

are located above the LLSVP while the longest Pacific hotspot tracks are located at or near its boundaries pointing at the positions of

large igneous province A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive (sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The formation ...

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

proposed a theory that explained the existence of reefs by means of slow subsidence of the ocean floor. His theories have been verified and expanded in the development of plate tectonics.

History

In the Early Jurassic, the supercontinent Pangaea was surrounded by the superocean Panthalassa, the ocean floor of which was composed of the

Izanagi Izanagi (イザナギ/伊邪那岐/伊弉諾) or Izanaki (イザナキ), formally known as , is the creator deity (''kami are the deities, divinities, spirits, phenomena or "holy powers", that are venerated in the Shinto religion. They can b ...

, Farallon and,

Phoenix Phoenix most often refers to: * Phoenix (mythology), a legendary bird from ancient Greek folklore * Phoenix, Arizona, a city in the United States Phoenix may also refer to: Mythology Greek mythological figures * Phoenix (son of Amyntor), a ...

plates. These three plates were joined at a migrating, or unstable, ridge-ridge-ridge (RRR)

triple junction A triple junction is the point where the boundaries of three tectonic plates meet. At the triple junction each of the three boundaries will be one of three types – a ridge (R), trench (T) or transform fault (F) – and triple junctions can ...

from which the

Pacific Plate The Pacific Plate is an oceanic tectonic plate that lies beneath the Pacific Ocean. At , it is the largest tectonic plate. The plate first came into existence 190 million years ago, at the triple junction between the Farallon, Phoenix, and Iza ...

began to grow 190 million years ago in an area east of the Mariana Trench; this area, known as the Pacific Triangle, is the oldest part of the Pacific Plate and therefore the oldest ocean floor of the Pacific. Spreading laterally from this triangle are the Hawaiian, Japanese, and Phoenix magnetic lineations, the earliest traces of how the Pacific Plate began to grow as a RRR triple junction fell apart into three triple junctions. Virtually all of the three Panthalassic plates have now been subducted beneath surrounding continents but their spreading rates have been preserved in the magnetic lineations around the Pacific Triangle. In the North Pacific,

magnetic anomalies In geophysics, a magnetic anomaly is a local variation in the Earth's magnetic field resulting from variations in the chemistry or magnetism of the rocks. Mapping of variation over an area is valuable in detecting structures obscured by overlying ...

south of the

Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...

, indicate the presence of a now almost completely subducted tectonic plate, known as the

Kula Plate The Kula Plate was an oceanic tectonic plate under the northern Pacific Ocean south of the Near Islands segment of the Aleutian Islands. It has been subducted under the North American Plate at the Aleutian Trench, being replaced by the Pacific P ...

, which probably existed from the Late Cretaceous to the Eocene ( 83–40 Ma). This plate probably broke off the Farallon Plate, and when subduction in the North Pacific shifted from Siberia to the Aleutian Trench c. 50 Ma, spreading ceased between the Kula plate and the Pacific Plate. The Pacific Plate kept growing and lineations south of the Pacific Triangle indicate the Pacific-Phoenix ridge remained a simple N–S trending spreading system 156–120 Ma. Following the formation and break-up of the

Ontong Java Ontong Java Atoll or Luangiua, (formerly ''Lord Howe Atoll'', not to be confused with Lord Howe Island) is one of the largest atolls on earth. Geographically it belongs to a scattered group of three atolls which includes nearby Nukumanu Atol ...

Hikurangi Hikurangi is a settlement in Northland, New Zealand. The city of Whangārei is 17 km (11 miles) to the south, and Kawakawa is 39 km (24 miles) northwest. The Glenbervie Forest is southeast of the settlement. State Highway ...

Manihiki 250px, Map of Manihiki Atoll Manihiki is an atoll in the northern group of the Cook Islands known informally as the "Island of Pearls". It is located in the Northern Cook Island chain, approximately north of the capital island of Rarotonga, ma ...

120 Ma, however, the Phoenix Plate broke into several smaller tectonic plates. The complexity of the Mid-Pacific and

Magellan Ferdinand Magellan ( or ; pt, Fernão de Magalhães, ; es, link=no, Fernando de Magallanes, ; 4 February 1480 – 27 April 1521) was a Portuguese explorer. He is best known for having planned and led the 1519 Spanish expedition to the East ...

lineations indicate the presence of a series of microplates around the Pacific-Phoenix-Farallon triple junction. The Farallon Plate subducted under North America from the late Mesozoic, while spreading between the Pacific and Farallon plates was initiated 190 Ma and lasted until the break-up of the Farallon Plate 23 Ma. During the Cenozoic the Farallon Plate broke-up along the eastern Pacific margin into the Kula, Vancouver/Juan de Fuca, and Cocos plates.

Geological origins of the Pacific islands

The islands of the Pacific have developed in a number of ways. Some have originated as chains of volcanic islands on the tectonic plates either as a result of

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic hot ...

s or by fracture propagation.

Atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can gr ...

s have developed in tropical waters when, after volcanoes sink, coral growth results in reefs as evidenced by the

Cook Islands ) , image_map = Cook Islands on the globe (small islands magnified) (Polynesia centered).svg , capital = Avarua , coordinates = , largest_city = Avarua , official_languages = , lan ...

Coral reef A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Co ...

s can develop into islands over a submerged extinct volcano following

uplift Uplift may refer to: Science * Geologic uplift, a geological process ** Tectonic uplift, a geological process * Stellar uplift, the theoretical prospect of moving a stellar mass * Uplift mountains * Llano Uplift * Nemaha Uplift Business * Uplif ...

as in

Makatea Makatea, or Mangaia-te-vai-tamae, is a raised coral atoll in the northwestern part of the Tuamotus, which is a part of the French overseas collectivity of French Polynesia. It is located southwest from Rangiroa to the west of the Palliser gro ...

and

Rennell Island Rennell Island, locally known as Mugaba, is the main island of two inhabited islands that make up the Rennell and Bellona Province in the nation state of Solomon Islands. Rennell Island has a land area of that is about long and wide. It is th ...

in the

Solomon Archipelago The Solomon Archipelago is a terrestrial ecoregion and marine ecoregion in the Pacific Ocean. It includes the tropical ocean waters surrounding most of Solomon Islands (excluding the Santa Cruz Islands, which is a part of the Vanuatu marine ecore ...

which have steep coral cliffs over 100 metres high. The Pacific Plate emigrates northeast towards extensive subduction trenches. South of Japan, the Izu-Bonin and Mariana island arcs (IBM) formed in front of a clockwise rotating

Philippine Sea Plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part of ...

. The IBM trenches began to grow in length , opening back-arc basins in the Philippine Sea. Between 30 and 17 Mya, the old age of the subducting Pacific Ocean floor (110-130 Ma) resulted in a very fast trench migration and new back-arc basins opening behind the trenches. The ocean floor of the Pacific Ocean is composed of nine oceanic tectonic plates, all located in the southeast where the

separates the

from the

Antarctic The Antarctic ( or , American English also or ; commonly ) is a polar region around Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica, the Kerguelen Plateau and other ...

, Juan Fernández, Nasca,

Easter Easter,Traditional names for the feast in English are "Easter Day", as in the '' Book of Common Prayer''; "Easter Sunday", used by James Ussher''The Whole Works of the Most Rev. James Ussher, Volume 4'') and Samuel Pepys''The Diary of Samuel ...

, Galápagos, Cocos,

Rivera Rivera () is the capital of Rivera Department of Uruguay. The border with Brazil joins it with the Brazilian city of Santana do Livramento, which is only a street away from it, at the north end of Route 5. Together, they form an urban area of aro ...

Juan de Fuca Juan de Fuca (10 June 1536, Cefalonia 23 July 1602, Cefalonia)Greek Consulate of Vancouver,Greek Pioneers: Juan de Fuca. was a Greeks, Greek maritime pilot, pilot who served Philip II of Spain, PhilipII of Spanish Empire, Spain. He is best know ...

plates. In the western and southwestern Pacific continental blocks and back-arc basins form one of the most complex regions on earth stretching from Japan to New Zealand. Plate movements have also caused fragments of

continental crust Continental crust is the layer of igneous, sedimentary, and metamorphic rocks that forms the geological continents and the areas of shallow seabed close to their shores, known as continental shelves. This layer is sometimes called ''sial'' be ...

to be rotated away from landmasses so as to form islands.

Zealandia Zealandia (pronounced ), also known as (Māori) or Tasmantis, is an almost entirely submerged mass of continental crust that subsided after breaking away from Gondwanaland 83–79 million years ago.Gurnis, M., Hall, C.E., and Lavier, L.L., ...

which broke off from

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

70 million years ago with the spreading of the

Tasman Sea The Tasman Sea (Māori: ''Te Tai-o-Rēhua'', ) is a marginal sea of the South Pacific Ocean, situated between Australia and New Zealand. It measures about across and about from north to south. The sea was named after the Dutch explorer Abe ...

, has since resulted in island protrusions such as

New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and over 700 smaller islands. It is the sixth-largest island count ...

and

New Caledonia ) , anthem = "" , image_map = New Caledonia on the globe (small islands magnified) (Polynesia centered).svg , map_alt = Location of New Caledonia , map_caption = Location of New Caledonia , mapsize = 290px , subdivision_type = Sovereign st ...

. Related causes of island formation include

obduction Obduction is a geological process whereby denser oceanic crust (and even upper mantle) is scraped off a descending ocean plate at a convergent plate boundary and thrust on top of an adjacent plate. When oceanic and continental plates converge, ...

and

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, the ...

at convergent plate boundaries. Malaita and Ulawa in the

Solomon Islands Solomon Islands is an island country consisting of six major islands and over 900 smaller islands in Oceania, to the east of Papua New Guinea and north-west of Vanuatu. It has a land area of , and a population of approx. 700,000. Its capita ...

are the result of obduction while the effects of subduction can be seen in the formation of volcanic

island arc Island arcs are long chains of active volcanoes with intense seismic activity found along convergent tectonic plate boundaries. Most island arcs originate on oceanic crust and have resulted from the descent of the lithosphere into the mantle alon ...

s such as the

Aleutian Arc The Aleutian Arc is a large volcanic arc in the U.S. state of Alaska. It consists of a number of active and dormant volcanoes that have formed as a result of subduction along the Aleutian Trench. Although taking its name from the Aleutian Islan ...

off

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

and the

Kermadec-Tonga Subduction Zone The Kermadec-Tonga subduction zone is a convergent plate boundary that stretches from the North Island of New Zealand northward. The formation of the Kermadec and Tonga Plates started about 4–5 million years ago. Today, the eastern boundary ...

north of New Zealand.

Andesite line

Along the rim of the Pacific Basin are convergent plate boundaries often referred to as the andesite line since

orogenic Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumpl ...

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...

is associated with this boundary. This line is often, but erroneously, confused with the boundaries of either the Pacific Plate or the Pacific basin; the andesite line, however, also includes the Juan de Fuca, Cocos, and Nazca plates on its eastern boundary. This

petrologic Petrology () is the branch of geology that studies rocks and the conditions under which they form. Petrology has three subdivisions: igneous, metamorphic, and sedimentary petrology. Igneous and metamorphic petrology are commonly taught together ...

boundary separates the deeper

mafic A mafic mineral or rock is a silicate mineral or igneous rock rich in magnesium and iron. Most mafic minerals are dark in color, and common rock-forming mafic minerals include olivine, pyroxene, amphibole, and biotite. Common mafic rocks include ...

igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock ...

of the Central Pacific Basin from the partially submerged continental areas of

felsic In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, whi ...

igneous rock on its margins. Outside of the andesite line,

volcanism Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called ...

is explosive; the Pacific

Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring o ...

is the world's foremost belt of explosive

. The Ring of Fire is named after the several hundred active volcanoes that sit above the various subduction zones. In 2009, the deepest undersea eruption ever recorded occurred at the

West Mata West Mata, located in the far northern portion of Tonga, is an active submarine volcano. Known for the deepest recorded volcanic eruption to date, West Mata does not have a very long recorded history since it was recently discovered in 2008 along ...

submarine volcano Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges ...

, a mile beneath the ocean, close to the

Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...

Kermadec Trench The Kermadec Trench is a linear ocean trench in the south Pacific Ocean. It stretches about from the Louisville Seamount Chain in the north (26°S) to the Hikurangi Plateau in the south (37°S), north-east of New Zealand's North Island. Toget ...

, within the Ring of Fire; it was filmed by the US Jason robotic submersible which descended over .

Earthquakes

In March and April 2008, a series or

swarm Swarm behaviour, or swarming, is a collective behaviour exhibited by entities, particularly animals, of similar size which aggregate together, perhaps milling about the same spot or perhaps moving ''en masse'' or migrating in some direction. ...

of moderate earthquakes occurred both near and within the

Blanco Fracture Zone The Blanco Fracture Zone or Blanco Transform Fault Zone (BTFZ) is a right lateral transform fault zone, which runs northwest off the coast of Oregon in the Pacific Northwest of the United States, extending from the Gorda Ridge in the south to the ...

. The swarm began on 30 March when over 600 measurable tremors began occurring north of the zone within the Juan de Fuca Plate. A decade earlier, in January 1998, another swarm was detected at

Axial Seamount Axial Seamount (also Coaxial Seamount or Axial Volcano) is a seamount and submarine volcano in the Pacific Ocean, located on the Juan de Fuca Ridge, approximately west of Cannon Beach, Oregon. Standing high, Axial Seamount is the youngest volc ...

in the

Juan de Fuca Ridge The Juan de Fuca Ridge is a mid-ocean spreading center and divergent plate boundary located off the coast of the Pacific Northwest region of North America. The ridge separates the Pacific Plate to the west and the Juan de Fuca Plate to the east ...

. At the time of its occurrence, scientists were not aware that the series of faults in this plate even existed. In a remote region of the central Pacific Ocean, at the southeastern section of the

Gilbert Islands The Gilbert Islands ( gil, Tungaru;Reilly Ridgell. ''Pacific Nations and Territories: The Islands of Micronesia, Melanesia, and Polynesia.'' 3rd. Ed. Honolulu: Bess Press, 1995. p. 95. formerly Kingsmill or King's-Mill IslandsVery often, this n ...

, a major swarm of intraplate earthquakes occurred between December 1981 and March 1983, with no prior seismicity having been reported in this region previously. Another swarm was detected on the Queen Charlotte Islands fracture zone in August–September 1967.

Features

Guyots and seamounts

* Alexa Bank *

Allison Guyot Allison Guyot (formerly known as Navoceano Guyot) is a tablemount (guyot) in the underwater Mid-Pacific Mountains of the Pacific Ocean. It is a trapezoidal flat mountain rising 1,500 metres above the seafloor to a depth of less than 1,500 m, wi ...

* Cape Johnson Guyot * Capricorn Seamount * Crough Seamount * Daiichi-Kashima Seamount * Darwin Guyot * Erimo Seamount *

Geologists Seamounts Geologists Seamounts (alternatively named South West Hawaii Group) are seamounts in the Pacific Ocean, south of Honolulu, Hawaii and southwest from Big Island. Clockwise from north they are named Perret, Jaggar, McCall, Pensacola, Daly, Sword ...

* Horizon Guyot *

Marshall Islands The Marshall Islands ( mh, Ṃajeḷ), officially the Republic of the Marshall Islands ( mh, Aolepān Aorōkin Ṃajeḷ),'' () is an independent island country and microstate near the Equator in the Pacific Ocean, slightly west of the Internati ...

* MIT Guyot * Rano Rahi seamounts * Resolution Guyot * Takuyo-Daini * Takuyo-Daisan

Seamount chains and hotspots

The Pacific Ocean contains several long

seamount A seamount is a large geologic landform that rises from the ocean floor that does not reach to the water's surface (sea level), and thus is not an island, islet or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abru ...

chains, formed by

hotspot volcanism Hotspot, Hot Spot or Hot spot may refer to: Places * Hot Spot, Kentucky, a community in the United States Arts, entertainment, and media Fictional entities * Hot Spot (comics), a name for the DC Comics character Isaiah Crockett * Hot Spot (Tr ...

. These include the

Hawaiian–Emperor seamount chain The Hawaiian–Emperor seamount chain is a mostly undersea mountain range in the Pacific Ocean that reaches above sea level in Hawaii. It is composed of the Hawaiian ridge, consisting of the islands of the Hawaiian chain northwest to Kure Atoll, ...

, the Tasmantid Seamount Chain, the

Lord Howe Seamount Chain The Lord Howe Seamount Chain formed during the Miocene. It features many coral-capped guyots and is one of the two parallel seamount chains alongside the east coast of Australia; the Lord Howe and Tasmantid seamount chains both run north-south ...

and the

Louisville Ridge The Louisville Ridge, also known as the Louisville Seamount Chain, is an underwater chain of over 70 seamounts located in the Southwest portion of the Pacific Ocean. As one of the longest seamount chains on Earth it stretches some Vanderkluysen, ...

. *

Arago hotspot Arago hotspot is a hotspot in the Pacific Ocean, presently located below the Arago seamount close to the island of Rurutu, French Polynesia. Arago is part of a family of hotspots in the southern Pacific, which include the Society hotspot and ...

Bowie hotspot The Bowie hotspot is a volcanic hotspot, located west of Haida Gwaii in the Pacific Ocean. Almost all magma created by the hotspot has the composition of basalt, and so the volcanoes are constructed almost entirely of this igneous rock. The eru ...

* Cobb hotspot *

Easter hotspot The Easter hotspot is a volcanic hotspot located in the southeastern Pacific Ocean. The hotspot created the Sala y Gómez Ridge which includes Easter Island, Salas y Gómez Island and the Pukao Seamount which is at the ridge's young western ed ...

Galápagos hotspot The Galápagos hotspot is a volcanic hotspot in the East Pacific Ocean responsible for the creation of the Galápagos Islands as well as three major aseismic ridge systems, Carnegie, Cocos and Malpelo which are on two tectonic plates. The hots ...

Hawaii hotspot The Hawaii hotspot is a volcanic hotspot located near the namesake Hawaiian Islands, in the northern Pacific Ocean. One of the best known and intensively studied hotspots in the world, the Hawaii plume is responsible for the creation of the ...

Juan Fernández hotspot The Juan Fernández hotspot is a volcanic hotspot located in the southeastern Pacific Ocean. The hotspot created the Juan Fernández Ridge which includes the Juan Fernández Archipelago and a long seamount chain that is being subducted in the ...

Lamont seamount chain Lamont seamount chain is a chain of submarine mountains in the eastern Pacific Ocean which are named "Sasha", "MIB", "MOK", "DTD" and "NEW". They are located close to the East Pacific Rise and reach a minimum depth of . These seamounts are sub ...

Louisville hotspot The Louisville hotspot is a volcanic hotspot responsible for the volcanic activity that has formed the Louisville Ridge in the southern Pacific Ocean. Location The Louisville hotspot is believed to lie close to the Pacific-Antarctic Ridge, alt ...

Macdonald hotspot The Macdonald hotspot (also known as "Tubuai" or "Old Rurutu") is a volcanic hotspot in the southern Pacific Ocean. The hotspot was responsible for the formation of the Macdonald Seamount, and possibly the Austral-Cook Islands chain. It probably ...

Marquesas hotspot The Marquesas hotspot is a volcanic hotspot in the southern Pacific Ocean. It is responsible for the creation of the Marquesas Islands – a group of eight main islands and several smaller ones – and a few seamounts. The islands and seamounts ...

* Ngatemato seamounts *

Pitcairn hotspot The Pitcairn hotspot is a volcanic hotspot located in the south-central Pacific Ocean. Over the past 11 million years, it has formed the Pitcairn-Gambier hotspot chain. It is responsible for creating the Pitcairn Islands and two large seamounts ...

Rarotonga hotspot The Rarotonga hotspot is a volcanic hotspot in the southern Pacific Ocean. The hotspot was responsible for the formation of Rarotonga and some volcanics of Aitutaki. In addition to these volcanoes in the Cook Islands, the composition of volcan ...

Samoa hotspot The Samoa hotspot is a volcanic hotspot located in the south Pacific Ocean. The hotspot model describes a hot upwelling plume of magma through the Earth's crust as an explanation of how volcanic islands are formed. The hotspot idea came from ...

* Tarava Seamounts * Tasmantid hotspot * Taukina seamounts * Ujlān volcanic complex

Arcs and belts

* Andesite line *

Halmahera Arc Halmahera Arc is the volcanic arc of the Halmahera region of eastern Indonesia. It is considered to belong to the Halmahera Plate within the Molucca Sea Collision Zone. Origin Potassium-argon ages of Neogene to Recent igneous rocks from the Halmah ...

Philippine Mobile Belt In the geology of the Philippines, the Philippine Mobile Belt is a complex portion of the tectonic boundary between the Eurasian Plate and the Philippine Sea Plate, comprising most of the country of the Philippines. It includes two subduction z ...

* Philippine-Halmahera Arc

Faults and fracture zones

* Eltanin Fault System *

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 ...

Molucca Sea Collision Zone The Molucca Sea Collision Zone is postulated by paleogeologists to explain the tectonics of the area based on the Molucca Sea in Indonesia, and adjacent involved areas. Tectonics The tectonic relationship of the Sangihe Plate, Halmahera Plate, ...

Queen Charlotte Fault The Queen Charlotte Fault is an active transform fault that marks the boundary of the North American plate and the Pacific plate. It is Canada's right-lateral strike-slip equivalent to the San Andreas Fault to the south in California. The Queen Ch ...

Sorong Fault Sorong fault also (Sorong Fault Zone, SFZ) is an active, broad zone of inferred left lateral shear at the triple junction of the Australian plate, Eurasian plate, and Pacific plates, where many plate fragments exist, such as the Philippine Sea Pl ...

Underwater ridges and plateaus

Carnegie Ridge The Carnegie Ridge is an aseismic ridge on the Nazca Plate that is being subducted beneath the South American Plate. The ridge is thought to be a result of the passage of the Nazca Plate over the Galapagos hotspot. It is named for the research ...

Chile Rise The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca Plate and the Antarctic Plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates t ...

Darwin Rise The Darwin Rise is broad triangular region in the north central Pacific Ocean where there is a concentration of atolls. During his voyage across the globe Charles Darwin realised that vertical crustal motion must be responsible for the formation ...

* East Tasman Plateau *

Explorer Ridge The Explorer Ridge is a mid-ocean ridge, a divergent tectonic plate boundary located about west of Vancouver Island, British Columbia, Canada. It lies at the northern extremity of the Pacific spreading axis. To its east is the Explorer Plate, ...

Galapagos Rise The Galapagos Rise is a divergent boundary located between the South American coast and the triple junction of the Nazca Plate, the Cocos Plate, and the Pacific Plate. The volcanically active Galapagos Islands exist on the Galápagos hotspot ...

Gorda Ridge The Gorda Ridge (41°36'19.6"N 127°22'03.1"W), aka ''Gorda Ridges'' tectonic spreading center, is located roughly off the northern coast of California and southern Oregon. Running NE – SW it is roughly in length.Carey, Stein, & Rona. (1990). ...

Hollister Ridge Hollister Ridge is a group of seamounts in the Pacific Ocean. They lie west from the Pacific-Antarctic Ridge and form three ridges that form a line; one of the ridges rises to a depth of and in the past formed an island. The seamounts are compo ...

Juan Fernández Ridge The Juan Fernández Ridge is a volcanic island and seamount chain on the Nazca Plate. It runs in a west–east direction from the Juan Fernández hotspot to the Peru–Chile Trench at a latitude of 33° S near Valparaíso. The Juan Fernánde ...

Kula-Farallon Ridge The Kula-Farallon Ridge was an ancient mid-ocean ridge that existed between the Kula and Farallon plates in the Pacific Ocean during the Jurassic period. There was a small piece of this ridge off the Pacific Northwest 43 million years ago. The r ...

Lord Howe Rise The Lord Howe Rise is a deep sea plateau which extends from south west of New Caledonia to the Challenger Plateau, west of New Zealand in the south west of the Pacific Ocean. To its west is the Tasman Basin and to the east is the New Caledonia ...

* Magellan Rise *

Mid-Pacific Mountains The Mid-Pacific Mountains (MPM) is a large oceanic plateau located in the central North Pacific Ocean or south of the Hawaiian–Emperor seamount chain. Of volcanic origin and Mesozoic in age, it is located on the oldest part of the Pacific Pla ...

Nazca Ridge The Nazca Ridge is a submarine ridge, located on the Nazca Plate off the west coast of South America. This plate and ridge are currently subducting under the South American Plate at a convergent boundary known as the Peru-Chile Trench at approx ...

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 c ...

Pacific-Antarctic Ridge The Pacific-Antarctic Ridge (PAR) is a divergent tectonic plate boundary located on the seafloor of the South Pacific Ocean, separating the Pacific Plate from the Antarctic Plate. It is regarded as the southern section of the East Pacific Rise ...

Pacific-Farallon Ridge The Pacific-Farallon Ridge was a spreading ridge during the Late Cretaceous that extended 10,000 km in length and separated the Pacific Plate to the west and the Farallon Plate to the east. It ran south from the Pacific-Farallon-Kula triple ...

Pacific-Kula Ridge The Pacific-Kula Ridge is a former mid-ocean ridge that existed between the Pacific and Kula plates in the Pacific Ocean during the Paleogene period. Its appearance was in an east-west direction and the Hawaiian-Emperor seamount chain had its att ...

Phoenix Ridge The Antarctic-Phoenix Ridge, also called the Phoenix Ridge, is an extinct mid-ocean ridge that consisted of three spreading ridge segments between the Antarctic Peninsula and the Scotia Sea. It initiated during the Late Cretaceous-Early Tertiary ...

Shatsky Rise The Shatsky Rise is Earth's third largest oceanic plateau, (after Ontong Java and Kerguelen) located in the north-west Pacific Ocean east of Japan. It is one of a series of Pacific Cretaceous large igneous provinces (LIPs) together with Hess R ...

Tehuantepec Ridge The Tehuantepec Ridge is a linear undersea ridge located off the west coast of Mexico in the Pacific Ocean. It is the remnant of an old fracture zone, and not a tectonic spreading center ridge (''see'' mid-ocean ridge). It extends from the easte ...

Trenches and troughs

Challenger Deep The Challenger Deep is the deepest-known point of the seabed of Earth, with a depth of by direct measurement from deep-diving submersibles, remotely operated underwater vehicles and benthic landers, and (sometimes) slightly more by sonar bathym ...

* HMRG Deep * Kilinailai Trench *

Manus Trench Manus Trench is an oceanic trench in the Bismarck Sea north of Papua New Guinea delineating the plate tectonic boundary between the Caroline Caroline may refer to: People *Caroline (given name), a feminine given name * J. C. Caroline (born 1933), ...

Mariana Trough The Mariana Trough is an active back-arc basin in the western Pacific Ocean . It is an integral part of the Izu–Bonin–Mariana Arc system. Location and Bathymetry The Mariana Trough stretches 1300 km from north to south, about the dista ...

Nankai Trough The is a submarine trough located south of the Nankaidō region of Japan's island of Honshu, extending approximately offshore. The underlying fault, the ''Nankai megathrust,'' is the source of the devastating Nankai megathrust earthquakes, w ...

Plates

Amurian Plate The Amurian Plate (or Amur Plate; also occasionally referred to as the China Plate, not to be confused with the South China Subplate) is a minor tectonic plate in the northern and eastern hemispheres. It covers Manchuria, the Korean Peninsula ...

Antarctic Plate The Antarctic Plate is a tectonic plate containing the continent of Antarctica, the Kerguelen Plateau, and some remote islands in the Southern Ocean and other surrounding oceans. After breakup from Gondwana (the southern part of the superconti ...

* Balmoral Reef Plate *

Banda Sea Plate The Banda Sea Plate is a minor tectonic plate underlying the Banda Sea in southeast Asia. This plate also carries a portion of Sulawesi Island, the entire Seram Island, and the Banda Islands. Clockwise from the east it is bounded by the Bird's Hea ...

Bird's Head Plate The Bird's Head Plate is a minor tectonic plate incorporating the Bird's Head Peninsula, at the western end of the island of New Guinea. Hillis and Müller consider it to be moving in unison with the Pacific Plate. Bird considers it to be unconne ...

Caroline Plate The Caroline Plate is a minor tectonic plate that straddles the Equator in the eastern hemisphere located north of New Guinea. It forms a subduction zone along the border with the Bird's Head Plate and the Woodlark Plate to the south. A transfo ...

Cocos Plate The Cocos Plate is a young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it. The Cocos Plate was created approximately 23 million years ago when the Farallon Plate ...

* Conway Reef Plate *

Easter Plate Easter Plate is a tectonic microplate located to the west of Easter Island off the west coast of South America in the middle of the Pacific Ocean, bordering the Nazca Plate to the east and the Pacific Plate to the west. It was discovered from lo ...

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

* Futuna Plate * Galapagos Microplate *

Gorda Plate The Gorda Plate, located beneath the Pacific Ocean off the coast of northern California, is one of the northern remnants of the Farallon Plate. It is sometimes referred to (by, for example, publications from the USGS Earthquake Hazards Program) a ...

Halmahera Plate Halmahera Plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia. Regional tectonics The tectonic setting of the Molucca Sea region is unique. It is the only global example of an ac ...

Indo-Australian Plate The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and the surrounding ocean and extends northwest to include the Indian subcontinent and the adjacent waters. It was formed by the fusion of the Indian an ...

* Juan de Fuca Plate * Juan Fernández Plate * Kermadec Plate *

Manus Plate The Manus Plate is a 100-km microplate located northeast of New Guinea. The Manus Plate was formed in between the North Bismark Plate and the South Bismark Plate. The Manus Plate currently rotates counter-clockwise in the Melanesia area. Forma ...

Maoke Plate The Maoke Plate is a small tectonic plate located in western New Guinea underlying the Sudirman Range from which the highest mountain on the island- Puncak Jaya rises. To its east is a convergent boundary with the Woodlark Plate. To the south lies ...

* Mariana Plate *

Molucca Sea Plate Located in the western Pacific Ocean near Indonesia, the Molucca Sea Plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex. The Molucca Sea Plate represents the only known example ...

* Nazca Plate * New Hebrides Plate *

Niuafo'ou Plate The Niuafo'ou Plate is a small tectonic plate located west of the islands of Tonga. This plate is sandwiched between the Pacific Plate to the north, the very unstable Tonga Plate to the east and the Australian Plate The Australian Plate is a ...

North American Plate The North American Plate is a tectonic plate covering most of North America, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. With an area of , it is the Earth's second largest tectonic plate, behind the Pacific ...

North Bismarck Plate The North Bismarck Plate is a small tectonic plate located in the Bismarck Sea off the northeast coast of New Guinea. Tectonics To the north it collides with the Pacific Plate and the Caroline Plate, part of the western part subducts under the W ...

* North Galapagos Microplate *

Okhotsk Plate The Okhotsk Plate is a minor tectonic plate covering the Kamchatka Peninsula, Magadan Oblast, and Sakhalin Island of Russia; Hokkaido, Kantō and Tōhoku regions of Japan; the Sea of Okhotsk, as well as the disputed Kuril Islands. It was ...

Okinawa Plate The Okinawa Plate, or Okinawa Platelet, is a minor continental tectonic plate in the northern and eastern hemispheres stretching from the northern end of Taiwan to the southern tip of the island of Kyūshū. The Okinawa Plate hosts typical eart ...

Rivera Plate The Rivera Plate is a small tectonic plate (a microplate) located off the west coast of Mexico, just south of the Baja California Peninsula. It is bounded on the northwest by the East Pacific Rise, on the southwest by the Rivera Transform Faul ...

Sangihe Plate Sangihe Plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia. Regional tectonics The tectonic setting of the Molucca Sea region is unique. It is the only global example of an acti ...

Solomon Sea Plate The Solomon Sea Plate is a minor tectonic plate to the northwest of the Solomon Islands archipelago in the south Pacific Ocean. Itt roughly corresponds with the Solomon Sea east of Papua New Guinea. Tectonics The tectonic regime in this part of t ...

South Bismarck Plate The South Bismarck Plate is a small tectonic plate located in the southern Bismarck Sea. The eastern part of New Guinea and the island of New Britain are on this plate. Tectonics Convergent boundaries line the southern border including the subdu ...

* Sunda Plate *

Timor Plate The Timor Plate is a microplate in southeast Asia carrying the island of Timor and surrounding islands. The Australian Plate is subducting under the southern edge of the plate, while a small divergent boundary is located on the eastern edge. Anot ...

Tonga Plate The Tonga Plate is a small southwest Pacific tectonic plate or microplate. It is centered at approximately 19° S. latitude and 173° E. longitude. The plate is an elongated plate oriented NNE - SSW and is a northward continuation of the Kermadec ...

Woodlark Plate The Woodlark Plate is a small tectonic plate located in the eastern half of the island of New Guinea. It subducts beneath the Caroline plate along its northern border while the Maoke Plate converges on the west, the Australian plate converges on ...

Yangtze Plate The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the s ...

Volcanoes

Alcedo Volcano Alcedo Volcano is one of the six coalescing shield volcanoes that make up Isabela Island in the Galapagos. The remote location of the volcano has meant that even the most recent eruption in 1993 was not recorded until two years later. It is als ...

* Alofi Island *

Ball's Pyramid Ball's Pyramid is an erosional remnant of a shield volcano and caldera lying southeast of Lord Howe Island in the Pacific Ocean. It is high, while measuring in length and only across, making it the tallest volcanic stack in the world. Bal ...

Bartolomé Island Bartolomé Island ( es, Isla Bartolomé) is a volcanic islet in the Galápagos Islands group, just off the east coast of Santiago Island. It is one of the "younger" islands in the Galápagos archipelago. This island, and Sulivan Bay on Santiago ...

Clarion Island Isla Clarión, formerly called Santa Rosa, is the second largest, westernmost and most remote of Mexico's Revillagigedo Islands. The island is located west of Socorro Island and over from the Mexican mainland. It has an area of and three pr ...

Daphne Major Daphne Major is a volcanic island just north of Santa Cruz Island and just west of the Baltra Airport in the Archipelago of Colón, commonly known as the Galápagos Islands. It consists of a tuff crater, devoid of trees, whose rim rises above the ...

* Eastern Gemini Seamount *

Futuna (Wallis and Futuna) Futuna (; ) is an island in the Pacific Ocean occupying area of with a population of 10,912. It belongs to the French overseas collectivity (''collectivité d'outre-mer'', or ''COM'') of Wallis and Futuna. It is one of the Hoorn Islands or Île ...

Galápagos Islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

Genovesa Island Genovesa Island (Spanish: ''Isla Genovesa''), referred to in English as Tower Island, is a shield volcano in the Galápagos Islands in the eastern Pacific Ocean. The island occupies about , and its maximum elevation is . The horse-shoe shaped i ...

Hallasan Hallasan is a shield volcano on Jeju Island in South Korea; it is the highest point of South Korea and the second-highest mountain in Korea overall, after Paektu Mountain. The area around the mountain is a designated national park, the Hallas ...

Isabela Island (Galápagos) Isabela Island () is the largest island of the Galápagos with an area of and length of , almost four times larger than Santa Cruz, the second largest of the archipelago. Isabela Island is larger than every other island in the Galápagos combin ...

Isla Salas y Gómez Isla Salas y Gómez, also known as Isla Sala y Gómez ( rap, Motu Motiro Hiva), is a small uninhabited Chilean island in the Pacific Ocean. It is sometimes considered the easternmost point in the Polynesian Triangle. Isla Salas y Gómez and its s ...

* Kilauea *

Lord Howe Island Lord Howe Island (; formerly Lord Howe's Island) is an irregularly crescent-shaped volcanic remnant in the Tasman Sea between Australia and New Zealand, part of the Australian state of New South Wales. It lies directly east of mainland P ...

Maquinna Maquinna (also transliterated Muquinna, Macuina, Maquilla) was the chief of the Nuu-chah-nulth people of Nootka Sound, during the heyday of the maritime fur trade in the 1780s and 1790s on the Pacific Northwest Coast. The name means "possessor of ...

Marchena Island The island's name, Marchena Island (Spanish: ''Isla Marchena''), comes from the Spanish monk, Frey Antonio de Marchena. It has an area of 130 km2 and a maximum altitude of 343 meters. The island is not set up for visitors, although the s ...

Matthew and Hunter Islands Hunter Island and Matthew Island are two small and uninhabited high islands in the South Pacific, located east of New Caledonia and south-east of Vanuatu archipelago. Hunter Island and Matthew Island, apart, are claimed by Vanuatu as part o ...

Mauna Loa Mauna Loa ( or ; Hawaiian: ; en, Long Mountain) is one of five volcanoes that form the Island of Hawaii in the U.S. state of Hawaii in the Pacific Ocean. The largest subaerial volcano (as opposed to subaqueous volcanoes) in both mass and ...

Mount Lidgbird Mount Lidgbird, also Mount Ledgbird and Big Hill, is located in the southern section of Lord Howe Island, just north of Mount Gower, from which it is separated by the saddle at the head of Erskine Valley, and has its peak at above sea level. ...

Norfolk Island Norfolk Island (, ; Norfuk: ''Norf'k Ailen'') is an external territory of Australia located in the Pacific Ocean between New Zealand and New Caledonia, directly east of Australia's Evans Head and about from Lord Howe Island. Together with ...

Nunivak Island Nunivak Island ( Central Alaskan Yup'ik: ; Nunivak Cup'ig: ''Nuniwar''; russian: Нунивак, Nunivak) is a permafrost-covered volcanic island lying about offshore from the delta of the Yukon and Kuskokwim rivers in the US state of Alaska, at ...

Phillip Island (Norfolk Island) Phillip Island is an island located south of Norfolk Island in the Southwest Pacific, and is part of the Norfolk Island group. It was named in 1788 by Lieutenant Philip Gidley King after Arthur Phillip, the first Governor of New South Wales. P ...

Pinta Island Pinta Island ( Spanish: ''Isla Pinta''), also known as Abingdon Island, after the Earl of Abingdon, is an island located in the Galápagos Islands group, Ecuador. It has an area of and a maximum altitude of . Pinta was the original home to Lon ...

Poike Poike is one of the three main extinct volcanoes that form Rapa Nui (Easter Island), a Chilean island in the Pacific Ocean. At 370 metres above sea level, Poike's peak is the island's second-highest point after the peak of the extinct volcano T ...

Rábida Island Rábida Island (), is one of the Galápagos Islands. The island has also been known as Jervis Island named in honour of the 18th-century British admiral John Jervis. In Ecuador it is officially known as Isla Rábida. Wildlife In addition to ...

Revillagigedo Islands The Revillagigedo Islands ( es, Islas Revillagigedo, ) or Revillagigedo Archipelago are a group of four volcanic islands in the Pacific Ocean, known for their unique ecosystem. They lie approximately from Socorro Island south and southwest of C ...

Rocas Alijos Rocas Alijos, or Escollos Alijos ( en, Alijos Rocks) are a group of tiny, steep and barren volcanic islets or above-water (as well as below-water) rocks in the Pacific Ocean at . They are part of Comondú municipality of the Mexican state of Baj ...

San Benedicto Island San Benedicto, formerly Isla de los Innocentes, is an uninhabited island, and third largest island of the Revillagigedo Islands, located in the Pacific Ocean. It is 4.8 km by 2.4 km in size, with an area 10 km². It is of volcanic ...

Santiago Island (Galápagos) Santiago Island () is one of the Galápagos Islands. It is also known as San Salvador, named after the first island discovered by Christopher Columbus, Columbus in the Caribbean Sea (see San Salvador Island), or as James Island. The island, ...

Sierra Negra (Galápagos) Sierra Negra (Spanish: ''Black Mountain'') is a large shield volcano at the southeastern end of Isabela Island in the Galapagos that rises to an altitude of 1124m. It coalesces with the volcanoes Cerro Azul to the west and Alcedo to the north ...

Socorro Island Socorro Island ( es, Isla Socorro) is a small volcanic island in the Revillagigedo Islands, a Mexican possession lying off the country's western coast. The size is 16.5 by 11.5 km (10.25 by 7.15 miles), with an area of . It is the largest ...

South Arch volcanic field South Arch volcanic field is an underwater volcanic field south of Hawaiʻi Island. It was active during the last 10,000 years, and covers an area of at a depth of . Although the field is related to the Hawaiian hotspot, it does not appear ...

Tamu Massif Tamu Massif is a seamount in the northwest Pacific Ocean, sitting atop a triple junction of mid-ocean ridges. Tamu Massif is located in the

Volcán Wolf Wolf Volcano ( es, Volcán Wolf, italic=no), also known as Mount Whiton, is the highest peak in the Galápagos Islands. It is situated on Isabela Island and reaches . It is a shield volcano with a characteristic upturned soup bowl shape. The v ...

References

Notes

Sources

* * * * * * {{portalbar, Oceans