Middle America Trench

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The trench is colored in dark blue MiddleAmericaTrench.jpg
The trench is colored in dark blue
The trench lies at the convergence of the, Cocos, Nazca, North American, and Caribbean plates Tectonic plates Caribbean.png
The trench lies at the convergence of the, Cocos, Nazca, North American, and Caribbean plates

The Middle America Trench is a major subduction zone, an oceanic trench in the eastern Pacific Ocean off the southwestern coast of Middle America, stretching from central Mexico to Costa Rica. The trench is 1,700 miles (2,750 km) long and is 21,880 feet (6,669 m) at its deepest point. The trench is the boundary between the Rivera, Cocos, and Nazca plates on one side and the North American and Caribbean plates on the other. It is the 18th-deepest trench in the world. Many large earthquakes have occurred in the area of the Middle America Trench. [1]

Oceanic trench Long and narrow depressions of the sea floor

Oceanic trenches are topographic depressions of the sea floor, relatively narrow in width, but very long. These oceanographic features are the deepest parts of the ocean floor. Oceanic trenches are a distinctive morphological feature of convergent plate boundaries, along which lithospheric plates move towards each other at rates that vary from a few millimeters to over ten centimeters per year. A trench marks the position at which the flexed, subducting slab begins to descend beneath another lithospheric slab. Trenches are generally parallel to a volcanic island arc, and about 200 km (120 mi) from a volcanic arc. Oceanic trenches typically extend 3 to 4 km below the level of the surrounding oceanic floor. The greatest ocean depth measured is in the Challenger Deep of the Mariana Trench, at a depth of 11,034 m (36,201 ft) below sea level. Oceanic lithosphere moves into trenches at a global rate of about 3 km2/yr.

Pacific Ocean Ocean between Asia and Australia in the west, the Americas in the east and Antarctica or the Southern Ocean in the south.

The Pacific Ocean is the largest and deepest of Earth's oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean in the south and is bounded by Asia and Australia in the west and the Americas in the east.

Middle America (Americas) region in the mid-latitudes of the Americas, consisting of Mexico, Central America, the Caribbean, Colombia, Venezuela, and the Guyanas

Middle America is a region in the mid-latitudes of the Americas. In southern North America, it usually comprises Mexico, the nations of Central America, and the Caribbean. In northern South America, it usually comprises Colombia and Venezuela. The Caribbean is occasionally excluded from the region, and the Guianas are infrequently included.

Division

The Middle America Trench can be divided into a northern and a southern section. The division, however, is not the same in its seaward side and its landward side. In the seaward side, the northern section, called the Acapulco Trench, runs from Jalisco to the Tehuantepec Ridge, and the southern section, called the Guatemala Trench, runs from the Tehuantepec Ridge to the Cocos Ridge. [2] On the landward side, the division is demarcated along the Polochic-Motagua fault system (see Motagua Fault), the boundary between the North American Plate and the Caribbean Plate. [3] The dividing point in the landward side is about 400 km east of that in the seaward side. [4]

Jalisco State of Mexico

Jalisco, officially the Free and Sovereign State of Jalisco, is one of the 31 states which, with Mexico City, comprise the 32 Federal Entities of Mexico. It is located in Western Mexico and is bordered by six states which are Nayarit, Zacatecas, Aguascalientes, Guanajuato, Michoacán and Colima. Jalisco is divided into 125 municipalities, and its capital city is Guadalajara. Jalisco is one of the most important states in Mexico because of its natural resources as well as its history. Many of the characteristic traits of Mexican culture, particularly outside Mexico City, are originally from Jalisco, such as mariachi, ranchera music, birria, tequila, jaripeo, etc., hence the state's motto: "Jalisco es México." Economically, it is ranked third in the country, with industries centered in the Guadalajara metropolitan area, the second largest metropolitan area in Mexico. The state is home to two significant indigenous populations, the Huichols and the Nahuas. There is also a significant foreign population, mostly retirees from the United States and Canada, living in the Lake Chapala and Puerto Vallarta areas.

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. It extends from the eastern end of the Clipperton Fracture Zone northeastward toward Mexico into Chiapas and El Chichón until it is subducted into the Middle America Trench. It lies within the tectonic Cocos Plate, separating the lower and older seafloor of the Guatemala Basin which lies southeast of the ridge from higher and younger seafloor which lies to its northwest.

Motagua Fault

The Motagua Fault is a major, active left lateral-moving transform fault which cuts across Guatemala, continuing offshore along the southern Pacific coast of Mexico, returning onshore along the southernmost tip of Oaxaca, then continuing offshore until it merges with the Middle America Trench near Acapulco. It forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It is considered the onshore continuation of the Swan Islands Transform Fault which runs under the Caribbean Sea.

Related Research Articles

Cayman Trough A complex transform fault zone pull-apart basin on the floor of the western Caribbean Sea

The Cayman Trough is a complex transform fault zone pull-apart basin which contains a small spreading ridge, the Mid-Cayman Rise, on the floor of the western Caribbean Sea between Jamaica and the Cayman Islands. It is the deepest point in the Caribbean Sea and forms part of the tectonic boundary between the North American Plate and the Caribbean Plate. It extends from the Windward Passage, going south of the Sierra Maestra of Cuba toward Guatemala. The transform continues onshore as the Motagua Fault, which cuts across Guatemala and extends offshore under the Pacific Ocean, where it intersects the Middle America Trench subduction zone.

Japan Trench An oceanic trench - part of the Pacific Ring of Fire - off northeast Japan

The Japan Trench is an oceanic trench part of the Pacific Ring of Fire off northeast Japan. It extends from the Kuril Islands to the northern end of the Izu Islands, and is 8,046 meters (26,398 ft) at its deepest. It links the Kuril-Kamchatka Trench to the north and the Izu-Ogasawara Trench to its south with a length of 800 km. This trench is created as the oceanic Pacific plate subducts beneath the continental Okhotsk Plate. The subduction process causes bending of the down going plate, creating a deep trench. Continuing movement on the subduction zone associated with the Japan Trench is one of the main causes of tsunamis and earthquakes in northern Japan, including the megathrust Tōhoku earthquake and resulting tsunami that occurred on 11 March 2011. The rate of subduction associated with the Japan Trench has been recorded at about 7.9-9.2 cm/yr.

North American Plate Large tectonic plate including most of North America, Greenland and a bit of Siberia

The North American Plate is a tectonic plate covering most of North America, Greenland, Cuba, the Bahamas, extreme northeastern Asia, and parts of Iceland and the Azores. It extends eastward to the Mid-Atlantic Ridge and westward to the Chersky Range in eastern Siberia. The plate includes both continental and oceanic crust. The interior of the main continental landmass includes an extensive granitic core called a craton. Along most of the edges of this craton are fragments of crustal material called terranes, accreted to the craton by tectonic actions over a long span of time. It is thought that much of North America west of the Rocky Mountains is composed of such terranes.

Pacific Plate An oceanic tectonic plate under the Pacific Ocean

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.

Cocos Plate A young oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America

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 broke into two pieces, which also created the Nazca Plate. The Cocos Plate also broke into two pieces, creating the small Rivera Plate. The Cocos Plate is bounded by several different plates. To the northeast it is bounded by the North American Plate and the Caribbean Plate. To the west it is bounded by the Pacific Plate and to the south by the Nazca Plate.

Trans-Mexican Volcanic Belt arc of volcanic mountains across central-southern Mexico

The Trans-Mexican Volcanic Belt, also known as the Transvolcanic Belt and locally as the Sierra Nevada, is a volcanic belt that covers central-southern Mexico. Several of its highest peaks have snow all year long, and during clear weather, they are visible to a large percentage of those who live on the many high plateaus from which these volcanoes rise.

Puerto Rico Trench An oceanic trench on a transform boundary between the Caribbean and North American Plates

The Puerto Rico Trench is located on the boundary between the Caribbean Sea and the Atlantic Ocean. The oceanic trench is associated with a complex transition between the Lesser Antilles subduction zone to the south and the major transform fault zone or plate boundary, which extends west between Cuba and Hispaniola through the Cayman Trough to the coast of Central America. The trench is 800 kilometres (497 mi) long and has a maximum depth of 8,376 metres (27,480 ft) or 5.20 miles in the Brownson Deep, which is the deepest point in the Atlantic Ocean and the deepest point not in the Pacific Ocean. On December 19, 2018, its deepest point was identified by the DSSV Pressure Drop using a state-of-the-art Kongsberg EM124 multibeam sonar and then directly visited and its depth verified by the manned submersible DSV Limiting Factor.

Triple junction The point where the boundaries of three tectonic plates meet

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 3 types - a ridge (R), trench (T) or transform fault (F) - and triple junctions can be described according to the types of plate margin that meet at them. Of the many possible types of triple junction only a few are stable through time. The meeting of 4 or more plates is also theoretically possible but junctions will only exist instantaneously.

Caribbean Plate A mostly oceanic tectonic plate including part of Central America and the Caribbean Sea

The Caribbean Plate is a mostly oceanic tectonic plate underlying Central America and the Caribbean Sea off the north coast of South America.

Geology of Puerto Rico

Puerto Rico is composed of Jurassic to Eocene volcanic and plutonic rocks, which are overlain by younger Oligocene to recent carbonates and other sedimentary rocks. Most of the caverns and karst topography on the island occurs in the northern Oligocene to recent carbonates. The oldest rocks are approximately 190 million years old (Jurassic) and are located at Sierra Bermeja in the southwest part of the island. These rocks may represent part of the oceanic crust and are believed to come from the Pacific Ocean realm.

Galápagos hotspot

The Galápagos hotspot is a volcanic hotspot in the East Pacific Ocean responsible for the creation of the Galapagos Islands as well as three major aseismic ridge systems, Carnegie, Cocos and Malpelo which are on two tectonic plates. The hotspot is located near the Equator on the Nazca Plate not far from the divergent plate boundary with the Cocos Plate. The tectonic setting of the hotspot is complicated by the Galapagos Triple Junction of the Nazca and Cocos plates with the Pacific Plate. The movement of the plates over the hotspot is determined not solely by the spreading along the ridge but also by the relative motion between the Pacific Plate and the Cocos and Nazca Plates.

The Chixoy-Polochic Fault, also known as Cuilco-Chixoy-Polochic Fault, is a major fault zone in Guatemala and southwestern Mexico. It runs in a light arc from the east coast of Guatemala to Chiapas, following the deep valleys of the Polochic River, Chixoy River and Cuilco River.

Geology of the Pacific Ocean

The Pacific Ocean evolved in the Mesozoic from the Panthalassic Ocean, which had formed when Rodinia 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 Sumatra Trench belongs to the Sunda Trench or Java Trench. The Sunda subduction zone is located in the east part of Indian Ocean, and is about 300 km from the southwest coast of Sumatra and Java islands. It extends over 5000 km long, starting from Burma in the northwest and ending at Sumba Island in the southeast.

Malpelo Plate A small tectonic plate off the coast west of Ecuador and Colombia

The Malpelo Plate is a small tectonic plate located off the coasts west of Ecuador and Colombia. It is the 57th plate to be identified. It is named after Malpelo Island, the only emerged part of the plate. It is bounded on the west by the Cocos Plate, on the south by the Nazca Plate, on the east by the North Andes Plate, and on the north by the Coiba Plate, separated by the Coiba Transform Fault (CTF). This microplate was previously assumed to be part of the Nazca Plate. The Malpelo Plate borders three major faults of Pacific Colombia, the north to south striking Bahía Solano Fault in the north and the Naya-Micay and Remolino-El Charco Faults in the south.

Chortis Block

The Chortis Block is a 400–600 km (250–370 mi)-wide continental fragment in Central America located in the northwest corner of the oceanic Caribbean Plate.

References

  1. Astiz, L.; Kanamori, H.; Eissler, H. (1987). "Source characteristics of earthquakes in the Michoacan seismic gap in Mexico". Bulletin of the Seismological Society of America. 77 (4): 1326–1346.
  2. Marina Manea; Vlad C. Manea; Vladimir Kostoglodov (2003). "Sediment Fill In the Middle America Trench Inferred From Gravity Anomalies". Geofisica Internacional. 42: 603–612.
  3. Lyon-Caen, H.; Barrier, E.; Lasserre, C.; Franco, A.; Arzu, I.; Chiquin, L.; Chiquin, M.; Duquesnoy, T.; Flores, O.; Galicia, O.; Luna, J.; Molina, E.; Porras, O.; Requena, J.; Robles, V.; Romero, J.; Wolf, R. (2006). "Kinematics of the North American–Caribbean-Cocos plates in Central America from new GPS measurements across the Polochic-Motagua fault system". Geophysical Research Letters. 33 (19): 19309. Bibcode:2006GeoRL..3319309L. doi:10.1029/2006GL027694.
  4. Aubouin, J.; Azema, J.; Carfantan, J.-Ch.; Demant, A.; Rangin, C.; Tardy, M.; Tournon, J. (2007) [1982]. "The Middle America Trench in the Geological Framework of Central America" (PDF). Initial Reports of the Deep Sea Drilling Project, 67 (Report). Deep Sea Drilling Project. doi:10.2973/dsdp.proc.67.141.1982.