Misplaced Pages

#609390

104-486: At 3,805 metres (12,484 ft) above sea level, Kerinci is the highest volcano in Indonesia , and the highest of any situated on an island that is a part of Asia. Kerinci is located on the border of the titular Kerinci Regency of Jambi province and South Solok Regency of West Sumatra province, in the west-central part of the island near the west coast, and is about 130 km (81 mi) south of Padang . It

208-748: A ghost town ) and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE. 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 tectonic belt of volcanoes and earthquakes . It is about 40,000 km (25,000 mi) long and up to about 500 km (310 mi) wide, and surrounds most of

312-587: A magnitude-8.8 earthquake struck central Chile on February 27, 2010 , the Puyehue-Cordón Caulle volcano erupted in 2011 , and a M8.2 earthquake struck northern Chile on April 1, 2014 . The main shock was preceded by a number of moderate to large shocks and was followed by a large number of moderate to very large aftershocks, including a magnitude-7.6 event on April 2. Bolivia hosts active and extinct volcanoes across its territory. The active volcanoes are located in western Bolivia where they make up

416-886: A mid-ocean ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift , the Wells Gray-Clearwater volcanic field , and the Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from

520-437: A graduated spectrum, with much overlap between categories, and does not always fit neatly into only one of these three separate categories. The USGS defines a volcano as "erupting" whenever the ejection of magma from any point on the volcano is visible, including visible magma still contained within the walls of the summit crater. While there is no international consensus among volcanologists on how to define an active volcano,

624-436: A lava flow. The last major eruption of Calbuco, in 1961, sent ash columns 12–15 km (7.5–9.3 mi) high and produced plumes that dispersed mainly to the southeast and two lava flows were also emitted. A minor, four-hour eruption happened on August 26, 1972. Strong fumarolic emission from the main crater was observed on August 12, 1996. Lonquimay is a stratovolocano of late-Pleistocene to dominantly Holocene age, with

728-443: A paper was published suggesting a new definition for the word 'volcano' that includes processes such as cryovolcanism . It suggested that a volcano be defined as 'an opening on a planet or moon's surface from which magma , as defined for that body, and/or magmatic gas is erupted.' This article mainly covers volcanoes on Earth. See § Volcanoes on other celestial bodies and cryovolcano for more information. The word volcano

832-632: A volcano is largely determined by the composition of the lava it erupts. The viscosity (how fluid the lava is) and the amount of dissolved gas are the most important characteristics of magma, and both are largely determined by the amount of silica in the magma. Magma rich in silica is much more viscous than silica-poor magma, and silica-rich magma also tends to contain more dissolved gases. Lava can be broadly classified into four different compositions: Mafic lava flows show two varieties of surface texture: ʻAʻa (pronounced [ˈʔaʔa] ) and pāhoehoe ( [paːˈho.eˈho.e] ), both Hawaiian words. ʻAʻa

936-555: A volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; however, this describes just one of the many types of volcano. The features of volcanoes are varied. The structure and behaviour of volcanoes depend on several factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus . Vents that issue volcanic material (including lava and ash ) and gases (mainly steam and magmatic gases) can develop anywhere on

1040-465: A volcano that has experienced one or more eruptions that produced over 1,000 cubic kilometres (240 cu mi) of volcanic deposits in a single explosive event. Such eruptions occur when a very large magma chamber full of gas-rich, silicic magma is emptied in a catastrophic caldera -forming eruption. Ash flow tuffs emplaced by such eruptions are the only volcanic product with volumes rivalling those of flood basalts . Supervolcano eruptions, while

1144-739: Is a volcanic field of over 60 cinder cones. Based on satellite images, it has been suggested that cinder cones might occur on other terrestrial bodies in the Solar system too; on the surface of Mars and the Moon. Stratovolcanoes (composite volcanoes) are tall conical mountains composed of lava flows and tephra in alternate layers, the strata that gives rise to the name. They are also known as composite volcanoes because they are created from multiple structures during different kinds of eruptions. Classic examples include Mount Fuji in Japan, Mayon Volcano in

SECTION 10

#1732772096610

1248-562: Is a major late Cenozoic volcanic province. Sabancaya is an active 5,976-metre (19,606 ft) stratovolcano in the Andes of southern Peru , about 100 km (60 mi) northwest of Arequipa . It is the most active volcano in Peru, with an ongoing eruption that started in 2016. Ubinas is another active volcano of 5,672-metre (18,609 ft) in southern Peru; its most recent eruption occurred in 2019. Volcanoes in Peru are monitored by

1352-479: Is a stratovolcano and the most active volcano of the northern Chilean Andes. The largest eruption of Lascar took place about 26,500 years ago, and following the eruption of the Tumbres scoria flow about 9,000 years ago, activity shifted back to the eastern edifice, where three overlapping craters were formed. Frequent small-to-moderate explosive eruptions have been recorded from Lascar in historical time since

1456-580: Is a stratovolcano in southern Chile, located southeast of Llanquihue Lake and northwest of Chapo Lake , in Los Lagos Region . The volcano and the surrounding area are protected within Llanquihue National Reserve . It is a very explosive andesite volcano that underwent edifice collapse in the late Pleistocene , producing a volcanic debris avalanche that reached the lake. At least nine eruptions occurred since 1837, with

1560-638: Is a stratovolcano located in the Antofagasta Region of Chile, immediately north of Cerro Miscanti . Laguna Lejía lies to the north of the volcano and has been dormant for at least 10,000 years, but is now showing signs of life. A January 6, 2002, nighttime thermal infrared image from ASTER revealed a hot spot in the summit crater, as well as several others along the upper flanks of the volcano's edifice, indicating new volcanic activity. Examination of an earlier nighttime thermal infrared image from May 24, 2000, showed no such hot spots. Calbuco

1664-837: Is being subducted beneath the Aleutian Islands arc. Farther west, the Pacific plate is being subducted at the Kamchatka Peninsula and Kuril arcs. Farther south, at Japan, Taiwan and the Philippines, the Philippine Plate is being subducted beneath the Eurasian plate. The southwest section of the Ring of Fire is more complex, with a number of smaller tectonic plates in collision with the Pacific plate at

1768-412: Is characterized by a rough, clinkery surface and is the typical texture of cooler basalt lava flows. Pāhoehoe is characterized by its smooth and often ropey or wrinkly surface and is generally formed from more fluid lava flows. Pāhoehoe flows are sometimes observed to transition to ʻaʻa flows as they move away from the vent, but never the reverse. More silicic lava flows take the form of block lava, where

1872-565: Is derived from the name of Vulcano , a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan , the god of fire in Roman mythology . The study of volcanoes is called volcanology , sometimes spelled vulcanology . According to the theory of plate tectonics, Earth's lithosphere , its rigid outer shell, is broken into sixteen larger and several smaller plates. These are in slow motion, due to convection in

1976-584: Is expressed using the volcanic explosivity index (VEI), which ranges from 0 for Hawaiian-type eruptions to 8 for supervolcanic eruptions. As of December 2022 , the Smithsonian Institution 's Global Volcanism Program database of volcanic eruptions in the Holocene Epoch (the last 11,700 years) lists 9,901 confirmed eruptions from 859 volcanoes. The database also lists 1,113 uncertain eruptions and 168 discredited eruptions for

2080-624: Is not related to subduction; therefore, they are not part of the Ring of Fire. The world's highest active volcano is Ojos del Salado (6,893 m or 22,615 ft), which is in the Andes Mountains section of the Ring of Fire. It forms part of the border between Argentina and Chile and it last erupted in AD 750. Another Ring of Fire Andean volcano on the Argentina-Chile border is Llullaillaco (6,739 m or 22,110 ft), which

2184-471: Is now eastern China. The Pacific plate came into existence in the Early Jurassic about 190 million years ago, far from the margins of the then Paleo-Pacific Ocean. Until the Pacific plate grew large enough to reach the margins of the ocean basin, other older plates were subducted ahead of it at the ocean basin margins. For example, subduction has been occurring at the coast of South America since

SECTION 20

#1732772096610

2288-537: Is one of the several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Butte was the first such landform analysed and so its name has entered the geological literature for this kind of volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies north of Tuya Lake and south of the Jennings River near

2392-611: Is part of the Barisan Mountains , a chain of volcanoes that span from the extreme northwest of the island (in Aceh province) to the extreme southeast (in Lampung province). It is the most prominent feature of the terrain of Kerinci Seblat National Park , with pine-forested slopes rising 2,400–3,300 metres (7,900–10,800 ft) above the surrounding basin, and a cone 13 km (8 mi) wide and 25 km (16 mi) long at

2496-495: Is subducted in the western Pacific, with steeper angles of slab descent. This variation affects, for example, the location of volcanoes relative to the ocean trench, lava composition, type and severity of earthquakes, sediment accretion , and the amount of compression or tension. A spectrum of subduction zones exists between the Chilean and Mariana end members. Oceanic trenches are the topographic expression of subduction zones on

2600-572: Is the world's highest historically active volcano, last erupting in 1877. Chile has experienced numerous volcanic eruptions from about 90 volcanoes during the Holocene Epoch. Villarrica is one of Chile's most active volcanoes, rising above the lake and town of the same name. It is the westernmost of three large stratovolcanoes that trend perpendicular to the Andes along the Gastre Fault . Villarrica, along with Quetrupillán and

2704-471: Is typically low in silica, shield volcanoes are more common in oceanic than continental settings. The Hawaiian volcanic chain is a series of shield cones, and they are common in Iceland , as well. Lava domes are built by slow eruptions of highly viscous lava. They are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount St. Helens , but can also form independently, as in

2808-617: The Cascade Volcanoes or the Japanese Archipelago , or the eastern islands of Indonesia . Hotspots are volcanic areas thought to be formed by mantle plumes , which are hypothesized to be columns of hot material rising from the core-mantle boundary. As with mid-ocean ridges, the rising mantle rock experiences decompression melting which generates large volumes of magma. Because tectonic plates move across mantle plumes, each volcano becomes inactive as it drifts off

2912-789: The Cordillera Occidental , the western limit of the Altiplano plateau. Some of the active volcanoes are international mountains shared with Chile . All Cenozoic volcanoes of Bolivia are part of the Central Volcanic Zone (CVZ) of the Andean Volcanic Belt that results due to processes involved in the subduction of the Nazca plate under the South American plate . The Central Volcanic Zone

3016-573: The Jurassic Period more than 145 million years ago, and remnants of Jurassic and Cretaceous volcanic arcs are preserved there. At about 120 to 115 million years ago, the Farallon plate was subducting under South America, North America and north-east Asia while the Izanagi plate was subducting under east Asia. By 85 to 70 million years ago, the Izanagi plate had moved north-eastwards and

3120-540: The Mariana Islands , the Philippines , eastern Indonesia , Papua New Guinea , Tonga , and New Zealand; this part of the Ring excludes Australia , because that landmass lies in the center of its tectonic plate far from subduction zones. If a tectonic plate's oceanic lithosphere is subducted beneath oceanic lithosphere of another plate, a volcanic island arc is created at the subduction zone. An example in

3224-464: The Pacific Ocean . The Ring of Fire contains between 750 and 915 active or dormant volcanoes, around two-thirds of the world total. The exact number of volcanoes within the Ring of Fire depends on which regions are included. About 90% of the world's earthquakes, including most of its largest, occur within the belt. The Ring of Fire is not a single geological structure. It was created by

Mount Kerinci - Misplaced Pages Continue

3328-804: The core–mantle boundary , 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism , of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide past one another. Large eruptions can affect atmospheric temperature as ash and droplets of sulfuric acid obscure the Sun and cool Earth's troposphere . Historically, large volcanic eruptions have been followed by volcanic winters which have caused catastrophic famines. Other planets besides Earth have volcanoes. For example, volcanoes are very numerous on Venus. Mars has significant volcanoes. In 2009,

3432-429: The crust of a planetary-mass object , such as Earth , that allows hot lava , volcanic ash , and gases to escape from a magma chamber below the surface. The process that forms volcanoes is called volcanism . On Earth, volcanoes are most often found where tectonic plates are diverging or converging , and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example,

3536-834: The landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Kīlauea in Hawaii. Volcanic craters are not always at the top of a mountain or hill and may be filled with lakes such as with Lake Taupō in New Zealand. Some volcanoes can be low-relief landform features, with the potential to be hard to recognize as such and be obscured by geological processes. Other types of volcano include cryovolcanoes (or ice volcanoes), particularly on some moons of Jupiter , Saturn , and Neptune ; and mud volcanoes , which are structures often not associated with known magmatic activity. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when

3640-923: The subduction of different tectonic plates at convergent boundaries around the Pacific Ocean. These include: the Antarctic , Nazca and Cocos plates subducting beneath the South American plate ; the Pacific and Juan de Fuca plates beneath the North American plate ; the Philippine Plate beneath the Eurasian plate ; and a complex boundary between the Pacific and Australian plate . The interactions at these plate boundaries have formed oceanic trenches , volcanic arcs , back-arc basins and volcanic belts . The inclusion of some areas in

3744-543: The 'Kecik Wok Gedang Wok' people are recognized as the first tribe to settle at a plateau around Mount Kerinci 10,000 years ago. Today, the Kecik Wong Gedang Wok people are limited due to assimilation with the Proto-Malay tribes which came later. Around 135 dialects are used only along the valley. This makes ethnographic analysis difficult to conduct. Volcano A volcano is a rupture in

3848-640: The Alpide belt). Some geologists include the Antarctic Peninsula and the South Shetland Islands in the Ring of Fire, other geologists exclude these areas. The rest of Antarctica is excluded because the volcanism there is not related to subduction. The Ring of Fire does not extend across the southern Pacific Ocean from New Zealand to the Antarctic Peninsula or from New Zealand to the southern tip of South America because

3952-519: The Chilean part of Lanín , are protected within Villarrica National Park . Villarrica, with its lava of basaltic-andesitic composition, is one of only five volcanoes worldwide known to have an active lava lake within its crater. The volcano usually generates strombolian eruptions , with ejection of incandescent pyroclasts and lava flows. Melting of snow and glacier ice , as well as rainfall, often causes lahars , such as during

4056-603: The Gulf of California and due partly to the San Andreas Fault (a non-volcanic transform boundary ). Another North American gap in subduction-related volcanic activity occurs in northern British Columbia, Yukon and south-east Alaska, where volcanism is caused by intraplate continental rifting . The four largest volcanic eruptions on Earth in the Holocene Epoch (the last 11,700 years) occurred at volcanoes in

4160-606: The Holocene epoch all occurred at volcanoes in the Ring of Fire. Most of Earth's active volcanoes with summits above sea level are located in the Ring of Fire. Many of these subaerial volcanoes are stratovolcanoes (e.g. Mount St. Helens ), formed by explosive eruptions of tephra alternating with effusive eruptions of lava flows. Lavas at the Ring of Fire's stratovolcanoes are mainly andesite and basaltic andesite but dacite , rhyolite , basalt and some other rarer types also occur. Other types of volcano are also found in

4264-468: The Kula and Farallon plates had been subducted and the Pacific plate was subducting around its rim in a configuration closely resembling the outline of the present-day Ring of Fire. The eastern parts of the Ring of Fire result from the collision of a few relatively large plates. The western parts of the Ring are more complex, with a number of large and small tectonic plates in collision. In South America,

Mount Kerinci - Misplaced Pages Continue

4368-562: The Philippines, and Mount Vesuvius and Stromboli in Italy. Ash produced by the explosive eruption of stratovolcanoes has historically posed the greatest volcanic hazard to civilizations. The lavas of stratovolcanoes are higher in silica, and therefore much more viscous, than lavas from shield volcanoes. High-silica lavas also tend to contain more dissolved gas. The combination is deadly, promoting explosive eruptions that produce great quantities of ash, as well as pyroclastic surges like

4472-522: The Ring of Fire at some parts of the Pacific coast of the Americas. In some places, the gaps are thought to be caused by flat slab subduction ; examples are the three gaps between the four sections of the Andean Volcanic Belt in South America. In North America, there is a gap in subduction-related volcanic activity in northern Mexico and southern California, due partly to a divergent boundary in

4576-471: The Ring of Fire is the Mariana Arc in the western Pacific Ocean. If, however, oceanic lithosphere is subducted under continental lithosphere, then a volcanic continental arc forms; a Ring of Fire example is the coast of Chile. The steepness of the descending plate at a subduction zone depends on the age of the oceanic lithosphere that is being subducted. The older the oceanic lithosphere being subducted,

4680-588: The Ring of Fire is the result of the Antarctic plate , the Nazca plate and the Cocos plate being subducted beneath the South American plate . In Central America , the Cocos plate is being subducted beneath the Caribbean plate . A portion of the Pacific plate and the small Juan de Fuca plate are being subducted beneath the North American plate . Along the northern portion, the northwestward-moving Pacific plate

4784-720: The Ring of Fire volcanoes as follows: "They [the Japanese Islands] are in the line of that immense circle of volcanic development which surrounds the shores of the Pacific from Tierra del Fuego around to the Moluccas ." ( Narrative of the Expedition of an American Squadron to the China Seas and Japan, 1852–54 . ) An article appeared in Scientific American in 1878 with the title "The Ring of Fire, and

4888-423: The Ring of Fire, such as subaerial shield volcanoes (e.g. Plosky Tolbachik ), and submarine seamounts (e.g. Monowai ). From Ancient Greek and Roman times until the late 18th century, volcanoes were associated with fire, based on the ancient belief that volcanoes were caused by fires burning within the Earth. This historical link between volcanoes and fire is preserved in the name of the Ring of Fire, despite

4992-496: The Ring of Fire, such as the Antarctic Peninsula and western Indonesia, is disputed. The Ring of Fire has existed for more than 35 million years but subduction has existed for much longer in some parts of the Ring; many older extinct volcanoes are located within the Ring. More than 350 of the Ring of Fire's volcanoes have been active in historical times , while the four largest volcanic eruptions on Earth in

5096-521: The Ring of Fire. The next most seismically active region (5–6% of earthquakes and some of the world's largest earthquakes) is the Alpide belt, which extends from central Indonesia to the northern Atlantic Ocean via the Himalayas and southern Europe. From 1900 to the end of 2020, most earthquakes of magnitude M w ≥ 8.0 occurred in the Ring of Fire. They are presumed to have been megathrust earthquakes at subduction zones, including four of

5200-421: The Ring of Fire. They are the eruptions at Fisher Caldera (Alaska, 8700 BC ), Kurile Lake (Kamchatka, 6450 BC), Kikai Caldera (Japan, 5480 BC) and Mount Mazama (Oregon, 5677 BC). More broadly, twenty of the twenty-five largest volcanic eruptions on Earth in this time interval occurred at Ring of Fire volcanoes. About 90% of the world's earthquakes and most of the world's largest earthquakes occur along

5304-575: The South Shetland subduction zone. The Antarctic Peninsula (Graham Land) is also sometimes included in the Ring. Volcanoes south of the Antarctic Circle (e.g. the volcanoes of Victoria Land including Mount Erebus , and the volcanoes of Mary Byrd Land ) are not related to subduction; therefore, they are not part of the Ring of Fire. The Balleny Islands , located between Antarctica and New Zealand, are volcanic but their volcanism

SECTION 50

#1732772096610

5408-613: The USGS defines a volcano as active whenever subterranean indicators, such as earthquake swarms , ground inflation, or unusually high levels of carbon dioxide or sulfur dioxide are present. The USGS defines a dormant volcano as any volcano that is not showing any signs of unrest such as earthquake swarms, ground swelling, or excessive noxious gas emissions, but which shows signs that it could yet become active again. Many dormant volcanoes have not erupted for thousands of years, but have still shown signs that they may be likely to erupt again in

5512-595: The Volcanic Peaks of the West Coast of the United States", which outlined the phenomenon of volcanic activity around the boundaries of the Pacific. Early explicit references to volcanoes forming a "ring of fire" around the Pacific Ocean also include Alexander P. Livingstone's book "Complete Story of San Francisco's Terrible Calamity of Earthquake and Fire" , published in 1906, in which he describes "...

5616-450: The base, elongated in the north-south direction. At the summit, there is a deep 600 m (1,969 ft) wide crater, often partially filled by a small crater lake on the northeast side of the crater floor. Kerinci is more active than most Indonesian volcanoes, with nearly annual phreatic eruptions . In 2004, Kerinci erupted and continues to spew clouds of sulfurous smoke, with plumes reaching as high as 1,000 m (3,281 ft) above

5720-441: The biggest being Kerinci Lake, followed by Gunung Tujuh Lake. The 4,200 hectares of Kerinci Lake lies at a height of 650 metres (2,130 ft), and is the host of the annual Kerinci Lake Festival. Gunung Tujuh Lake (literally, Seven Mountains Lake) is a caldera lake formed in an extinct volcano and is surrounded by seven peaks. It is also the highest lake in Southeast Asia at 1,996 metres (6,549 ft). Based on research in 1973,

5824-446: The boundary with the Yukon Territory . Mud volcanoes (mud domes) are formations created by geo-excreted liquids and gases, although several processes may cause such activity. The largest structures are 10 kilometres in diameter and reach 700 meters high. The material that is expelled in a volcanic eruption can be classified into three types: The concentrations of different volcanic gases can vary considerably from one volcano to

5928-402: The case of Lassen Peak . Like stratovolcanoes, they can produce violent, explosive eruptions, but the lava generally does not flow far from the originating vent. Cryptodomes are formed when viscous lava is forced upward causing the surface to bulge. The 1980 eruption of Mount St. Helens was an example; lava beneath the surface of the mountain created an upward bulge, which later collapsed down

6032-559: The central parts of the Pacific Basin, for example the Hawaiian Islands , are very far from subduction zones and they are not part of the Ring of Fire. The Ring of Fire has existed for more than 35 million years. In some parts of the Ring of Fire, subduction has been occurring for much longer. The current configuration of the Pacific Ring of Fire has been created by the development of the present-day subduction zones, initially (by about 115 million years ago) in South America, North America and Asia. As plate configurations gradually changed,

6136-432: The current subduction zones of Indonesia and New Guinea were created (about 70 million years ago), followed finally by the New Zealand subduction zone (about 35 million years ago). Along the coast of east Asia, during the Late Triassic about 210 million years ago, subduction of the Izanagi plate (the Paleo-Pacific plate) was occurring, and this continued in the Jurassic , producing volcanic belts, for example, in what

6240-553: The enormous area they cover, and subsequent concealment under vegetation and glacial deposits, supervolcanoes can be difficult to identify in the geologic record without careful geologic mapping . Known examples include Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Lake Taupō in New Zealand; Lake Toba in Sumatra , Indonesia; and Ngorongoro Crater in Tanzania. Volcanoes that, though large, are not large enough to be called supervolcanoes, may also form calderas in

6344-545: The eruptions of 1964 and 1971. A two-kilometre-wide ( 1 + 1 ⁄ 4  mi) postglacial caldera is located at the base of the presently active dominantly basaltic-to-andesitic cone at the northwest margin of the Pleistocene caldera. About 25 scoria cones dot Villarica's flanks. Plinian eruptions and pyroclastic flows have been produced during the Holocene from this dominantly basaltic volcano, but historical eruptions have consisted of largely mild-to-moderate explosive activity with occasional lava effusion. Lahars from

SECTION 60

#1732772096610

6448-442: The fact that volcanoes do not burn the Earth with fire. The existence of a belt of volcanic activity around the Pacific Ocean was known in the early 19th century; for example, in 1825 the pioneering volcanologist G. P. Scrope described the chains of volcanoes around the Pacific Ocean's rim in his book Considerations on Volcanos [ sic ]. Three decades later, a book about the Perry Expedition to Japan commented on

6552-458: The floor of the oceans. Oceanic trenches associated with the Ring of Fire's subduction zones are: Subduction zones around the Pacific Ocean do not form a complete ring. Where subduction zones are absent, there are corresponding gaps in subduction-related volcanic belts in the Ring of Fire. In some gaps there is no volcanic activity; in other gaps, volcanic activity does occur but it is caused by processes not related to subduction. There are gaps in

6656-431: The flow is covered with angular, vesicle-poor blocks. Rhyolitic flows typically consist largely of obsidian . Tephra is made when magma inside the volcano is blown apart by the rapid expansion of hot volcanic gases. Magma commonly explodes as the gas dissolved in it comes out of solution as the pressure decreases when it flows to the surface . These violent explosions produce particles of material that can then fly from

6760-434: The formation of a submarine volcano off the coast of Mayotte . Subglacial volcanoes develop underneath ice caps . They are made up of lava plateaus capping extensive pillow lavas and palagonite . These volcanoes are also called table mountains, tuyas , or (in Iceland) mobergs. Very good examples of this type of volcano can be seen in Iceland and in British Columbia . The origin of the term comes from Tuya Butte , which

6864-445: The future. In an article justifying the re-classification of Alaska's Mount Edgecumbe volcano from "dormant" to "active", volcanologists at the Alaska Volcano Observatory pointed out that the term "dormant" in reference to volcanoes has been deprecated over the past few decades and that "[t]he term "dormant volcano" is so little used and undefined in modern volcanology that the Encyclopedia of Volcanoes (2000) does not contain it in

6968-482: The glacier-covered volcanoes have damaged towns on its flanks. The Llaima Volcano is one of the largest and most active volcanoes in Chile. It is situated 82 km (51 mi) northeast of Temuco and 663 km (412 mi) southeast of Santiago , within the borders of Conguillío National Park . Llaima's activity has been documented since the 17th century, and consists of several separate episodes of moderate explosive eruptions with occasional lava flows. Lascar

7072-412: The glossaries or index", however the USGS still widely employs the term. Previously a volcano was often considered to be extinct if there were no written records of its activity. Such a generalization is inconsistent with observation and deeper study, as has occurred recently with the unexpected eruption of the Chaitén volcano in 2008. Modern volcanic activity monitoring techniques, and improvements in

7176-440: The great ring of fire which circles round the whole surface of the Pacific Ocean.". In 1912, geologist Patrick Marshall introduced the term " Andesite Line " to mark a boundary between islands in the southwest Pacific, which differ in volcano structure and lava types. The concept was later extended to other parts of the Pacific Ocean. The Andesite Line and the Ring of Fire closely match in terms of location. The development of

7280-492: The interior of a continent and lead to rifting. Early stages of rifting are characterized by flood basalts and may progress to the point where a tectonic plate is completely split. A divergent plate boundary then develops between the two halves of the split plate. However, rifting often fails to completely split the continental lithosphere (such as in an aulacogen ), and failed rifts are characterized by volcanoes that erupt unusual alkali lava or carbonatites . Examples include

7384-406: The intersection of the Ring of Fire and the Alpide belt (which is the Earth's other very long subduction-related volcanic and earthquake zone, also known as the Mediterranean–Indonesian volcanic belt, running east–west through southern Asia and southern Europe). Some geologists include all of Indonesia in the Ring of Fire; many geologists exclude Indonesia's western islands (which they include in

7488-574: The latest one in 1972. One of the largest historical eruptions in southern Chile took place there in 1893–1894. Violent eruptions ejected 30 cm (12 in) bombs to distances of 8 km (5.0 mi) from the crater, accompanied by voluminous hot lahars. Strong explosions occurred in April 1917, and a lava dome formed in the crater accompanied by hot lahars. Another short explosive eruption in January 1929 also included an apparent pyroclastic flow and

7592-475: The mid-19th century, along with periodic larger eruptions that produced ash and tephra fall up to hundreds of kilometers away from the volcano. The largest eruption of Lascar in recent history took place in 1993, producing pyroclastic flows as far as 8.5 km (5 mi) northwest of the summit and ash fall in Buenos Aires , Argentina, more than 1,600 km (1,000 mi) to the southeast. Chiliques

7696-419: The mid-oceanic ridge is above sea level, volcanic islands are formed, such as Iceland . Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. The oceanic plate subducts (dives beneath the continental plate), forming a deep ocean trench just offshore. In a process called flux melting , water released from the subducting plate lowers the melting temperature of

7800-551: The modelling of the factors that produce eruptions, have helped the understanding of why volcanoes may remain dormant for a long time, and then become unexpectedly active again. The potential for eruptions, and their style, depend mainly upon the state of the magma storage system under the volcano, the eruption trigger mechanism and its timescale. For example, the Yellowstone volcano has a repose/recharge period of around 700,000 years, and Toba of around 380,000 years. Vesuvius

7904-415: The most dangerous type, are very rare; four are known from the last million years , and about 60 historical VEI 8 eruptions have been identified in the geologic record over millions of years. A supervolcano can produce devastation on a continental scale, and severely cool global temperatures for many years after the eruption due to the huge volumes of sulfur and ash released into the atmosphere. Because of

8008-538: The most powerful earthquakes on Earth since modern seismological measuring equipment and magnitude measurement scales were introduced in the 1930s: Some geologists include the volcanoes of the South Shetland Islands , off the northern tip of the Antarctic Peninsula, as part of the Ring of Fire. These volcanoes, e.g. Deception Island , are due to rifting in the Bransfield back-arc basin close to

8112-438: The mud volcano is actually a vent of an igneous volcano. Volcanic fissure vents are flat, linear fractures through which lava emerges. Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent. They generally do not explode catastrophically but are characterized by relatively gentle effusive eruptions . Since low-viscosity magma

8216-452: The next. Water vapour is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide . Other principal volcanic gases include hydrogen sulfide , hydrogen chloride , and hydrogen fluoride . A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen , carbon monoxide , halocarbons , organic compounds, and volatile metal chlorides. The form and style of an eruption of

8320-876: The north side of the mountain. Cinder cones result from eruptions of mostly small pieces of scoria and pyroclastics (both resemble cinders, hence the name of this volcano type) that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 metres (100 to 1,300 ft) high. Most cinder cones erupt only once and some may be found in monogenetic volcanic fields that may include other features that form when magma comes into contact with water such as maar explosion craters and tuff rings . Cinder cones may form as flank vents on larger volcanoes, or occur on their own. Parícutin in Mexico and Sunset Crater in Arizona are examples of cinder cones. In New Mexico , Caja del Rio

8424-549: The ocean surface as new islands or floating pumice rafts . In May and June 2018, a multitude of seismic signals were detected by earthquake monitoring agencies all over the world. They took the form of unusual humming sounds, and some of the signals detected in November of that year had a duration of up to 20 minutes. An oceanographic research campaign in May 2019 showed that the previously mysterious humming noises were caused by

8528-420: The ocean surface, due to the rapid cooling effect and increased buoyancy in water (as compared to air), which often causes volcanic vents to form steep pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support peculiar ecosystems based on chemotrophs feeding on dissolved minerals. Over time, the formations created by submarine volcanoes may become so large that they break

8632-471: The ocean's surface. In the deep ocean basins, the tremendous weight of the water prevents the explosive release of steam and gases; however, submarine eruptions can be detected by hydrophones and by the discoloration of water because of volcanic gases . Pillow lava is a common eruptive product of submarine volcanoes and is characterized by thick sequences of discontinuous pillow-shaped masses which form underwater. Even large submarine eruptions may not disturb

8736-468: The one that destroyed the city of Saint-Pierre in Martinique in 1902. They are also steeper than shield volcanoes, with slopes of 30–35° compared to slopes of generally 5–10°, and their loose tephra are material for dangerous lahars . Large pieces of tephra are called volcanic bombs . Big bombs can measure more than 1.2 metres (4 ft) across and weigh several tons. A supervolcano is defined as

8840-425: The overlying mantle wedge, thus creating magma . This magma tends to be extremely viscous because of its high silica content, so it often does not reach the surface but cools and solidifies at depth . When it does reach the surface, however, a volcano is formed. Thus subduction zones are bordered by chains of volcanoes called volcanic arcs . Typical examples are the volcanoes in the Pacific Ring of Fire , such as

8944-619: The plume, and new volcanoes are created where the plate advances over the plume. The Hawaiian Islands are thought to have been formed in such a manner, as has the Snake River Plain , with the Yellowstone Caldera being part of the North American plate currently above the Yellowstone hotspot . However, the mantle plume hypothesis has been questioned. Sustained upwelling of hot mantle rock can develop under

9048-435: The same time interval. Volcanoes vary greatly in their level of activity, with individual volcanic systems having an eruption recurrence ranging from several times a year to once in tens of thousands of years. Volcanoes are informally described as erupting , active , dormant , or extinct , but the definitions of these terms are not entirely uniform among volcanologists. The level of activity of most volcanoes falls upon

9152-492: The same way; they are often described as "caldera volcanoes". Submarine volcanoes are common features of the ocean floor. Volcanic activity during the Holocene Epoch has been documented at only 119 submarine volcanoes, but there may be more than one million geologically young submarine volcanoes on the ocean floor. In shallow water, active volcanoes disclose their presence by blasting steam and rocky debris high above

9256-478: The shape of a truncated cone. The cone is largely andesitic, though basaltic and dacitic rocks are present. It is located in La Araucanía Region of Chile , immediately southeast of Tolhuaca volcano. Sierra Nevada and Llaima are their neighbors to the south. The snow-capped volcano lies within the protected area Malalcahuello-Nalcas . The volcano last erupted in 1988, ending in 1990. The VEI

9360-622: The solidified erupted material that makes up the mantle of a volcano may be stripped away that its inner anatomy becomes apparent. Using the metaphor of biological anatomy , such a process is called "dissection". Cinder Hill , a feature of Mount Bird on Ross Island , Antarctica , is a prominent example of a dissected volcano. Volcanoes that were, on a geological timescale, recently active, such as for example Mount Kaimon in southern Kyūshū , Japan , tend to be undissected. Eruption styles are broadly divided into magmatic, phreatomagmatic, and phreatic eruptions. The intensity of explosive volcanism

9464-504: The steeper the angle of descent of the subducted slab. As the Pacific's mid-ocean ridges , which are the source of its oceanic lithosphere, are not actually in the middle of the ocean but located much closer to South America than to Asia, the oceanic lithosphere consumed at the South American subduction zones is younger and therefore subduction occurs at the South American coast at a relatively shallow angle. Older oceanic lithosphere

9568-717: The submarine plate boundaries in this part of the Pacific Ocean (the Pacific–Antarctic Ridge , the East Pacific Rise and the Chile Ridge ) are divergent instead of convergent. Although some volcanism occurs in this region, it is not related to subduction. Some geologists include the Izu Islands , the Bonin Islands , and the Mariana Islands , other geologists exclude them. Volcanoes in

9672-477: The summit. In 2009, Kerinci erupted again followed by June 2, 2013 eruption with 600 m (1,969 ft) spewed black smoke. Kerinci was first climbed in December 1877 by Dutch mountaineers Arend Ludolf van Hasselt and Daniël David Veth. It can be climbed from the village of Kersik Tuo, 6 or 7 hours away from Padang by car or bus. The climb and descent normally takes 2 days and 1 night, when choosing to go all

9776-406: The surrounding areas, and initially not seismically monitored before its unanticipated and catastrophic eruption of 1991. Two other examples of volcanoes that were once thought to be extinct, before springing back into eruptive activity were the long-dormant Soufrière Hills volcano on the island of Montserrat , thought to be extinct until activity resumed in 1995 (turning its capital Plymouth into

9880-447: The theory of plate tectonics since the early 1960s has provided the current understanding and explanation of the global distribution of volcanoes and earthquakes, including those in the Ring of Fire. There is consensus among geologists about most of the regions which are included in the Ring of Fire. There are, however, a few regions on which there is no universal agreement. (See: § Distribution of volcanoes ). Indonesia lies at

9984-434: The theory of plate tectonics. For example, some volcanoes are polygenetic with more than one period of activity during their history; other volcanoes that become extinct after erupting exactly once are monogenetic (meaning "one life") and such volcanoes are often grouped together in a geographical region. At the mid-ocean ridges , two tectonic plates diverge from one another as hot mantle rock creeps upwards beneath

10088-444: The thinned oceanic crust . The decrease of pressure in the rising mantle rock leads to adiabatic expansion and the partial melting of the rock, causing volcanism and creating new oceanic crust. Most divergent plate boundaries are at the bottom of the oceans, and so most volcanic activity on Earth is submarine, forming new seafloor . Black smokers (also known as deep sea vents) are evidence of this kind of volcanic activity. Where

10192-431: The underlying ductile mantle , and most volcanic activity on Earth takes place along plate boundaries, where plates are converging (and lithosphere is being destroyed) or are diverging (and new lithosphere is being created). During the development of geological theory, certain concepts that allowed the grouping of volcanoes in time, place, structure and composition have developed that ultimately have had to be explained in

10296-492: The volcano. Solid particles smaller than 2 mm in diameter ( sand-sized or smaller) are called volcanic ash. Tephra and other volcaniclastics (shattered volcanic material) make up more of the volume of many volcanoes than do lava flows. Volcaniclastics may have contributed as much as a third of all sedimentation in the geologic record. The production of large volumes of tephra is characteristic of explosive volcanism. Through natural processes, mainly erosion , so much of

10400-424: The volcanoes of the East African Rift . A volcano needs a reservoir of molten magma (e.g. a magma chamber), a conduit to allow magma to rise through the crust, and a vent to allow the magma to escape above the surface as lava. The erupted volcanic material (lava and tephra) that is deposited around the vent is known as a volcanic edifice , typically a volcanic cone or mountain. The most common perception of

10504-685: The way to the summit. Climbers may also choose to go up only as far as Camp 2 or 3, skipping the summit attempt, which requires a pre-dawn climb. Kerinci's terrain consists of thick jungle and can get muddy and slippery even if there are only mild drizzles, which may occur occasionally even during the dry season. To climb the volcano a guide is needed, as required by the Kerinci Seblat National Park. There have been rare cases of people disappearing and/or dying from exposure or falls after attempting to trek alone. The Kerinci Seblat National Park has at least fifteen lakes of note, with

10608-597: Was 3. The eruption was from a flank vent and involved lava flows and explosive eruptions. Some fatalities occurred. The volcanoes in Chile are monitored by the National Geology and Mining Service (SERNAGEOMIN) Earthquake activity in Chile is related to subduction of the Nazca plate to the east. Chile notably holds the record for the largest earthquake ever recorded, the 1960 Valdivia earthquake . More recently,

10712-421: Was described by Roman writers as having been covered with gardens and vineyards before its unexpected eruption of 79 CE , which destroyed the towns of Herculaneum and Pompeii . Accordingly, it can sometimes be difficult to distinguish between an extinct volcano and a dormant (inactive) one. Long volcano dormancy is known to decrease awareness. Pinatubo was an inconspicuous volcano, unknown to most people in

10816-534: Was subducting under east Asia and North America, while the Farallon plate was subducting under South America and the Pacific plate was subducting under east Asia. About 70 to 65 million years ago, the Farallon plate was subducting under South America, the Kula plate was subducting under North America and north-east Asia, and the Pacific plate was subducting under east Asia and Papua New Guinea. About 35 million years ago,

#609390