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91-534: Sairecabur ( Spanish pronunciation: [sajɾekaˈβuɾ] ) is a volcano located on the frontier between Bolivia and Chile . It is part of the Andean Central Volcanic Zone . Sairecabur proper is 5,971 m (19,590 ft) high; other mountains in the range are 5,722 m (18,773 ft) high Curiquinca , 5,819 m (19,091 ft) high Escalante and 5,748 m (18,858 ft) high Cerro Colorado, all of which have erupted

182-525: A crater lake . Puritama volcano west of Sairecabur has generated 16 kilometres (9.9 mi) lava flows that extend along tectonic canyons. 5,722-metre (18,773 ft) high Curiquinca ( 22°36′00″S 67°52′00″W  /  22.60000°S 67.86667°W  / -22.60000; -67.86667 ) and 5,748-metre (18,858 ft) high Cerro Colorado ( 22°35′00″S 67°55′00″W  /  22.58333°S 67.91667°W  / -22.58333; -67.91667 ) are found northwest and northeast, respectively, of

273-621: A drainage divide between the Salar de Atacama on the western side and a number of small endorheic basins in Bolivia on the eastern side. Licancabur and Juriques farther south and Tocorpuri farther north are part of the same divide. Dry valleys on the eastern side of the Sairecabur range ultimately drain into Laguna Verde. The Rio Purifica originates on Sairecabur's slope at an altitude of 3,950 metres (12,960 ft), it later converges with

364-560: A ghost town ) and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE. Antofagasta Region Antofagasta's climate is extremely arid, albeit somewhat milder near the coast. Nearly all of the region is devoid of vegetation, except close to the Loa River and at oases such as San Pedro de Atacama . Much of the inland is covered by salt flats , tephra and lava flows , and

455-886: 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

546-414: 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,

637-519: A few have documented activity. The geologist Juan Brüggen in 1950 estimated that there were about 800 volcanoes in northern Chile, about 37 of them east of the Salar de Atacama . Also part of the volcanism are large ignimbrites , which are usually thought to be of Miocene age. Those in the area of Sairecabur often originated in the neighbourhood to the conical volcanoes. The volcanoes formed over crust with thicknesses reaching 70 km (43 mi), thus

728-437: 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,

819-405: A large degree of autonomy. The mining industry regularly accounts for more than 90% of the region's exports. Fishing and manufacturing also contribute to the income of the area. The availability of infrastructure and services, due to the region's mining boom, together with its abundance of beautiful natural scenery, have opened vast prospects for the travel industry, both in the interior and on

910-610: A massive Chilean colonization of the coastline. Friction between the new settlers from both countries grew until 1879 when the War of the Pacific erupted. Antofagasta was permanently annexed by the Chilean government at the end of the war. Colonization by Chileans followed mainly from Norte Chico (the contemporary regions of Atacama and Coquimbo , also known as the III and IV regions), into

1001-423: A number of lava flows . Also in close proximity to Sairecabur lie the volcanic centres Licancabur , Putana and Juriques . Sairecabur proper is accompanied by a 4.5 km (2.8 mi) wide caldera . Before the formation of this caldera the volcano may have been 7,000 m (23,000 ft) high and thus one of the highest volcanoes on Earth. After the formation of this caldera lava effusion occurred during

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1092-443: 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

1183-412: A telescope which operates in the terahertz range of the electromagnetic spectrum ; ground-based astronomy in this range was long considered to be impossible since the atmosphere absorbs radiation in that frequency range heavily. With an altitude of 5,525 metres (18,127 ft) the telescope is the highest submillimeter telescope in the world. Volcano A volcano is a rupture in the crust of

1274-632: 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

1365-555: 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

1456-465: 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

1547-403: A west–east pattern. Other volcanoes in the area such as Lascar - Aguas Calientes , Licancabur-Juriques and La Torta -Tocorpuri also form such alignments which seem to be controlled by north–south tension in the crust. Sairecabur is located on faults which are also apparent at Laguna Verde. Escalante and Sairecabur have erupted dark andesites, and later also dacites. Mafic enclaves are found in

1638-739: 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

1729-412: 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

1820-565: 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

1911-584: 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

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2002-462: Is inconsistent with stratigraphic relationships of this ignimbrite to older ignimbrite. The lava formations are named Post-Caldera Lavas I and Post-Caldera Lavas II; the first is of Pleistocene and the second of Holocene age. A fresh flow that extends northwest from Sairecabur appears to be the most recent flow. The formation of the caldera occurred before the Holocene and preceded the formation of

2093-499: Is no volcanism, associated with a shallow dip of the seismic zone of the subducting plate. Sairecabur is part of the Andean Central Volcanic Zone (CVZ). A number of stratovolcanoes can be found in the area, many of which were affected by explosive eruptions that have destroyed parts of their edifices. Effusion of large amounts of lava took place from several cones. Many volcanoes are extinct and only

2184-537: 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

2275-457: Is the highest volcano in the range. A 4.5-kilometre (2.8 mi) wide caldera exists south of Sairecabur and formed on an older volcano. Lava flows extend from Sairecabur as far as 2.5 kilometres (1.6 mi) to the northwest, and further young lava flows formed south of this caldera. The 5,819-metre (19,091 ft) high Escalante ( 22°37′00″S 67°33′00″W  /  22.61667°S 67.55000°W  / -22.61667; -67.55000 ) has

2366-471: 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

2457-599: The Antofagasta is just 1 millimetre (0.04 in) per year. From the coast, east to the Chilean Coast Range , is the south-central part of the Atacama Desert , the driest desert in the world. Further to the east, it is part of the less arid Central Andean dry puna ecoregion. The surroundings of abandoned Yungay town have been named the driest place in the world. Most of the population lives on

2548-617: 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

2639-646: The Kunza language , from Saire "rain" and cabur or caur "mountain". Sairecabur and Curiquinca both have mountain sanctuaries made by the Inca . Licancabur and Juriques farther south were also sites of such sanctuaries. Sairecabur was considered to be a sacred mountain , and andesite found at some archeological sites in the Atacama may come from Sairecabur. A sulfur mine is active at Saciel, north of Sairecabur. Sulfur mining there, at Cerro Colorado and Putana in

2730-536: The Loa River basin, and valleys and oases across the altiplano, with the most important settlement being the village of San Pedro de Atacama . The Atacaman culture was deeply influenced by Tiwanaku culture and later fell under Inca rule. The Atacamans harvested mainly corn and beans and developed trade as far as the Amazon basin and Pacific shores. The arrival of the Spaniards in the 16th century did not destroy

2821-556: The Pleistocene and Holocene ; there is no reported historical activity, however. Eruption products on Escalante and Sairecabur include andesite and dacite . The climate is dry, cold and very sunny. An Inca sanctuary has been found on Sairecabur, and sulfur mines exist in the mountain chain. More recently, the Receiver Lab Telescope was installed on the volcano. It is the highest submillimeter telescope in

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2912-525: The Rio Puritama to form the San Pedro de Atacama River . The Sairecabur range is a 22-kilometre (14 mi) long chain of volcanoes going from Escalante volcano (south of Putana Volcano ) to Sairecabur proper in the south, including at least ten centres which have been active in postglacial time. Two additional centres exist northeast of Escalante. 5,971-metre (19,590 ft) high Sairecabur

3003-804: 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,

3094-834: 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

3185-466: The mantle involving peridotite and subsequent interaction with the crust and fractional crystallization . Andesites erupted before the caldera formation were produced at temperatures 90 °C (160 °F) higher than dacites erupted after the formation of the caldera. Oxygen , lead and strontium isotope ratios are typical for magmas in CVZ. The Pb isotope ratios are consistent with these found in

3276-520: The 1950s contributed to the growth of San Pedro de Atacama, where the mined sulfur was transported to. A report in 1955 indicated the presence of about 600,000 tonnes (590,000 long tons; 660,000 short tons) ore containing 55–60% sulfur. A 21-kilometre (13 mi) long mining dirt road with a single lane leads from the El Tatio highway to Sairecabur. Sairecabur is since 2003 the site of the 0.8-metre (2 ft 7 in) diameter Receiver Lab Telescope,

3367-622: 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

3458-672: The Purico formation, which is of Pleistocene age and includes ignimbrites from the Purico Complex . The basement beneath Sairecabur and Licancabur contains a large number of faults . Sairecabur is located at a distance of 25 kilometres (16 mi) from San Pedro de Atacama . The volcano saddles the frontier between Bolivia and Chile, where it lies in the Antofagasta Region . Laguna Verde lake, Licancabur volcano and Portezuelo de Chaxas pass lie south of Sairecabur. East of

3549-439: The Sairecabur range lie Mount Nelly and Cerro Laguna Verde . The Treaty of Peace and Friendship (1904) traced the frontier between Bolivia and Chile along the Sairecabur chain. Disagreements between the topographic maps in the two countries mean that the naming of the mountains is often confusing. Escalante is also known as Apagado. The volcano is associated with a mountain range of the same name. The Sairecabur range forms

3640-613: 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

3731-415: The average speed of wind amounted to 5–11 metres per second (16–36 ft/s). Research on plant diversity in the region west of Sairecabur and Licancabur has shown that about 250 plant species occur there, and on the volcano itself extremophilic yeast species have been found. In 1955, penitentes , a form of ice, was reported to be widespread at Saciel. The name of the mountain means "rain mountain" in

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3822-510: 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

3913-446: The caldera-forming eruption of Sairecabur contain glass and have a microlithic texture. The magmas are calc-alkaline with medium-high potassium content. Fumarolically altered rocks are found on the eastern flanks of the chain. Desert patine covers post-caldera lavas. Based on crystal composition, the magmas of Sairecabur formed at temperatures of 850–950 °C (1,560–1,740 °F). The process started by partial melting of

4004-402: 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

4095-604: The climate was wetter. Tritium isotope ratios of present-day snowfall are consistent with the isotope ratios determined for precipitation that arises in the continent, rather than from the Pacific Ocean . The rainshadow effect exercised by the Andes and the stability of the South Pacific High are responsible for this dryness. The dry and cloudless climate together with the low latitude and high altitude gives

4186-400: The coast exhibits prominent cliffs . The region was sparsely populated by indigenous Changos and Atacameños until massive Chilean immigration in conjunction with a saltpeter boom in the later 19th century. Most of the region was organised as Bolivia 's only coastal territory until Chilean takeover in 1879 at the onset of the War of the Pacific . Antofagasta's history is divided, as

4277-587: The coast in Antofagasta and Mejillones , or in Calama in the interior, the hub of the mining industry and the home of a large part of its work force. In the late 19th and early 20th centuries, immigrant settlers also arrived from Europe (mainly Croatians , Italians , Spaniards , Greeks , English , French , and Portuguese peoples), from the Levant , and in smaller numbers from China , Japan , Korea , Peru and Bolivia . Various immigration flows joined with

4368-456: The crust, specifically of the so-called "Antofalla" domain of Andean crust, the remnant of a terrane of Gondwana . The 7 million year-old Chaxas ignimbrite massif has been related to the caldera-forming eruption at Sairecabur. These dacitic ignimbrites spread southwest towards the Salar de Atacama. This high age estimate for the Chaxas ignimbrite however has been questioned, considering that it

4459-473: The culture but transformed it deeply through the process of mestizaje , in which both cultures mixed. Under Spanish rule, Atacaman territory was placed under the administration of the Audiencia Real de Charcas , though it is disputed whether the Audiencia Real de Charcas was to administer only the inland portion or the coast as well. At the time of independence general Simón Bolívar integrated it into

4550-586: The culture of the altiplano region creating the modern culture of the north of Chile, which arguably presents more Andean- and multi-European-features than the Central Valley and mainstream Chilean culture. The Antofagasta Region is the heart of the mining industry, Chile's main source of export revenue. It represents 53% of Chile's mining output, led by copper and followed by potassium nitrate , gold , iodine , and lithium , which means it could have had GDP per capita higher than Luxembourg had it had

4641-799: 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

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4732-461: The erupted magmas are heavily influenced by the crust. A number of the highest stratovolcanoes in the world are in the CVZ. Historical activity has been low in comparison to the volcanic zones of southern Chile and Colombia / Ecuador . In Chile, much of the area of the CVZ is desert and thus difficult to research. Sairecabur is constructed on the two Pliocene -Pleistocene Puripicar and Chaxas formations . Some lavas from Sairecabur have also overrun

4823-431: 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

4914-610: 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

5005-585: 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

5096-492: The glacier, which also left lateral and terminal moraines. Sairecabur volcano is the youngest volcano in the chain; Escalante is also young but not as young as Sairecabur. There are no reports of contemporaneous activity nor has fumarolic activity been reported, although fumaroles and hot springs were found at the shores of Laguna Verde which border on Sairecabur. Future activity at Sairecabur may disturb activity at Atacama Large Millimeter Array , and will most likely involve

5187-466: 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

5278-492: 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

5369-419: 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

5460-551: 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

5551-415: 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

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5642-438: 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

5733-638: The new Republic of Bolivia , under the name of " Litoral Department ". This decision was disputed by the Chilean Government and has been a source of conflict until present times. Chile claimed that according to the Uti possidetis of the Spanish crown, the coastal region belong to them and their territory bordered directly with Peru . Chilean explorers such as Juan López and José Santos Ossa discovered rich nitrate and guano deposits which produced

5824-440: The new territories of Antofagasta and Tarapacá , known as Norte Grande . In the early 20th century the region became a significant base of Chile's union-organizing movements. It continued to depend economically on the nitrate-extraction industry until its replacement by copper mining. Two of the largest and richest open pit mines in the world are located inland from Antofagasta: La Escondida and Chuquicamata . Each province in

5915-452: 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

6006-876: 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

6097-526: The northern cone. Glacial erosion has affected Sairecabur and moraines cover some lava flows south of Sairecabur. The total volume of the Sairecabur proper is about 35 cubic kilometres (8.4 cu mi). Lava flows with a young appearance extend from each of these ten centres. An older centre has generated a 30 kilometres (19 mi) long lava flow that flowed southwestwards. Some older lava flows from Sairecabur were later buried by lava flows from Licancabur. Cerro Colorado and Curiquinca are aligned in

6188-549: 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

6279-420: 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

6370-471: 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

6461-468: 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

6552-474: The other cones in the range. The edifice this caldera formed during the Pliocene- Quaternary considering the morphology of its deposits. During the ice ages , a valley due west of the main Sairecabur summit was occupied by a 8-kilometre (5.0 mi) long glacier that extended down to an elevation of 4,600 metres (15,100 ft); the main Sairecabur summit grew inside of the valley occupied by

6643-425: 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

6734-619: 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

6825-435: The post-caldera lavas. The colour of the rocks is black, brown or gray. Minerals include amphibole , biotite , bronzite , calcium -containing augite , clinopyroxene , hornblende , magnetite , orthopyroxene , plagioclase , pyroxene and quartz . In addition, apatite , ilmenite , iron oxides and zirconia are found. At least one lava erupted after the caldera-forming eruption contains olivine . Lavas erupted before

6916-501: The production of lava domes and lava flows with local impacts. The climate at Sairecabur is dry and cloudless, leading to the absence of glaciers and permanent snowcover at Sairecabur although a 1985 map shows a persistent ice/snow cover in the summit area. Overall the Atacama Altiplano has a desert climate with precipitation below 200 millimetres per year (7.9 in/year), but during the late Pleistocene and early Holocene

7007-520: The range. The caldera is bounded by cliffs reaching a height of 400 metres (1,300 ft), which are buried by lava flows from Sairecabur on the northern rim; one of these lava flows reaches the caldera bottom. The pre-collapse volcano was about 7,000 metres (23,000 ft) high and would have been one of the highest volcanoes in the world; Ojos del Salado reaches an altitude of 6,885 metres (22,589 ft). Sairecabur proper has three cones. Thick (10 metres (33 ft)) and short lava flows emanated from

7098-604: The region is further subdivided into communes . The main river is the Loa . Along the Coastal Cordillera lies Atacama Fault . The area of the Coastal Cordillera around the fault is rich in iron ore constituting the northern part of the so-called Chilean Iron Belt . These ore deposits are often of the manto-type deposits and are chiefly emplaced on rocks of La Negra Formation . The average rainfall in

7189-1056: The region some of the highest insolations on Earth; at Sairecabur it amounts to 98% of the solar constant . The coincidence between the southern hemisphere summer solstice on 21 December and the perihelion , the point of lowest Earth-Sun distance, on 3 January contribute to the high insolation. Ultraviolet radiation is also high in the area, with values 15.6–36.4 watts per square metre (0.00194–0.00453 hp/sq ft) reported for ultraviolet radiation B and ultraviolet radiation A respectively. Temperatures at 5,820 metres (19,090 ft) ranged from −8.7 to −16.3 °C (16.3 to 2.7 °F) in 1991–1994. A series of measurements in 1995 indicated that surface temperatures at an altitude of 5,820 metres (19,090 ft) range from −20 to 20 °C (−4 to 68 °F) in winter, and soil temperatures at depths of 5 centimetres (2.0 in) also in winter between almost 10 °C (50 °F) and less than −10 °C (14 °F). There are large differences between daytime and night temperatures. Between 1991 and 1994

7280-435: 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

7371-492: 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

7462-622: 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

7553-406: 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

7644-527: The territory itself, into two sections: the coastal region, and the highlands plateau or altiplano around the Andes . In pre-Columbian times, the coastline was populated by nomadic fishing clans of Changos Indians, of which very little is known due to very limited contact with the Spanish conquerors . The inland section was populated by the Atacaman culture around the great dry salt lake Salar de Atacama ,

7735-434: 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

7826-444: 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

7917-431: 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

8008-492: 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

8099-424: 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

8190-908: The world at an altitude of 5,525 m (18,127 ft). West of South America , the Nazca Plate subducts beneath the South America Plate . This process has formed the Andean Volcanic Belt , which is subdivided into the Northern Volcanic Zone , the Central Volcanic Zone and the Southern Volcanic Zone . These belts have different underlying crusts and thus have different typical magma compositions. These volcanic zones are separated from each other by zones where there

8281-421: 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

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