103-539: Licancabur ( Spanish pronunciation: [likaŋkaˈβuɾ] ) is a stratovolcano on the border between Bolivia and Chile, south of the Sairecabur volcano and west of Juriques . Part of the Andean Central Volcanic Zone , it has a prominent, 5,916-metre (19,409 ft)-high cone . A 400–500-metre (1,300–1,600 ft) summit crater containing Licancabur Lake , a crater lake which
206-479: A magma chamber , where crystals formed. The climate is cold, dry, windy with low atmospheric pressure and large day-night temperature differences. On the summit, daytime temperatures range between 5 – −25 °C (41 – −13 °F) and nighttime temperatures between −25 – −40 °C (−13 – −40 °F). Annual mean precipitation at Licancabur is estimated to reach 360 millimetres (14 in), decreasing to 200 metres (660 ft) at its base, but
309-747: A 4-inch thick ash layer can weigh 120-200 pounds and can get twice as heavy when wet. Wet ash also poses a risk to electronics due to its conductive nature. Dense clouds of hot volcanic ash can be expelled due to the collapse of an eruptive column , or laterally due to the partial collapse of a volcanic edifice or lava dome during explosive eruptions . These clouds are known as pyroclastic surges and in addition to ash , they contain hot lava , pumice , rock , and volcanic gas . Pyroclastic surges flow at speeds over 50 mph and are at temperatures between 200 °C – 700 °C. These surges can cause major damage to property and people in their path. Lava flows from stratovolcanoes are generally not
412-546: A ceremonial platform, all in the eastern part of the crater. The structures may have had had roofs and are built like pircas (no mortar). Reports in 1887 and 1955 mention piles of wood. A semicircle of stones surrounding an upright stone has been compared to an altar, ushnu . The summit sites were presumably used for equinox and solstice feasts. Notably, no human sacrifices ( capacocha ) are associated with Licancabur. Another site, Tambo de Licancabur or Tambo Licancabur, lies at 4,600 metres (15,100 ft) elevation on
515-419: A continued supply of lava and its pressure on a solidified crust. Most basaltic lavas are of ʻaʻā or pāhoehoe types, rather than block lavas. Underwater, they can form pillow lavas , which are rather similar to entrail-type pahoehoe lavas on land. Ultramafic lavas, such as komatiite and highly magnesian magmas that form boninite , take the composition and temperatures of eruptions to the extreme. All have
618-455: A darker groundmass , including amphibole or pyroxene phenocrysts. Mafic or basaltic lavas are typified by relatively high magnesium oxide and iron oxide content (whose molecular formulas provide the consonants in mafic) and have a silica content limited to a range of 52% to 45%. They generally erupt at temperatures of 1,100 to 1,200 °C (2,010 to 2,190 °F) and at relatively low viscosities, around 10 to 10 cP (10 to 100 Pa⋅s). This
721-420: A dome forms on an inclined surface it can flow in short thick flows called coulées (dome flows). These flows often travel only a few kilometres from the vent. Lava tubes are formed when a flow of relatively fluid lava cools on the upper surface sufficiently to form a crust. Beneath this crust, which being made of rock is an excellent insulator, the lava can continue to flow as a liquid. When this flow occurs over
824-479: A fast moving mudflow . Lahars are typically about 60% sediment and 40% water. Depending on the abundance of volcanic debris the lahar can be fluid or thick like concrete. Lahars have the strength and speed to flatten structures and cause great bodily harm, gaining speeds up to dozens of kilometers per hour. In the 1985 eruption of Nevado del Ruiz in Colombia , Pyroclastic surges melted snow and ice atop
927-515: A final intermediate composition . When the magma nears the top surface, it pools in a magma chamber within the crust below the stratovolcano. The processes that trigger the final eruption remain a question for further research. Possible mechanisms include: These internal triggers may be modified by external triggers such as sector collapse , earthquakes , or interactions with groundwater . Some of these triggers operate only under limited conditions. For example, sector collapse (where part of
1030-465: A massive dense core, which is the most active part of the flow. As pasty lava in the core travels downslope, the clinkers are carried along at the surface. At the leading edge of an ʻaʻā flow, however, these cooled fragments tumble down the steep front and are buried by the advancing flow. This produces a layer of lava fragments both at the bottom and top of an ʻaʻā flow. Accretionary lava balls as large as 3 metres (10 feet) are common on ʻaʻā flows. ʻAʻā
1133-471: A mixture of volcanic ash and other fragments called tephra , not lava flows.) The viscosity of most lava is about that of ketchup , roughly 10,000 to 100,000 times that of water. Even so, lava can flow great distances before cooling causes it to solidify, because lava exposed to air quickly develops a solid crust that insulates the remaining liquid lava, helping to keep it hot and inviscid enough to continue flowing. The word lava comes from Italian and
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#17327942576841236-769: A result of intraplate volcanism on oceanic islands far from plate boundaries. Examples are Teide in the Canary Islands , and Pico do Fogo in Cape Verde . Stratovolcanoes in the East African Rift include Ol Doinyo Lengai in Tanzania, and Longonot in Kenya. Subduction zone volcanoes form when hydrous minerals are pulled down into the mantle on the slab. These hydrous minerals, such as chlorite and serpentine , release their water into
1339-461: A significant threat to humans or animals because the highly viscous lava moves slowly enough for everyone to evacuate. Most deaths attributed to lava are due to related causes such as explosions and asphyxiation from toxic gas . Lava flows can bury homes and farms in thick volcanic rock which greatly reduces property value. However, not all stratovolcanoes erupt viscous and sticky lava . Nyiragongo , near Lake Kivu in central Africa ,
1442-960: A silica content greater than 63%. They include rhyolite and dacite lavas. With such a high silica content, these lavas are extremely viscous, ranging from 10 cP (10 Pa⋅s) for hot rhyolite lava at 1,200 °C (2,190 °F) to 10 cP (10 Pa⋅s) for cool rhyolite lava at 800 °C (1,470 °F). For comparison, water has a viscosity of about 1 cP (0.001 Pa⋅s). Because of this very high viscosity, felsic lavas usually erupt explosively to produce pyroclastic (fragmental) deposits. However, rhyolite lavas occasionally erupt effusively to form lava spines , lava domes or "coulees" (which are thick, short lava flows). The lavas typically fragment as they extrude, producing block lava flows. These often contain obsidian . Felsic magmas can erupt at temperatures as low as 800 °C (1,470 °F). Unusually hot (>950 °C; >1,740 °F) rhyolite lavas, however, may flow for distances of many tens of kilometres, such as in
1545-450: A silica content under 45%. Komatiites contain over 18% magnesium oxide and are thought to have erupted at temperatures of 1,600 °C (2,910 °F). At this temperature there is practically no polymerization of the mineral compounds, creating a highly mobile liquid. Viscosities of komatiite magmas are thought to have been as low as 100 to 1000 cP (0.1 to 1 Pa⋅s), similar to that of light motor oil. Most ultramafic lavas are no younger than
1648-441: A similar manner to ʻaʻā flows but their more viscous nature causes the surface to be covered in smooth-sided angular fragments (blocks) of solidified lava instead of clinkers. As with ʻaʻā flows, the molten interior of the flow, which is kept insulated by the solidified blocky surface, advances over the rubble that falls off the flow front. They also move much more slowly downhill and are thicker in depth than ʻaʻā flows. Pillow lava
1751-575: A temperature of 1,100 to 1,200 °C (2,010 to 2,190 °F). On the Earth, most lava flows are less than 10 km (6.2 mi) long, but some pāhoehoe flows are more than 50 km (31 mi) long. Some flood basalt flows in the geologic record extend for hundreds of kilometres. The rounded texture makes pāhoehoe a poor radar reflector, and is difficult to see from an orbiting satellite (dark on Magellan picture). Block lava flows are typical of andesitic lavas from stratovolcanoes. They behave in
1854-501: A volcano extrudes silicic lava, it can form an inflation dome or endogenous dome , gradually building up a large, pillow-like structure which cracks, fissures, and may release cooled chunks of rock and rubble. The top and side margins of an inflating lava dome tend to be covered in fragments of rock, breccia and ash. Examples of lava dome eruptions include the Novarupta dome, and successive lava domes of Mount St Helens . When
1957-402: Is a large subsidence crater, can form in a stratovolcano, if the magma chamber is partially or wholly emptied by large explosive eruptions; the summit cone no longer supports itself and thus collapses in on itself afterwards. Such features may include volcanic crater lakes and lava domes after the event. However, calderas can also form by non-explosive means such as gradual magma subsidence. This
2060-531: Is a passive release of gas during periods of dormancy. As per the above examples, while eruptions like Mount Unzen have caused deaths and local damage, the impact of the June 1991 eruption of Mount Pinatubo was seen globally. The eruptive columns reached heights of 40 km and dumped 17 megatons of SO 2 into the lower stratosphere . The aerosols that formed from the sulfur dioxide (SO 2 ), carbon dioxide (CO 2 ), and other gases dispersed around
2163-462: Is among the highest lakes in the world, caps the volcano. There are no glaciers owing to the arid climate . Numerous animal species and plants live on the mountain. Licancabur formed atop of Pleistocene ignimbrites and has been active during the Holocene , after the ice ages . Three stages of lava flows emanate from the edifice and have a young appearance. Although no historic eruptions of
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#17327942576842266-415: Is basaltic lava that has a smooth, billowy, undulating, or ropy surface. These surface features are due to the movement of very fluid lava under a congealing surface crust. The Hawaiian word was introduced as a technical term in geology by Clarence Dutton . A pāhoehoe flow typically advances as a series of small lobes and toes that continually break out from a cooled crust. It also forms lava tubes where
2369-544: Is capped by a 500 metres (1,600 ft)-400 metres (1,300 ft) wide summit crater . The 70 by 90 metres (230 ft × 300 ft) freshwater Licancabur Lake in the crater is one of the highest lakes in the world. The western slopes are better developed than the eastern. The total volume of the volcano is about 35 cubic kilometres (8.4 cu mi) or 44 cubic kilometres (11 cu mi), formed by layers of lava and pyroclastics . There are traces of lahars . Young-looking black-grey lava flows emanate from
2472-719: Is concentrated in a thin layer in the toothpaste next to the tube and only there does the toothpaste behave as a fluid. Thixotropic behavior also hinders crystals from settling out of the lava. Once the crystal content reaches about 60%, the lava ceases to behave like a fluid and begins to behave like a solid. Such a mixture of crystals with melted rock is sometimes described as crystal mush . Lava flow speeds vary based primarily on viscosity and slope. In general, lava flows slowly, with typical speeds for Hawaiian basaltic flows of 0.40 km/h (0.25 mph) and maximum speeds of 10 to 48 km/h (6 to 30 mph) on steep slopes. An exceptional speed of 32 to 97 km/h (20 to 60 mph)
2575-578: Is difficult owing to the unstable slopes of the upper cone. Stratovolcano A stratovolcano , also known as a composite volcano , is a conical volcano built up by many alternating layers ( strata ) of hardened lava and tephra . Unlike shield volcanoes , stratovolcanoes are characterized by a steep profile with a summit crater and explosive eruptions. Some have collapsed summit craters called calderas . The lava flowing from stratovolcanoes typically cools and solidifies before spreading far, due to high viscosity . The magma forming this lava
2678-565: Is highly variable in space and time. The Atacama Desert is one of the driest on Earth. The arid climate is due to subsidence of air within the South Pacific Anticyclone , which extends to the Andes. Owing to the dry climate, snow cover on Licancabur is ephemeral and there are no glaciers . During the local Last Glacial Maximum the snowline may have decreased to 4,000–4,800 metres (13,100–15,700 ft) elevation but there
2781-546: Is mostly determined by composition but also depends on temperature and shear rate. Lava viscosity determines the kind of volcanic activity that takes place when the lava is erupted. The greater the viscosity, the greater the tendency for eruptions to be explosive rather than effusive. As a result, most lava flows on Earth, Mars, and Venus are composed of basalt lava. On Earth, 90% of lava flows are mafic or ultramafic, with intermediate lava making up 8% of flows and felsic lava making up just 2% of flows. Viscosity also determines
2884-475: Is no evidence of glacial activity on Licancabur. Periglacial phenomena occur on Licancabur. The region likely has Earth's highest insolation rate. Plants growing on Licancabur include grasses, tola and yareta at high and cacti at low elevations. There is a vertical structure, with cushion plants and tussocks dominating between 3,850–4,200 metres (12,630–13,780 ft) elevation, widely spaced shrubs between 2,700–3,100 metres (8,900–10,200 ft), and
2987-476: Is often felsic , having high to intermediate levels of silica (as in rhyolite , dacite , or andesite ), with lesser amounts of less viscous mafic magma . Extensive felsic lava flows are uncommon, but can travel as far as 8 km (5 mi). The term composite volcano is used because the strata are usually mixed and uneven instead of neat layers. They are among the most common types of volcanoes; more than 700 stratovolcanoes have erupted lava during
3090-694: Is on the edge between the Altiplano and the Salar de Atacama basin. The basement contains intrusions of Paleozoic and sedimentary rocks of Mesozoic age, forming the " Antofalla domain" of the Arequipa-Antofalla tectonic block that originated separately from South America. Between 4 kilometres (2.5 mi) and 30 kilometres (19 mi) depth is the Altiplano-Puna Magma Body , a giant magma chamber that extends under
3193-737: Is one of several volcanoes that figure on the Chilean passport . The volcano is in the Puna de Atacama / Cordillera Occidental of the Andes. Politically, it is located in the Antofagasta Region of Chile and the Potosí Department of Bolivia; the border goes over Licancabur. Less than 20 kilometres (12 mi) south is the Llano del Chajnantor Observatory . San Pedro de Atacama is 32 kilometres (20 mi) west of Licancabur while
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3296-444: Is one of three basic types of flow lava. ʻAʻā is basaltic lava characterized by a rough or rubbly surface composed of broken lava blocks called clinker. The word is Hawaiian meaning "stony rough lava", but also to "burn" or "blaze"; it was introduced as a technical term in geology by Clarence Dutton . The loose, broken, and sharp, spiny surface of an ʻaʻā flow makes hiking difficult and slow. The clinkery surface actually covers
3399-613: Is part of the Eduardo Avaroa Andean Fauna National Reserve . In Chile, there were plans to create a protected area including Licancabur and El Tatio , but as of 2018 no progress had been made. The volcano formed mostly during the Late Pleistocene - Holocene , and bears no traces of glacial erosion. There are three generations of lava flows distinguishable through their appearance and chemistry: The basal unit, which crops out at
3502-478: Is probably derived from the Latin word labes , which means a fall or slide. An early use of the word in connection with extrusion of magma from below the surface is found in a short account of the 1737 eruption of Vesuvius , written by Francesco Serao , who described "a flow of fiery lava" as an analogy to the flow of water and mud down the flanks of the volcano (a lahar ) after heavy rain . Solidified lava on
3605-474: Is similar to the viscosity of ketchup , although it is still many orders of magnitude higher than that of water. Mafic lavas tend to produce low-profile shield volcanoes or flood basalts , because the less viscous lava can flow for long distances from the vent. The thickness of a solidified basaltic lava flow, particularly on a low slope, may be much greater than the thickness of the moving molten lava flow at any one time, because basaltic lavas may "inflate" by
3708-454: Is the lava structure typically formed when lava emerges from an underwater volcanic vent or subglacial volcano or a lava flow enters the ocean. The viscous lava gains a solid crust on contact with the water, and this crust cracks and oozes additional large blobs or "pillows" as more lava emerges from the advancing flow. Since water covers the majority of Earth 's surface and most volcanoes are situated near or under bodies of water, pillow lava
3811-451: Is the most famous example of a hazardous stratovolcano eruption. It completely smothered the nearby ancient cities of Pompeii and Herculaneum with thick deposits of pyroclastic surges and pumice ranging from 6–7 meters deep. Pompeii had 10,000-20,000 inhabitants at the time of eruption. Mount Vesuvius is recognized as one of the most dangerous of the world's volcanoes, due to its capacity for powerful explosive eruptions coupled with
3914-422: Is typical of many shield volcanoes. Cinder cones and spatter cones are small-scale features formed by lava accumulation around a small vent on a volcanic edifice. Cinder cones are formed from tephra or ash and tuff which is thrown from an explosive vent. Spatter cones are formed by accumulation of molten volcanic slag and cinders ejected in a more liquid form. Another Hawaiian English term derived from
4017-450: Is typically between 700 and 1,200 °C (1,300-2,200 °F). Volcanic bombs are masses of unconsolidated rock and lava that are ejected during an eruption. Volcanic bombs are classified as larger than 64mm (2.5 inches). Anything below 64mm is classified as a volcanic block . When erupted Bombs are still molten and partially cool and solidify on their descent. They can form ribbon or oval shapes that can also flatten on impact with
4120-516: Is usually of higher viscosity than pāhoehoe. Pāhoehoe can turn into ʻaʻā if it becomes turbulent from meeting impediments or steep slopes. The sharp, angled texture makes ʻaʻā a strong radar reflector, and can easily be seen from an orbiting satellite (bright on Magellan pictures). ʻAʻā lavas typically erupt at temperatures of 1,050 to 1,150 °C (1,920 to 2,100 °F) or greater. Pāhoehoe (also spelled pahoehoe , from Hawaiian [paːˈhoweˈhowe] meaning "smooth, unbroken lava")
4223-646: Is very common. Because it is formed from viscous molten rock, lava flows and eruptions create distinctive formations, landforms and topographical features from the macroscopic to the microscopic. Volcanoes are the primary landforms built by repeated eruptions of lava and ash over time. They range in shape from shield volcanoes with broad, shallow slopes formed from predominantly effusive eruptions of relatively fluid basaltic lava flows, to steeply-sided stratovolcanoes (also known as composite volcanoes) made of alternating layers of ash and more viscous lava flows typical of intermediate and felsic lavas. A caldera , which
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4326-403: Is very dangerous because its magma has an unusually low silica content , making it much less viscous than other stratovolcanoes. Low viscosity lava can generate massive lava fountains , while lava of thicker viscosity can solidify within the vent, creating a volcanic plug . Volcanic plugs can trap gas and create pressure in the magma chamber, resulting in violent eruptions. Lava
4429-456: The Earth's crust is predominantly silicate minerals : mostly feldspars , feldspathoids , olivine , pyroxenes , amphiboles , micas and quartz . Rare nonsilicate lavas can be formed by local melting of nonsilicate mineral deposits or by separation of a magma into immiscible silicate and nonsilicate liquid phases . Silicate lavas are molten mixtures dominated by oxygen and silicon ,
4532-494: The Hawaiian language , a kīpuka denotes an elevated area such as a hill, ridge or old lava dome inside or downslope from an area of active volcanism. New lava flows will cover the surrounding land, isolating the kīpuka so that it appears as a (usually) forested island in a barren lava flow. Lava domes are formed by the extrusion of viscous felsic magma. They can form prominent rounded protuberances, such as at Valles Caldera . As
4635-571: The Holocene . Andesites are the main rocks at Licancabur, with some basaltic andesite and dacite . They define an adakite -like suite, and are less crystalline than rocks of other CVZ volcanoes. The lavas were highly viscous, explaining why the Licancabur cone is so steep. The main phenocryst phase is plagioclase , while amphibole , clinopyroxene , iron- titanium oxides , olivine and orthopyroxene are subordinate. Crystals often form aggregates. Xenoliths of gabbro are found within
4738-824: The Holocene Epoch (the last 11,700 years), and many older, now extinct, stratovolcanoes erupted lava as far back as Archean times. Stratovolcanoes are typically found in subduction zones but they also occur in other geological settings. Two examples of stratovolcanoes famous for catastrophic eruptions are Krakatoa in Indonesia (which erupted in 1883 claiming 36,000 lives) and Mount Vesuvius in Italy (which erupted in 79 A.D killing an estimated 2,000 people). In modern times, Mount St. Helens (1980) in Washington State , US, and Mount Pinatubo (1991) in
4841-579: The Philippines have erupted catastrophically, but with fewer deaths. Stratovolcanoes are common at subduction zones , forming chains and clusters along plate tectonic boundaries where an oceanic crust plate is drawn under a continental crust plate (continental arc volcanism, e.g. Cascade Range , Andes , Campania ) or another oceanic crust plate ( island arc volcanism, e.g. Japan , Philippines , Aleutian Islands ). Stratovolcanoes also occur in some other geological settings, for example as
4944-838: The Proterozoic , with a few ultramafic magmas known from the Phanerozoic in Central America that are attributed to a hot mantle plume . No modern komatiite lavas are known, as the Earth's mantle has cooled too much to produce highly magnesian magmas. Some silicate lavas have an elevated content of alkali metal oxides (sodium and potassium), particularly in regions of continental rifting , areas overlying deeply subducted plates , or at intraplate hotspots . Their silica content can range from ultramafic ( nephelinites , basanites and tephrites ) to felsic ( trachytes ). They are more likely to be generated at greater depths in
5047-520: The Snake River Plain of the northwestern United States. Intermediate or andesitic lavas contain 52% to 63% silica, and are lower in aluminium and usually somewhat richer in magnesium and iron than felsic lavas. Intermediate lavas form andesite domes and block lavas and may occur on steep composite volcanoes , such as in the Andes . They are also commonly hotter than felsic lavas, in
5150-548: The South American Plate in the Peru-Chile Trench . The subduction is still ongoing at a rate of 6.6 centimetres per year (2.6 in/year) and is responsible for the volcanism in the Andes, as fluids emanating from the downgoing plate trigger melting within the overlying asthenosphere . The Andean Central Volcanic Zone (CVZ) extends from southern Peru over Bolivia to Chile and Argentina, it features
5253-891: The magma is too viscous to allow easy escape of volcanic gases . As a consequence, the tremendous internal pressures of the trapped volcanic gases remain and intermingle in the pasty magma . Following the breaching of the vent and the opening of the crater, the magma degasses explosively. The magma and gases blast out with high speed and full force. Since 1600 CE , nearly 300,000 people have been killed by volcanic eruptions . Most deaths were caused by pyroclastic flows and lahars , deadly hazards that often accompany explosive eruptions of subduction-zone stratovolcanoes. Pyroclastic flows are swift, avalanche-like, ground-sweeping, incandescent mixtures of hot volcanic debris, fine ash , fragmented lava , and superheated gases that can travel at speeds over 150 km/h (90 mph). Around 30,000 people were killed by pyroclastic flows during
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#17327942576845356-443: The mantle which decreases its melting point by 60 to 100 °C. The release of water from hydrated minerals is termed " dewatering ", and occurs at specific pressures and temperatures for each mineral, as the plate descends to greater depths. This allows the mantle to partially melt and generate magma . This is called flux melting . The magma then rises through the crust , incorporating silica-rich crustal rock, leading to
5459-418: The most abundant elements of the Earth's crust , with smaller quantities of aluminium , calcium , magnesium , iron , sodium , and potassium and minor amounts of many other elements. Petrologists routinely express the composition of a silicate lava in terms of the weight or molar mass fraction of the oxides of the major elements (other than oxygen) present in the lava. The silica component dominates
5562-616: The 1902 eruption of Mount Pelée on the island of Martinique in the Caribbean . During March and April 1982, El Chichón in the State of Chiapas in southeastern Mexico , erupted 3 times, causing the worst volcanic disaster in that country's history and killied more than 2,000 people in pyroclastic flows . Two Decade Volcanoes that erupted in 1991 provide examples of stratovolcano hazards. On 15 June, Mount Pinatubo erupted and caused an ash cloud to shoot 40 km (25 mi) into
5665-485: The 1982 eruption of Galunggung in Java , British Airways Flight 9 flew into the ash cloud, causing it to sustain temporary engine failure and structural damage. Although no crashes have happened due to ash, more than 60, mostly commercial aircraft , have been damaged. Some of these incidents resulted in emergency landings. Ashfalls are a threat to health when inhaled and are also a threat to property. A square yard of
5768-585: The 5,321 m (17,457 ft) high Andean volcano. The ensuing lahar killed 25,000 people and flooded the city of Armero and nearby settlements. As a volcano forms, several different gases mix with magma in the volcanic chamber. During an eruption the gases are then released into the atmosphere which can lead to toxic human exposure. The most abundant of these gases is H 2 O ( water ) followed by CO 2 ( carbon dioxide ), SO 2 ( sulfur dioxide ), H 2 S ( hydrogen sulfide ), and HF ( hydrogen fluoride ). If at concentrations of more than 3% in
5871-594: The adjacent region in Bolivia is largely uninhabited. The border crossing Paso de Jama and the Chile Route 27 between Argentina and Chile pass along the southern foot of Licancabur. In 1953, a road led to 4,300 metres (14,000 ft) elevation. Licancabur is a 1.5 kilometres (0.93 mi) high and 9 kilometres (5.6 mi) wide uneroded symmetrical cone with steep slopes. The mountain dominates its surroundings. The summit at 5,916 metres (19,409 ft) elevation
5974-819: The air, when breathed in CO 2 can cause dizziness and difficulty breathing. At more than 15% concentration CO 2 causes death. CO 2 can settle into depressions in the land, leading to deadly, odorless pockets of gas. SO 2 classified as a respiratory, skin, and eye irritant if come into contact with. It is known for its pungent egg smell and role in ozone depletion and has the potential to cause acid rain downwind of an eruption. H 2 S has an even stronger odor than SO 2 as well as being even more toxic. Exposure for less than an hour at concentrations of over 500 ppm causes death. HF and similar species can coat ash particles and once deposited can poison soil and water. Gases are also emitted during volcanic degassing, which
6077-748: The air. It produced large pyroclastic surges and lahar floods that caused a lot of damage to the surrounding area. Pinatubo , located in Central Luzon just 90 km (56 mi) west-northwest of Manila , had been dormant for six centuries before the 1991 eruption. This eruption was one of the 2nd largest in the 20th century. It produced a large volcanic ash cloud that affected global temperatures, lowering them in areas as much as .5 °C. The volcanic ash cloud consisted of 22 million tons of SO 2 which combined with water droplets to create sulfuric acid . In 1991 Japan's Unzen Volcano also erupted, after 200 years of inactivity. It's located on
6180-989: The aspect (thickness relative to lateral extent) of flows, the speed with which flows move, and the surface character of the flows. When highly viscous lavas erupt effusively rather than in their more common explosive form, they almost always erupt as high-aspect flows or domes. These flows take the form of block lava rather than ʻaʻā or pāhoehoe. Obsidian flows are common. Intermediate lavas tend to form steep stratovolcanoes, with alternating beds of lava from effusive eruptions and tephra from explosive eruptions. Mafic lavas form relatively thin flows that can move great distances, forming shield volcanoes with gentle slopes. In addition to melted rock, most lavas contain solid crystals of various minerals, fragments of exotic rocks known as xenoliths , and fragments of previously solidified lava. The crystal content of most lavas gives them thixotropic and shear thinning properties. In other words, most lavas do not behave like Newtonian fluids, in which
6283-403: The environment at Laguna Verde, causing changes in water chemistry. An explosive eruption took place at some point, producing pyroclastic flows . The flank lava flows are the most recent activity. There are no known historical or Holocene eruptions, and the preservation of Inca ruins in the summit crater implies that it has been inactive for 600–1000 years. However, the elevated temperatures of
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#17327942576846386-418: The eruption. A cooling lava flow shrinks, and this fractures the flow. Basalt flows show a characteristic pattern of fractures. The uppermost parts of the flow show irregular downward-splaying fractures, while the lower part of the flow shows a very regular pattern of fractures that break the flow into five- or six-sided columns. The irregular upper part of the solidified flow is called the entablature , while
6489-540: The flank of a volcano collapses in a massive landslide) can only trigger the eruption of a very shallow magma chamber . Magma differentiation and thermal expansion also are ineffective as triggers for eruptions from deep magma chambers . In recorded history , explosive eruptions at subduction zone ( convergent-boundary ) volcanoes have posed the greatest hazard to civilizations. Subduction-zone stratovolcanoes, such as Mount St. Helens , Mount Etna and Mount Pinatubo , typically erupt with explosive force because
6592-654: The flood basalts of South America formed in this manner. Flood basalts typically crystallize little before they cease flowing, and, as a result, flow textures are uncommon in less silicic flows. On the other hand, flow banding is common in felsic flows. The morphology of lava describes its surface form or texture. More fluid basaltic lava flows tend to form flat sheet-like bodies, whereas viscous rhyolite lava flows form knobbly, blocky masses of rock. Lava erupted underwater has its own distinctive characteristics. ʻAʻā (also spelled aa , aʻa , ʻaʻa , and a-aa , and pronounced [ʔəˈʔaː] or / ˈ ɑː ( ʔ ) ɑː / )
6695-483: The former. The whole Licancabur complex was one of the most important in the region, and may have been part of a wider regional religious centre. The archaeological sites on Licancabur are sometimes interpreted to be part of a lookout system for the region, or as a symbol of Inca dominance in the San Pedro de Atacama area. The Inca road passed at the foot of the volcano, making the site easily accessible. The mountain
6798-478: The ground. Volcanic Bombs are associated with Strombolian and Vulcanian eruptions and basaltic lava . Ejection velocities ranging from 200 to 400 m/s have been recorded causing volcanic bombs to be destructive. Lahars (from a Javanese term for volcanic mudflows) are a mixture of volcanic debris and water. Lahars can result from heavy rainfall during or before the eruption or interaction with ice and snow. Meltwater mixes with volcanic debris causing
6901-458: The high population density of the surrounding Metropolitan Naples area (totaling about 3.6 million inhabitants). In addition to potentially affecting the climate, volcanic ash clouds from explosive eruptions pose a serious hazard to aviation . Volcanic ash clouds consist of ash which is made of silt or sand sized pieces of rock, mineral, volcanic glass . Ash grains are jagged, abrasive, and don't dissolve in water. For example, during
7004-638: The highest plant density found between these belts. Some areas are used as pastures . Isolated wetlands occur at the foot of the volcano. The fauna includes birds ( black-hooded sierra finch , black-winged ground dove and Puna tinamou ), frogs ( Rhinella spinulosa ), insects ( butterflies , cuckoo bees and flies ), lizards ( Liolaemus audituvelatus , Liolaemus barbarae , Liolaemus constanzae , Liolaemus fabiani and Liolaemus puritamensis ), mammals ( Andean hairy armadillo , chinchilla , culpeo , guanaco , southern vizcacha and vicuña ) and toads ( Telmatobius vilamensis ). The Bolivian sector
7107-567: The highest volcanoes in the world ( Ojos del Salado ) and the Altiplano-Puna volcanic complex , one of the largest ignimbrite provinces on Earth. Licancabur is part of the southern CVZ, where there are over a thousand volcanoes. Older ( Miocene ) volcanoes are widespread, while Pleistocene - Holocene systems are concentrated in the main volcanic chain. Lascar erupts every few years. The volcanic chain continues north across Portezuelo Chaxas mountain pass , beginning with Sairecabur . To
7210-497: The icy satellites of the Solar System 's giant planets . The lava's viscosity mostly determines the behavior of lava flows. While the temperature of common silicate lava ranges from about 800 °C (1,470 °F) for felsic lavas to 1,200 °C (2,190 °F) for mafic lavas, its viscosity ranges over seven orders of magnitude, from 10 cP (10 Pa⋅s) for felsic lavas to 10 cP (10 Pa⋅s) for mafic lavas. Lava viscosity
7313-463: The interior of a terrestrial planet (such as Earth ) or a moon onto its surface. Lava may be erupted at a volcano or through a fracture in the crust , on land or underwater, usually at temperatures from 800 to 1,200 °C (1,470 to 2,190 °F). The volcanic rock resulting from subsequent cooling is also often called lava . A lava flow is an outpouring of lava during an effusive eruption . (An explosive eruption , by contrast, produces
7416-504: The island of Kyushu about 40 km (25 mi) east of Nagasaki . Beginning in June, a newly formed lava dome repeatedly collapsed. This generated a pyroclastic flow that flowed down the mountain's slopes at speeds as high as 200 km/h (120 mph). The 1991 eruption of Mount Unzen was one of the worst volcanic disasters in Japan's history, once killing more than 15,000 people in 1792. The eruption of Mount Vesuvius in 79 AD
7519-551: The lake turned bitter and its colour green. Ascending the mountain was considered taboo , and the mountain vigorously defends against violations of its summit; allegedly the 1953 Calama earthquake was in retaliation for the ascent of the mountain in that year. Whether there are legends of Inca treasury associated with Licancabur is unclear. The mountain was first ascended by the Inca or the Atacameno people. The first documented ascent
7622-404: The lava's chemical composition. This temperature range is similar to the hottest temperatures achievable with a forced air charcoal forge. Lava is most fluid when first erupted, becoming much more viscous as its temperature drops. Lava flows quickly develop an insulating crust of solid rock as a result of radiative loss of heat. Thereafter, the lava cools by a very slow conduction of heat through
7725-610: The lava. Other cations , such as ferrous iron, calcium, and magnesium, bond much more weakly to oxygen and reduce the tendency to polymerize. Partial polymerization makes the lava viscous, so lava high in silica is much more viscous than lava low in silica. Because of the role of silica in determining viscosity and because many other properties of a lava (such as its temperature) are observed to correlate with silica content, silicate lavas are divided into four chemical types based on silica content: felsic , intermediate , mafic , and ultramafic . Felsic or silicic lavas have
7828-530: The local communities and fertilize the ground during their copulation . In the local Atacameno mythology the mountain controls fire (and San Pedro water), while in Socaire 's mythology it is a source of water. In another myth Licancabur is the tomb of a legless Inca king that was carried around the region in a litter. A final tale says that once, the crater lake had fresh water. When Inca fled from white people to Licancabur, they hid their treasures. The waters of
7931-464: The lower and upper boundaries. These are described as pipe-stem vesicles or pipe-stem amygdales . Liquids expelled from the cooling crystal mush rise upwards into the still-fluid center of the cooling flow and produce vertical vesicle cylinders . Where these merge towards the top of the flow, they form sheets of vesicular basalt and are sometimes capped with gas cavities that sometimes fill with secondary minerals. The beautiful amethyst geodes found in
8034-467: The lower part that shows columnar jointing is called the colonnade . (The terms are borrowed from Greek temple architecture.) Likewise, regular vertical patterns on the sides of columns, produced by cooling with periodic fracturing, are described as chisel marks . Despite their names, these are natural features produced by cooling, thermal contraction, and fracturing. As lava cools, crystallizing inwards from its edges, it expels gases to form vesicles at
8137-422: The mantle than subalkaline magmas. Olivine nephelinite lavas are both ultramafic and highly alkaline, and are thought to have come from much deeper in the mantle of the Earth than other lavas. Tholeiitic basalt lava Rhyolite lava Some lavas of unusual composition have erupted onto the surface of the Earth. These include: The term "lava" can also be used to refer to molten "ice mixtures" in eruptions on
8240-521: The minimal heat loss maintains a low viscosity. The surface texture of pāhoehoe flows varies widely, displaying all kinds of bizarre shapes often referred to as lava sculpture. With increasing distance from the source, pāhoehoe flows may change into ʻaʻā flows in response to heat loss and consequent increase in viscosity. Experiments suggest that the transition takes place at a temperature between 1,200 and 1,170 °C (2,190 and 2,140 °F), with some dependence on shear rate. Pahoehoe lavas typically have
8343-450: The most important in the region. The mountain is the subject of a number of myths, which view it as the husband of another mountain, the hiding place of Inca or the burial of an Inca king. The name Licancabur comes from the Kunza language , where lican means "people" or "town" and cábur / caur , caure or cauri "mountain"; it may refer to the archaeological sites at
8446-649: The mountain. The name of the volcano has also been translated as "upper village". Other names are Licancáguar, Licancaur (which is another orthography ), Tata Likanku and Volcán de Atacama. It is one of the best known volcanoes of Bolivia and Chile and can be seen from San Pedro de Atacama . The Inca conquered the region in the 14th century, with the Spaniards following in the 16th; today mountaineering and tourism are increasingly important. Research on animal health, remote sensing , telecommunication and Mars -like environments has been conducted at Licancabur. The mountain
8549-435: The northeastern foot of Licancabur. It consists of over a hundred man-made structures and a 70 metres (230 ft) long public square. More than a hundred people could stay at Tambo de Licancabur, which was not permanently inhabited. Both Inca and local pottery styles have been found there. From Tambo de Licancabur, a zig-zag path led up to the mountain, along which there are further Inca structures from which Tambo de Licancabur
8652-446: The physical behavior of silicate magmas. Silicon ions in lava strongly bind to four oxygen ions in a tetrahedral arrangement. If an oxygen ion is bound to two silicon ions in the melt, it is described as a bridging oxygen, and lava with many clumps or chains of silicon ions connected by bridging oxygen ions is described as partially polymerized. Aluminium in combination with alkali metal oxides (sodium and potassium) also tends to polymerize
8755-440: The range of 850 to 1,100 °C (1,560 to 2,010 °F). Because of their lower silica content and higher eruptive temperatures, they tend to be much less viscous, with a typical viscosity of 3.5 × 10 cP (3,500 Pa⋅s) at 1,200 °C (2,190 °F). This is slightly greater than the viscosity of smooth peanut butter . Intermediate lavas show a greater tendency to form phenocrysts . Higher iron and magnesium tends to manifest as
8858-409: The rate of flow is proportional to the shear stress . Instead, a typical lava is a Bingham fluid , which shows considerable resistance to flow until a stress threshold, called the yield stress, is crossed. This results in plug flow of partially crystalline lava. A familiar example of plug flow is toothpaste squeezed out of a toothpaste tube. The toothpaste comes out as a semisolid plug, because shear
8961-489: The rocks. Unlike many neighbouring volcanoes, Licancabur lacks sulfur deposits. The magmas that built Licancabur formed through melting of altered oceanic crust in the slab at 50–100 kilometres (31–62 mi) depth, which in turn leads to melting in the mantle wedge that gives rise to the Licancabur magmas. Assimilation of continental crustal rocks and fractional crystallization of amphibole and garnet would explain trace element patterns. The magmas were stored in
9064-625: The rocky crust. For instance, geologists of the United States Geological Survey regularly drilled into the Kilauea Iki lava lake, formed in an eruption in 1959. After three years, the solid surface crust, whose base was at a temperature of 1,065 °C (1,949 °F), was still only 14 m (46 ft) thick, even though the lake was about 100 m (330 ft) deep. Residual liquid was still present at depths of around 80 m (260 ft) nineteen years after
9167-464: The size of Mount Pinatubo affected the weather for a few years; with warmer winters and cooler summers observed. A similar phenomenon occurred in the April 1815, the eruption of Mount Tambora on Sumbawa island in Indonesia . The Mount Tambora eruption is recognized as the most powerful eruption in recorded history. Its eruption cloud lowered global temperatures as much as 0.4 to 0.7 °C. In
9270-596: The southeast is 5,704 metres (18,714 ft) high Juriques , which formed during the Pleistocene and has a 1.5 kilometres (0.93 mi) wide summit crater; the two volcanoes form an offset in the volcanic chain. Farther south next to Portezuelo del Cajon is Cerro Toco of the Purico complex . The Chaxas lava dome was active during the Pliocene , forming ignimbrites that are now buried under Licancabur. The volcano
9373-598: The southern Altiplano and to Licancabur. At the volcano, the basement is covered by ignimbrites from the Chaxas, La Pacana and Purico volcanoes, and lava domes of dacitic - rhyodacitic composition. Ignimbrites crop out in gorges south of Licancabur. Faults associated with the Calama-Olacapato-El Toro lineament cut through the basement in southeast direction and probably influenced the growth of Licancabur and Juriques. Some faults were active during
9476-420: The summit and the flanks of Licancabur, especially the western one. The volcano is remote from inhabited areas and pyroclastic fallout would be of limited extent. Impacts may extend to Argentina. Prehistoric manmade constructions are widespread on the mountains of the region, including Licancabur and Juriques. The complex on Licancabur includes multiple structures with mostly semicircular or rectangular shapes and
9579-412: The summit crater and surround the cone, reaching distances of 15 kilometres (9.3 mi) from the summit west of Licancabur. The flows are 10–50 metres (33–164 ft) thick block lavas , and feature structures like ridges, levees and blocks several metres thick. A debris avalanche deposit is found on the western side of Licancabur. The slopes of the mountain are notably unstable. The landscape around
9682-420: The summit crater lake imply there is still heat in the volcano, and lava flows overran 13,240 ± 100 years old shorelines at Laguna Verde. Licancabur is considered to be potentially active owing to its good preservation. SERNAGEOMIN deems it a low-hazard volcano, Chile's 68th most dangerous volcano out of 87 as of 2023. Future eruptive processes will probably involve the emission of lava or pyroclastic flows from
9785-520: The volcano are known, lava flows extending into Laguna Verde have been dated to 13,240 ± 100 BP and there may be residual heat in the mountain. The volcano has primarily erupted andesite , with small amounts of dacite and basaltic andesite . Several archaeological sites occur on the mountain, both on its summit and at its northeastern foot. They were built presumably by the Inca or Atacama people for religious and cultural ceremonies, and are among
9888-706: The volcano consists of basins separated by mountain chains. At the northeastern foot of Licancabur is Laguna Verde . The mountain is part of the drainage divide between the Altiplano and the Salar de Atacama . Southwest of Licancabur are the Vilama and San Pedro rivers, which flow to San Pedro de Atacama. Starting in the Jurassic , the Farallon Plate and later the Nazca Plate have been subducting under
9991-448: The western and northeastern foot of the volcano and are the most primitive magmas; the intermediate unit, which forms most of its western and southern sectors; and the upper unit, which forms the central cone and represents the most differentiated magmas. The older flows are found north and west of Licancabur, overlap with flows from Sairecabur and are partly buried by debris avalanche deposits and moraines . Activity at Licancabur impacted
10094-412: The world. The SO 2 in this cloud combined with water (both of volcanic and atmospheric origin) and formed sulfuric acid , blocking a portion of the sunlight from reaching the troposphere . This caused the global temperature to decrease by about 0.4 °C (0.72 °F) from 1992 to 1993. These aerosols caused the ozone layer to reach the lowest concentrations recorded at that time. An eruption
10197-502: The year following the eruption, most of the Northern Hemisphere experienced cooler temperatures during the summer. In the northern hemisphere , 1816 was known as the " Year Without a Summer ". The eruption caused crop failures, food shortages, and floods that killed over 100,000 people across Europe , Asia , and North America . Lava Lava is molten or partially molten rock ( magma ) that has been expelled from
10300-637: Was by Severo Titichoca in November 1884, and the first by Westerners in 22 November 1953 by a group of engineers in Chuquicamata , which reached the summit from the northwest. Licancabur is frequently climbed from the Bolivian side. It can be ascended year round, although more caution is needed during winter. Ascents take six hours, descents about half that. There is a wide panorama from the summit. Bad weather can develop quickly, and ascending Licancabur
10403-480: Was recorded following the collapse of a lava lake at Mount Nyiragongo . The scaling relationship for lavas is that the average speed of a flow scales as the square of its thickness divided by its viscosity. This implies that a rhyolite flow would have to be about a thousand times thicker than a basalt flow to flow at a similar speed. The temperature of most types of molten lava ranges from about 800 °C (1,470 °F) to 1,200 °C (2,190 °F) depending on
10506-425: Was visible; today the path is largely destroyed or blocked by landslides . Tambo de Licancabur has been interpreted either as a site where, during festivities, people who could not ascent the mountain congregated – a base camp , corpahuasi – or as a tambo , an Inca waystation, on the road between San Pedro de Atacama and Inca territories in present-day Bolivia. This interpretation is not mutually exclusive with
10609-557: Was worshipped by the Atacameno and Inca until the 20th century. Licancabur was important in local cultural rituals, and is to this day used in culturally important events. At least one burial in a local cemetery was oriented to Licancabur. There are several legends tied to the mountain: The male Licancabur was married to female Quimal in the Cordillera Domeyko , and the two are considered paramount mountains which protect
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