150-469: Misti is a dormant volcano located in the Andes mountains in southern Peru , rising above Peru's second-largest city, Arequipa . It is a conical volcano with two nested summit craters , the inner one of which contains a volcanic plug or lava dome with active fumaroles . The summit of the volcano lies on the margin of the outer crater and is 5,822 metres (19,101 ft) above sea level. Snow falls on
300-520: A ghost town ) and Fourpeaked Mountain in Alaska, which, before its September 2006 eruption, had not erupted since before 8000 BCE. Juliaca Juliaca ( Spanish: [xuˈljaka] ; Quechua and Aymara : Hullaqa ) is the capital of San Román Province in the Puno Region of southeastern Peru . It is the region's largest city with a population of 276,110 inhabitants ( 2017 ). On
450-484: 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, a mid-ocean ridge , such as the Mid-Atlantic Ridge , has volcanoes caused by divergent tectonic plates whereas
600-410: A subtropical highland climate ( Köppen Cwb/Cwc ) bordering on an alpine tundra climate ( ETH ) with cool to cold temperatures most of the year. The average annual precipitation is 610 millimetres or 24 inches. Winters are dry with freezing nights and mornings, and pleasant afternoon temperatures. The city of Juliaca and its surroundings have various natural and historical tourist attractions, among
750-554: A ceremonial area was reported in 2024. Professor S. I. Bailey from the Harvard College Observatory in 1893 installed the world's highest weather station on Misti. The station was one of several high-altitude stations built at the time, which aimed to investigate the atmosphere at such high altitudes; additionally, the Observatory performed research on the response of the human body to high altitudes and on
900-437: 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,
1050-464: A hydrothermal system. The fumaroles outside of the summit crater are colder, with temperatures of 50–80 °C (122–176 °F), and do not smell of sulfur. Fumarolic vents are surrounded by concentric deposits of anhydrite close to the vent, gypsum at some distance, and sulfur in the colder vents. Other minerals are ammonium sulfate , hematite , ralstonite , soda alum and sodium chloride . Elemental compositions and isotope ratios indicate that
1200-640: A new monitoring station for the volcano was inaugurated. In May 2009 and April 2010, two exercise evacuations of several suburbs of Arequipa were carried out. In 2013, the Peruvian Volcano Observatory (OVI) was inaugurated in Arequipa; it monitors Misti, Ubinas, Ticsani and other Peruvian volcanoes. As of 2021, the monitoring network on Misti includes seismometers , equipment that measures the composition and temperature of hot springs and fumaroles, and sensors for movements or deformations of
1350-443: 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
1500-632: 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
1650-555: 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
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#17327827954791800-465: 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
1950-590: A wet and cold start to the Holocene, the climate in the Western Cordillera may have been moist until 5,200–5,000 years ago, followed by a dry period that lasted until the 16th century AD when the Little Ice Age began. Dormant volcano A volcano is a rupture in the crust of a planetary-mass object , such as Earth , that allows hot lava , volcanic ash , and gases to escape from
2100-432: A yellow "low risk" zone. These are defined by the risk of debris flows , lava flows, mudflows, pyroclastic flows, and tephra fallout. The "high risk" zone encompasses the entire volcanic cone, its immediate surroundings and the valleys that emanate from it. Parts of Arequipa lie in the "high risk" zone. The "intermediate risk" zone surrounds the "high risk" zone, including the lower slopes of neighbouring mountains and most of
2250-739: 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
2400-464: Is a Plinian eruption like the "Fibroso" and "Sacaroso" events or the 1600 Huaynaputina eruption; pyroclastic flows would sweep all the flanks of Misti and past Arequipa, blocking the Rio Chili. Thick ash fall would occur over the entire region, including over the cities of El Alto , La Joya and agricultural areas. A Plinian eruption would require the evacuation of Arequipa. Other hazard scenarios are
2550-539: Is a viewpoint, from which it is possible to see the urban and non-urban areas that comprise the city. The complex was built in just two and a half weeks, and was opened in 1987. It is a three-floor building, located in the north wing of the Plaza Bolognesi. It is a shopping center for handicrafts, where all kinds of clothing are sold (socks, chullos, bootees , shawls, sweaters, rugs, gloves, etc.) woven or manufactured with native materials (llama, alpaca, vicuña ),
2700-411: Is also the principal water resource for the city. Roads leaving the city cross the river on bridges. According to Italian geographer Cumin 1925, there were three small man-made structures of unknown origin in the crater. He noted that they were known since 1677. Inka ceremonial platforms on the summit associated with human sacrifices were probably destroyed by human activities around 1900 AD , although
2850-510: Is at 5,822 metres (19,101 ft) on the northwestern outer crater rim; an iron cross marks the highest point. Other mountains of the Western Cordillera , including Ubinas and Pichu Pichu , can be seen from the summit. The volcano is about 20 kilometres (12 mi) wide and rises abruptly from the surrounding terrain. Estimates of the edifice's volume range reach 150 cubic kilometres (36 cu mi), but more likely its volume
3000-412: 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
3150-411: Is constrained to 2,060–1,920 years before present ; ages of 2,300 BP are probably too old. The eruption produced about 0.4 cubic kilometres (0.096 cu mi) dense rock equivalents of rock and probably lasted a few hours. The eruption had a volcanic explosivity index of 4 or 5. The eruption was probably triggered when fresh andesitic magma entered a pre-existent rhyolitic body. Magma rose through
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#17327827954793300-534: Is constructed on mudflow and pyroclastic flow deposits of the volcano and all the valleys that drain Misti pass directly or indirectly through Arequipa. At least 220,000 people live on the alluvial fans and in the ravines on the southern side of Misti, and are threatened by floods, mudflows and pyroclastic flows emanating from the volcano that can be channelled through the ravines. Individual threats from Misti include: Hazards at Misti are not limited to volcanism. During
3450-1225: Is contentious. The outer summit crater probably formed during this eruption. Tephra layers in the Sallalli and (in this case with less certainty) Mucurca peat bogs close to Sabancaya, and (tentatively) for an ice core in the Antarctic Plateau in Antarctica , are attributed to this eruption. This is the only Plinian eruption during the Holocene. After the 2 ka eruption, activity was limited to small Vulcanian eruptions , mudflows and tephra fallout, including scoria and volcanic ash. Dating has yielded ages of 330, 340, 520, 620, 1035 and 1,300 years before present for several such events. Mudflows took place 1,035 ± 45, 520 ± 25, 340 ± 40 and 330 ± 60 years ago and left 5–15-metre (16–49 ft) thick deposits. Not all of these mudflows are associated with eruptions. Pyroclastic flows and ash falls were emplaced 1,290 ± 100 and 620 ± 50 years ago. The last eruption took place in AD 1440–1470 and produced about 0.006 cubic kilometres (0.0014 cu mi) of ash. It
3600-615: Is currently under the command of the Franciscan Order . This church is a beautiful work of architecture from the time of the republic. It is located in the west wing of the Plaza Bolognesi in the city center. Carved out of red limestone (due to its characteristic color) and with a structure typical of the modern era (iron frame). Like the main Church of Santa Catalina, it only has a bell tower arranged symmetrically unlike
3750-565: 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
3900-432: Is erupted, with mixing particularly important during the last 21,000 years. A recharge of the magma chamber may have occurred at some point before 2000 AD. The overall rate of magma supply is 0.63 cubic kilometres per kiloare (0.15 cu mi/ka), comparable to other stratovolcanoes in volcanic arcs, but with brief surges reaching about 2.1 cubic kilometres per kiloare (0.50 cu mi/ka) and an increased rate during
4050-584: 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
4200-596: Is high enough to melt the sulfur and the fumarolic gases can ignite. Hot springs occur at the foot of the volcano. These include the Humaluso/Umaluso spring north and the Agua Salada, Bedoya/La Bedoya, Calle Cuzco, Charcani V, Chilina Norte, Chilina Sur, Jésus, Ojo de Milagro, Puente de Fierro, Sabandia, Tingo, Yumina and Zemanat south and southwest of Misti. The hottest of these is the Charcani V spring in
4350-400: Is in the southeastern part of the outer crater. The inner crater cuts across metre-thick ash and scoria deposits and historical lava domes and is rimmed by scoria. In the crater is a 120-metre (390 ft) wide and 15-metre (49 ft) high volcanic plug /lava dome, covered with cracks, boulders and fumarolic sulfur deposits; it is fumarolically active. The highest point of the volcano
4500-413: Is made up of pyroclastic rocks and stubby lava flows , which form a 2.2-kilometre (1.4 mi) thick pile. On the northwestern foot, there is a rhyolitic landform named "Hijo de Misti" ("son of Misti"). Misti is surrounded by a fan of volcanic debris, which covers an area of 200 square kilometres (77 sq mi) on Misti and extends 25 kilometres (16 mi) from the volcano. On the southern side,
4650-551: Is no evidence that a supposed Inka settlement was destroyed by this eruption, but the local population fled and the Inka had to resettle the area. Along with other volcanic eruptions around that time and the beginning Spörer Minimum , the AD 1440–1470 eruption of Misti may have affected global climate conditions. In 1600, the volcano was covered by ash from the Huaynaputina. There is no clear evidence of historical eruptions, while
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4800-580: Is no memory of the hazards of volcanic activity, unlike the hazards of earthquake. Before the eruption of Ubinas in 2006–2007, volcanic hazards drew little attention from the Peruvian state and there was little awareness in Arequipa. The volcano is frequently considered a protective figure and not as a threat. A number of people associate volcanoes with lava flows and neglect other volcanic hazards. Beginning in 2005, INGEMMET began monitoring volcanoes in Peru;
4950-529: Is one of the most dangerous volcanoes in the world, as it lies less than 20 kilometres (12 mi) from Arequipa. The city's population exceeds one million people and its northeastern suburbs have expanded on to the slopes of the volcano. The narrow valleys on western and southern flanks are a particular threat, as mudflows and pyroclastic flows can be channelled into the urban area and into important infrastructure, like hydropower plants . Even moderate eruptions can deposit volcanic ash and tephra over most of
5100-537: 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
5250-400: Is only 90 cubic kilometres (22 cu mi) or 40 cubic kilometres (9.6 cu mi). It is notably asymmetric, with the western side more heavily eroded and featuring older rocks than the eastern side. The western rim of the outer crater is about 150 metres (490 ft) higher than the southern. Underneath the Misti cone is an older, eroded stratovolcano ("Misti 1"). The stratovolcano
5400-471: 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
5550-421: The 2007 Peru earthquake . Over time old fumarolic vents shut down and new vents develop, but the configuration of the dome vents is stable over time. The fumarolic activity is correlated to earth tides . The region has a semi-arid climate with temperate temperatures; the annual mean temperature in Arequipa is 13.7 °C (56.7 °F). Temperatures decrease with elevation; in 1910 monthly mean temperatures at
5700-691: The Altiplano , Juliaca is 3,825 metres (12,549 ft) above sea level, is located on the Collao Plateau and is northwest of Lake Titicaca (45 km). It is the largest trade center in the Puno region. Juliaca is near Chachas Lake , the Maravillas river, and near the ruins of Sillustani . The city hosts Juliaca's Carnival each year between February and March. During this very popular event participants, dressed in colorful costumes, gather on
5850-535: The Arequipa Airport , landslides could damage the dams on the Rio Chili, and mudflows would descend the southern slopes. The second scenario involves an eruption like the 2 ka eruption. Thicker ash falls (exceeding 10 centimetres (3.9 in)) could cause buildings to collapse, and pyroclastic flows down the steep slopes south of Misti would reach the suburbs of Arequipa and Chiguata. Most risk assessments are based on these two scenarios. The third scenario
6000-617: 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
6150-626: 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,
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6300-520: The Labor force . In 2008, Juliaca had 15,439 commercial establishments, which amounts to 41% of trade done in the Puno region. It is the commercial hub for the La Rinconada high-altitude city of informal gold mining. The city of Juliaca has become a center of capital investment. As a result, poverty has been reduced, and increased per capita income has come to some of its residents. Juliaca has
6450-582: The Nazca Plate subducts under South America at a rate of 5–6 centimetres per year (2.0–2.4 in/year). The subduction is responsible for the volcanism of the CVZ, as the downgoing slab releases fluids that chemically modify the overlying mantle , causing it to produce melts. Most Peruvian volcanoes have produced potassium -rich andesitic magmas, derived from the mantle and further modified by fractional crystallization and assimilation of material from
6600-551: The Spanish conquest : Andagua volcanic field , Huaynaputina, Sabancaya and Ubinas, and possibly Ticsani , Tutupaca and Yucamane . Other Peruvian volcanoes in the CVZ are Ampato , Casiri , Coropuna , Huambo volcanic field , Purupuruni and Sara Sara . Ubinas is the most active volcano in Peru, having erupted 24 times since 1550. The 1600 eruption of Huaynaputina claimed more than 1,000 casualties; recent eruptions of Sabancaya 1987–1998 and Ubinas 2006–2007 had severe impacts on
6750-834: 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
6900-501: The solar eclipse of April 16, 1893 . Misti was in its time the highest permanently inhabited location on Earth. Another weather station, named "Mt. Blanc Station", was installed at the base of the volcano after 1888. Both were shut down in 1901 when the Observatory decided to only maintain a station in Arequipa; subsequently storms have erased any trace of the summit observatory. Observation of physics phenomena, such as cosmic ray measurements, were sporadically carried out on Misti during
7050-420: The wet season , Arequipa is frequently flooded. Heavy metals , presumably from Misti and Chachani, have been found in river water. In 2001, there was neither emergency planning nor land use planning around Misti; the 2002–2015 development plan mentioned volcanic hazards but did not envisage any specific measures. The last eruption of Misti had taken place shortly before the foundation of Arequipa, and thus there
7200-470: The 1.65 ± 0.04 million years old Aeropuerto or Sencca ignimbrite, and the 1.02 million years old Yura Tuff and Capillune Formation. They were erupted from multiple calderas , one of which is now buried under Chachani. The ignimbrites are covered by volcanic sedimentary rocks and debris from the sector collapse of Pichu Pichu. Misti has erupted mainly andesite , while dacite and rhyolite are less common. There are reports of trachyandesite erupted during
7350-565: The 20th century. Misti rises about 3.5 kilometres (2.2 mi) above Arequipa, the second-largest city in Peru, and is the best known volcano of Peru. The Inka empire 's Condesuyos province included the volcano; presently it is in the Arequipa Department . The mountain is visible from the sea. The volcanoes of Peru are part of the Andean Central Volcanic Zone (CVZ), one of the four volcanic belts of
7500-746: The Andes; the others are the Northern Volcanic Zone , the Southern Volcanic Zone and the Austral Volcanic Zone . The CVZ extends for 1,000 kilometres (620 mi) from southern Peru through Bolivia to northern Argentina and Chile. Volcanoes are numerous in the CVZ, but most are poorly known due to the low population density of much of the Central Andes. Several Peruvian volcanoes have been active since
7650-425: The Central Andes 43,000 years ago. Between 50,000 and 40,000 years ago, the summit of Misti collapsed one or more times above 4,400 metres (14,400 ft) elevation, forming a 6-by-5-kilometre (3.7 mi × 3.1 mi) caldera. Intense pyroclastic eruptions yielded ignimbrites with volumes of 3–5 cubic kilometres (0.72–1.20 cu mi), which cover an area of 100 square kilometres (39 sq mi) on
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#17327827954797800-520: The Global Volcanism Program reports a last eruption in 1985. Mudflows descended the southern valleys until the 17th century. Phreatic eruptions may have taken place in 1577, on the 2 May 1677, 9 July 1784, 28 July 1787 and 10 October 1787. Questionable eruptions are recorded in 1542, 1599, August 1826, August 1830, 1831, September 1869, March 1870. They probably constitute fumarolic activity and often took place after heavy precipitation;
7950-506: The Holocene eruptions. Rhyolites and dacites are associated with explosive eruptions. The volcanic rocks are subdivided into several classes: Pyroxene - amphibole andesites, amphibole andesites, amphibole dacites and amphibole rhyolites; mica has also been reported. The rocks define a potassium-rich calc-alkaline suite typical for Peruvian volcanoes. Phenocrysts include amphibole, augite , biotite , enstatite , plagioclase and titanomagnetite . Magma composition has varied over time and
8100-648: The Inca troops arrived at this part of the Altiplano chasing the collas , they noticed that in the Huaynarroque hill it had drizzled. However, Justo Ruelas affirms that Juliaca comes from the Quechua word Shulla Qaqa (roquedal dew), due to the fact that in the vicinity of the Huaynarroque and Santa Cruz hills, small quartz particles can be seen, which resembles the morning dew that falls on rocks. The Altiplano
8250-883: 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 the core–mantle boundary , 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism , of which
8400-568: The Pacific Ocean and Lake Titicaca. Radiocarbon dating has identified eruptions 8,140, 6,390, 5,200, 4,750, 3,800 and 2,050 years ago; the 3,800 eruption deposited fallout on Nevado Mismi more than 90 kilometres (56 mi) northwest of Misti. The Global Volcanism Program lists eruptions in 310 BCE ± 100, 2230 BCE ± 200, 3510 BCE ± 150, 4020 BCE ± 200, 5390 BCE ± 75 and 7190 BCE ± 150. The last major explosive eruption – one or several events – took place about 2,000 years ago. The date
8550-622: 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
8700-456: The Plaza de Armas de Juliaca, it presents a style essentially Romanesque Due to its importance during the republican era, today it constitutes one of the main tourist attractions of the city. Located in a southeast of the Plaza de Armas, on the top of the hill Waynaruqi. The White Christ, made entirely in concrete and fiberglass, stands out on the horizon of Juliaca. At the foot of the monument
8850-583: The Rio Chili gorge; it is also the closest to the volcano, being only 6 kilometres (3.7 mi) from the crater. The Jésus and Umaluso springs produce gas bubbles. The springs are fed by a low-temperature geothermal system that mostly produces alkaline waters containing bicarbonate , chloride and sulfate . Their waters appear to originate through the mixing of freshwater, magmatic water and chloride-rich deep water. Many of these springs form artificial pools or have water intakes, and several are monitored by INGEMMET for changes in activity. High soil temperatures on
9000-471: The Rio Socabaya and Rio Chili, forming temporary lakes south and north of the volcano that were later affected by earthquakes. Between 24,000 and 12,000 years ago ice fields formed on Chachani and Misti during the last glacial maximum; tephra fell on ice and was reworked by meltwater. Two eruptions 13,700 and 11,300 years ago produced pyroclastic surges that extended 12 kilometres (7.5 mi) away from
9150-613: 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
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#17327827954799300-508: The austral summer (December to March) and amounts to 89.1 millimetres per year (3.51 in/year), a 1910 study found most precipitation to be in the form of snow or hail. During the wet season, rainstorms and flash floods erode the volcanic debris deposits. The snow cover rapidly melts away during the dry season. The El Niño-Southern Oscillation and sea surface temperatures in the Atlantic and Pacific Oceans govern annual rainfall. After
9450-465: The banks where they fish, with which they support themselves...they are strong Indians and of good disposition and there are many who are in the lakes without making sementeras or clothes, eating from roots that they call totora." The constitution of these settlers were registered as Uros de Coata and Uros de Desaguadero , from where the Uros of Coata would be better communicated and related to Juliaca, by
9600-510: 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
9750-402: 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
9900-521: The city's location on the windy Collao Plateau. It is also called the "Sock City" or "Knitting City" because Juliaca was a major center of sock, sweater, and handicraft production. Now the production of clothes, wool and fabrics are industrial processes. It is also home to Inca Manco Capac Airport , the region's main airport. The historian Ramon Rios argues that Juliaca comes from the Quechua words Xullaskca kaipi (it had drizzled) in allusion that when
10050-493: The city. Until 2005, there was little awareness or monitoring of the volcano. Since then, the Peruvian INGEMMET has set up a volcano observatory in Arequipa, run public awareness campaigns on the dangers of renewed eruptions and published a hazard map. The Inca viewed the volcano as a threat and during the 1440–1470 eruption offered human sacrifices ( capacocha ) on its summit and that of its neighbours to calm
10200-426: The cone, hot springs and fumaroles indicate that Misti contains a hydrothermal system. Electric potential measurements indicate that the system appears to be confined between faults or to the older caldera. The activity has not been stable over time; after the 2001 southern Peru earthquake flow at the Charcani V spring and the temperature of the crater emissions increased noticeably. Water temperatures decreased after
10350-417: The crater rim, and, at times, the gas becomes so concentrated that it causes irritations to the eyes, nose and throat. Fumarolic activity has been reported since the 1440–1470 eruption. In 1948–1949 and 1984–1985 it was intense enough to be seen from Arequipa. The fumarolic activity is visible in satellite images as a temperature anomaly of about 6 K (11 °F). Water is the most important component of
10500-406: The edifice and expelled part of the hydrothermal system, causing initial phreatic eruptions . Tephra rained down around the edifice, with pumice falling 25 kilometres (16 mi) from the volcano. Owing to magma mixing, the pumice deposits have an appearance resembling chocolate and vanilla swirls. Eventually, the conduit fully cleared and a 29-kilometre (18 mi) high eruption column rose above
10650-581: The edifice slip southward over time. A northwest-southeast trending fault system includes the Huanca fault at Chachani and the Chili fault on Misti. The faults were active during the Holocene , offsetting tephra deposits, and may have provided a pathway for magma to ascend and form the volcanoes of Arequipa. Other faults include north- and northeast-trending faults, which are inactive but could have influenced
10800-508: The edifice. These efforts have yielded an increased awareness of the dangers posed by Misti, which is now being increasingly perceived as an active volcano. Efforts have been made to slow the growth of the northern suburbs of Arequipa, which are closest to Misti. A volcano hazard map was developed in 2005 by numerous local and international organizations, and officially presented on the 17 January 2008. It defines three hazard categories: A red "high risk" zone, an orange "intermediate risk" zone and
10950-556: The edifice. They eventually join to the Rio Chili west and Rio Andamayo south of Misti; the Andamayo joins the Chili south of Arequipa. Quebrada San Lazaro and Quebrada Huarangual have formed alluvial fans at the foot of the volcano. The quebradas (dry valleys) carry water during the wet season in November–December and March–April. During the wet season, snow can cover an area of 1–7 square kilometres (0.39–2.70 sq mi) on
11100-403: The emissions of short lava flows , the formation and collapse of lava domes and the collapse of part of the volcanic edifice. Fumaroles on Misti occur in three locations: on the volcanic plug, the northern/northeastern walls of the inner crater, and on the southeastern flank of the volcano. They emit noises, visible clouds of water vapour and the smell of hydrogen sulfide . The smell reaches
11250-815: The emplacement of numerous large ignimbrites . During the Cretaceous - Paleogene , the Toquepala Group of volcanics was emplaced. The Tacaza Arc is the source of the Huaylillas Formation and the Barroso Group of the Sencca Formation. The Nazca fracture zone on the Nazca Plate projects under Misti. Misti is part of the Western Cordillera of the Andes. It is the youngest of a group of three Plio-Pleistocene volcanoes;
11400-799: 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
11550-474: The first Altiplano polities to influence the region or whether previous cultures played a role, but by the arrival of the Spanish the area was densely populated. The pre-Hispanic people built canals, roads and buildings in the area where Arequipa is today. The city itself was founded on 15 August 1540. Misti is the house mountain of Arequipa, appearing on the seal of the city for example. The old roads heading from Arequipa to Chivay and Juliaca run along
11700-515: The first builders of waruwarus and developed a special textile industry. In the years 200 BC to 200 AD, the domain of the Pukara culture expanded in this region of the highlands. Between the third and fourth centuries, the Huaynarroque tribe flourished. Subsequently, the hegemony of Tiahuanaco , Colla and Inka arises consecutively. The kollas and Inka were ruthless rivals and only under
11850-402: The first monitoring equipment was targeted at the Charcani V hot spring . Later the monitoring was extended to other hot springs and to fumaroles in the crater; the latter both visually from Arequipa and in the crater. Monitoring of seismic activity commenced in 2005. Beginning in 2008 geodesic measurement stations were installed on the northeastern and southern slopes of the volcano. In 2012,
12000-431: 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
12150-610: 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
12300-627: The formation of the Rio Chili canyon . The crust under the volcano is 55 kilometres (34 mi) thick. The basement under Misti crops out in the Rio Chili gorge. It consists of Proterozoic rocks of the Arequipa Terrane , which are more than a billion years old, Jurassic sediments of the Socosani Formation and Yura Group, and the Cretaceous-Paleogene La Caldera batholith . The batholith forms
12450-405: The fumarole deposits are derived from the leaching of volcanic rocks and the water from precipitation. The chemistry of the deposits changed between 1967 and 2018, with decreasing zinc and increasing lead concentrations, concomitant with a warming of the fumarolic system that may be due to the arrival of new magma in the volcano during the 20th century. Sometimes the temperature of the fumaroles
12600-446: The fumarole gases, followed by carbon dioxide , sulfur dioxide , hydrogen sulfide and hydrogen . The gases are highly acidic, containing hydrogen chloride and hydrogen sulfide. Fumarole temperatures have varied through the years, generally they are between 125–310 °C (257–590 °F) with peaks of 430 °C (806 °F). The present-day (21st century) fumarole gases appear to derive directly from magma, with no interaction with
12750-585: 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
12900-466: 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
13050-523: The hills south of Arequipa. These formations are covered by rhyodacitic ignimbrites known as "sillars". They are between 13.8 and 2.4 million years old; the older are part of the Huaylillas Formation and the younger of the Barroso Arc. Individual ignimbrites crop out in the Rio Chili gorge and include the 300-metre (980 ft) thick Río Chili ignimbrite from 13.19 ± 0.09 million years ago, the 4.89 ± 0.02 million years old La Joya ignimbrite or "sillar",
13200-492: 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
13350-426: The last 21,000 years. Misti is a young volcano. It developed in four stages, numbered 1 through 4; a pre-Misti volcano may have formed the southwestern debris avalanche. On average, sub- Plinian eruptions take place every 2,000–4,000 years, while ash fallout occurs every 500–1,500 years and large ignimbrite -producing eruptions every 20,000–10,000 years. Outcrops showing the stratigraphy of Misti are found mainly in
13500-507: The local populations. The volcano is a young, symmetric cone with 30° degree slopes and a nested summit crater . The outer crater has a diameter of 950 metres (3,120 ft) or 835 metres (2,740 ft) and is 120 metres (390 ft) deep. There is a gap in the southwestern rim, almost to the bottom of the crater; otherwise the inner crater walls are nearly vertical and consist of lapilli , lava and volcanic ash . The 550-metre (1,800 ft) wide and 200-metre (660 ft) deep inner crater
13650-449: The magmas of Misti is a complicated process, involving the arrival of new magma, assimilation of crustal material, and fractional crystallization. Initially mantle -derived melts pool in a reservoir at the base of the crust , where they assimilate crustal material and undergo fractional crystallization. Afterwards they ascend to a shallower reservoir, where they interact with Proterozoic gneisses . Assimilation of basement rocks gave rise to
13800-419: 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
13950-483: The military command of Pachacútec and his son Mayta Capac were able to subdue the brave Sapana, Chuchicápac and Huaynarroque tribes after bloody wars of conquest. During a political crisis , 18 protestors were shot dead by the police . Juliaca is a large trade center for goods and services , and is considered the financial capital of the Puno region . Trade is its principal economic activity, comprising 26.5% of
14100-551: 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
14250-415: 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
14400-532: The most outstanding are: The Santa Catalina church, Waynaruqi hill, Chacas lagoon and the Kokan community. Located in the Plaza de Armas, it has an indigenous baroque architectural style. The start of its construction dates back to 1649, started by the Jesuits; however it was not completed until 125 years later. Proof of this is its only bell tower, built entirely with ashlar brought from the quarries of Arequipa. It
14550-425: The most recent volcanic stage has produced slightly different magmas, but overall the composition of Misti magmas is highly homogeneous. The composition of Misti magmas and these of its neighbours Pichu Pichu and Chachani resembles adakite , an unusual kind of volcanic rock formed by the direct melting of a subducting plate. Some rocks erupted by the volcano show evidence of hydrothermal alteration. The formation of
14700-408: The mountain. The water source for the mudflows is unclear, but the eruption took place during the neoglacial between 2,500 and 1,000 years ago. Thus Misti may have featured a snow or ice cap at the time of the eruption; its melting would have given rise to mudflows. Rainfall generated further mudflows after the eruption. The relative importance of pyroclastic flows and mudflows during the 2 ka eruption
14850-438: 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
15000-417: The municipality of Arequipa decreed that the hazard map would have to be considered in future city zoning decisions. Three different scenarios of future eruptions have been evaluated. The first envisages a small eruption, similar to recent activity at Sabancaya or the 1440–1470 AD eruption of Misti. Ash fall would occur around the volcano, reaching 5 centimetres (2.0 in) in the urban area and shutting down
15150-401: The nested summit craters. Tephra forms 5–6-metre (16–20 ft) thick deposits around the volcano, and pyroclastic surges reached distances of many kilometres more than 6,400 and 5,200 years ago. The 9,000 and 8,500 years old eruptions produced the "Sándwich" deposits. They extend for more than 15 kilometres (9.3 mi) on the southwestern flank of Misti, but they also resulted in ash fall over
15300-452: 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
15450-876: 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
15600-425: The northeastern parts of Arequipa. The "low risk" zone in turn surrounds the "intermediate risk" zone and includes the rest of the city. Additional maps show areas at risk of tephra fallout and of being flooded by mudflows. The hazard map of Misti is the first hazard map of a Peruvian volcano. These maps serve to mitigate volcano hazards and to inform local development. A 3D map was published in 2018. In November 2010,
15750-467: The northern/western and southern/eastern foot of Misti, respectively. Inca roads from the Arequipa area passed by the volcano. There are numerous dams on the Rio Chili, including the Aguada Blanca Dam and reservoir north of the volcano, El Fraile, and Hidroeléctrica Charcani I, II, III, IV, V and VI. These dams have hydroelectric power plants which supply electricity to Arequipa. The river
15900-482: The northwest and Pichu Pichu to the southeast, and developed on top of a basement formed by numerous Miocene - Pliocene ignimbrites and volcano-derived debris. Numerous intense explosive eruptions took place during the last 50,000 years and covered the surrounding terrain with tephra . The last two significant eruptions were 2,000 years ago and in 1440–1470 AD ; since then, phases of increased fumarolic activity have sometimes been mistaken for eruptions. Misti
16050-454: The northwest flank of the volcano. The seismic activity appears to be linked to Misti's hydrothemal system. Seismic swarms were recorded in August 2012, May 2014 and June 2014. No deformation of the volcanic edifice is evident in satellite images. Clouds rising from the mountain are sometimes mistaken for renewed activity. Misti is Peru's most dangerous volcano and one of the most dangerous in
16200-549: 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
16350-420: 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
16500-471: 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
16650-729: The often thick crust . Volcanic activity in southern Peru goes back to the Jurassic . Various volcanic arcs formed in Peru during the past 30 million years: The Tacaza Arc 30–15 million years ago, the Lower Barroso 9–4 million years ago, the Upper Barroso 3–1 million years ago and the Pleistocene-Holocene Frontal Arc during the past one million years. Two distinct episodes of uplift took place 24–13 and 9–4 million years ago, and were accompanied by
16800-518: The oldest edifice. They have an age of 833,000 years, but it is not clear if they should be considered part of "Misti 1" or of a pre-Misti volcano. Sometimes, they are considered the first stage of Misti activity, with all the subsequent activity making up the second stage. After the south-southwestern collapse, the present stratovolcano began to grow 112,000 years ago. During the following 42,000 years lava flows and lava domes built an edifice with an elevation of 4,000–4,500 metres (13,100–14,800 ft), in
16950-468: 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
17100-485: The others are the dormant Chachani 15 kilometres (9.3 mi) northwest and extinct Pichu Pichu 20 kilometres (12 mi) southeast. This group lies at the margin of the Altiplano, next to the 600-square-kilometre (230 sq mi) tectonic depression of Arequipa where the city lies. The depression has dimensions of 30 by 15 kilometres (18.6 mi × 9.3 mi) and appears to be formed by fault activity. The terrain under Misti slopes south and this might make
17250-425: 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
17400-619: 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
17550-431: The previous one, and it also features a clock with four circular faces. Its construction is due to a group of faithful devotees who commissioned the construction from Don Gregorio Layme. It was inaugurated in 1959 and renovated in 1995, where they included indigenous elements. Also called Convent of Santa Bárbara . It is a four-level building built on the hill Hatun Rumi or Santa Bárbara (Spanish name), 40 m from
17700-406: The rafts of Juliaca, there have been some names of places: Totoral, Torococha..." Between the years 1000 to 500 BC, Juliaca flourished under the influence of Qaluyo (ancient settlement), in the place of Qomer Moqo ( Taparachi ). Archaeologists discovered a small village dating back to this time, whose settlers were fed with potatoes , quinoa , kañiwa , carachi, guinea pig, among others. They were
17850-404: The ravines on the southern side and the Rio Chili gorge; the older volcanic structures lie mainly in the western sector of Misti. Only a few eruptions have been thoroughly investigated. Seismic tomography has identified solidified buried magma bodies from the early stages of volcanism. Long andesitic lava flows and ignimbrites, which reach a thickness of more than 400 metres (1,300 ft), form
18000-406: The rhyolitic magmas erupted 34,000–31,000 years ago. Crystal-poor magma can form in the magmatic system through numerous processes and gives rise to the rhyolites and the volcanic plug. The existence of a third magma storage zone hosting mafic magmas at the base of the crust has been proposed. It is not clear whether Misti has a single magma chamber or multiple magma reservoirs at depth, although
18150-413: The river that linked them, also these riverine settlers developed a sailing technique, on rafts made of totora , fastened with yarned ropes based on the ichus , which would serve as support for fishing, and at times, of transport from Lake Titicaca to the smaller lakes that were between the territories of Juliaca. "As a testimony of the ancient presence of the Uros, in the balsero partiality, and later in
18300-600: The rock composition implies that only one large magma system is present. The reservoir appears to be located at 6–15 kilometres (3.7–9.3 mi) depth and has a volume of several cubic kilometres. Every few millennia, a secondary rhyolitic reservoir forms at about 3 kilometres (1.9 mi) depth; it was last reactivated during the eruption 2 ka ago. The magma system is periodically recharged, but such an influx of new magma does not trigger eruptions; instead multiple recharges are necessary to cause activity. Numerous mixing and decompression events can happen to each magma batch before it
18450-435: 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
18600-492: 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
18750-581: The second forms a flat-topped terrain with an area of about 40 square kilometres (15 sq mi) on both sides of the Rio Chili. The perennial Rio Chili rounds the northern and western sides of Misti, where it has cut the 20-kilometre (12 mi) long and 150–2,600-metre (490–8,530 ft) deep Charcani Gorge. From southeast to southwest the Quebrada Carabaya, Quebrada Honda, Quebrada Grande, Quebrada Agua Salada, Quebrada Huarangual, Quebrada Chilca, Quebrada San Lazaro and Quebrada Pastores drain
18900-622: 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
19050-405: The southern and eastern sectors of present-day Misti. During the subsequent 20,000 years, repeated collapses of lava domes deposited blocks, fallout deposits and scoria on the southern side of Misti and on Chachani to the northwest. Traces of glacial erosion like cirques , evidence of hydromagmatic activity and mudflows imply that Misti was glaciated during the first last glacial maximum of
19200-609: The southern side of Misti. This activity brought "Misti 2" to an end; subsequently lava domes built "Misti 3" to an elevation of 5,600 metres (18,400 ft), almost entirely erasing the caldera. Between 36,000 and 20,000 years ago collapses of lava domes produced numerous block-and-ash flows of dacitic to andesitic composition, which reach thicknesses of several tens of metres on the southern side of Misti. The activity between 50,000 and 20,000 years ago has been christened "Cayma stage", and several eruption deposits from this time have been named: Eruptions 43,000 and 14,000 years ago dammed
19350-451: The streets to dance in the style of the Collao Plateau. Saint Sebastian's feast is celebrated on 20 January of every year. Juliaca's citizens rely on cars, trains, and bicycles. It is a major transit point in the region and has strong ties with Peru's southern cities, including Arequipa , Puno , Tacna , Cuzco , Ilo , and with La Rinconada and Bolivia . Like Chicago , Illinois, it is nicknamed "The Windy City", in its case, because of
19500-403: The summit during the wet season , but does not persist; there are no glaciers . The upper slopes of the volcano are barren, while the lower slopes are covered by bushland . The volcano developed over four different stages. During each stage, lava flows and lava domes built up a mountain, whose summit then collapsed to form a caldera . The volcano is part of a volcano group with Chachani to
19650-596: The summit ranged from −6 °C (21 °F) in January to −9.7 °C (14.5 °F) in May, June and August but in 1968 temperatures at the summit rose above freezing for a few days per year. During most of the year, dry westerly winds blow over the Western Cordillera except during summer months, when convection over the Amazon forces easterly flow that draws moisture to the Cordillera. Most precipitation falls during
19800-406: 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
19950-434: 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
20100-444: 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
20250-431: 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
20400-417: The upper cone. Unlike neighbouring Chachani, Misti lacks any evidence of glacial or periglacial processes, probably due to its inner heat. There is no clear indication of past glaciation, either, except possibly on the western flank. A thin ice cover may not have left traces on the volcano, however. The present-day snowline lies above 5,800 metres (19,000 ft) elevation. Off the western coast of Peru,
20550-457: The visitor can also visualize the handwork done by the artisan ladies with their typical clothing (called hosiery), in different types of wool and fiber, highly appreciated in the international market. Located 10 km northwest of the city of Juliaca, in the area corresponding to the towns of Kokan and Chacas. It is a lagoon surrounded by vast hills, like the Iquinito (which is the highest in
20700-469: The volcano down; the mummies on Misti are the largest Inca sacrifice known. The name is either Quechua or Spanish and means "mixed", " mestizo " or "white"; it may refer to snow cover. The indigenous names are Putina ("mountain that growls") and in Aymara "Anukara" or Anuqara ("dog"); they both refer to the dog-like appearance of the volcano when viewed from the Altiplano . The original name of
20850-412: The volcano is cut by 20-to-80-metre (66 to 262 ft) deep ravines , while the northern side is flatter. Dune fields and volcanic ash deposits extend for 20 kilometres (12 mi) northeast of Misti; they are formed by wind-blown ash. The terrain between Arequipa and Misti is initially gently sloping, before reaching the steep flanks of the cone. There are no obvious traces of a sector collapse on
21000-450: The volcano was Putina; it only became known as "Misti" beginning in the 1780s. Other names for the volcano are Guagua-Putina, El Volcán ("the volcano"), San Francisco, and Volcán de Arequipa ("the Arequipa volcano"). Sometimes chroniclers confused it with other volcanoes like Ubinas and Huaynaputina . Settlement of the region began about 1,500 years ago. It is unclear whether the Inka were
21150-429: The volcano, except on its western foot and a narrow chute on the northwestern flank of Misti that reaches its summit. Two debris avalanche deposits lie on the southeastern and southwestern-southern side of Misti, extending 25 kilometres (16 mi) and 12 kilometres (7.5 mi) from the volcano. The first is made up by hummock-shaped hills of mixed debris and covers an area of 100 square kilometres (39 sq mi);
21300-425: The volcano. Pyroclastic flows emanated from the column and descended the southern flanks of the volcano, possibly through the gap in the crater rim. During the course of the eruption, collapses of the crater and conduit walls caused a temporary decline in the intensity of the column. The eruption column periodically collapsed and reformed, until the eruption ended with phreatomagmatic explosions. Mudflows descended
21450-492: 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
21600-402: The volcano; a 2-kilometre (1.2 mi) wide caldera formed at an elevation of 5,400 metres (17,700 ft). More than ten eruptions took place during the last 11,000 years, with only brief pauses in activity. The activity between 21,000 and 2,000 years ago is known as the "Pacheco" stage. Holocene activity filled the younger caldera with scoria and lava flows, forming the "Misti 4" edifice with
21750-424: 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
21900-416: The water would have infiltrated the edifice and evaporated from the volcanic heat. Comparisons between 1967 photos of the volcanic plug and more recent images show no changes. The volcano is seismically active, with long-period earthquakes, tremors, "tornillos" and volcano-tectonic earthquakes recorded. The hypocentres , the actual sites of the earthquakes, are found within the edifice of Misti and cluster on
22050-454: The world, owing to its proximity (17 kilometres (11 mi)) to Arequipa, where more than a million inhabitants live. The city has expanded to within 12 kilometres (7.5 mi) of the volcano, with new towns like Alto Selva Alegre, Mariano Melgar, Miraflores and Paucarpata and towns such as Chiguata getting within 11 kilometres (6.8 mi). About 8.6% of Peru's GDP depends on Arequipa and would be impacted by future eruption of Misti. The city
22200-421: 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
22350-467: Was inhabited from around 4,000 BC by sedentary communities dedicated to agriculture and livestock ( llamas and guinea pigs ). The Uros settled in the river towns, taking advantage of the benefits of the totora and the fish of Lake Titicaca , settled in the surrounding lakes: Chacas , Qoriwata, Cochapampa, and the Juliaca River, today Coata River. "The Indians who are called Uros...live on
22500-584: Was probably a prolonged eruption that lasted for months or years, depositing ash in the Peruvian Laguna Salinas and possibly as far as Siple Dome and Law Dome in Antarctica. It is the oldest eruption of a South American volcano for which historical records exist. The eruption was severe enough that Mama Ana Huarque Coya, the wife of the Inka emperor Pachacutec , came to Chiguata, where black ash had fallen, to provide assistance. There
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