Mount Saint Helens
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Mount St. Helens or Louwala-Clough is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 96 miles south of Seattle, Washington, and 50 miles northeast of Portland, Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc and this volcano is well known for its ash explosions and pyroclastic flows. Mount St. Helens is most notorious for its major 1980 eruption, fifty-seven people were killed,250 homes,47 bridges,15 miles of railways, and 185 miles of highway were destroyed. The debris avalanche was up to 0.7 cubic miles in volume, the Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied. As with most other volcanoes in the Cascade Ran
1.
3,000 ft (1 km) steam plume on May 19, 1982, two years after its major eruption
2.
A view of St. Helens and the nearby area from space
3.
Mount St. Helens the day before the 1980 eruption, which removed much of the northern face of the mountain, leaving a large
crater
4.
3-D perspective view of Mount St. Helens
Volcanic
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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 a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose
3.
A 2007 eruptive column at
Mount Etna producing volcanic ash, pumice and lava bombs
Eruption
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Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed, some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions, the most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of eruption, driven by the compression of gas within magma. Within these wide-defining eruptive types are several subtypes, the weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, subglacial and phreatic eruptions are defined b
3.
An example of the lava arcs formed during Strombolian activity. This image is of
Stromboli itself.
Mount St. Helens
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Mount St. Helens or Louwala-Clough is an active stratovolcano located in Skamania County, Washington, in the Pacific Northwest region of the United States. It is 96 miles south of Seattle, Washington, and 50 miles northeast of Portland, Mount St. Helens takes its English name from the British diplomat Lord St Helens, a friend of explorer George Vancouver who made a survey of the area in the late 18th century. The volcano is located in the Cascade Range and is part of the Cascade Volcanic Arc and this volcano is well known for its ash explosions and pyroclastic flows. Mount St. Helens is most notorious for its major 1980 eruption, fifty-seven people were killed,250 homes,47 bridges,15 miles of railways, and 185 miles of highway were destroyed. The debris avalanche was up to 0.7 cubic miles in volume, the Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for its aftermath to be scientifically studied. As with most other volcanoes in the Cascade Ran
1.
3,000 ft (1 km) steam plume on May 19, 1982, two years after its major eruption
2.
A view of St. Helens and the nearby area from space
3.
Mount St. Helens the day before the 1980 eruption, which removed much of the northern face of the mountain, leaving a large
crater
4.
3-D perspective view of Mount St. Helens
Magma
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Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion, magma is capable of intruding into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock. Magma is a complex high-temperature fluid substance, temperatures of most magmas are in the range 700 °C to 1300 °C, but very rare carbonatite magmas may be as cool as 600 °C, and komatiite magmas may have been as hot as 1600 °C. Environments of magma formation and compositions are commonly correlated, environments include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Despite being found in such locales, the bulk of the Earths crust. Except for the outer core, most of the Earth takes the form of a rheid. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several ki
Volcanic ash
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Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm in diameter. The term volcanic ash is often loosely used to refer to all explosive eruption products. Volcanic ash is formed during volcanic eruptions when dissolved gases in magma expand. The force of the escaping gas shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, once in the air, ash is transported by wind up to thousands of kilometers away. Volcanic ash is formed during volcanic eruptions, phreatomagmatic eruptions. Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles to exsolve into gas bubbles, as more bubbles nucleate a foam is produced, which decreases the density of the magma, accelerating it up the conduit. Fragmentation occurs whe
Lava plug
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A volcanic plug, also called a volcanic neck or lava neck, is a volcanic object created when magma hardens within a vent on an active volcano. When present, a plug can cause an extreme build-up of pressure if rising volatile-charged magma is trapped beneath it, glacial erosion can lead to exposure of the plug on one side, while a long slope of material remains on the opposite side. Such landforms are called crag and tail, if a plug is preserved, erosion may remove the surrounding rock while the erosion-resistant plug remains, producing a distinctive upstanding landform. An example of two volcanic plugs can be found at the Pitons, in Saint Lucia, as they rise out of the eastern Caribbean Sea. Near the village of Rhumsiki in the Far North Province of Cameroon, spectacular volcanic plugs are present in the center of La Gomera island in the Canary Islands archipelago, within the Garajonay National Park. In New Zealands South Island, Ōnawe Peninsula on Banks Peninsula is a prominent volcani
3.
New Zealand's Lion Rock was fortified as a refuge for local
Maori.
Pyroclastic
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Pyroclastic rocks or pyroclastics are clastic rocks composed solely or primarily of volcanic materials. Where the volcanic material has been transported and reworked through mechanical action, such as by wind or water, pyroclastic rocks may be a range of clast sizes, from the largest agglomerates, to very fine ashes and tuffs. Pyroclasts of different sizes are classified as bombs, lapilli. Ash is considered to be pyroclastic because it is a fine dust made up of volcanic rock, one of the most spectacular forms of pyroclastic deposit are the ignimbrites, deposits formed by the high-temperature gas-and-ash mix of a pyroclastic flow event. Three modes of transport can be distinguished, pyroclastic flow, pyroclastic surge, during Plinian eruptions, pumice and ash are formed when silicic magma is fragmented in the volcanic conduit, because of decompression and the growth of bubbles. Pyroclasts are then entrained in a buoyant eruption plume which can rise several kilometers into the air, part
Pyroclastic flow
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A pyroclastic flow is a fast-moving current of hot gas and volcanic matter, which reaches speeds moving away from a volcano of up to 700 km/h. The gases can reach temperatures of about 1,000 °C, Pyroclastic flows normally touch the ground and hurtle downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the output rate. They are a common and devastating result of explosive eruptions. The word pyroclast is derived from the Greek πῦρ, meaning fire, a name for some pyroclastic flows is nuée ardente, this was first used to describe the disastrous 1902 eruption of Mount Pelée on Martinique. In the dark, these pyroclastic flows glowed red, Pyroclastic flows that contain a much higher proportion of gas to rock are known as fully dilute pyroclastic density currents or pyroclastic surges. The lower density sometimes allows them to flow over higher topographic features or water such as ridges, hills, rivers and seas. They may also contain steam, water a
3.
A scientist examines pumice blocks at the edge of a pyroclastic flow deposit from
Mount St. Helens
Sarychev Peak
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Sarychev Peak, is a stratovolcano covering almost the entirety of Matua Island in the Kuril Islands, Russia. It is a young, highly symmetrical stratovolcanic cone, the peak was named after admiral Gavril Sarychev of the Imperial Russian Navy. The volcano erupted June 11-21,2009, sending out ash plumes, as the volcano is near some of the main air routes between East Asia and North America, there was some disruption to air traffic. During an early stage of the eruption, on June 12,2009, a hole in the overhead clouds, possibly caused by the shock wave from the explosion, allowed a clear view of the plume and pyroclastic flow down the sides of the mountain. A cap-like pileus cloud is visible atop the rising column, Sarychev Peak previously erupted in 1760,1805,1879,1923,1927,1928,1930,1932,1946,1954,1960,1965,1976,1986 and 1989. List of volcanoes in Russia Global Volcanism Program
2.
Sarychev Peak
3.
Sarychev Peak Volcano erupts June 12, 2009, 22:16:14.
4.
Sarychev Peak, June 14, 2009, 1:05 p.m.
Viscous
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The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. For liquids, it corresponds to the concept of thickness, for example. Viscosity is a property of the fluid which opposes the motion between the two surfaces of the fluid in a fluid that are moving at different velocities. For a given velocity pattern, the stress required is proportional to the fluids viscosity, a fluid that has no resistance to shear stress is known as an ideal or inviscid fluid. Zero viscosity is observed only at low temperatures in superfluids. Otherwise, all fluids have positive viscosity, and are said to be viscous or viscid. A fluid with a high viscosity, such as pitch. The word viscosity is derived from the Latin viscum, meaning mistletoe, the dynamic viscosity of a fluid expresses its resistance to shearing flows, where adjacent layers move parallel to each other with different speeds. It can be defined through the situation known as a Couette flow.
1.
Pitch has a viscosity approximately 230 billion (2.3 × 10 11) times that of water.
2.
A simulation of substances with different viscosities. The substance above has lower viscosity than the substance below
3.
Example of the viscosity of milk and water. Liquids with higher viscosities make smaller splashes when poured at the same velocity.
Andesitic
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For the extinct cephalopod genus, see Andesites. Andesite is an igneous, volcanic rock, of intermediate composition. In a general sense, it is the type between basalt and dacite, and ranges from 57 to 63% silicon dioxide as illustrated in TAS diagrams. The mineral assemblage is dominated by plagioclase plus pyroxene or hornblende. Magnetite, zircon, apatite, ilmenite, biotite, and garnet are common accessory minerals, alkali feldspar may be present in minor amounts. The quartz-feldspar abundances in andesite and other rocks are illustrated in QAPF diagrams. Classification of andesites may be refined according to the most abundant phenocryst, example, hornblende-phyric andesite, if hornblende is the principal accessory mineral. Andesite can be considered as the equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs, the average composition of the continental crust is andesitic. Along with basalts they are a component
1.
Photomicrograph of andesite in
thin section (between crossed polars)
2.
A sample of andesite (dark groundmass) with
amygdaloidal vesicules filled with
zeolite. Diameter of view is 8 cm.
3.
Andesite Mount Žarnov (
Vtáčnik), Slovakia
4.
Andesite pillar in Slovakia
Rhyolitic
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Rhyolite is an igneous, volcanic rock, of felsic composition. It may have any texture from glassy to aphanitic to porphyritic, the mineral assemblage is usually quartz, sanidine and plagioclase. Biotite and hornblende are common accessory minerals and it is the extrusive equivalent to granite. Rhyolite can be considered as the equivalent to the plutonic granite rock. Due to their content of silica and low iron and magnesium contents, rhyolite melts are highly polymerized. They also occur as breccias or in volcanic plugs and dikes, rhyolites that cool too quickly to grow crystals form a natural glass or vitrophyre, also called obsidian. Slower cooling forms microscopic crystals in the lava and results in such as flow foliations, spherulitic, nodular. Some rhyolite is highly vesicular pumice, many eruptions of rhyolite are highly explosive and the deposits may consist of fallout tephra/tuff or of ignimbrites. Eruptions of rhyolite are relatively rare compared to eruptions of less felsic
3.
Rhyolite quarry,
Löbejün, Saxony-Anhalt
Pumice
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Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker walls and being dark colored. Pumice is created when super-heated, highly pressurized rock is violently ejected from a volcano, the unusual foamy configuration of pumice happens because of simultaneous rapid cooling and rapid depressurization. The depressurization creates bubbles by lowering the solubility of gases that are dissolved in the lava, the simultaneous cooling and depressurization freezes the bubbles in a matrix. Eruptions under water are cooled and the large volume of pumice created can be a shipping hazard for cargo ships. Pumice is composed of highly microvesicular glass pyroclastic with very thin and it is commonly, but not exclusively of silicic or felsic to intermediate in composition, but basal
2.
Illustrates the porous nature in detail.
3.
Rocks from the
Bishop tuff, uncompressed with pumice on left; compressed with
fiamme on right.
4.
A 15 centimeter (6 inch) piece of pumice supported by a rolled-up U.S. 20-dollar bill demonstrates its very low density.
Volcanic vent
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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 a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose
3.
A 2007 eruptive column at
Mount Etna producing volcanic ash, pumice and lava bombs
Eruption column
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An eruption column is a cloud of hot volcanic ash suspended in volcanic gas emitted during an explosive volcanic eruption. The ash forms a column that may rise many kilometres into the air above the vent of the volcano, in the most explosive eruptions, the eruption column may rise over 40 km, penetrating the stratosphere. Stratospheric injection of aerosols by volcanoes is a cause of short-term climate change. A common occurrence in explosive eruptions is for column collapse to occur, in this case, the eruption column is too dense to be lifted high into the air by air convection, and instead falls down the flanks of the volcano to form a pyroclastic flow or surge. On some occasions, if ash isnt dense enough to fall, eruption columns form in explosive volcanic activity, when the high concentration of volatile materials in the rising magma causes it to be disrupted into fine volcanic ash and coarser tephra. The ash and tephra are ejected at speeds of several hundred metres per second, er
Vulcanian eruption
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The term vulcanian was first used by Giuseppe Mercalli, witnessing the 1888-1890 eruptions on the island of Vulcano. His description of the style is now used all over the world for eruptions characterised by a dense cloud of ash-laden gas exploding from the crater. Mercalli described vulcanian eruptions as. Explosions like cannon fire at irregular intervals and their explosive nature is due to increased silica content of the magma. Almost all types of magma can be involved, but magma with about 55% or more silica is most common, increasing silica levels increase the viscosity of the magma which means increased explosiveness. They usually commence with phreatomagmatic eruptions which can be noisy due the rising magma heating water in the ground. This is usually followed by the clearing of the vent. As the vent clears, further ash clouds become grey-white and creamy in colour, vulcanian eruptions display several common characteristics. The mass of rock ejected during the eruption is usua
1.
The Gran Cratere,
Vulcano. A sense of scale is provided by the tourist visible near the centre of the crater.
2.
Volcanic eruption: 1 Ash plume, 2 Lapilli, 3 Lava fountain, 4 Volcanic ash rain, 5 Volcanic bomb, 6 Lava flow, 7 Layers of lava and ash, 8 Stratum, 9 Sill, 10 Magma conduit, 11 Magma chamber, 12 Dike
Plinian eruption
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Plinian eruptions, also known as Vesuvian eruptions, are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in 79 AD. The eruption was described in a written by Pliny the Younger, it killed his uncle. Plinian eruptions are marked by columns of gas and volcanic ash extending high into the stratosphere, the key characteristics are ejection of large amount of pumice and very powerful continuous gas blast eruptions. According to the Volcanic Explosivity Index, Plinian eruptions have a VEI of 4,5 or 6, short eruptions can end in less than a day, but longer events can take several days to months. The longer eruptions begin with production of clouds of volcanic ash, the amount of magma erupted can be so large that it depletes the magma chamber below, causing the top of the volcano to collapse, resulting in a caldera. Fine ash can deposit over large areas, Plinian eruptions are often accompanied by loud noises, such as those generated by Krakatoa. The lava is usual
2.
A
Stone Pine, the type of tree used by Pliny to describe the eruption.
3.
April 21, 1990 eruption cloud from
Redoubt Volcano as viewed to the west from the Kenai Peninsula
Phreatomagmatic eruption
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Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions, unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile clasts. It is common for an explosive eruption to have magmatic and phreatomagmatic components. Several competing theories exist as to the mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water, in many cases the water is supplied by the sea, for example with Surtsey. In other cases the water may be present in a lake or caldera-lake, for example Santorini, there have also been examples of interaction between magma and water in an aquifer. Many of the cones on Tenerife are believed to be phreatomagmatic because of these circumstances. The other competing theory is based on fuel-coolant reactions, which have been modeled for the nuclear indus
1.
Ashfall deposit of phreatomagmatic origin, overlying magmatic lapilli fall deposit of magmatic origin.
2.
Crest of old tuff ring, including part of the maar crater of a monogenetic volcano,
Tenerife,
Canary Islands. The maar crater has been used for agriculture.
3.
Koko Crater is an old extinct tuff cone in the Hawaiian Island of Oahu.
Phreatic eruption
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A phreatic eruption, also called a phreatic explosion, ultravulcanian eruption or steam-blast eruption, occurs when magma heats ground or surface water. The extreme temperature of the magma causes near-instantaneous evaporation to steam, resulting in an explosion of steam, water, ash, rock, at Mount St. Helens, hundreds of steam explosions preceded a 1980 plinian eruption of the volcano. A less intense geothermal event may result in a mud volcano, phreatic eruptions typically include steam and rock fragments, the inclusion of lava is unusual. The temperature of the fragments can range from cold to incandescent, if molten magma is included, it is classified as a phreatomagmatic eruption. These eruptions occasionally create broad, low-relief craters called maars, phreatic explosions can be accompanied by carbon dioxide or hydrogen sulfide gas emissions. The former can asphyxiate at sufficient concentration, the latter is a broad spectrum poison, a 1979 phreatic eruption on the island of
1.
Phreatic eruption at the summit of
Mount St. Helens, Washington, in the spring of 1980
2.
A scheme of a phreatic eruption
Surtseyan eruption
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A Surtseyan eruption is a type of volcanic eruption that takes place in shallow seas or lakes. It is named after the island of Surtsey off the southern coast of Iceland, tuff rings, pyroclastic cones of primarily ash, are built by explosive disruption of rapidly cooled magma. Although similar in nature to phreatomagmatic eruptions, there are specific characteristics, Physical nature of magma, viscous. Character of explosive activity, violent ejection of solid, warm fragments of new magma, continuous or rhythmic explosions, nature of effusive activity, short, locally pillowed, lava flows, lavas may be rare. Nature of dominant ejecta, lithic, blocks and ash, often accretionary lapilli, spatter, fusiform bombs and lapilli absent
1.
Surtsey was the most famous example of a Surtseyan eruption.
Pyroclastic fall
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A pyroclastic fall is a uniform deposit of material which has been ejected from a volcanic eruption or plume such as an ash fall or tuff. They exhibit mantle bedding—the deposits directly overlie pre-existing topography and maintain a uniform thickness over relatively short distances, sorting by size is more pronounced than pyroclastic surge or pyroclastic flows. Early settling of crystals and lithic fragments near an eruptive vent, the St Vincent eruption in 1902 ejected a large eruption column which when settled near the vent contained 73% crystals, and ash deposited in Jamaica 1,600 km away consisted entirely of glass dust. The distribution of pyroclastic ash depends largely on the direction of wind at intermediate, the general trend of pyroclastic dispersal is shown using isopachs and show the dispersal as elongated with wind direction. The Krakatoa eruption of 1883 produced a column which rose to more than 50 km. An ash flow from this explosion was recognised 2,500 km west of the
1.
Pyroclastic fall layers of
volcanic ash on
Izu Oshima volcano in Japan. The ash fell on an uneven ground surface. The ash layers have not been folded after deposition.
Pyroclastic flows
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A pyroclastic flow is a fast-moving current of hot gas and volcanic matter, which reaches speeds moving away from a volcano of up to 700 km/h. The gases can reach temperatures of about 1,000 °C, Pyroclastic flows normally touch the ground and hurtle downhill, or spread laterally under gravity. Their speed depends upon the density of the current, the output rate. They are a common and devastating result of explosive eruptions. The word pyroclast is derived from the Greek πῦρ, meaning fire, a name for some pyroclastic flows is nuée ardente, this was first used to describe the disastrous 1902 eruption of Mount Pelée on Martinique. In the dark, these pyroclastic flows glowed red, Pyroclastic flows that contain a much higher proportion of gas to rock are known as fully dilute pyroclastic density currents or pyroclastic surges. The lower density sometimes allows them to flow over higher topographic features or water such as ridges, hills, rivers and seas. They may also contain steam, water a
3.
A scientist examines pumice blocks at the edge of a pyroclastic flow deposit from
Mount St. Helens
Lahars
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A lahar is a type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris, and water. The material flows down from a volcano, typically along a river valley, lahars are extremely destructive, they can flow tens of metres per second, be 140 metres deep, and destroy any structures in their path. Notable lahars include those at Mount Pinatubo and Nevado del Ruiz, the word lahar is the Javanese term for flowing lava. A lahar is a volcanic mudflow or debris flow, lahars have the consistency, viscosity and approximate density of wet concrete, fluid when moving, solid at rest. Lahars can be huge.3 cubic kilometres, a lahar of sufficient size and intensity can erase virtually any structure in its path, and is capable of carving its own pathway, making the prediction of its course difficult. Conversely, a lahar quickly loses force when it leaves the channel of its flow, even frail huts may remain standing, a lahars viscosity decreases with time, and can be further t
3.
The aftermath of a lahar from the 1982 eruption of
Galunggung, Indonesia.
Mount Rainier
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Mount Rainier, Mount Tacoma, or Mount Tahoma is the highest mountain of the Cascade Range of the Pacific Northwest, and the highest mountain in the U. S. state of Washington. It is an active stratovolcano located 54 miles south-southeast of Seattle. Because of its amount of glacial ice, Mt.7 million living in its metropolitan area. Mount Rainier was first known by the Native Americans as Talol, one hypothesis of the word origin is, in the Lushootseed language spoken by the Puyallup people. Another hypothesis is that Tacoma means larger than Mount Baker in Lushootseed, Ta, larger, plus Koma, other names originally used include Tahoma, Tacobeh, and Pooskaus. The current name was given by George Vancouver, who named it in honor of his friend, the map of the Lewis and Clark expedition of 1804-1806 refers to it as Mt. Regniere. Tacoma was preferred in the city of Tacoma, in 1890, the United States Board on Geographic Names declared that the mountain would be known as Rainier. Following this
1.
Mount Rainier as viewed from the northeast.
2.
A panorama of the south face of Mount Rainier viewed from Westside Road, Washington State Route 706
Seattle
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Seattle is a seaport city on the west coast of the United States and the seat of King County, Washington. With an estimated 684,451 residents as of 2015, Seattle is the largest city in both the state of Washington and the Pacific Northwest region of North America. In July 2013, it was the major city in the United States. The city is situated on an isthmus between Puget Sound and Lake Washington, about 100 miles south of the Canada–United States border, a major gateway for trade with Asia, Seattle is the fourth-largest port in North America in terms of container handling as of 2015. The Seattle area was inhabited by Native Americans for at least 4,000 years before the first permanent European settlers. Arthur A. Denny and his group of travelers, subsequently known as the Denny Party, arrived from Illinois via Portland, the settlement was moved to the eastern shore of Elliott Bay and named Seattle in 1852, after Chief Siahl of the local Duwamish and Suquamish tribes. Logging was Seattles
4.
Seattle's first
streetcar, at the corner of Occidental and Yesler, 1884. All of the buildings visible in this picture were destroyed by fire five years later.
Tacoma, Washington
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Tacoma is a mid-sized urban port city in and the county seat of Pierce County, Washington, United States. The city is on Washingtons Puget Sound,32 miles southwest of Seattle,31 miles northeast of the capital, Olympia. The population was 198,397, according to the 2010 census, Tacoma is the second-largest city in the Puget Sound area and the third largest in the state. Tacoma also serves as the center of activity for the South Sound region. Tacoma adopted its name after the nearby Mount Rainier, originally called Takhoma or Tahoma and it is locally known as the City of Destiny because the area was chosen to be the western terminus of the Northern Pacific Railroad in the late 19th century. The decision of the railroad was influenced by Tacomas neighboring deep-water harbor, by connecting the bay with the railroad, Tacomas motto became When rails meet sails. Today, Commencement Bay serves the Port of Tacoma, a center of trade on the Pacific Coast. Like most central cities, Tacoma suffered
1.
Tacoma, Washington
2.
Flag
4.
The Commencement Bay Land and Improvement Co. played a major role in the city's early growth.
Supervolcano
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A supervolcano is a volcano capable of producing a volcanic eruption with an ejecta mass greater than 1015 kg. This can occur at hotspots or at subduction zones, the Oruanui eruption of New Zealands Taupo Volcano, the worlds most recent supereruption, had a Volcanic Explosivity Index of 8. The origin of the term supervolcano is linked to an early 20th-century scientific debate about the geological history, in 1925, Edwin T. Hodge suggested that a very large volcano, which he named Mount Multnomah, had existed in that region. He believed that several peaks in the Three Sisters area are the left after Mount Multnomah had been largely destroyed by violent volcanic explosions. In 1948, the existence of Mount Multnomah was ignored by volcanologist Howel Williams in his book The Ancient Volcanoes of Oregon. The book was reviewed in 1949 by another volcanologist, F. M. Byers Jr, in the review, Byers refers to Mount Multnomah as a supervolcano. Volcanologists and geologists do not refer to sup
1.
Location of Yellowstone hotspot over time (numbers indicate millions of years before the present).
2.
Satellite image of
Lake Toba, the site of a VEI 8 eruption ~75,000 years ago.
4.
Volcano, lake, and caldera locations in the Taupo Volcanic Zone
Volcanic winter
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Volcanic stratospheric aerosols cool the surface by reflecting solar radiation and warm the stratosphere by absorbing terrestrial radiation. The volcanic aerosols, resulting from the 1991 Pinatubo eruption and others, have shown to contribute to anthropogenic ozone depletion. The variations in atmospheric warming and cooling results in changes in tropospheric and stratospheric circulation, the effects of volcanic eruptions on recent winters are modest in scale, but historically have been significant. Most recently, the 1991 explosion of Mount Pinatubo, a stratovolcano in the Philippines, in 1883, the explosion of Krakatoa created volcanic winter-like conditions. The four years following the explosion were unusually cold, and the winter of 1887-1888 included powerful blizzards, northern hemisphere temperatures dropped by about 1 °C in the year following the Laki eruption. However Franklins proposal has been questioned, in 1600, the Huaynaputina in Peru erupted. Tree ring studies show th
Effusive eruption
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An effusive eruption is a type of volcanic eruption in which lava steadily flows out of a volcano onto the ground. Effusive eruption differs from explosive eruption, wherein magma is violently fragmented when expelled from a volcano, the shape of the lava flows created by effusive eruptions is governed by the type of lava, rate and duration of eruption, and slope of the surrounding areas. A volcanic eruption is effusive when low-viscosity magma, usually basaltic in composition, is released from the Earths crust, in an effusive eruption, gas escapes the magma as it erupts and forms lava that flows downhill continuously. This type of flow can build shield volcanoes, which are numerous in Hawaii. Eruptions of basaltic magma often transition between effusive and explosive eruption patterns, the behavior of these eruptions is largely dependent on the permeability of the magma and the magma ascent rate. For an effusive eruption to occur, magma must be enough to allow the expulsion of gas bub
Volcanic explosivity index
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The Volcanic Explosivity Index is a relative measure of the explosiveness of volcanic eruptions. It was devised by Chris Newhall of the United States Geological Survey, volume of products, eruption cloud height, and qualitative observations are used to determine the explosivity value. The scale is open-ended with the largest volcanoes in history given magnitude 8, the scale is logarithmic, with each interval on the scale representing a tenfold increase in observed ejecta criteria, with the exception of between VEI0, VEI1 and VEI2. With indices running from 0 to 8, the VEI associated with an eruption is dependent on how much material is thrown out, to what height. The scale is logarithmic from VEI2 and up, an increase of 1 index indicates an eruption that is 10 times as powerful, as such there is a discontinuity in the definition of the VEI between indices 1 and 2. The lower border of the volume of ejecta jumps by a factor of 100 from 10,000 to 1,000,000 m3 while the factor is 10 betwee
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VEI and ejecta volume correlation
International Standard Book Number
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The International Standard Book Number is a unique numeric commercial book identifier. An ISBN is assigned to each edition and variation of a book, for example, an e-book, a paperback and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January 2007, the method of assigning an ISBN is nation-based and varies from country to country, often depending on how large the publishing industry is within a country. The initial ISBN configuration of recognition was generated in 1967 based upon the 9-digit Standard Book Numbering created in 1966, the 10-digit ISBN format was developed by the International Organization for Standardization and was published in 1970 as international standard ISO2108. Occasionally, a book may appear without a printed ISBN if it is printed privately or the author does not follow the usual ISBN procedure, however, this can be rectified later. Another identifier, the International Standard Serial
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A 13-digit ISBN, 978-3-16-148410-0, as represented by an
EAN-13 bar code
Types of volcanic eruptions
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Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed, some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions, the most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of eruption, driven by the compression of gas within magma. Within these wide-defining eruptive types are several subtypes, the weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, subglacial and phreatic eruptions are defined b
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An example of the lava arcs formed during Strombolian activity. This image is of
Stromboli itself.
Hawaiian eruption
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A Hawaiian eruption is a type of volcanic eruption where lava flows from the vent in a relatively gentle, low level eruption, it is so named because it is characteristic of Hawaiian volcanoes. Typically they are effusive eruptions, with basaltic magmas of low viscosity, low content of gases, very little amounts of volcanic ash are produced. This type of eruption occurs most often at hotspot volcanoes such as Kīlauea and Iceland, though it can occur near subduction zones, another example of Hawaiian eruptions occurred on Surtsey from 1964 to 1967, when molten lava flowed from the crater to the sea. In fissure-type eruptions, lava spurts from a fissure on the rift zone. In central-vent eruptions, a fountain of lava can spurt to a height of 300 meters or more, Hawaiian eruptions usually start by the formation of a crack in the ground from which a curtain of incandescent magma or several closely spaced magma fountains appear. The lava can overflow the fissure and form ʻaʻā or pāhoehoe styl
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Hawaiian eruption: 1: Ash plume, 2: Lava fountain, 3: Crater, 4: Lava lake, 5: Fumaroles, 6: Lava flow, 7 Layers of lava and ash, 8: Stratum, 9: Sill, 10: Magma conduit, 11: Magma chamber, 12: Dike
Strombolian eruption
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Strombolian eruptions are relatively mildly explosive, with a volcanic explosivity index of about 2 to 3. They are named for the Italian volcano Stromboli, which is the eponym for the type, Strombolian eruptions consist of ejection of incandescent cinder, lapilli, and lava bombs, to altitudes of tens to a few hundreds of metres. The eruptions are small to medium in volume, with sporadic violence, the Italian vulcanologist Giuseppe Mercalli studied eruptions at Stromboli and Vulcano in 1888-1890, and observed that the characteristic features of eruptions were different between the two. To distinguish between them, Mercalli defined Strombolian eruptions as. Mildly explosive at discrete but fairly regular intervals of seconds to minutes, the tephra typically glows red when leaving the vent, but its surface cools and assumes a dark to black colour and may significantly solidify before impact. The tephra accumulates in the vicinity of the vent, forming a cinder cone, cinder is the most comm
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A Strombolian eruption
Submarine eruption
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Submarine eruptions are those volcano eruptions which take place beneath the surface of water. These occur at constructive margins, subduction zones and within tectonic plates due to hotspots and this eruption style is far more prevalent than subaerial activity. For example, it is believed that 70 to 80% of the Earth’s magma output takes place at mid-ocean ridges, submarine eruptions are less studied than subaerial volcanoes due to their inaccessibility. Developments in technology mean that submarine volcanoes can now be studied in greater detail, despite this progress, understanding is still limited. Mid ocean ridges for example are the most active systems on Earth. Initial knowledge of these came from volcanic rocks being recovered from the ocean floor when repairs were made to the Transatlantic telegraph cable in the 1800s. More recently a variety of techniques have been used to study these eruptions with significant developments being made since 1990 and these include the use of re
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Scheme of a submarine eruption. 1 Water vapor cloud 2 Water 3 Stratum 4 Lava flow 5 Magma conduit 6 Magma chamber 7 Dike 8 Pillow lava
Subglacial eruption
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Subglacial eruptions, those of ice-covered volcanoes, result in the interaction of magma with ice and snow, leading to meltwater formation, jökulhlaups, and lahars. Flooding associated with meltwater is a significant hazard in some areas, including Iceland, Alaska. It is important to explore volcano-ice interactions to improve our ability to monitor these events. The resulting flood severely damaged buildings on the island, with destruction of a British scientific station. Over a period of 13 days,3 km2 of ice was melted with erupted magma fracturing into glass to form a 7 km long and 300 m high hyaloclastite ridge under 750 m of ice. Meltwater flowed along a narrow basal glacier bed into a lake for five weeks, before being released as a sudden flood. Research demonstrated that for warm-based glaciers, the effects of volcanic eruptions are localised, with eruptions forming deep depressions. In the first two days of the eruption, ice cauldrons were formed over the volcanic vents, radar
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Subglacial eruption: 1 water vapor cloud, 2 lake, 3 ice, 4 layers of lava and ash, 5 strata, 6 pillow lava, 7 magma conduit, 8 magma chamber, 9 dike
Limnic eruption
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Such an eruption may also cause tsunamis in the lake as the rising CO2 displaces water. Scientists believe earthquakes, volcanic activity, or explosions can be a trigger for such phenomenon, Lakes in which such activity occurs may be known as limnically active lakes or exploding lakes. To date, this phenomenon has been observed only twice, the first was in Cameroon at Lake Monoun in 1984, causing the asphyxiation and death of 38 people living nearby. Due to the nature of the event, it is hard to determine if limnic eruptions have happened elsewhere, a third lake, Lake Kivu, exists on the border between the Democratic Republic of the Congo and Rwanda, and contains massive amounts of dissolved CO2. Limnic eruptions can be measured on a scale using the concentration of CO2 in the surrounding area, the Messel pit fossil deposits of Messel, Germany, show evidence of a limnic eruption there in the early Eocene. Among the victims are perfectly preserved insects, frogs, turtles, crocodiles, bi
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Lake Nyos, silty after a limnic eruption
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Cattle killed by the limnic eruption at Lake Nyos
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A siphon used by French scientists to de-gas Lake Nyos.
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Satellite image of Lake Kivu.
