Natural Disaster || Volcano
This article is about geological characterization. For other uses, see Volcano (distribution) and Volcano (distribution).
For comprehensive coverage related to this topic, see Volcanoes.
For comprehensive coverage related to this topic, see Volcanoes.
The Cleveland volcano in the Aleutian Islands of Alaska photographed the International Space Station in May 2006
Ash plumes reached a height of 19 kilometres (12 mi) during the climactic explosive eruption at Mount Pinatubo, Philippines in 1991.
Aerial view of the Barren Island, Andaman Islands, India, during an eruption in 1995. It is the only active volcano in South Asia.
Santa Ana Volcano, El Salvador. A close-up aerial view of the nested summit calderas and craters, along with the crater lake.
A volcano is a rupture in the crust of a planet-mass object, such as the Earth, which allows hot lava, volcanic ash and gases to escape from a magma chamber below the surface.
Earth's volcanoes occur because its crust breaks into 17 major, rigid tectonic plates, which float on a warm, soft layer in its mantle. On Earth, volcanoes are commonly found where tectonic plates deviate or transform. For example, a central oceanic ridge, such as the Mid-Atlantic Ridge, draws volcanoes due to distinct tectonic plates; The Pacific Ring of Fire contains volcanoes that occur because of convergent tectonic plates coming together. Volcanoes may also form where there is a spread and thinning of the inner plates of the crust [clarify], for example, in the East African Rift and the Wales Gray – Clearwater Volcanic Zone in North America and the Rio Grande Rift. This type of volcano falls under the umbrella of the "plate hypothesis". Volcanoes far away from the plate boundaries are also interpreted as mantle plums. These so-called "hotspots", for example, Hawaii, have been postulated to originate from diapers uplifted with magma from the core-mantle boundary, 3,000 km deep into the Earth. Volcanoes are not usually formed where two tectonic plates slide past each other.
Destroying the volcano can create many hazards, not only in the immediate vicinity of the eruption. One such danger is that volcanic ash can be a threat to the aircraft, especially with jet engines where ash particles can be melted at high operating temperatures; The molten particles then adhere to the blades of the turbine and change their shape, disrupting the operation of the turbine. Large explosions can affect temperatures because the ash and droplets of sulfur acid obscure the sun and cool the Earth's lower atmosphere (or troposphere); However, they also absorb heat from the earth, heating the upper atmosphere (or stratosphere). Historically, the so-called volcanic winter has given rise to horrific famines.
Etymology
The word volcano is derived from the name Vulcano, a volcanic island in the Aeolian Islands of Italy, whose name in Roman mythology comes from Vulcan, the god of fire. The study of volcanoes is called volcanism, sometimes also called vulcanology.
Plate tectonics
Map showing the divergent plate boundaries (OSR – Oceanic Spreading Ridges) and recent sub-aerial volcanoes
Divergent plate boundaries
On the mid-oceanic ridges, the two tectonic plates diverge from each other as the new oceanic crust is formed by the cooling and freezing of the warm sea rock. Because the crust is very thin in these ridges due to stretching of tectonic plates, the release of pressure causes adiabatic expansion and partial melting of the mantle, creating volcanoes and creating new marine crusts. Most diver plate boundaries lie at the bottom of the oceans; Therefore, most of the volcanic activity is submarines, forming new seabed. Black smokers (also known as deep seas) are evidence of such volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, Iceland.
Convergent plate boundaries
Subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the oceanic plate is submerged or submerged under the continental plate. In a process called flux melting, the water coming out of the subducting plate lowers the melting temperature of the overlying mantle wedge, creating magnums. This magma becomes very viscous due to its high silica content, so it often does not reach the surface but cools at depth. When it reaches the surface, a volcano is formed. Typical examples of such volcanoes are Mount Etna and the volcanoes in the Pacific Ring of Fire.
"Hotspots"
"Hotspots" is a name given to volcanic regions that are believed to be composed of mantle plums, which are conceived to be columns of hot material rising from the core-mantle boundary at a certain location, which cause large amounts of perforation. Causes. As tectonic plates cross them, each volcano becomes dormant and eventually the plate reforms as the plate advances. The island of Hawaii has been suggested to be built in this way, as well as the Snake River Plain, the Yellowstone Caldera currently part of the North American Plate above the hot spot. This theory is currently under criticism.
Volcanic features
Skjaldbreiður, a shield volcano whose name means "broad shield"
The most common notion of a volcano is that of a conical mountain, on which the top of a crater spews lava and poisonous gases; However, it describes one of several types of volcanoes. The characteristics of volcanoes are more complex and their structure and behavior depends on many factors. Some volcanoes have rugged peaks formed by lava domes rather than summit peaks, while others have landscape features such as massive plateaus. Vents that release volcanic material (including lava and ash) and gases (mainly steam and magmatic gases) can develop anywhere on landforms and give rise to small cones such as Puʻu ʻ on one side of Kilauea, Hawaii. Can. Other types of volcanoes include cryovolcano (or ice volcanoes), particularly on Jupiter, Saturn, and some moons of Neptune; And clay volcanoes, structures that are often not associated with known magical activity. Active clay volcanoes have much lower temperatures than igneous volcanoes, except when clay volcanoes actually flow igneous volcanoes.
Fissure vents
Shield volcanoes
Shield volcanoes, so named for their broad, shield-like profiles, are formed by eruptions of low-viscosity lava that can flow a great distance from a vent. They generally do not explode disastrously. Since low-viscosity magma is generally low in silica, gradient volcanoes are more common in the ocean than in continental settings. The Hawaiian volcanic chain is a series of gradient cones, and they are also common in Iceland.
Lava domes
The lava domes are formed by slow eruptions of highly viscous lava. In the case of Mount St. Helens they sometimes form within the pit of previous volcanic eruptions, but can also form independently, as in the case of Lassen Peak. Like stratovolcanoes, they can produce violent, explosive eruptions, but their lava typically does not flow very far from the origin vent.
Cryptodomes
Cryptodomes are formed when the viscous lava surface is forced to rise. An example was the 1980 eruption of Mount St. Helens; Below the surface of the mountain, the lava formed an upward bulge that slid down the north side of the mountain.
Volcanic cones (cinder cones)
Izalco (volcano), located in the Cordillera de Apaneca volcanic range complex in El Salvador. Only a few generations old, Izalco is the youngest and best-known cone volcano. Izalco erupted almost continuously from 1770 (when it formed) to 1958, earning it the nickname of "Lighthouse of the Pacific".
Volcanic cones or cinder cones arise mostly as a result of eruptions of small fragments, which are formed around the vents of the scoria and pyroclastics (both similar to vermilion, hence the name of this volcano type). These can be relatively short-lived explosions that probably form a cone-shaped hill 30 to 400 meters high. Most cinder cones burst only once. Cinder cones can be in the form of flank vents on large volcanoes, or on their own. Examples of periketin in Mexico and sunset crater cinder cones in Arizona. In New Mexico, Caja del Rio is a volcanic region of more than 60 cinder cones.
Based on satellite images, it was suggested that cinder cones may also occur on other terrestrial bodies in the solar system; On the surface of Mars and the Moon.
Stratovolcanoes (composite volcanoes)
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1. Large magma chamber
2. Bedrock 3. Conduit (pipe) 4. Base 5. Sill 6. Dike 7. Layers of ash emitted by the volcano 8. Flank |
9. Layers of lava emitted by the volcano
10. Throat 11. Parasitic cone 12. Lava flow 13. Vent 14. Crater 15. Ash cloud |
Stratovolcano or composite volcanoes are long conical ridges made up of lava flows and other evictions in alternating layers, giving rise to the name Strata. Stratovolcanoes are also known as composite volcanoes because they are constructed from multiple structures during different types of eruptions. Strato / composite volcanoes are made of cinders, ash, and lava. Cinder and ash pile on top of each other, lava flows over the ash, where it cools and hardens, and then the process repeats. Classic examples include Mount Fuji in Japan, Mayon Volcano in the Philippines, and Mount Vesuvius and Stromboli in Italy.
Throughout recorded history, the ash generated by the explosive eruption of Stratovolcano has posed the greatest volcanic threat to civilizations. Not only do stratovolcanoes create more pressure from the underlying lava flows than the gradient volcanoes, but their fissure vents and monogenetic volcanic zones (volcanic cones) have more powerful eruptions, as they occur many times under expansion. They are also thicker than gradient volcanoes, usually with a slope of 30–35 ° compared to a slope of 5–10 ° and their loose tephra are material for dangerous lacquers. Large pieces of tephra are called volcanic bombs. Larger bombs can measure more than 4 feet (1.2 m) and weigh several tons.
Supervolcanoes
A supervolcanoe usually has a large caldera and can sometimes cause continental, large-scale destruction. Such volcanoes are able to cool severely freezing temperatures for many years, as a large amount of sulfur and ash is released into the atmosphere. They are the most dangerous type of volcano. Examples include: Yellowstone Caldera in Yellowstone National Park and Valles Caldera in New Mexico (both western United States); Tupo Lake in New Zealand; Lake Toba in Sumatra, Indonesia; And the Ngorongoro Crater in Tanzania. Because of the vast area they can cover, it is difficult to identify the centuries after the eruption. Similarly, large igneous provinces are also considered observers because large amounts of basalt lava erupted (even if the flow of lava is non-explosive).
Submarine volcanoes
Submarine volcanoes are common features of the ocean floor. In shallow waters, active volcanoes reveal their presence by destroying steam and rocky debris above the sea surface. At the depths of the ocean, the tremendous weight of the water above prevents the explosive release of steam and gases; however, they can be detected by hydrophones and water discoloration due to volcanic gases. Pillow lava is a common explosive product of submarine volcanoes and is characterized by thick views of a pillow-shaped mass formed underwater. Even large submarine eruptions cannot disturb the ocean's surface due to the rapid cooling effect and increased buoyancy of water (as compared to air), often causing volcanoes to form vertical pillars on the ocean floor. Hydrothermal vents are common near these volcanoes, and some support strange ecosystems based on dissolved minerals. Over time, the structures formed by submarine volcanoes can become so large that they break the ocean surface as new islands or floating pumice rafts.
Subglacial volcanoes
Icecaps develop beneath subglacial volcanoes. They are made of flat lava which flows over the top of broad pillow lava and palegonite. When the icap melts, lava falls at the top, breaking a flat-topped mountain. These volcanoes are also called Table Mountain, Tuyas or (Apoorva) Roberts. Very good examples of such volcanoes can be seen in Iceland, however, there are also tua in British Columbia. The term originates from the Tuya Batt, one of several tuyas in the area of the Tuya River and Tuya Range in northern British Columbia. Tuya Batte was the first such geo-analysis and hence its name has entered the geological literature for such volcanic formation. The Tuya Mountains Provincial Park was recently established to protect this unusual landscape, which lies on the border with the Yukon Territory, north of Lake Tuya and south of the Jennings River.
Mud volcanoes
Mud volcanoes or mud domes are formations created by geo-excreted liquids and gases, although there are several processes which may cause such activity. The largest structures are 10 kilometers in diameter and reach 700 meters high.
Erupted material
Paveho lava flows over the air. The picture shows the overflow of the main lava channel.
Stromboli stratovolcano has erupted continuously for thousands of years off the coast of Sicily, giving rise to the term Strombolian.
San Miguel (volcano), El Salvador. On 29 December 2013, the San Miguel volcano, also known as the "chaperstyke", rises in the sky at 10:30 am local time with a large column of ash and smoke; The eruption, for the first time in 11 years, was seen from space and prompted the evacuation of thousands of people living within a 3 km radius around the volcano.
Stromboli stratovolcano has erupted continuously for thousands of years off the coast of Sicily, giving rise to the term Strombolian.
San Miguel (volcano), El Salvador. On 29 December 2013, the San Miguel volcano, also known as the "chaperstyke", rises in the sky at 10:30 am local time with a large column of ash and smoke; The eruption, for the first time in 11 years, was seen from space and prompted the evacuation of thousands of people living within a 3 km radius around the volcano.
Ash plume from San Miguel (volcano) "Chaparrastique", seen from a satellite, as it heads towards the Pacific Ocean from the El Salvador Central America coast, December 29, 2013
Lava composition
Another way to classify volcanoes is by the composition of material eruption (lava), as it affects the size of the volcano. Lava can be broadly classified into four different compositions (Cass & Wright, 1987):
If the cracked magma has a high percentage (> 63%) of silica, the lava is called felsic.
Felsic lava (dacite or rheolites) are highly viscous (not very fluid) and burst as domes or small, stubby flows. Viscose lava forms the stratovolcano or lava dome. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
Because siliceous magmas are very viscous, they trap the volatiles (gases) present, which cause the magma to destructively ignite, which eventually forms stratovolcanoes. Pyroclastic flows (ignimbrites) are highly dangerous products of such volcanoes, because they are made of molten volcanic ash, which is too heavy to move up into the atmosphere, so they embrace the volcano's slope and during large eruptions Travel away from your vents. High temperatures are known as temperatures of 1,200 ° C in pyroclastic flows, which will stir everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid, often up to several meters thick. . The Valley of Alaska, formed by the Novarupt eruption near Katmai in 1912, is an example of ten thousand smokes, thick pyroclastic flows or ignimbrit deposits. Volcanic ash that erupts high in the Earth's atmosphere can travel several kilometers before returning.
If the cracked magma contains 52–63% silica, the lava is of intermediate composition.
These "andesitic" volcanoes usually occur only above the subsurface zones (eg Mount Merapi in Indonesia).
Endacetic lava usually forms at the convergent boundary margin of tectonic plates by several processes:
If the cracked magma has a high percentage (> 63%) of silica, the lava is called felsic.
Felsic lava (dacite or rheolites) are highly viscous (not very fluid) and burst as domes or small, stubby flows. Viscose lava forms the stratovolcano or lava dome. Lassen Peak in California is an example of a volcano formed from felsic lava and is actually a large lava dome.
Because siliceous magmas are very viscous, they trap the volatiles (gases) present, which cause the magma to destructively ignite, which eventually forms stratovolcanoes. Pyroclastic flows (ignimbrites) are highly dangerous products of such volcanoes, because they are made of molten volcanic ash, which is too heavy to move up into the atmosphere, so they embrace the volcano's slope and during large eruptions Travel away from your vents. High temperatures are known as temperatures of 1,200 ° C in pyroclastic flows, which will stir everything flammable in their path and thick layers of hot pyroclastic flow deposits can be laid, often up to several meters thick. . The Valley of Alaska, formed by the Novarupt eruption near Katmai in 1912, is an example of ten thousand smokes, thick pyroclastic flows or ignimbrit deposits. Volcanic ash that erupts high in the Earth's atmosphere can travel several kilometers before returning.
If the cracked magma contains 52–63% silica, the lava is of intermediate composition.
These "andesitic" volcanoes usually occur only above the subsurface zones (eg Mount Merapi in Indonesia).
Endacetic lava usually forms at the convergent boundary margin of tectonic plates by several processes:
- Hydration melting of peridotite and fractional crystallization
· Magma mixing between felsic rhyolitic and mafic basaltic magmas in an intermediate reservoir prior to emplacement or lava flow.
· If the cracked magma contains <52% and> 45% silica, the lava is called mafic (because it contains high percentages of magnesium (Mg) and iron (Fe) or basaltic. Comparisons are much lower viscosity, depending on their blast temperature; they are warmer than felsic lavas. Mafia lava occurs in a wide range of settings:
· Middle ocean ridges, where the two oceanic plates are pulling apart, burst into basaltic lava pillows to fill the gap;
· Shield volcanoes (such as the Hawaiian Islands including Mauna Loa and Kilauea), on both oceanic and continental crusts;
· Some erupted magmas contain <=45% silica and produce ultramafic lava. Ultramafic flows, also known as komatiites, are very rare; indeed, very few have been erupted at the Earth's surface since the Proterozoic, when the planet's heat flow was higher. They are (or were) the hottest lavas, and probably more fluid than common mafic lavas.
Lava texture
Two types of lava are named according to the surface texture: ʻA (a (pronounced) and pāhoehoe, both aerial passwords. IsAinka is characterized by a rough, wrinkled surface and is the typical texture of viscous lava flows. However, Even basaltic or mafic flows can erupt, as basa flowsa flow, especially if the eruption rate is high and the slope is steep.
Pāhoएe is characterized by its smooth and often ropey or wrinkled surface and is usually formed by more fluid lava flows. Typically, only mafic flows will erupt as PAHO, as they often burst at high temperatures or have the proper chemical makeup to allow them to flow with greater fluidity.
Volcanic activity
Fresco with Mount Vesuvius behind Bacchus and Agathodaemon, as seen in Pompeii's House of the Centenary
Popular classification of volcanoes
A popular way of classifying magmatic volcanoes is the frequency of their eruptions [according to whom?], Along with those that erupt regularly, which erupt in historical times, but are now quietly inactive. . Or are called passive, and which are never. In historical times it is said to be extinct. However, these popular classes - particularly extinct ones - are practically meaningless to scientists. They use classifications that refer to the processes of the formation and eruption of a particular volcano, and the resulting shapes, which are allowed to be written.]
There is no consensus among volcanoes on how to define an "active" volcano. The lifespan of a volcano can vary from months to several million years, making such a difference sometimes pointless compared to the lifetimes of humans or even civilizations. For example, many of Earth's volcanoes have erupted dozens of times over the past few thousand years, but are currently not showing signs of eruption.] Given the long lifespan of such volcanoes, they are very active. Since human lifetimes, however, they are not.
Scientists generally believe the volcano to erupt or explode if it is currently eroding, or is showing signs of unusual activity or significant new operational capabilities such as turbulence. Most scientists consider a volcano to be active if it has erupted in the last 10,000 years (Holocene time) - the Smithsonian Global Volcano Program uses this definition of active. Most volcanoes are located on the Pacific Ring of Fire. 500 million people live near active volcanoes.
Historical time (or recorded history) is another time limit for the active. The list of active volcanoes of the Catalog of the World published by the International Association of Volcanoes uses this definition, by which there are more than 500 active volcanoes. Nevertheless, the period of recorded history varies from region to region. In China and the Mediterranean, it reaches back about 3,000 years, but in the Pacific Northwest of the United States and Canada, it reaches back less than 300 years, and in Hawaii and TV, only around 200 years.
Kīlauea lava entering the sea.
As of 2013, the following are considered Earth's most active volcanoes:
· Kīlauea, the famous Hawaiian volcano, has been in continuous, effusive eruption since 1983, and has the longest-observed lava lake.
· Mount Etna and nearby Stromboli, two Mediterranean volcanoes in "almost continuous eruption" since antiquity.
The longest currently ongoing (but not necessarily continuous) volcanic eruptive phases are:
· Mount Yasur, 111 years
· Mount Etna, 109 years
· Stromboli, 108 years
Other very active volcanoes include:
Nyiragongo's lava lake
.
Extinct
"Extinct volcano" redirects here. For the category [of extinct volcanoes], see Category:Extinct volcanoes.
Extinct volcanoes are those that scientists consider unlikely to erupt again because the volcano no longer has magma supplies. Examples of extinct volcanoes are the many volcanoes over Hawaii - the Emperor Seamount Chain in the Pacific Ocean, Hountviel, Shippock and Zuidwal volcanoes in the Netherlands. Edinburgh Castle in Scotland is famous atop an extinct volcano. Otherwise, whether a volcano is truly extinct is often difficult to determine. Since the "supervolcanoe" calander can sometimes have a life span measured in millions of years, a caldera that has not exploded in tens of thousands of years may be considered dormant rather than extinct. Some volcanologists consider extinct volcanoes to be dormant, although the term is usually used once to mean extinct volcanoes.
Dormant and reactivated
See also: Category:Dormant volcanoes and Category:Inactive volcanoes
It is difficult to distinguish extinct volcanoes form a dormant (dormant) one. The volcano is often considered extinct if there are no written records of its activity. Nevertheless, volcanoes can remain dormant for a long time. For example, Yellowstone has a repurchase/recharge period of approximately 700,000 years, and a Toba of approximately 380,000 years. Vesuvius was described by Roman writers, as it was covered with gardens and vineyards before the eruption of AD 79, which destroyed the cities of Herculaneum and Pompeii. Before its devastating eruption of 1991, Pinatubo was an imperceptible volcano, unknown to most people in the surrounding areas. Two other examples are the long-dormant Soirier Hills volcano on the island of Montserrat, thought to be extinct before activity resumed in 1995, and the Forbeck Mountains in Alaska, which preceded the September 2006 eruption in 8000 BCE. Was not torn before and was long before. Is considered extinct. Climate change can reportedly trigger volcanic activity in sensitive areas by changing ice or seawater and extreme weather pressures.
Technical classification of volcanoes
Volcanic-alert level
The three common popular classifications of volcanoes can be subjective and some volcanoes thought to have been extinct have erupted again. To help prevent people from falsely believing they are not at risk when living on or near a volcano, countries have adopted new classifications to describe the various levels and stages of volcanic activity.Some alert systems use different numbers or colors to designate the different stages. Other systems use colors and words. Some systems use a combination of both.
Volcano warning schemes of the United States
The United States Geological Survey (USGS) has adopted a common system nationwide for characterizing the level of unrest and eruptive activity at volcanoes. The new volcano alert-level system classifies volcanoes now as being in a normal, advisory, watch or warning stage. Additionally, colors are used to denote the amount of ash produced. Details of the U.S. system can be found at Volcano warning schemes of the United States.
Decade volcanoes
Decade volcanoes are 17 volcanoes, identified by the International Association of Volcanoes and the Chemistry of the Earth's Interior (IAVCEI), as they deserve special study in light of their history of large, devastating eruptions and proximity to populated areas. These have been named Decade Volcanoes since the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction. 17 present decade are volcanoes
The Deep Carbon Observatory Project, an initiative of the Deep Carbon Observatory, monitors nine volcanoes, two of which are volcanoes of the decade. The focus of the Deep Earth Carbon degassing project is to use multi-component gas analyzer system devices to measure CO2 / SO2 ratios in real-time and, in high-speed resolution, allow for pre-burst detection of increased asthma. To give, is to improve prediction. volcanic activity.
Effects of volcanoes
Schematic of volcano injection of aerosols and gases
Solar radiation graph 1958–2008, showing how the radiation is reduced after major volcanic eruptions
Sulfur dioxide concentrations over the Sierra Negra volcano, the Galápagos Islands, during an eruption in October 2005
There are many different types of volcanic eruptions and related activity: phytic eruptions (steam-generated explosions), explosive eruptions of high-silica lava (eg, resolite), low-silica lavas (eg, basalt), pyroclastic flows, degenerative explosion. Lahars (debris flow) and carbon dioxide emissions. All these activities can pose a threat to humans. Earthquakes, hot springs, fumaroles, pottery and geysers are often accompanied by volcanic activity.
Volcanic gases
The concentrations of different volcanic gases can vary greatly from one volcano to another. Water vapor is usually the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other major volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of small and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds and volatile metal chlorides.
Water vapor (H2O), carbon dioxide (CO2), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF) and ash (pulverized rock and pieis) in the stratosphere reach a height of 16 from large, explosive volcanic eruptions. Huh. -32 kilometers (10–20 mi) above the Earth's surface. The most important effects from these injections are the conversion of sulfur dioxide into sulfuric acid (H2SO4), which condenses rapidly in the stratosphere to form sulfate aerosols. SO2 emissions alone of two different explosions are sufficient to compare their potential climatic effects. Aerosols enhance the Earth's albedo - its reflection back into space from radiation in the Sun - and thereby cool the Earth's lower atmosphere or troposphere; However, they also absorb the heat emitted from the Earth, causing the stratosphere to warm. During the last century, many eruptions have caused average temperatures on the Earth's surface to fall by half a degree (Fahrenheit scale) for a period of one to three years; The Huaynaputinaprobably eruption caused the Russian famine of sulfur dioxide 1601–1603.
Significant consequences
A proposed volcanic winter occurred. 70,000 years ago after the super eruption of Lake Toba on the island of Sumatra in Indonesia. According to the theory of Toba catastrophe, to which some anthropologists and archaeologists subscribe, it had global consequences, then most humans died and created a population bottleneck that affected genetic inheritance. All humans today. The 1815 eruption of Mount Tambora caused global climatic anomalies, known as "Year Without a Summer" due to the effects on North American and European weather. Agricultural crops failed and livestock died in the Northern Hemisphere, resulting in the worst famine of the 19th century. In the cold of 1740–41, which caused widespread famine in northern Europe, it may also have its origin from a volcano. explosion.
It has been suggested that volcanic activity contributed to the end-Ordovian, Permian-Trasic, Late Devonian mass extinctions, and possibly others. The massive eruption event that formed the Siberian Trap, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for one million years and is considered a possible cause of the "Great Dyeing" Which is about 250 million. Years ago, it is estimated that 90% of the existing species died at that time.
Acid rain
Ash plume rising from Eyjafjallajökull on April 17, 2010
Sulfate aerosols promote complex chemical reactions on their surfaces that alter the chlorine and nitrogen chemical species in the stratosphere. This effect, combined with increased stratospheric chlorine levels from chlorofluoro carbon pollution, produces chlorine monoxide (ClO), which destroys ozone (O3). As the aerosols grow and coagulate, they settle in the upper troposphere where they serve as nuclei for the cirrus clouds and modify the Earth's radiation balance. Mostly hydrogen chloride (HCl) and hydrogen fluoride (HF) dissolve into water droplets in the blast cloud and the acid quickly falls to the ground as rain. Injected ash also falls rapidly from the stratosphere; Most are removed within several days to a few weeks. Finally, explosive volcanic eruptions emit greenhouse gas carbon dioxide and thus provide a deeper source of carbon for biochemical cycles.
Acidic precipitation is a natural contribution to gas emissions from volcanoes. Volcanic activity releases about 130 to 230 terrograms (145 million to 255 million short tons) of carbon dioxide each year. Aerosol can be injected into the Earth's atmosphere by a volcanic eruption. Larger injections can produce visual effects in the form of unusually colorful sunsets and by cooling it can mainly affect the global climate. Volcanic eruptions also provide the benefit of adding soil nutrients to the soil through the weathering process of volcanic rocks. These fertile soils help in the growth of plants and various crops. Volcanic eruptions can also create new islands, as the magma cools and comes into contact with water.
Hazards
Ashes thrown into the air by explosions can pose a threat to airplanes, especially jet aircraft where particles can be melted at high operating temperatures; The molten particles then adhere to the blades of the turbine and change their shape, disrupting the operation of the turbine. Dangerous encounters raised awareness of the incident following the eruption of Galunggung in Indonesia in 1922. and Mount Ridout in Alaska in 19 raised. Nine volcanic ash advisory centers were established by the International Civil Aviation Organization to monitor ash clouds and advise pilots accordingly. Eyjafjallajökull's 2010 explosions caused major disruptions to air travel in Europe.
Volcanoes on other celestial bodies
List of extraterrestrial volcanoes, Geology of the Moon, Volcanology of Mars, Volcanology of Io, and Volcanology of Venus
The planet Venus has a surface that is 90% basalt, indicating that volcanism played a major role in shaping its surface. The planet may have had a major global resurfacing event about 500 million years ago,from what scientists can tell from the density of impact craters on the surface. Lava flows are widespread and forms of volcanism not present on Earth occur as well. Changes in the planet's atmosphere and observations of lightning have been attributed to ongoing volcanic eruptions, although there is no confirmation of whether or not Venus is still volcanically active. However, radar sounding by the Magellan probe revealed evidence for comparatively recent volcanic activity at Venus's highest volcano Maat Mons, in the form of ash flows near the summit and on the northern flank.
Olympus Mons (Latin, "Mount Olympus"), located on the planet Mars, is the tallest known mountain in the Solar System.
There are several extinct volcanoes on Mars, four of which are vast shield volcanoes far bigger than any on Earth. They include Arsia Mons, Ascraeus Mons, Hecates Tholus, Olympus Mons, and Pavonis Mons. These volcanoes have been extinct for many millions of years,but the European Mars Expressspacecraft has found evidence that volcanic activity may have occurred on Mars in the recent past as well.
Jupiter's moon Io is the most volcanically active object in the solar system because of tidal interaction with Jupiter. It is covered with volcanoes that erupt sulfur, sulfur dioxide and silicate rock, and as a result, Io is constantly being resurfaced. Its lavas are the hottest known anywhere in the solar system, with temperatures exceeding 1,800 K (1,500 °C). In February 2001, the largest recorded volcanic eruptions in the solar system occurred on Io. Europa, the smallest of Jupiter's Galilean moons, also appears to have an active volcanic system, except that its volcanic activity is entirely in the form of water, which freezes into ice on the frigid surface. This process is known as cryovolcanism, and is apparently most common on the moons of the outer planets of the solar system.
In 1989 the Voyager 2 spacecraft observed cryovolcanoes (ice volcanoes) on Triton, a moon of Neptune, and in 2005 the Cassini–Huygens probe photographed fountains of frozen particles erupting from Enceladus, a moon of Saturn. The ejecta may be composed of water, liquid nitrogen, dust, or methane compounds. Cassini–Huygens also found evidence of a methane-spewing cryovolcano on the Saturnian moon Titan, which is believed to be a significant source of the methane found in its atmosphere. It is theorized that cryovolcanism may also be present on the Kuiper Belt Object Quaoar.
A 2010 study of the exoplanet COROT-7b, which was detected by transit in 2009, suggested that tidal heating from the host star very close to the planet and neighboring planets could generate intense volcanic activity similar to that found on Io.
Traditional beliefs about volcanoes
Many ancient accounts ascribe volcanic eruptions to supernatural causes, such as the actions of gods or demigods. To the ancient Greeks, volcanoes' capricious power could only be explained as acts of the gods, while 16th/17th-century German astronomer Johannes Kepler believed they were ducts for the Earth's tears.One early idea counter to this was proposed by Jesuit Athanasius Kircher (1602–1680), who witnessed eruptions of Mount Etna and Stromboli, then visited the crater of Vesuvius and published his view of an Earth with a central fire connected to numerous others caused by the burning of sulfur, bitumen and coal.
Various explanations were proposed for volcano behavior before the modern understanding of the Earth's mantle structure as a semisolid material was developed. For decades after awareness that compression and radioactive materials may be heat sources, their contributions were specifically discounted. Volcanic action was often attributed to chemicalreactions and a thin layer of molten rock near the surface.
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. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle.
What is a volcano for kids?
A volcano is a mountain from where the molten rocks or magma erupt through the surface. In simple terms, a volcano is an opening in the earth's surface from which the molten rocks and gases escape out. Once the magma erupts through the Earth's surface, it is called lava.
How does a volcano form and work?
Volcanoes are formed when magma from within the Earth's upper mantle works its way to the surface. At the surface, it erupts to form lava flows and ash deposits. Over time as the volcano continues to erupt, it will get bigger and bigger.
How do you prepare for a volcanic eruption?
· Cover your mouth and nose. Volcanic ash can irritate your respiratory system.
· Wear goggles to protect your eyes.
· Keep skin covered to avoid irritation from contact with ash.
· Clear roofs of ashfall. ...
· Avoid driving in heavy ashfall. ...
· If you have a respiratory ailment, avoid contact with any amount of ash.
What do you do if a volcano erupts?
During a Volcanic Eruption
· Follow the evacuation order issued by authorities and evacuate immediately from the volcano area to avoid flying debris, hot gases, lateral blast and lava flow.
· Be aware of mudflows. ...
· Avoid river valleys and low-lying areas.
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