Volcanoes are underground lava melted at high temperature and pressure 50 to 200 kilometers below the crust, which consists of solid debrisLava flowOr dome shaped ejecta around itSpray outletA raised hill or mountain formed by accumulation.Volcanic vent is amantleorlithospherePipelines to the surface, most of which are deposited incraterNearby, some are carried to high places by the atmosphere and spread hundreds or thousands of kilometers away.The formation and migration of magma is the key to volcanic eruption.The formation of magma mainly includes temperature reduction, pressure reduction and the addition of volatile components.According to the composition and volatile content of magma, volcanic eruption can be divided into two main types: overflow eruption and explosive eruption.Volcanoes that are erupting or have erupted recently are called active volcanoes, while volcanoes that completely stop erupting are called dead volcanoes.[8]
Volcanoes are mainly formed at the junction of plates.This is because at the junction of plates, one plate will subduct under another plate, and the rocks of the subducted plate will melt and form due to strong pressureMagmaMagma will rise, some will stop after rising to a certain extent, and others (most of them) will rise to the ground to form volcanoesRadioactive materialThe heat released by the decay will also cause the rock to melt and rise to the surface to form volcanoes (most volcanoes not at the junction of plates).
The primary magma isearth 's coreFormed of captured molten material.The core of the earth captures molten materials and other materials to form a very thick molten layer.The composition of these substances is uneven.The primary magma solidified to form the most primitive crust of the earth.
Regenerative magma includes magma derived from primary magma and remelted magma.
The current liquid layer of the earth is composed of regenerated magma formed by the variation of primary magma through temperature, composition andState of matterFormed by the change of.
Dynamics of magma migration
The magma moves from the depth of the earth to the crust to form intrusive rocks or erupts to the surface to form volcanoes. The main driving forces for magma movement are:
First, because the proportion of the inner sphere of the earth is greater than that of the liquid layer and the outer sphere, when orbiting the sun, the inner sphere always tends to the opposite direction of gravity, and the inner sphere is not at the center of the earth.To form an inner sphere to the liquid layer from the inside to the outsideExtrusion forceSo that magma and other gaseous and liquid substances move outward from the earth's interior or erupt to the earth's surface.
Secondly, magma crystallization or other physical and chemical reactions produce some water, gas and other substances, forming expansion and extrusion pressureMagmaAnd other gaseous and liquid substances move outward from the earth's interior or erupt to the earth's surface.
Main cause of magma eruption
Announce
edit
The sea water flows into the sea floor along the cracksMagmaThe water is boiled by the magma to produce gas, and the gas moves to the high position of the magma layer and gathers, generating pressure here and finally breaking through the pressuremantleGaps up to the surface of the earth,gas pressure The magma is also driven to erupt, and finally form a volcano.
There are about 2000 known "extinct volcanoes" on the earth;There are 523 "active volcanoes" discovered, 455 of which are on land,Submarine volcanoThere are 68 seats.Volcanoes are unevenly distributed on the earth. They all appear in the crustFault zone。Worldwide, volcanoes are mainly concentrated in the ringthe pacific oceanBelt and Indonesia northwardMyanmar、Himalayas、Central AsiaFrom West Asia to the Mediterranean, most of the active volcanoes on the earth today are distributed in these two belts.
volcanoIt has a long history.Some volcanoes erupted before human history, but they are no longer active. Such volcanoes are called“Extinct volcano”, such as AnhuiDashushan, Hefei；It has erupted in history, but it has been in a relative position for a long timeQuiescent stateVolcanoes of, such volcanoes have well preserved volcanic cone shape, still have volcanic activity ability, or can not be determined to have lost the volcanic activity ability, people call it“Dormant volcano”, such as Mount Fuji in Japan;Since the history of mankind, volcanoes have erupted from time to time, called“Active volcano”, such as the United StatesMount St. Helens。
There is a "liquid region" 100 to 150 kilometers below the crust（Asthenosphere）, there is gas under high temperature and pressure in the areaVolatile matterMelting state ofsilicateMaterial, namely magma.Once it rushes out of the earth's surface from the weak section of the crust, it forms a volcano.
Volcanic activity can eject a variety of materials. Among the solid materials ejected, there are usually some that have been blasted and brokenRock block, detritus and volcanic ash, etc;In the ejected liquid materials, there are generally lava flows, water, various aqueous solutions, and debris mixed with volcanic ashMudflowEtc;Among the ejected gaseous substancesWater vaporAnd carbon, hydrogen, nitrogen, fluorine, sulfur, etcoxide。In addition, in volcanic activities, visible or invisible light, electricity, magnetism, sound and radioactive substances are often ejected. These substances can sometimes kill people, or make electricity, instruments, etc. fail, causing aircraft, ships, etc. to crash.
root
Announce
edit
Volcano eruption
At a depth of about 32 kilometers from the ground, there is a large amount of high-temperature liquid, whose temperature is high enough to melt most of the rock.
Rock expands when it melts, requiring more space.In some parts of the world, mountains are rising.The pressure under these rising mountains is decreasing, and a lava (also called lava) may form under these mountains“Magma”）Library.
This material rises along the cracks caused by uplift.When the pressure in the lava pool is greater than the pressure of the rock roof above it, it bursts out into a volcano.
When erupting, hot gas, liquid or solid matter suddenly emerges.These materials accumulate around the opening to form a conical hill.Crater isVolcanic coneThe top depression is open to the surface.Cone shaped mountain is the product of volcanic formation.The material ejected from the volcano is mainly gas, but like a large amount of slag and ashlavaAnd solid matter also sprayed out.In fact, volcanic rocks are magma erupted by volcanoes. When the magma rises to the height close to the surface, its temperature and pressure begin to decline, and physical and chemical changes occur,MagmaIt becomes volcanic rock.
formation
The formation of volcanoes involves a series ofphysical chemistryProcess.Dissolved in magma during risingVolatile matterIt gradually dissolves and forms bubblesvolume fraction When it exceeds 75%, bubbles trapped in the liquid will be released quickly, resulting inExplosiveAfter eruption and gas release, the magma viscosity drops to a very low level, and the flow changes into turbulent.If the viscosity of magma is low or the volatile matter is low, there will be only quiet overflow.frompartial melting To a series of eruptionsPhysicochemical changesThe difference between the two forms various volcanic activities.
distribution
Plate tectonic theorySince its establishment, many scholars havePlate theoryThe global volcanic model has been established. It is believed that most volcanoes are distributed on the plate boundary, and a few volcanoes are distributed in the plate. The former form the four major volcanoesVolcanic zone, i.eCircum Pacific volcanic belt、Mid Ocean Ridge Volcanic Belt、East African Rift Volcanic BeltAnd the Alps Himalayan volcanic belt.plate tectonicsThe significance in volcanic research is that it can combine many phenomena that appear to be isolated from each other into an organic whole, but the volcanic activity model established by this theory is not perfect, such asAtlanticWhy is there no volcanic zone;Intraplate volcanoNot on the plate boundary, useMantle plumeIt seems that the explanation of its causes is not enough.Recently, another scholar (Li Hongye, 1993) proposed the theory of bipolar extrusion, revealing the mystery of the earth's developmentEquatorial axisExpansion forming meridional directionSchistosisAnd latitudinal compression, the global volcanoes are mainly distributed in the longitudinal and latitudinal directionsTectonic zoneInside.Global volcanoes andStrong earthquakeDistribution, red refers to Holocene volcanoes, data is taken from Smithsonian Research Institute, and white refers to strong earthquakes above magnitude 7, according toChina Seismic NetworkDirectory drawing.
In the Pacific Rim, volcanic activity is frequent. According to historical records, 80% of the volcanoes erupted in the world today, mainly inNorth America, Kamchatka Peninsula, Japan, Philippines and Indonesia.Indonesia is known as the "country of volcanoes", and its south includesSumatraThe arc formed by Java islandsoceanic trenchThere are nearly 400 volcanoes, 129 of which are active volcanoes. There were 22 volcanoes erupting here only from 1966 to 1970. In addition, submarine volcanic eruptions also occur frequently, resulting in some new volcanic islands emerging from the sea.
The volcanic rocks in the circum Pacific volcanic belt are mainly the products of the eruption of neutral magma, formingCalcium alkaline seriesThe most common type of volcanic rock isAndesiteIn the land 150-300km away from the trench axis, andesite is distributed in an arc parallel to the trench, which is called“Andesite line”。Another feature is that the rocks from the trench to the land have obvious horizontal zoning, which is generally distributed in turn as the distance from the trench increasesPlaque seriesRock, calciumAlkaline seriesRocks and rocks of alkaline series.Most of the volcanoes here areCentral eruptionThe intensity of volcanic eruption is large, and if it occurs in densely populated areas, it often causes seriousVolcanic disaster。
oceanMidribAlso calledOceanic rift, it is distributed in a "W" shape around the world, fromarcticThe basin passes through Iceland to the South Atlantic Ocean, which bisects the Atlantic shell and is parallel to the coastline on both sides.Circumambulate southwardAfricaThe south end of is turned to NE andIndian Ocean RidgeConnect.The Mid Indian Ridge extends northward toAfrican continentNorth end andEast African Rift ValleyConnect.It goes around Australia to the south and east, and is adjacent to the southern end of the Pacific Ridge. The Pacific Ridge leans towards the east of the Pacific Ocean, and extends northward and then entersArcticSea area, wholeMid ocean ridgeIt forms a "W" shaped pattern and becomes a global oceanic rift valley, with a total length of more than 80000 kilometers.The middle of the oceanic rift valley is mostly upliftedHailingIt is 2-3 kilometers higher than the two sides of the Haiyuan, so it is called the mid ocean ridge. In the middle of the ridge, there are many 20-30 kilometers wide and 1-2 kilometers deepGraben, so it is also called Ocean Rift Valley.Volcanoes in the ocean are concentrated in the oceanRift zoneIt is called the mid ocean ridge volcanic belt.according toOcean floor rockAge determination, indicating that the oceanic rift was formed earlier, but the expansion and intense activity of tension fracture weremesozoicIn the Cenozoic era, especially since the Quaternary, it was more active, especially in volcanic activity.
The distribution of volcanoes in the mid ocean ridge volcanic belt is also uneven, and most of them are concentrated in the Atlantic Oceanrift, starting from the northGreenland, viaIceland、AzoresTo Cape Verde Islands, this section is more than ten thousand kilometers long, and the seamount is composed of basalt, which is the product of volcanic eruption along the oceanic rift valley.Because most volcanoes areSubmarine eruptionIt is not easy to be found. According to relevant data,Mid Atlantic RidgeThere are only more than 60 active volcanoes.Iceland is located in the mid Atlantic ridge. We can directly observe the volcanoes on Iceland. There are more than 200 volcanoes on the island, including more than 30 active volcanoes, which are called volcanic islands.According to geologist SAccording to Thorarinsson (1960), more than 200 volcanic eruptions occurred in the past 1000 years, with an average eruption of once every five years.The famous active volcanoes areHycla volcanoSince 1104, there have been more than 20 major eruptions.Laki volcanoAn eruption in 1783 was witnessed. The lava flowing from a crack 25 kilometers long reached more than 12 kilometers. The lava flow covered an area of about 565 km ², and the lava flow was more than 70 kilometers long, causing major disasters.In 1963, a volcano erupted in the southern waters of Iceland. This eruption lasted until 1967, creating a new island——Soutese Volcano Island, about 150m above the sea level, with an area of 2.8km2.After 6 years, theWestThe Haimai Island volcano in the Mann Islands has another large eruption.The eruption of these volcanoes reflects the characteristics of volcanic eruptions in the Atlantic Rift Valley.
At the Pacific Ridge, the axis of the Pacific East Rise at 6 ° - 14 ° Sfissure eruptions A basalt platform with a width of 40-60 km and a length of 800 km has been formed, and only 14 active volcanoes have been foundActivity intensityIt is not as frequent as the volcanic belt of the Atlantic Rift Valley.
the indian oceanIt is found that there are three trains ofUndersea mountain range, that is, the sea ridge. Only some volcanoes emerge from the sea to form volcanic islands, such asSeychellesandMarqueThe Lin Islands are all formed by the eruption of modern submarine volcanoes.
3、 The Red Sea coast andEast African volcanic belt
East African Rift ValleyyesmainlandThe largest rift zone is divided into two branches: the east branch of the rift zone starts from the southShire RiverEstuary, viaMalawiXiao, running northwardEast African PlateauCentral andEthiopiaIn the middle, to the northern end of the Red Sea, about 5800 kilometers long, and then to the northwest AsiaOfJordanRiver valley connection;The west branch starts from the southLake Malawi At the northwest end, passing through Tankaganika LakeLake Kivu、Lake Edward, Albert Lake, and Albert Nile Valley, about 1700km long.The rift zone is generally 1000-2000m deep and 30-300km wide, forming a series of narrow and deep valleys and lakes, such asEthiopian PlateauIn the eastern Great Rift ValleyLake AsarThe lake is 150m below sea level, which is the lowest point on African land.
sincemesozoicSince the formation of the rift valley, volcanic activity has been frequent, especially lateCenozoic eraSince then, it has become more popular. According to statistics, there are more than 30 active volcanoes in Africa, most of which are distributed near the faults of the rift valley, and some are also distributed 100 kilometers away from the edge of the rift valley, such asMount Kenya 、KilimanjaroandElgon MountainTheir eruption is also closely related to rift activities.East African Rift Volcanic BeltEruption type There are two kinds, one isFissure eruption, mainly in EthiopiaRift systemOn both sides, basalt is formedLava plateau(Platform), accounting for 2/3 of the national area of Ethiopia, with lava thickness of 4000m, which is hundreds of times since 300000 to 500000 years agoBasaltic magmaIt is formed by overflow along fractures.stayKenyaIn the northwest, a 1000m thickLava platform, whichFormation timeThe lava platform later than Ethiopia was formed during 140000-230000 yearsPhonoliteDuring 110000-130000 years, a 300 km long phonolite lava platform was formed.The second type is central eruption, which is mainly distributed at the edge of the rift zone. The main active volcanoes arezaireOfNyiragongo Mountain, Nyamakira Mountain, Tereke Volcano in KenyaMozambiqueLanai Mountain and EthiopianEitel Volcanoes, etc.Some volcanic eruptions only generate bursting crater, or crater depression, orCrater LakeFor example, Ngorongoro (Tanzania) crater depression has a diameter of 19 km and an area of 304km ².
Modern volcanic activity centers are concentrated in three areasUganda－Rwanda－zaireThe western rift system on the border has had 13 volcanic eruptions since 1912-1977,Nyiragongo VolcanoStill active;Second, Erta volcano and Afdara volcano in Afer (Oman) depression, Ethiopia, have erupted many times since 1960 to 1977;ThirdTanzaniaThe Lungai (Tanzania) volcano on the Grgory Rift Valley in the south of Natron (Tanzania) has erupted many times from 1954 to 1966,Extrusive rockCarbonate rocks with high contentsodium carbonateIs rare in the world.be locatedKenny The Treki volcano at the southern end of Turkana also erupted several times in the 1980s and 1990s.In the modern volcanic activity area, hot springs are widely developed, and volcanic eruptions are obvious, most of which are water vapor andSulfurGas, which is a sign of volcanic activity today.
There are more than 70 active volcanoes in this area, includingmediterranean seaThere are 13 along the coast,IndonesiaThere are more than 60 seats.The nature of magma erupted in this volcanic belt ranges from alkaline to acidic. Different volcanoes show different behaviors, and the same volcano also changes in different stages of eruption.
distribution
There are 516 active volcanoes in the world, 69 of which are submarine volcanoesPacific regionMost.Active volcanoes are mainly distributed in the ringthe pacific oceanVolcanic belt, Mediterranean Himalayan Indonesia volcanic belt, mid ocean ridge volcanic belt andCrimson Sea-East AfricaContinental riftBand.There are about 900 Cenozoic volcanic cones in ChinaInner MongoliaThe largest number is about 600-700.The volcano that erupted once today is located in XinjiangYutian CountyKarda's volcano.The distribution of volcanoes is controlled byGlobal plate tectonics。
asRussiaKamchatka PeninsulaHivelucci Volcano。On the morning of April 17, 2012,Hivelucci VolcanoStrong eruption, the eruption of volcanic ash 9500 meters above sea level.According to the report,Russian Academy of Sciencesfar eastVolcanoes and earthquakesThe professional staff of the research institute observed the eruption of volcanic ash at the research station 40 kilometers away from the volcano.The volcanic ash flow extends for 100 kilometers in the east.This eruption is the strongest eruption of the volcano since the beginning of 2012.Although the volcanic ash will not have a serious impact on nearby settlementsaviation safetyIt poses a threat.
Volcanic activity is a kind ofCosmic naturePhenomenon.Space exploration and discoveryMoon, Mars, VenusIoThere is volcanic activity on the.
A volcano that is still active or periodically erupts.Such volcanoes are in a period of vigorous activity.asJavaSince this century, the Merapi volcano has been erupting continuously for a period of two or three years on averageTaiwan IslandDatun VolcanoesThe main peak ofSeven Star MountainMost famous.On the mainland, only in the western section of Kunlun Mountains in XinjiangYutianOfKardashi VolcanoesThere are records of volcanic eruptions.The eruption of the volcano formed a flat topped cone.
A volcano that erupted in prehistoric times but has never been active in history.Such volcanoes have lost their ability to move.Some volcanoes still maintain a complete volcanic form, while others have been weathered and eroded, leaving only incomplete volcanic remainsDatong Volcanic Group, ShanxiThere are 99 isolated volcanic cones in the area of 123 square kilometers, of which the Langwo Mountain volcanic cone is nearly 1900 meters high.
It refers to the eruption that has occurred in history, but has been in a relative position for a long timeQuiescent stateVolcanoes.Such volcanoes have well preserved cone shape, and still have volcanic activity capacity, or it can not be concluded that they have lost their volcanic activity capacity.Such as ChinaChangbai Mountain TianchiIt erupted twice in 1327 and 1658, and there were many activities before that.Although there is no eruptive activity, some unfathomableJet holeThe volcano is now in theSleep state。All dormant active volcanoes have an active magma system underground. The magma in the magma chamber starts to rise, which means that the eruption of the volcano will begin.[7]
Fissure eruptionAlso known as Icelandic volcanic eruption.MagmaticFault zoneOr the fissure overflows the surface, and the volcanic channel formed in this way is narrow and long in line shape on the surface and wall shape downward.This kind of eruption has no strong explosion phenomenon, and the eruption is gentle and quiet, and the magma ejected is of small viscosityBasicityBasaltic magma with few clasts and gases.After the basic lava overflows, a wide and thin lava flow, lava slope orLava platform, and even formLava plateau。
Penetration eruptionWhen the magma of penetration eruption rises, due to the high temperature and some chemical actions between the magma and the rock, the rock above is melted and jacked open, forming a volcanic channel with large diameter and irregular shape;After losing pressure, magma overflowed the surface in a large area.The hot magma slowly overflows from the volcanic channel to form lava flow, and finally gradually condenses to form lava.Volcanic rocks formed by penetration eruption are widely distributed, and the crater is generally not obvious.This kind of eruption sometimes happens when the magma rises and stops in the middle, and it condenses without melting the top rock layer, and only rises on the ground to form hills. This kind of volcano is called“Subvolcano”Or "underground volcano".Some scholars believe that,remote dateThe crust is thin, and the underground magma has a large thermal power, which often results in penetration type magma eruption, which has disappeared in modern times.
Central eruptionMagma spewed out of the ground along the volcanic throat.It can also be divided into the following categories according to the intensity of ejecta and activitiesRepresentativenessThe name of the volcano, place name and person name.
According to volcanic cone
Volcanic lava is composed ofLava cone, its shape is flat and the slope is gentle (2 °-10°), with bowl shaped crater on the top.The large-scale ones are calledShield volcano。The clastic cone is composed entirely of volcanic debris.Its plane is approximately circular, with a slope of about 30 °, and there is a funnel shaped crater on the top.Composed of lava and debrisInterbeddingThe constituent is calledCompound cone, also called layered volcanic cone.The slope is mostly more than 30 °, and the shape is relatively symmetrical. The upper part is full of lava, and the lower part and edge are mainly volcanic debris.The crater is bowl shaped or funnel shaped.Some volcanoesConical slopeThere is also a small volcanic cone, whose channel is connected with the channel of the main volcanic cone, and there is no independent magma source.These small volcanic cones are called parasitic cones.
Schematic diagram of volcanic cone type classification[12]
According to destructiveness
SupervolcanoIt is one of the most destructive forces on earth.Once it erupts, it will cause at least 1000 cubic kilometers of rocks and ashes to burst out of the earth.This volume was basically devastating in 1980Mount St. HelensThe eruption amount is 2500 times.[6]
harm
Announce
edit
Volcanic debris flow
A large amount of volcanic ash ejected by volcanic eruption is formed in combination with rainstormDebris flowIt can destroy roads and bridges, submerge nearby villages and cities, and make countless people homeless.Mud formed by mud and rock debris can flood the whole city.
Although the rock isVolcanic ash cloudIt is covered, but when the volcano just erupted, you can still see the huge rocks sprayed into the air.
Debris contamination
PyroclasticIt is the lava condensed debris from the volcano andVolcanic passageRock debris in the inner and four walls.Volcanic debris is divided into those larger than eggs according to sizeVolcanic block, smaller than eggsVolcanic gravel, smaller than soybeanVolcanic sandAnd extremely fine volcanic ash;Divided into:Spindle, strip or twist shapedVolcanic bomb, flatdriblet , filiformVolcanic hair；According to internal structure, it can be divided into porous and light coloredPumice, foam, porous, black and brown volcanic debris inside.Volcanic debris ejected into the air falls roughly near the crater, light and small, or is blown hundreds of kilometers away by the wind to settle, or rise tostratospherealong withatmospheric circulation。Hot during volcanic eruptionVolcanic ash flowMixed with water (rainstorm in volcanic area, nearby rivers and lakes, etc.)Volcanic mudflow。Volcanic ash flow andMudflowAre disastrous.
Pyroclastic flowIt is one of the major volcanic killers, with great destructiveness and lethality.Because of its high speed, it is difficult to avoid.Pyroclastic flows are gas andPyroclasticA mixture of.It is not water flow, but a high-density, high-temperature, high-speed air flow mixed with rock debris, which often sweeps close to the ground.The pyroclastic flow can reach a temperature of 1500 ℉ (about 816 ℃) and a speed of 100-150 miles per hour (Myers et al., 1995). It can break and burn any life and property in its path.Pyroclastic flows result from volcanic explosive eruptions orLava domeThe collapse of.
Lava flow
After volcanic eruption, there is a certain probability thatLava flow。Flowing on the surface in liquid formLava mantleIt is called lava flow, and the solid rock accumulation formed by the cooling of lava flow is sometimes called lava flow.The temperature of lava flowing in liquid state is usually between 900 ℃ and 1200 ℃. If there is more gas in lava, it can flow at lower temperature.Acid lavaViscous, not far flowing, large area of lava flow is oftenBasic lava。When the temperature is high and the slope is steep, the flow velocity of lava flow can reach 65km per hour.The shape of lava flow depends on many aspects, such as lava composition（basalt、AnshanRockDacite、Rhyolite）, flow, terrain and environment, etc.
Mountain landslide
After the volcanic eruption, the huge vibration generated by the volcanic eruption will cause the soil around the volcano to loosen, thus causingMountain landslide。
corrosive
On May 21, 2018,Hawaii, USAKilawe VolcanoThe lava from the mouth has flowed into the Pacific Ocean.When lava meets seawater, it will produce high-temperature and corrosive gas lava mist.
American Geological SurveySaid,Big Island Two streams of lava on the southeast Pune coast flowed into the sea overnight.The lava mist produced in this process ishydrochloric acidGas, steam andVolcanic glassThe irritant mixture formed by particles is harmful to human body.
This kind of extremely hot and corrosive mixed gas once appeared in 2000 and caused two deaths in the local area.Due to the continuous eruption of the volcano, the amount of volcanic gas discharged has increased three times.Especially in the area of volcanic downwind, "volcanic smoke" with different concentrations may be formed.
value
Announce
edit
Increase resources
Volcanic resourcesThe use of can also bring us joy and convenience in life.Generally speaking, volcanic resources are mainly reflected in itsTourism value、Geothermal utilizationandlavaMaterial.Volcano and geothermal are a pairtwin brothersWhere there are volcanoesGeothermal resources。geothermal energyIt is a kind of cheap new energy without pollution, so it has been widely used.From medical treatment, tourism, agricultural greenhouseAquacultureThe application of geothermal energy can be seen all the way to civil heating, industrial processing and power generation.Geothermal calculations have been carried out in the Kamet volcanic area, where there are thousands of natural steam and hot waterSpoutOn average, 20000 cubic meters of hot water and steam are ejected every second, which can bring 40 trillion calories of heat from the earth's interior within a year, equivalent to 6 million tons of coal.Iceland is located in the zone with frequent volcanic activities, and the geothermal energy that can be developed is 45 billionKilowatt hour, geothermal energyAnnual power generationIt can reach 7.2 billion kilowatt hours. The people there have made good use of this resource. Although only 7% of it has been developed, it has brought many benefits to the local people.Among them,Reykjavik3 aroundGeothermal power stationIt provides 150000 Icelanders with hot water and electricity, and 85% of the residents of Iceland pass throughGeothermal heating。Geothermal resources are clean and sanitary, greatly reducing the import of oil and other energy.Since 1975, Icelandair qualityGreat improvement.Icelanders are also good at improving the use efficiency of geothermal resources, including planting greenhouse vegetables, flowers and plants, building all-weather outdoor swimming poolsSidewalkAnd laying hot water pipes under the parking lot to speed up the melting of winter snow.Geothermal power generation, ChinaYangbajing, TibetIt has established the largest geothermal test base in China and achieved good results.
Volcanic activity can also form a variety of minerals, the most common is the formation of sulfur ore.Terrestrial eruptivebasalt, often crystallizedNative copperandcalcite，Submarine volcanoThe eruption basalt can often form large-scale iron ore andcopper mine。In addition, the formation of diamonds we know well is also related to volcanoes.Basalt is the most widely distributed volcanic rock, and it is also a good building material.The melted basalt is called“Cast stone”, can be made into variousboard, appliances, etc.The biggest characteristics of cast stone are hard, wear-resistant, acid resistant, alkali resistant, non-conductive andThermal insulation material。
Revival of vitality
Volcanic eruptionnatural landscapeIts influence is very far-reaching.Land is the most precious resource in the world, because it can breed various plants to support everything.If the volcanic eruption can cover the farmland with volcanic ash less than 20 cm thick, it is really a blessing for farmers, because the volcanic ash is rich in nutrients and can make the land more fertile.
After the lava collapsed, weeds and mosses began to emerge.
Volcanic ash makes the surrounding land fertileGrapeEvery year there is a bumper harvest.
Although volcanoes often bring huge disasters to human beings, they are not useless.
Make a spectacle
GeyserIt is one of the late volcanic eruptionnatural phenomena。When the underground high temperature heats the underground water to a certain pressure, the water and steam will rush out from the nozzle, and the pressure will be reduced, and the ejection will stop and enter the next process.Yellowstone National Park The geysers are very famous, some of which can reach more than 100 meters high, and their roaring like waves is soul stirring.asOld Faithful The water column it ejects can reach about 180 meters, and the steam from the boiling water hangs on the blue sky like a white cloud.It sprays once an hour and lasts for 5 minutes each time. It is very punctual, so it got such a name.
Some craters have lava lakes at the bottom, just like a pot of boiling porridge.The Kilauea crater on the Hawaiian island has a diameter of more than 4000 meters and a depth of 130 meters. At the bottom of this "cauldron" is a magma lake more than 10 meters deep. Sometimes, magma fountains as high as several meters will appear on the lake.
Some craters can be regarded as the works of nature's ghost axe magic skill.As it is called "the world"The eighth miracle”OfNgorongoro craterIt is more than 600 meters deep, with a diameter of 18 kilometers and an area of 254 square kilometers,Bottom areaFor 260 square kilometers, it looks like a giant well going straight up and down.In this "well", there is still lifelion、giraffe、buffalo、zebraWaiting for many animals is like a busy zoo.
The largest crater in the world is JapanKyushuInsularAso Volcano The crater is 17 kilometers from the east to the west, 25 kilometers from the north to the south, and more than 100 kilometers in circumference. From its size, we can imagine the great power of the eruption at that time.There is often a hot spring near the volcano, and people like it very much.
Eruption
Announce
edit
1、 The process of volcanic eruption
The process of volcanic eruption can be summarized into three stages: magma formation and initial stageAscending stage、Magma sac stageAnd leaving magma sac to surface stage.
1. Magma formation and initial ascending stage
The generation of magma must have two processes: partial melting and separation of molten body from parent rock.In fact, these two processes are unlikely to be independent of each other, and the separation of molten body and parent rock may occur when melting begins.Partial melting is the coexistence of liquid (i.e. magma) and solid (crystallization), with temperature rising, pressure decreasing andSolidusPartial melting can be produced when it is reduced.When part of the molten materialmantleWhen the flow rises, liquid and solid will also be produced in the flowSeparation phenomenon, resulting in the movement and even aggregation of liquid, which is calledMelting away。
2. Magma pocket stage
Magma pocket is the area filled with magma under the volcano, which is the crust or upperMantle rockWhere magma is relatively enriched in the medium.It is generally regarded asReservoirThe high-temperature fluid in the pores (or fissures) of similar rocks is generally considered that magma only accounts for 5% - 30% of the total volume in the mantle plume.Locally, it can be regarded as a collection of relatively flowing liquids inside.Magma is composed of magma meltVolatilesAnd a mixture of crystals.
3. From magma pocket to surface stage
The rise of the path from the magma source area to the near surface is related to the excess pressure of the magma pocket, the formation and connection of the path, and the crystallization and degassing process of the magma rising.When the crust is stretched or stretched-Shear stressGreater than local rockRupture strengthIf these fractures are connected with each other, they can be used as channels for magma eruption.The eruption is often accompanied by huge lightning.
2、 Formation of caldera
1. When the caldera is formed
During the slight eruption of the volcano, the magma rises to the top of the main rift of the volcano.
2. Next stage
When the eruption force is strengthened, the magma quickly falls back to the top of the magma pool.
3. Vertex
After the eruption of Pliny type or Pellet type volcanoes reaches the peak, the magma falls back to the bottom of the top of the magma pool, leaving a space where the top of the pool was supported in the past.
4. Collapse
Once the magma support is lost, the caldera will sink into the magma pool, and there will be more eruptions at the bottom of the caldera.
The formation of volcanoes in a place mainly depends on the following conditions:
1. The formation of partial melting body must have high geothermal energy (self accumulated or externalboundary condition ), or uplift decompression process, or dehydration to reduce the solid phase line;
2．MagmaIntracrustalenrichment, or the location of magma sac formation andNeutral buoyancyThe depth of the neutral buoyancy surface is related to the crustRheologyDiscontinuity related;
3. The physical and chemical processes in the magma pocket are mainly the fraction and interaction of crystals, volatiles and fluids, and the magma eruption plays a role in promoting, orinhibition。The existence of magma pockets in the crust plays a role in intercepting and reforming the magma rising from the mantle.It is also an important condition for the formation of explosive volcanic eruption;
4. The existence of magma chamber has a significant impact onMagmatic channelThe formation ofFacilitationThe extensional stress field caused by tectonic activity is the main reason for the formation of magma channel;
5. The rising of magma after leaving magma sac is affected byPressure gradientAnd buoyancy.
benefit
Announce
edit
Benefits of volcanoesVolcanic geologyVolcanic terrain, post volcanism geothermal and hot springs, and fertile volcanic soil all bring people considerable benefits.
Volcanism is not entirely harmful to us.For example, magma is a good source of geothermal as long as it can stay below the surface.Hot springs orHot spring, which is becauseMagmaIt is formed when the heat emitted heats the groundwater.This heat source is called geothermal, which can be formed on a large scale“Geothermal field”。
Another advantage of volcanism is to create land for us.About 71% of the earth's surface is covered by sea water. Submarine volcanoes continuously emit magma and condense into rocks over the years, which accumulate for such a long time until one day the rocks rise above the water to form an island.hawaiian islandsAndIcelandThis is how it was formed. In 2024, there will be active volcanoes on the island that will erupt magma from time to time.
In addition, the volcanic ash cloud formed by the volcanic eruption will affect the blocking of the area for a period of time after the eruptionsunlightThe average temperature in this area has also decreased. Scientists believe that volcanic eruptions are the natural climate of the earthadjustment mechanism 。
Volcanologists often visit volcanoes (especiallyActive volcano）To observeVolcano eruption, collecting eruption products, such asVolcanic eruption debris, rock and lava samples.Another focus of research is to predict volcanic eruptions.There is no accurate method to predict volcanic eruption, but predicting volcanic eruption can save many lives just like predicting earthquakes.
One of the most dangerous professions of scientists is volcanologists, because a sudden volcanic eruption may occur at any time when studying active volcanoes.
appendix
Announce
edit
Largest volcano
Mauna Loa Volcanobe locatedhawaiian islandsThe middle part of the sea is 4170 meters above sea level, about 9300 meters high from the bottom of the sea.The mountain top is often surrounded by white clouds.Island NorthMauna Kea At 4205 meters above sea level, it is the highest peak in Hawaii.The highest in the worldobservatoryIt is located at the top of this mountain.
Mauna Loa is aActive volcanoThe Mauna Loa volcano erupted again. At that time, boiling lava burst out from a gap of one and a half kilometers long with bubbles, lasting up to a month. The highest level of magma eruption exceeded that of New YorkEmpire State Building。In March 1984,Monaloa VolcanoAnother outbreak, the world's rare magnificent scenery, attracted tourists from all over the world.It is an activity on the Hawaiian islandShield volcanoIs one of the five volcanoes that form Hawaii.Although its peak is more than the adjacentMauna Kea VolcanoIt is 36 meters lower, but Hawaiians still name it "MaunaLoa", meaning "Long Mountain".It is estimated that its capacity is about 75000cubic kilometers (18000 cubic miles).The lava from Mauna Loa volcano is very mobile, which leads to the very small slope of the volcano.
The Mauna Loa volcano erupted for at least 700000 years and exposed about 400000 years agosea levelHowever, the oldest rock known locally is less than 200000 years old.The magma at one of the hot spots under the island has formed over the past ten million yearsHawaii IslandChain.along withPacific plate The Mauna Loa volcano was finally taken away from the hot spot and will stop erupting in 500000 to 1 million years.
Famous volcano
Fuji
JapanFuji(located in JapanYamanashi CountySoutheast andShizuoka PrefectureThe junction, 3776m above sea level, isJapanThe first peak.The mountain peaks are towering into the clouds and covered with snow.It is the pride and symbol of the Japanese.
Stramboli Volcano(onItalySicilyFengshen Island, which often erupts 2-3 times per hour on time, has lasted for more than 2000 years, and has been called "Fengshen Island" since ancient times“mediterranean seaLighthouse ").
Mount St. Helens(located in the United StatesWashington StateBefore the eruption in 1980, the mountain top was covered with snow, known as "AmericanFuji”）。
Mount Rainier(USAThe highest volcano, covered with ice and snow all the year round, is a famous tourist attraction in the United States.Washington State).
Mayong volcano(onthe PhilippinescapitalManilaIt is the highest active volcano in the Philippines, about 300 kilometers from the east to the south.
Etna volcano(located in Italysicily, is a famous active volcano, with more than 200 eruptions recorded).
Kodopasi Volcano（EcuadorWith an altitude of 5897 meters, it is the highest active volcano in the world.
Santorin Volcano (located atGreeceaegean seaOfSantorin IslandOn.There were three small-scale eruptions in the 20th century.There was a very violent eruption around 1645 BC).
IcelandVolcano eruptionThe volcanic eruption in Iceland seems to have no sign of stopping, and the fact has proved that the dust column generated by the volcano is very dangerous.without doubt,Icelandic volcanoEjectiveashIt is still increasing.No fly order, ejected dust and harmfulEmissionsAre the adverse consequences that the world needs to bear.There have been such scale beforeVolcano eruption, their serious consequences are enough to shakehuman civilization。Here are the ten largest volcanic eruptions.EyjafjallajokullDust generated by explosioncloud clusterUp to 5000 feet (1.52 kilometers) above the glacier.From a long distance, we can see that the smoke and dust are drifting southward and submergedEnglandThe sky and parts of Europe have caused traffic chaos.Many flights in the state were cancelled.geologistHe said that the activity of this volcano is intensifying, and volcanic ash can causeairplane enginemalfunction.
La Garita Caldera is located in the United StatesColoradosouthwestSan JuanA large crater in the San Juan Volcano region of the mountains, located west of the town of Lagarita, Colorado.It broke out 28 million years ago, which may beEarth historyThe largest volcanic eruption in China, which spewed more than 1200 cubic miles (500 billion cubic meters)lava, leaving these beautiful landscapes composed of volcanic ash.
Iceland Volcanic Eruption
The largest volcanic eruption in the 20th century occurred in 1912. The eruption lasted from June 6 to June 8, and finally formed Novalaputa volcano.Burst index6 Novalaputa volcano, produced by eruptionAlaskaPeninsula components,Than historyAll other Alaskan volcanic eruptions have brought much material to the peninsula.stayKodiak IslandVolcanic ash fell from the sky one after another in the Selikov Strait, which lasted for three days. The ash on the ground of the main towns was 1 foot (30.48 cm) thick.This volcanic eruption was very violent, which led to6 miles(9.66 km)CarterThe top of the mountain collapsed.
Indonesia Tambora Volcano Eruption
IndonesiaTambora Volcano eruptionThe eruption of Tambora volcano in Indonesia is the largest volcanic eruption in the past two centuries.The eruption lasted from April 10 to 11, 1815, and its eruption index reached level 7. It is said that the most deadly volcano killed nearly 92000 people.Volcanic eruption and the volcanic ash it produces have reduced the global temperature by more than 5%Fahrenheit degree(About 2.8centigrade）。In 1816, it was impossible to sow normally. This year was also called "the year without summer".
Krakatoa VolcanoOn August 27, 1883, Krakatoa Volcano erupted. It made a deafening sound from a distance of about 2000 miles (3218.69 kilometers)AustraliaCan also hear.The large-scale eruption with an eruption index of 6 triggered a series of tsunamis up to 150 feet (45.72 meters), which affectedhawaiian islandsandSouth AmericaMore than 36000 people lost.It generated five cubic miles of dust, and for two days the surrounding area remained dark.It was the most eye-catching sunset scene seen in the world for many years.
Pinatubo Volcano eruption
Mount Pinatubo erupted in 1991Pinatubo Volcano eruptionIts outbreak index reached level 6. It is said that its outbreak scale was the second in the 20th century, and this outbreak resulted in about 800 deaths.The volcano is located inthe philippine islandsBangpanya, Chalice Province andTara ProvinceJunction.Occurring in the same periodtropical stormIt contributes to the spread of volcanic lava.Results The global temperature continued to decline in three yearsConsumptionIt is also temporarily increased.
Kilauea Volcano The eruption of Kilauea volcano is the Hawaiian Islands and the most active volcano in the worldHawaii IslandOne of the five shield volcanoes in the Tibetan Plateau.The volcano began erupting in 1983 and has continued to this day.See inflowthe pacific oceanOfLava flowYou will be surprised.In order to see the spectacular scene of volcanic eruption at sunset, a large number of tourists took the trouble to come here.
Mount St. Helens eruption
Mount St. HelensThe eruption of Mount St. Helens is an active volcano, located in Scarmeny County, Washington State, in the Pacific Northwest of the United StatesCascade MountainsPart of.It was dormant for about 100 years before it broke out in 1980.The hot volcanic ash rose to about 80000 feet (24.38 km), cutting the mountain top down about 1400 feet (426.72 meters), killing 57 people and causing economic losses of up to $3 billion.
Santa Maria Volcano eruption Santa Maria Volcano is located inGuatemalaA large active volcano in the Western Highlands province, nearKesartenangoCity.The first recorded eruption of Mount Santa Maria occurred in October 1902.The eruption index of this volcanic eruption was 6, and the ash it produced spread to San Francisco.The volcanic eruption in 1902crater, resulting in the steepness of the south side of the volcano on Santiago Gudo.Every earthquake or volcanic eruption in Santiago Gudo will trigger a large-scale landslide, making the area as large as 100square kilometre% of the land is covered.
Perry VolcanoThe eruption of Mount Perry is an overseas dependency of FranceCaribbeanLesser Antilles island arcMartiniqueAn active volcano on the.It's the deadliest thing in the worldStratiform volcanoone of.The eruption of the volcano on May 8, 1902, killed 29000 people and destroyed the port city of St. Pierre Fort, about 4 miles (6.44 kilometers) away from the place.The rapidly flowing hot gas and dense liquefied volcanic particles have caused great damage to the places they have visited.
be locatedHawaii, USASoutheast of the island.Kilauea volcano is an active volcano with strong activity in the world, and it still erupts frequently today.There is a hugeCalderaIt has a diameter of 4027 meters and a depth of more than 130 meters, including many volcanic craters.The whole crater seems to be aCauldronThere are many small pots (craters) in the big pot.In the southwest corner of the Caldera Pass, there is a hot oneKarstThe diameter of the crater is about 1000 meters and the depth is about 400 meters. The lava in the crater sometimes sprays upward to form a fountain, and sometimes overflows outside the crater, like a waterfall. The local natives call it "Harimomo", which means "the home of eternal flame".
There used to be the largest magma lake in the world for a long time, with an area of 100000 square meters. The red and hot magma is generally more than ten meters deep, rolling and hissing in the lake, like a furnace of boiling steel.At the edge of the lake, dark redOrange peelThey stack up like bundles of rope, and sometimes the orange peel is broken and then dumped into the white hot magma.There are also lava fountains several meters high on the lake from time to time, splashing colorful sparks.Such breathtaking scenes can be called wonders of nature.
When Kilauea Volcano erupted in 1960, lava flows from high places and flows into the sea, filling a new land of about 2 square kilometers at the seaside.On July 29, 2002, billowing magma gushed out of Kilauea volcano and flowed into the sea. Water and fire mingled, forming a spectacular scene.On August 17, 2002, the fiery magma from the volcano poured into the sea like a lava dragon.
For more than 20 years, a large amount of magma continuously gushed from Kilauea volcano has formed several newBlack sand beachAnd the area of the island continues to expand.
Volcanic fissures and mountains in southern Iceland, close to Iceland's largestIce fieldWatner Ice Field(Vatnajokull) southwest end.Laki Mountain is a volcanoFissure eruptionThe only significantTopographical features, now called Lakagigar.The fracture is northeast southwest trending, and Laki Mountain cuts it into two nearly equal parts.Laki Mountain is 818 meters (2684 feet) above sea level, 200 meters (650 feet) higher than the nearby area.Laki Mountain has not been completely opened by cracks.There are only a few tiny craters flowing a little magma between the cracks on the hillside.
The volcanic eruption began on June 8, 1783, and only the cracks in the south of the west of Laki were still active until July 29.On the same day, the northeast cracks began to erupt, and the subsequent eruptions were almostAll inThis half of the crack.The eruption lasted until the beginning of February 1784 and is considered to be the largest lava eruption ever on the earth.It is generally believed that the amount of magma eruption is about 12.3Cubic kilometer(2.95 cubic miles), covering an area of about 565 square kilometers (220 square miles).
a large number ofVolcanic gascauseContinental EuropeMost areas are filled with smog, which even affectsSyria、SiberiaWesternAltai MountainsAnd North Africa.A large amount of sulfur gas released has hindered the growth of crops and vegetation in Iceland, causing most of thelivestockDeath.The famine caused by smog finally killed one fifth of Iceland's residents.
stayHawaii Volcano National Park(Built in 1916), it is one of the largest isolated mountains in the world.The altitude is 4169 meters (13678 feet).Its dome is 120 km (75 miles) long and 103 km (64 miles) wide, with a lava flow area of 5120 square kilometers (2000 square miles).The crater Mokuaweoweo covers an area of about 10 square kilometers (4 square miles) and is 152-183 meters (500-600 feet) deep.The top is often covered with ice and snow in winter.
Since 1832, it has erupted once every three and a half years on average. Most of the eruptions are confined to the Mokua Veo Veo crater, and the rest are along the northeast or southwest side of theFissure zoneFlow down.In the outbreak of 1935, American aircraft threatenedShiloh(Hilo) Magma of the cityFlow pathThrow bombs.In June 1950, a 23 day long vast magma flowed down from a 21 km (13 mile) southwest fissure, destroying a small village.In 1975 and 1984, there was a big eruption at the top of the mountain.
It is an active volcano, which has erupted about 35 times in the past 200 years.There are still several pot shaped craters and large calderas with a width of 2700 meters on the top of the mountain.In November 1959, the Mauna Loa volcano erupted again. At that time, boiling lava burst out from a one kilometer and a half gap with bubbles, lasting for a month. The highest height of the lava eruption exceeded the Empire State Building in New York.In March 1984, the Mauna Loa volcano erupted again, attracting tourists from all over the world with its rare and magnificent scenery.
One of the most famous volcanoes in the world, located inCampaniaPlainGulf of Naples Bank.More than 2000000 people live in the Vesuvius Volcano area and low mountain slopes.Industrial towns are distributed along the coast of Naples Bay, and small agricultural centers are located in the north of the foothills.
After centuries of inaction, a series of earthquakes occurred, which lasted for six months and gradually increased in intensity. A large eruption occurred on December 16, 1631.Many villages on the hillside were destroyed, and about 3000 people died;Lava flows to the sea, and the sky is dark for several days.The characteristics of volcanic eruption changed after 1631,volcanic activityContinuous.Volcanic activity can be observed in two stages: quiescence and eruption.The crater is closed in the quiescent period, and nearly continuously opened in the eruption period.
The foothills are covered with vineyards and orchardsWineIt is called "Lacrima Christi";ancientPompeiiThere are many on the wine jar of“vesuvius ”(Vesuvinum).High in the mountainOakandChestnutMiscellaneous forest。The trees on the north slope grow along the slope of Soma Mountain to the top of the mountain.There are chestnut trees growing on the west side. Above 600 meters (2000 feet) above sea level, there is a rugged plateau full of broom plants. The crater left by the eruption in AD 79 has been filled.Higher up, the slope of the fire cone and the inner slope of Mount Soma are almost barren, and they growClustersGrassland plants.
Vesuvius erupted from time to time in 12000 years. The crater is always surrounded by rising smoke, which can emit enough heat to ignite a piece of paper.The foot of the mountain is covered with orchards and vineyards, while the slope on the volcano is desolate and dangerous.In the 20th century, Vesuvius had six large-scale eruptions.
One of the most famous eruptions of Vesuvius occurred in AD 79, when Herculaneum andPompeiiTwo towns were destroyed.The volcano emits black smoke clouds, and hot volcanic ash drops like rain,Toxic gasInto the air.Pompeii Only a quarter of the residents survived, and the rest were either buried by volcanic ash, suffocated by smoke, or crushed to death by collapsed buildings.
Located in Washington State in the northwest of the United States,Cascade Mountain North section.2950 meters above sea level (1983).After 123 years of dormancy, it suddenly revived on March 27, 1980. The eruption on May 18 was the most violent. The smoke cloud rushed to 20000 meters high, and the volcanic ash spread to 4000 kilometers away with the airflow. The ash scattered 800 kilometers away from the volcano was 1.8 cm thick.Rivers near the volcano were blocked and diverted, and many roads were buried.Caused by lava flowforest fire, tens of kilometers aroundEndophyteVanished.Due to the massive melting of ice and snow in the mountain, a turbulent torrent is formed, and a large amount of water vapor in the updraft condenses at high altitude, resulting in a disaster of rainstorm, which makes the washed volcanic ash form a slurry torrent and pour down from the mountain,Severe damageFarmland, forest and all facilities along the way.After the eruption of the volcano, the surrounding terrain changed significantlyVolcanic coneThe top collapsed to form a new crater 3 km long, 1.5 km wide and 125 m deep.The volcanic eruption caused more than 60 deaths and 390 square kilometers of land became barren, causing huge losses. It is one of the largest volcanic eruptions on the earth in the history of the United States and since the 20th century.Today, it is still active.
Before the eruption in 1980, Mount St. Helens was called "Mount Fuji of the United States" because of its symmetrical shape and snow covered peak, which is similar to Mount Fuji in Japan, and has attracted many tourists.The eruption in 1980 marked the revival of the volcano after 123 years of sleep in 1857.Since then, unexpected changes have taken place.
Due to the long-termseismic activityWith the steam eruption, the volcano emergency work was proper and made a good prediction. The eruption of Mount St. Helens did not cause more casualties.Saint HelensDormancy periodthanActive periodIt's much longer. The experience of the eruption of Mount St. Helens tells us not to take the active volcano that looks like death lightly.
An active volcano on the eastern coast of Sicily, Italy.Its name comes from the Greek Atine (aithn, meaning "I burned").It is the highest active volcano in Europe.At an altitude of more than 3200 meters (10000 feet), like other active volcanoes, their heights vary from time to time. For example, in 1865, they were 52 meters (170 feet) higher than at the end of the 20th century.It covers an area of 1600 square kilometers (600 square miles).The perimeter of the base is about 150 kilometers (93 miles).Mount Etna is located above the brightly lit city of Catania, Italy. It constantly shoots flames into the air, while lava flows out from both wings like a river.Although it looks dizzy, Mount Etna is relatively safe because thisMountain fireThe eruption is very rare and compact, and the lava flows slowly, which gives people a chance to escape.
The highest active volcano in Europe.The most violent eruption was in 1669, lasting for four months, and about 780 million cubic meters of lava was ejected.The damage was very serious, and 20000 people were killed in Catania and other nearby cities.The eruption on March 17, 1981 was the most violent in recent decades, burying dozens of hectares of trees and many vineyards, and hundreds of houses were destroyed.Distribution of hillside vegetation: the lowest zone, full of fruit treesPlantation；Median, manyBeechOak and pine trees;The highest zone, with sparsely scattered shrubs andalgae。There is a memorial on the mountainRoman emperorHistoric sites for mountaineering.
Sanggai National ParkLocated in central EcuadorMorona- SantiagoChinborasoandTungurawaAt the junction of three provinces.Located near the equator, with an area of 2720Square kilometers。The park has the world famous active volcano Sanggai Volcano, which has the longest activity duration in the world.The mountain top of Sanggai Volcano, 5410 meters above sea level, is covered with snow and steepAltitudeThis is the unique landscape of Ecuador.Because the whole park is located near the equator, with sufficient sunshine and different elevations, it presents different ecological scenes and lives with many rare animals and plants.
Tropical rain forestThere are trees as high as 30-40 meters in the middle, tall and straight.The extremely fertile ground formed by volcanic ash makes the plants here flourish.Except hardWoody plantBesidesmoss and lichen、Lichens, with bulbous stem and cristate leavesCompositaeEtc.
Volcanoes in the solar system
MoonThere is no volcanic activity, but it still has many characteristics of volcanic activity, such asMoon Sea、Moon ValleyAnd arch mound, etc.
The surface of Venus is 90%basalt80% of the surface terrain is volcanic terrain, indicating that volcanoes played a very important role in the formation of the surface of Venus.Venus may have undergone the surface reconstruction movement of the whole planet 500 million years ago, and the evidence discovered by scientists includes the density of surface craters.Lava flows are very common in Venus, and all kinds of lava flows do not appear on EarthVolcanismIt also appears on Venus.Venus atmosphereThe change of composition and the occurrence of lightning are believed to be caused by the ongoing volcanic eruption.But there is no conclusive evidence that Venus' volcanoes are still active.
There are some on MarsExtinct volcano, i.eOlympus Mons , including four huge shield volcanoes, which are larger than any other mountain on the earth.These mountains include:Arsia Mons Arsia Mons, Ascraeus MonsHecates Tholus （Hecates Tholus）、Olympus Mons (Olympius Mons) and Pavonis Mons.NASAEuropean Space Agency and Italian Space AgencyCooperative launchHasMars explorationspacecraft, "Mars Express".The main goal of this plan is to findGroundwater sourceAnd suitable landing sites, and study theatmosphere, planetary structure andgeological structure 。The plan found some evidence that Olympus may not have completely extinguished.This may overturn the statement that "these volcanoes have become extinct volcanoes millions of years ago".
JupiterThe satellite Io issolar systemThe reason for the most violent volcanic activity is that it is associated with JupiterEuropaandGanymedeOfTidal forceFunction, this power makesIoTwist and bend, with an amplitude of about 100 meters, and generate energy in this process.Eo's volcano will eruptsulfurSulfonatesulfur dioxideandsilicateRocks completely change the landform of the whole satellite.There are a lot of calderas, sulfur lakes and continuous volcanic mountains on the surface of Io.The magma ejected from E'o volcano is the hottest known at present, with a temperature of about 1800K (1500 ℃).The eruption of Io volcano can reach a very high altitude, with a distance of more than 300 kilometers from the surface. At the moment of eruption, its speed can reach one kilometer per second.In February 2001, the largest ever volcanic activity in the solar system occurred in Io.From Saint Louis University andUniversity of WashingtonResearchers on Io used computers to monitor the volcanic eruptions on Iosimulation experiment。The experimental results show that the lava ejected by Io's volcano can melt and evaporate sodium, potassium, silicon, iron and other substances and compounds on its surface into the atmosphere.These gaseous substances and gases from volcanoes (includingsulfideandchloride）The reaction takes place and forms the unique composition of Io's atmosphere: sodium chloride, potassium chloride and magnesium and iron dichloride.Another moon of Jupiter,Europa(Four of JupiterGalileo satelliteThe smallest) is also considered to have an active volcanic system.But its volcanic "lava" is composed entirely of water and freezes on the cold surface of Europa.This makes its volcano look like a frozen fountain when it erupts.This type of volcano is calledIce volcano(cryovolcanism), yesJupiter like planetThe most common form of volcanic eruption on the moon.Glacial volcanicEjectaIt may be caused by water, iceLiquid nitrogenAnd liquidmethaneform.In 1998,NavigatorSpaceship Two has foundNeptuneOne of the satellites,Triton The ice volcano on the.In 2005,Cassini-HuygensThe detector ofSaturnOne of its satellites,EnceladusOnsteamEruption.Cassini Huygens also foundtitanEvidence that the last ice volcano spewed liquid methane.This is considered to causeTitan's atmosphereThe reason of high methane content.Scientists infer that,Kuiper beltCelestialasteroid50,000（Quaoar50000) may also haveIce volcanoThe existence of the activity.
Volcano monitoring and early warning
Announce
edit
Volcanic monitoring
Volcanic monitoring technology can be divided into three categories, namely volcanic earthquake monitoring, volcanic deformation monitoring and volcanic gas monitoring.Other commonly used volcanic monitoring methods include thermal infrared remote sensing monitoring, infrasound monitoring and electromagnetic monitoring.[9]
Volcano monitoring station
Volcanic monitoring stations are institutions for studying and monitoring volcanic activities. Many countries around the world have established volcano monitoring station systems.Vesuvius Volcano Monitoring Station is the earliest volcano monitoring station in the world. It was founded in 1841 and will be the largest volcano monitoring station in the world in 2024.The United States, Japan, Iceland, the Philippines, Indonesia and China are all located in the volcanic belt. These countries have established their own volcano monitoring station systems to monitor volcanic activities.For example, China's Changbaishan Tianchi volcano in Jilin Province and Tengchong volcano in Yunnan Province have also established corresponding volcanic monitoring stations.[10]
Volcano warning
Hazard level
differentiation by type
level
name
Description of volcanic activity
Refuge action
Special alarm
five
take refuge
Major volcanic activities (eruptions) occur in the area, and may (have been) severely damaged, which is in an extremely dangerous state
The area is classified as dangerous area, and nearby residents must evacuate
four
Prepare for refuge
Large scale volcanic activities (eruptions) will occur in the area, which is in a dangerous state and has a high risk of disaster
People in special need of care will be evacuated first, and nearby residents will also be prepared for evacuation
alert
three
Mountain entry control
Volcanic activity (eruptions) will occur in the area, which may affect nearby houses
As the case may be, restrictions will be imposed on mountaineering and all mountaineering activities will be prohibited.Those who need special care should be prepared for evacuation
two
Control around the crater
The lives of people in and around the crater may be directly threatened and endangered by volcanic activities
Access restrictions around the crater
prediction
one
Watch out for active volcanoes
Volcanic activity is relatively quiet, but be careful that the volcanic ash emitted near the fire crater and any change in activity state, or the area near the crater may pose a life risk
According to the actual situation, access restrictions are implemented around the crater
