冰岛火山或将喷发

Icelanddisruptivevolcano冰岛火山破坏

Iceland'sdisruptivevolcano

Today,Britishcivilaviationauthoritiesorderedthecountry'sairspaceclodasof

noon,duetoacloudofashdriftingfromtheeruptingEyjafjallajökullvolcanoinIceland.

Thevolcanoharuptedforthecondtimeinlessthanamonth,meltingice,shooting

smokeandsteamintotheairandforcinghundredsofpeopletofleerisingfloodwaters.

Thevolcanicashhasforcedthecancellationofmanyflightsanddisruptedairtraffic

acrossnorthernEurope,tedherearephotosof

themostrecenteruption,andoflastmonth'ruptions,whichwerefromthesamevolcano,

justveralmilesfurthereast.(17photostotal)

SmokebillowsfromaneruptingvolcanowhichemstobeclotothetopoftheEyjafjalla

glacieronApril14,donflights,includingthofrom

Heathrow,willbesuspendedfromnoon(1100GMT)todayduetovolcanicashfromIceland

thathasalreadycaudalmost300cancellationshere,officialssaid.(AFP/GettyImages)

2

AnaerialhandoutphotofromtheIcelandicCoastGuardshowsfloodcaudbyavolcanic

eruptionatEyjafjallaGlacierinsouthernIcelandApril14,caniceruption

onWednesdaypartiallymeltedaglacier,ttingoffamajorfloodthatthreatenedto

damageroadsandbridgesandforcinghundredstoevacuatefromathinlypopulatedarea.

PicturetakenApril14,2010.(REUTERS/IcelandicCoastGuard/ArniSaeberg)#

3

MeltingicecaudbyavolcaniceruptionatEyjafjallaGlacierinsouthernIcelandApril

14,2010.(REUTERS/IcelandicCoastGuard/ArniSaeberg)#

4

PhototakenonApril14,2010theMarkarfljotglacialriver,westoftheEyjafjallaglacier.

Iceland'scondvolcanoeruptioninlessthanamonthmeltedpartofaglacierandcaud

heavyfloodingonApril14,forcingupto800peopletoevacuateandgroundingsomeflights

overNorway.(HALLDORKOLBEINS/AFP/GettyImages)#

5

FloodingcaudbyavolcaniceruptionatEyjafjallaGlacierinsouthernIcelandApril

14,2010.(REUTERS/IcelandicCoastGuard/ArniSaeberg)#

6

Amantakesapictureofaroadthathasbeenwashedawaybyfloodwaterfollowingthe

meltingoftheEyjafjallaglacierduetotheeruptionofavolcanoonApril14,2010near

Reykjavik.(HALLDORKOLBEINS/AFP/GettyImages)#

7

InthisWednesdayApril14,2010photograph,smokeandsteamareenrisingfromthe

volcanoundertheEyjafjallaglacierinIceland,whicheruptedforthecondtimein

lessthanamonth,meltingice,shootingsmokeandsteamintotheairandforcinghundreds

ofpeopletofleerisingfloodwaters.(APPhoto/IcelandicCoastguard)#

8

Anatural-colorsatelliteimageshowslavafountains,lavaflows,avolcanicplume,and

gewasacquiredonMarch24,2010,bytheAdvancedLand

Imager(ALI)aboardNASA'sEarthObrving-1(EO-1)afountainsare

orange-red,barelyvisibleatthe10-meter(33-foot)

scoriaconessurroundingthefissureareblack,asisthelavaflowextendingtothe

olcanicgascapefromtheventanderuptinglava,whileasteam

plumeriswherethehotlavameetssnow.(Thebrightgreencoloralongtheedgeofthe

lavaflowisanartifactofthensor.)(NASA'sEarthObrvatory/RobertSimmon)#

9

ThispicturetakenonMarch27,2010showslavaspurtingoutofthesiteofavolcanic

eruptionattheEyjafjallajövastill

gushing,asmallIcelandicvolcanothatinitiallynthundredsfleeingfromtheirhomes

isturningintoaboonfortheislandnation'stourismindustry,asvisitorsflockto

catchaglimpoftheeruption.

10

Touristsgathertowatchlavaspurtoutofthesiteofavolcaniceruptionatthe

EyjafjallajökullvolcanoonMarch27,800peoplewereevacuatedinIceland

earlyonApril14,2010duetoavolcanoeruptionundertheEyjafjallajokullglacierin

thesouthoftheisland,policeandgeophysicistssaid.

11

PeoplegathertowatchlavaflowatthesiteofavolcaniceruptionattheEyjafjallajökull

volcanoneartheEyjafjallaglacieronMarch27,2010.#

12

HeatshimmersabovelavaflowingfromtheEyjafjallajökullvolcanoinIcelandonMarch

28th,alhere.(

13

LavaspewsoutofamountainonMarch21,2010intheregionoftheEyjafjallaglacier

inIceland

14

LavaspurtsoutofthesiteofavolcaniceruptionattheEyjafjallajökullvolcanonear

theEyjafjallaglacierinIcelandonMarch27,2010

15

SmokeandsteamhangoverthevolcanoundertheEyjafjallaglacierinIceland,early

ThursdayApril15,2010.

16

LavaspewsoutofamountainonMarch21,2010inHvolsvöllurintheregionofthe

EyjafjallaglacierinIceland.

17

SteamandhotgasriabovelavaflowingfromtheEyjafjallajökullvolcanoonApril

3rd,alhere.(UlrichLatzenhofer/CCBY-SA)

#The2010eruptionsofEyjafjallajökull（埃亚菲亚德拉火山）[ɛɪjaˌfjatlaˌjœkʏtl]area

timelineofvolcaniceventsatEyjafjöllinIcelandwhich,althoughrelativelysmallforvolcanic

eruptions（爆发）,caudenormousdisruptiontoairtravelacrosswesternandnorthern

onallocaliddisruption

ptionwasdeclaredofficiallyoverinOctober2010,when

snowontheglacierdidnotmelt.

Beginningon14April2010,theeruptionenteredacondphaandcreatedanashcloudthat

ledtotheclosure(结束)ofmostofEurope'sIFRairspacefrom15until20April2010.

Conquently,averyhighproportionofflightswithin,to,andfromEuropewerecancelled,

creatingthehighestlevelofairtraveldisruptionsincetheSecondWorldWar.

Thecondphaoftheeruptionstartedon14April2010andresulted

inanestimated250millioncubicmetresofejectedtephra（喷出的火山

灰）.Theashplumerotoaheightofapproximately9kilometres,which

ratestheexplosive（爆炸性的）poweroftheeruptionasa4ontheVolcanic

ExplosivityIndex.（火山爆炸性指数）。

Background

Eyjafjallajökull(pronounced[ˈɛɪjaˌfjatlaˌjœkʏtl̥]isoneoftheIceland's

'ssituated

tothenorthofSkógarandtothewestofthelargericecapMýrdalsjökull.

Theicecapcoversthecalderaofavolcano1,666metres(5,466ft)in

mostrecentmajoreruptionsoccurredin1921,1612(believedtohave

lastedonlythreedays)andfrom1821to1823.[6]Previouruptionsof

Eyjafjallajökullhavebeenfollowedbyeruptionsatitslargerneighbour,

Katla;.[7]On20April2010IcelandicPresidentÓlafurGrímssonsaidthat,

"thetimeforKatlatoeruptiscomingclo...we[Iceland]have

prepared...itishightimeforEuropeangovernmentsandairline

authoritiesallovertheworldtostartplanningfortheeventualKatla

eruption".[8]

ThevolcaniceventsstartinginMarch2010areconsideredtobeasingle

steruptionphaejected

olivinebasalticandesitelava[9]veralhundredmetresintotheairin

ctionfromthisphaof

theeruptionissmall,risingtonomorethan4kilometres(2.5mi)into

theatmosphere.

On14April2010,however,theeruptionenteredanexplosivephaand

ejectedfine,glass-richashtoover8kilometres(5.0mi)intothe

ondphaistimatedtobeaVEI4eruption,which

islarge,butnotnearlythemostpowerfuleruptionpossiblebyvolcanic

fcomparison,eruptionof1980

wasratedas5ontheVEI,andthe1991eruptionofMountPinatubowas

ratedasa6.[citationneeded]

Whatmadethisvolcanicactivitysodisruptivetoairtravelwasthe

combinationofthefollowingfourfactors:[citationneeded]

cano'slocationisdirectlyunderthejetstream

ectionofthejetstreamwasunusuallystableatthetime

oftheeruption'scondpha,maintainingacontinuous

south-easterlyheading

onderuptivephatookplaceunder200m(660ft)ofglacial

ultingmeltwaterflowedbackintotheeruptingvolcano

whichcreatedtwospecificphenomena:

idlyvapourisingwatersignificantlyincreadthe

eruption'xplosivepower

ptinglavacooledveryrapidly,whichcreatedacloud

ofhighlyabrasive,glass-richash,thiscaudalarge

amountofflightstobecancelledintheU.K.

cano'xplosivepowerwassufficienttoinjectashdirectly

intotheJetStream.

Withoutthespecificcombinationoftheabovefactors,theeruptionof

Eyjafjallajökullwouldhavebeenamediumsized,somewhatnon-descript

eruptionthatwouldhavebeenoflittleinteresttothooutsidethe

scientificcommunityortholivingintheimmediatevicinity.[citationneeded]

However,theabovefactorswereprecilythorequiredforthejet

streamtocarrytheashdirectlyovernorthernEuropeintosomeofthe

busiestairspaceintheworld.

Evacuations

About500farmersandtheirfamiliesfromtheareasofFljótshlíð,

Eyjafjöll,andLandeyjarwereevacuatedovernight(includingagroupof

30schoolchildrenandtheir3teachers[19][20]fromCaistorGrammarSchool

inEngland),andflightstoandfromReykjavíkandKeflavíkInternational

Airportwerepostponed,butontheeveningof21March,domesticand

internationalairtrafficwasallowedagain.[21][22][23]Inhabitantsofthe

riskzoneofFljótshlíð,Eyjafjöll,andLandeyjarareawereallowedto

returntotheirfarmsandhomesafteraneveningmeetingwiththeCivil

ProtectionDepartmenton22Marchandtheevacuationplanwastemporarily

d,thepoliceclodtheroadtoÞórsmörk,andthe

four-wheel-drivetrailfromSkógarvillagetotheFimmvörðuhálsmountain

pass,buttheroadsandtrailswerereopenedon29March,thoughonly

econdfissureappeared,theroad

wasclodagainbecauofthedangerofflashfloods,whichcouldhave

developedifthefissurehadopenednearbigicecapsorothersnow

rervoirs,buttheroadwasagainopenedataroundnoonon1April.[24][25][26]

Effectonriverwater

On22March,aflowmeterdevicesituatedintheKrosságlacialriver

(whichdrainsEyjafjallajökullandMýrdalsjökullglaciers)inthe

Þórsmörkarea(afewkilometresnorth-westoftheeruptinglocation)

startedtorecordasuddenriinwaterlevelandinwatertemperature

–thetotalwatertemperatureroby6°C(11°F)overatwo-hour

period,whichhadneveroccurredsoquicklyintheKrossáriversince

yafterward,thewaterlevelreturnedtonormal

andwatertemperaturedecreadaswell.[27]Itisthoughtthatthisri

inwatertemperatureisrelatedtotheeruptionnearbyandisaffecting

partoftheKrossáperatureofHrunáriver,which

flowsthroughthenarrowHrunárgilcanyon,intowhichpartofthelava

streamhasbeenflowing,wasrecentlyrecordedbygeologiststobebetween

50°C(122°F)and60°C(140°F),indicatingthattheriverhasbeen

coolingthelavainthatcanyon.[28]

Fissure

Secondfissure,viewedfromthenorth,on2April2010

Thefirstphaofthe2010eruptionbeganlateontheeveningof20March

attheEyjafjallajökull.

Theinitialvisualreportoftheeruptionwasat23:52GMT,whenared

cloudwasobrvedatthenorthernslopesofFimmvörðuhálsmountain

pass,[29][30]ptionwas

precededwithintenismicityandhighratesofdeformationinthe

weeksbeforetheeruption,inassociationwithmagmarechargingofthe

atelypriortotheeruptionthedepthofismicityhad

becomeshallow,butwasnotsignificantlyenhancedfromwhatithadbeen

ationwasoccurringatratesofuptoa

centimetreadaysince4MarchatvariousGPSsitesinstalledwithin

12kilometres(7.5mi)fromtheeruptivesite.[citationneeded]

Afissureopenedupabout150metres(490ft)inlengthrunningina

north-easttosouth-westdirection,with10to12eruptinglavacraters

ejectinglavaatatemperatureofabout1,000°C(1,800°F)upto

150metres(490ft)aisalkaliolivinebasalt[31]

andisrelativelyviscouscausingthemotionofthelavastreamtothe

tenlavahasflowedmore

than4,000metres(2.5mi)tothenorth-eastofthefissureandinto

Hrunagilcanyon,formingalavafallmorethan200metres(660ft)long

andisslowlyapproachingÞórsmörk,buthasnotyetreachedtheflood

plainsofKrossá.[32][33][34]

Ashanalysis

Samplesofvolcanicashcollectedneartheeruptionshowedasilica

concentrationof58%—muchhigherthaninthelavaflows.[41]The

concentrationofwater-solublefluorideisonethirdoftheconcentration

typicalinHeklaeruptions,withameanvalueof104milligramsof

ltureisimportantinthisregionof

Iceland,[42]andfarmersnearthevolcanohavebeenwarnednottolettheir

livestockdrinkfromcontaminatedstreamsandwatersources,[43]ashigh

concentrationsoffluoridecanhavedeadlyrenalandhepaticeffects,

particularlyinsheep.[44]

Impactonfarming

TheIcelandicFoodandVeterinaryAuthorityreleadanannouncementon

18April2010,askingthatallhorownerswhokeeptheirherdsoutside

hereissignificantashfallallhors

mustbeshelteredindoors.[45]Thethicklayerofashthathasfallenon

someIcelandicfarmsandpasturesatRaufarfellhasbecomewetandcompact,

makingitverydifficulttocontinuefarming,harvestingorgrazing

livestock.[46]

Timelineoftheconderuptionpha

Unliketheearliereruptionpha,thecondphaoccurredbeneath

terfrommeltedicequicklychilledthelavacausing

ittofragmentintohighlyabrasiveglassparticlesthatwerethencarried

,togetherwiththemagnitudeoftheeruption

(estimatedtobeVEI4)[2]andbeingtentotwentytimeslargerthanthe

eruptionofFimmvörðuhálson20March,injectedaglass-richashplume

intotheJetStream.

Inadditiontothefactthatvolcanicashisveryhazardoustoaircraft,[47]

thelocationofthiruptiondirectlyundertheJetStreamensuredthat

theashwascarriedintotheheavilyudairspaceovernorthernand

centralEurope.