Bárðarbunga is a subglacial volcano in Iceland responsible for a whole passel of seismal activity this week . If it belch , it could fade the Vatnajökull glacier and produce telling downstream flooding . At least the tardy Icelandic vent to take in our eye is a lot easier to pronounce than the last one !
Bárðarbunga , northwesterly Vatnajökull ice - cap , in 1996 . effigy credit : Oddur Sigurðsson
First thing first : to the right way sophisticate your lingua around this name , you ’re go to require to say something akin to “ ” b - OW - universal gas constant - tha - blessing - ga ” ( as suggested byDave McGarvie ) , or “ Bau - thar - bunga ” ( as suggested byIan Stimpson ) , but neither seem to catch the rolling r quite as well asthis ready to hand tutorial by MBL . Alternatively , you’re able to work purely in write formats , and just keep copy / pasting the name on an as - needed foundation without venturing into writing it from scrape .
Iceland occupies a strange place as both a hot spot and a continental rift wheretectonic plates are pulling aside . Consequently , the volcanoes candefy dim-witted classification , as eruptions can have magmas ofvariable geochemistryfrom gentle basalt through volatile rhyolite .
Iceland straddle a diverging plate bound , balanced atop the Icelandic plume . Red triangle designate major vent . ikon credit : USGS
To make things even more complicated , the vent can be bury under massive ice weather sheet , preventing us from examining them easily . One of the central tools for supervise these subglacial volcanoes is by recording any seismal activity from seism swarm .
Seismicity under the Vatnajökull glacier has been increasing for the preceding seven year , with a pearl whenGrímsvötn break out . Now seismicity is back to pre - eruption levels , this time in the northwesterly region of the methamphetamine sheet where Bárðarbunga is settle . Bárðarbunga is a more accurately a arrangement of volcanoes , not a undivided vent . Its caldera stretches ten kilometre across swallow under 700 meters of ice , with fissures stretch sou'-west and northeast . Some of the fissures are in swarms , or even have distinguishable volcanic crater rows formed over centuries of eruptions .
Seismographs of earthquakes near Bárðarbunga . ikon deferred payment : IMO
A pair of earthquake swarm near Bárðarbunga were record onAugust 16thand17th , prompting theIcelandic Meteorological Office(IMO ) to raise the vent ’s warning level to yellow thenorange . It ’s been sitting one pace below the maximum red-faced - alarum peril point all week , with continuingseismic activity . Iver 3,000 earthquakes have been detect in decided bunch , most happen between 5 and 10 kilometers depth .
Earthquakes from August 16th to 19th , colour - coded by day . quake form distinct clusters near the Bárðarbunga caldera ( dark blue , Saturday ) , north ( light blue , Sunday ) and east ( orange Monday ) . Green stars are earthquakes larger than magnitude 3 . Image credit : IMO
The earthquakes could point that magma is rising within the vent proceed an eruption , but it could also well be the startle of an intrusive dyke that never breaches the Earth’s surface in an eruption . One of theearlier IMO notes concludes :
Presently there are no signs of eructation , but it can not be excluded that the current activity will lead in an volatile subglacial volcanic eruption , leading to an outburst flood ( jökulhlaup ) and ash tree emanation . The situation is monitored intimately .
The point that so far Bárðarbunga turn over no indicant of an imminent bam is underline in each subsequent notice of activity , most recentlyreiterated as :
No signs of migration towards the surface or any other signs of imminent or on-going volcanic activity have been detected so far .
Aflyover of the region on August 17thaffirms this undramatic take , with no obvious grounds for business concern . An Icelandic Coast Guard eggbeater flew a team of scientists out to install additional monitoring equipment , include seismometers andwebcams .
An overview of the area , as seen from Askja . ruddy lines are the approximate positioning of a volcanic dyke beneath the ice ; yellow arrows are rising tide H2O way of life . Image credit : Dave McGarvie
Bárðarbunga may not erupt at all . But if it does , what would it look like ? as luck would have it for us , Dave McGarvieworks specifically on Icelandic ( and Chilean ) volcanoes , is combat-ready on Twitter , and headed toThe Conversationfor an interview on the situation . As of Monday , his most likely scenario were :
Nothing . Any magma trend never infract the surface as an eruption . An encroachment is formed , geophysicists get frantic , and journalist everywhere roll their eyes at the letdown .
A pocket-sized eruption under thick ice-skating rink . If not much magma erupts , it may not break through a 400 - meter thick ice sheet . If the eruption happens mostly under the ice , the hot lava could melt the ice , producing volumes of water supply up to 14 times the volume of molten stone . We might be able to maintain a depression on the glacier ’s open , but more dramatically , all that water will runoff into the river system , causing downstream implosion therapy .
A large fissure eruption under thick ice . Ifa long scissure of magma erupts , it could melt through even a fatheaded ice bed sheet . This would be a repetition of the 1996Gjálp eruption , with the lava evaporate through the overlaying glacier within hour . After breaking through the internal-combustion engine , a small clap plume would form .
An eruption under slight ice . If the magma erupt along the polar margin , the hot material could generate minuscule but knock-down steam plosion in the saturated sediment adjacent to the glacier . After the local water is explosively convert to steamer , the eruption would descend into a normal fissure eruption .
Former geology consultant , Icelandic presidential candidate , and current skill writerAri Trausti Guðmundsson make out up with a very similar list of possible eruption while drop a line for Discover Geography .
By Wednesday , McGarvie theorized on Twitterthat the cluster form of earthquakes could be translate as sidelong dyke formation . This type of geological formation is common in Iceland severance volcano as the island pulls itself asunder in fits and jumps over the 100 . TheKrafla fervidness in the 1970sare the most recent outstanding instance of this type of event , but only about 1 in 3 of these dike result in clap . One of the additive clump of temblor does n’t seem to align with either vent summit meeting , direct McGarvie to muse that it may be an reading that themagma has hop over to a weaker area of the rock .
A bridge potentially threatened by jökulhlaup . effigy credit : Dave McGarvie
Due to the low universe density in the area , no settlements are at - risk if the volcano does flare . However , as a care , thePolice Commissioner of Húsavíkclosedall highland roadseast of Skjálfandafljót up to Askja along witha few other locationsdue to the likely risk of a jökulhlaup .
Dettifoss falls . Image credit : Dave McGarvie
This is the region that gave jökulhlaups their name : traditionally , the condition included only geothermally - triggered subglacial inundation like those on a regular basis produced by eruptions under the Vatnajökull ice sheet . Over time , the term ’s meaning has expanded to admit a wide-cut smorgasbord of icy outburst photoflood , not just those triggered by eruption - related melting .
A flood of water from Vatnajökull would overwhelm the downstream river system . It ’d take ten hours for water to feed out to the ocean . As it followed the path of least resistivity , a jökulhlaup could easily wipe out the only bridge , increase the flow of the already - larger-than-life Dettifoss falls , and summarise its antecedently - abandon labor of roll bowlder across the plains .
Boulders tumble by a long - agone jökulhlaup near Dyngjujökul . double credit : Andy Russell
chill lava stream deposit overlay older jökulhlaup down payment near Dyngjujökul . Image citation : Andy Russell
right on now , the two master clustering of earthquakes are place along the wing of the volcano , not at the summit . This means that whilehistorically Bárðarbunga has produce some monumental eruptions , if it erupts now , it ’ll likely be a more mild outbreak with a mild ejection plumage .
But enough with being fair ; what ’s the worst that could materialize ? McGarvie indulges the catastrophist in all of us , laying out his take on the worst - case scenario :
That this is the start of a major volcano - tectonic event at Bárðarbunga , which may further spring up to the southwestward . This is a concern because in the southwest there are fissures that have create Iceland ’s most tortuous lava flows , since the icing melted some 9,000 eld ago .
These crevice are up to 100 klick long , and far to the southwest they can spark extravasation at theTorfajökull volcano . Torfajökull happens to have an teemingness of sticky magma that can belch explosively and produce lots of fine ash . The last eruption , in 1477 - 1480 , get just two lava flows and minor explosions . But the one before , in about 874 AD , producedan volatile volcanic eruption plumethat was carried over much of Iceland .
To add to the day of reckoning scenario , most of Iceland ’s hydroelectricity is generate in the rivers southwest of Bárðarbunga . If major crack irruption start up , it ’s run short to bring mayhem on the power provision . On the up side , Iceland is well cognisant of this scenario , and even has specific reply plans in situation if the domain set off blowing up .
crack shape vertical to the cool off Earth’s surface , head to this spectacular curvature capturing where sure-enough lava was rapidly cooled by water in a past bang . paradigm recognition : Dave McGarvie
The strangest part of McGarvie ’s nightmare scenario is that we wo n’t know decently away if it ’s occur . Even if Bárðarbunga erupts ( which it might not ) , we have no way of roll in the hay if it is an isolated incident , or part of some greater prolonged volcano - tectonic episode remold the island .
In the meantime , about all we can do leavethe webcamsrunning , count the downrightextravagant phone number of earthquakes , poke at anyother outside tracking data , and wait .
Update August 23 : A modest , subglacial eruption started at Bárðarbunga at 2:10 necropsy local time on Saturday . See further updates here .
https://gizmodo.com/icelandic-scientists-mobilize-monitoring-for-uneasy-vol-1625759095
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