Fire and Ice and Airplanes

The Eyjafjallajökull volcanic eruptions are why I became a geologist. No, the recent eruptions on March 20th and April 14th did not inspire me to became a geologist. I’ve been a geologist of sorts since childhood, and I’ve studied geology formally for the past eight years. Even though I am currently studying volcanism in Iceland, I did not know much about Eyjafjallajökull before the news reports surfaced on March 20th. No, it wasn’t these recent Eyjafjallajökull eruptions that inspired me to become a geologist, but it was similar geological events- modern, historical, even ancient- that inspired me. Geology, the study of our planet, is an awesome, awe-inspiring field. Since I’m an atheist, awe-inspiring geological events are the closest I come to spirituality.

I find myself in awe that European air travel has been brought to a standstill by a relatively small plume of ash. Volcanic ash consists of small dust-like particles that eventually settle and make a thin, dark layer within an ice sheet or a series of volcanic flows. A thousand years from now, a geologist studying and dating (with her magical mass spectrometer gun) the Eyjafjallajökull ash flow from the 2010 eruptions will write in her field notebook: “this thin ash flow indicates that there was minor volcanic eruption activity in this area around 2000 +/- 50 years.”

Eyjafjallajökull is one of the smaller glaciers on Iceland and, on a geological scale, the recent eruptions are very small. Historical eruptions at places such as Mt. St. Helen’s, Krakatoa, and Pinatubo were larger by several magnitudes. Yet, small eruptions from a small volcano under a small glacier in Iceland have wreaked havoc on air travel and will undoubtedly have a large impact on the European economy (as if Iceland hasn’t done enough already, huh?). For the planet, the Eyjafjallajökull volcanic eruptions are insignificant. A little ash, a little lava, a little glacial meltwater. Nothing too significant in terms of gas or lava or water budgets for the Earth. Small eruptions barely worth mentioning in the geology books, but definitely worth mentioning in the history books. For these small eruptions are having an enormous impact on the world at the moment, even keeping Rebecca & Sid from attending NECSS!

In light of the recent geological events, I would like to quickly remind you of Louisiana governor Bobby Jindal, who criticized the $140 million given to the United States Geological Survey for volcano monitoring by saying, “Instead of monitoring volcanoes, what Congress should be monitoring is the eruption of spending in Washington.”

Booby Jindal, as I like to call him, has been widely criticized for his remarks. Sure, there are no volcanoes in Louisiana but what about Alaska, Hawaii, and the Pacific Northwest? And, as the Eyjafjallajökull eruptions demonstrate, places relatively far away from a volcano can be affected by plumes of volcanic ash. The entire globe can be affected by volcanic ash, depending on the size of the eruption.

According to a recent TIME magazine article, the estimated impact of the Eyjafjallajökull delays on the airline industry is $200 million A DAY. Which, I will point out, is more than the $140 million A YEAR for volcano monitoring which Booby criticized.

As a geologist, I am so excited about the Eyjafjallajökull eruptions and their effect on airplanes. I am awed and humbled by the power and beauty of the eruptions. A little puff of ash (okay, a 7 mile puff but still a puff) has grounded thousands of flights. There is nothing we can do about it, other than wait for Eyjafjallajökull to calm down. I am supposed to go to Switzerland and Italy in May, however. If my trip is delayed or cancelled, I suppose that Eyjafjallajökull will seem less-awesome and more annoying.

As a geologist, I find the news reports about the eruption very entertaining. Everyone wants to know when they will be able to travel. They want to know when the ash cloud will pass and air travel will be safe again. People want a volcanic weather report. And the best the geologists (and, I suppose, the Icelandic government) can do is say, “Umm… whenver the volcano decides it’s done erupting.”

Unfortunately, predicting volcanic ash clouds is not nearly as easy as predicting rain clouds. Scientists don’t really know when Eyjafjallajökull will stop erupting. Nor can they precisely predict when she (are volcanoes feminine? Sure, why not…) will erupt again nor when those eruptions will produce large plumes of ash that will disrupt air travel. Last time this particular volcano was active in the 1800s, the eruptions occurred on-and-off for two years.

Let me say that again for emphasis:
Last time Eyjafjallajökull volcano was volcanically active, the eruptions continued for two years. Two. Years. TWO YEARS.

Two years is a mere blip of geologic time. The volcano could just as easily erupt for five or ten years. Unlike Mt. St. Helen’s or Krakatoa, Icelandic volcanoes do not just explode once and then are finished. Icelandic volcanoes erupt over long periods of time, similar to Hawaiian volcanoes. Iceland is always erupting, somewhere. I’ll explain why in a moment.

Iceland is always erupting, but unless you are an Icelandic farmer whose farm was recently covered over by basalt, you don’t care most of the time. This is because most eruptions in Iceland do not produce significant ash clouds. The lava flows quietly (well, quietly for lava) over the surface, forming some new basaltic crust but not producing very much ash. The explosive nature of the Eyjafjallajökull eruptions is largely due the presence of this volcano under the Eyjafjallajökull glacier. The melting water from the glacier makes the eruption more explosive, since water is- after all- a volatile gas inside of lava. If Eyjafjallajökull volcano continues to erupt, the eruptions are likely to continue to be explosive and produce ash. And this could very well go on for TWO YEARS. Certainly, the ash clouds will not always affect European travel- depends on the wind direction and weather patterns. But the impact could nonetheless be significant and unpredictable.

So why are there volcanoes in Iceland anyway? In a way, all of Iceland is a volcano. All of Iceland’s crust was produced through volcanic activity. Iceland is located along the Mid-Atlantic Ridge, which is part of a global system of mid-ocean ridges where oceanic crust is produced through volcanism. There are two types of crust on the Earth: continental crust, which is older (up to 4+ billion years) and consists of various types of rocks accumulated over millions and millions of years, and oceanic crust, which is relatively young (0 – 200 million years) and more or less homogeneous.

The oceanic crust consists of black basalts, similar to those found in Hawaii and Iceland. The ocean crust is like a conveyor belt: new oceanic crust is produced at mid-ocean ridges and old crust is destroyed at subduction zones, places where the denser oceanic crust goes underneath the continental crust, eventually melting and being recycled back into the deep Earth. The reason there is no oceanic crust older than ~200 million years is that the oceanic crust is continually being recycled. The ocean basins are dynamic, moving. Not all have equally-balanced subduction and mid-ocean ridge volcanism. The Atlantic ocean, for instance, is growing wider. The conveyer belt oceanic crust allows the tectonic plates to move around and continents to “drift.”

A map of the seafloor. Note the mid-ocean ridges, which are giant underwater mountain chains along which there is constantly volcanism and new ocean crust being produced. These ridges are found in every ocean basin.

Schematic of the ocean crust conveyor belt.

Mid-ocean ridge volcanism usually occurs deep in the ocean under several km of water. Iceland is the only place in the entire world where an active mid-ocean ridge is exposed subaerially. This is AMAZING, if you think about. Iceland is a place where you can go and walk on actively-forming seafloor. Well, island-floor technically, but the volcanic processes occurring are in many ways similar to what is happening deep below the ocean on the seafloor.

Iceland is a geological anomaly. The reason the mid-ocean ridge rises above the ocean is that there is a large thermal anomaly beneath Iceland. Geophysicists have imaged a deep, hot plume of rising material directly underneath Iceland. Thus, Iceland is considered a hotspot. Hotspots are places on the planet where deep thermal anomalies create volcanism at the surface, even when there is no tectonic reason for volcanism. Volcanoes generally only occur where plates move apart (material can upwell and melt because of decompression) or where they come together (subduction of material releases volatiles, such as water, which induce melting). A common misconception (even for first-year geology students) is that rocks melt because they get hot. Actually, that’s rather rare- most of the time, rocks melt because they decompress (such as below mid-ocean ridges) or because volatiles (water, carbon dioxide) lower their melting temperatures. But at hotspots melting does occur because rocks get hot. Some places in the world, such as Hawaii and Yellowstone, volcanoes occur in the middle of plates because of deep hot anomalies in the Earth. Iceland is a place where a hotspot is located at a spreading center. Compared the surrounding parts of the Mid-Atlantic Ridge, in Iceland volcanic activity is more volumetrically abundant (because it’s hotter under Iceland) and an island has been formed.

Because of its location along the Mid-Atlantic ridge, Iceland will always erupt. The plate is spreading apart, and this leads to volcanism throughout pretty much the entire island of Iceland. The details are a little more complex- there are faults and active zones of volcanism and such– but all of Iceland is a volcano, more or less. All of Iceland was born in fire.

My research on Iceland focuses on the Northern Volcanic Zone, in particular on two rift zones named Krafla and Theistareykir (which I can pronounce poorly, unlike Eyjafjallajökull, which I cannot pronounce at all). I am actually studying cycles of glacial-postglacial volcanism. I will try to write another blog on this later this week, but what is remarkable is that there is an important link between deglaciation and volcanism in Iceland. During the last Ice Age, a ~2km thick ice sheet covered all of Iceland. That ice sheet rapidly melted ~13,000 years ago, leaving only isolated glaciers such as Eyjafjallajökull. The unloading of this ice sheet led to an up to 100 fold increase in volcanic activity. For about 2,000 years, eruption rates in Iceland were up to 100 times greater than they are today!

Just imagine if there were airplanes 13,000 years ago. That would be a large number of European flights cancelled.

I’ll write more (soon!) about the possible links between deglaciation and volcanism in Iceland and other places, since it’s something that has been in the science news recently.


Evelyn is a geologist, writer, traveler, and skeptic residing in Cape Town, South Africa with frequent trips back to the US for work. She has two adorable cats; enjoys hiking, rock climbing, and kayaking; and has a very large rock collection. You can follow her on twitter @GeoEvelyn. She also writes a geology blog called Georneys.

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  1. I read aloud the bit about the cost of volcanic monitoring, and my honey replied: ” well, maybe the airlines ought to be paying for the monitoring.”
    (he was kidding)
    My local (Portland OR) science museum is hosting a lecture on earthquakes on Tuesday, and it’s been on the schedule since before the Icelandic plume happened. I suspect volcanoes are going to take over a portion of the talk!

  2. Great post, Evelyn. I haven’t been able to keep up on the news about this so this was very informative. Like everyone, I would like to know the long term effects if this does keep going for several years. How long will planes be grounded? What effect will this have on the climate/weather in that part of the world? Will that in turn damage the agriculture in the region? Is this going to have long term health effects too?

    It’s ok if you can’t answer all of them. I have a habit of asking too many questions.

  3. Wow, awesome post! I don’t usually find geology and volcanoes that interesting, but once started reading this entry, I was hooked. Thanks for the work and the wonderful dose of fascinating science.

  4. Once the glacier is melted away, will it go back to being a typical quiet lava flow vulcano? And how long might this take to happen?

    I’m sure they won’t ground airliners throughout Europe for two years. Already they are testing the ability to fly under the ash cloud: (actually, I expected this to happen within about 24 hours of the problem starting.) Also the vulcano may be intermittant, as may be the weather patterns that carry the cloud over Europe.

    I expect it will settle down to: sometimes flight operations as normal, sometimes restricted to low altitudes (messing up ATC, scheduling, airliner range, possibly requiring extra maintenance, and so causing reduced and/or delayed services) and sometimes flights shut down, as now.

    By the end of this, we’ll have a very good idea what you can and can’t safely do with airliners near vulcanic clouds.

  5. On linguistic grounds I oppose the use of the term Eyjafjallajökull glacier, as jökull means glacier. ;) The full translation of Eyjafjallajökull becomes Island-mountains-glacier, according to Icelandic wikipedia because it can be seen from the Vestmannaeyjar islands. (See what I did there? :D)

  6. @Elyse: I believe Bjornar’s criticitism is similar that leveled at us Americans for saying Mount Fuji Yama, when yama in fact means mountain. So we are in effect saying Mount Fuji Mountain.

    I believe I have now properly dragged this conversation down to proper stick-in-the-mud levels.

  7. @weatherwax:

    Vestmannaeyjar means islands I guess?

    Dear Iceland,

    Next time you’re picking a language, pick an easier one.

    Also, pick a better location and economy.

    Actually, aside from elven sex partners, why don’t you just let the rest of the world choose your stuff for you.

    Don’t feel bad, though. We can’t all be good at everything. And really, you guys mastered the elf sex thing. You’re as good at that as Australians are at walking upside down. It’s impressive to say the least. And America? We’re brilliant at being the Texas of the entire world. The important thing is to stick at what you’re good at. Language, not living in a volcano, and international pop stars just isn’t your thing.

    We still love you.

    The Western World
    (By which I mean just America)

  8. Having lived in–and frequently traveled and flown around–Iceland in the mid-70s while in the US Navy, I found the place endlessly fascinating. The language can be a little tricky at first, but after a while it can become at least semi-comprehensible. I especially enjoyed visiting the spouting hot spring named (in Icelandic) “Geysir” from which we’ve adopted the now familiar word “geyser” to describe similar geographic features elsewhere. “Vestmannaeyjar” means Westman Islands as you induced, Elyse. Thanks for the informative post Evelyn.

  9. So you did see what I did there. I committed the same “offense” I spoke up against, cause it’s a very useful thing to do if you want to be understood and not just nitpickingly correct.
    Minimising it forces people to learn more foreign words though.

  10. Icelandic Names, and please forgive my spelling mistakes: When my mother was stationed at Keflavik, she lived in nearby Njarvik on Kirkabrout (Church Street). The next street over was Njarvik Strasa, which connected with Njarviker Strasa, which turned into Njarvikervagervassa.

    It’s almost as bad as trying to get directions in Hawaii.

  11. @weatherwax: According to wiki braut means path, and according to google it means track. This, combined with the facts that it’s a road within Keflavik Airport which up until recently had an American military presence, and that “Int’l Highway” is very much not Icelandic, leads me to the conclusion it’s an American joke.

  12. @Filias Cupio: Good post. They’ll need to be very cautious flying around the ash clouds, though. The airlines may have to use satellite imagery to stay out of it if they start flying again.

    Ash clouds don’t show up on weather radar and the damage they cause to jet turbines alone is horrific. For one thing, volcanic ash turns to a melted, glassy form in the hot section of jet engines, which coats the parts and renders them useless. It also opaques aircraft windshields very quickly and sandblasts the outside of the aircraft, as well as the guts and filters in the pressurization/HVAC systems.

    Volcanic ash is somewhat corrosive and makes a great abrasive. All in all, a good thing to stay far away from with any machinery. Once the volcanic eruption subsides, it will take a few days for the ash to settle out to the point that aircraft can fly safely again.

    I have heard accounts that those with pre-existing breathing issues like athsma may have problems with the ash. It MAY have a cooling effect, but I’m not sure that anyone can tell just yet. The sunrises/sunsets should be spectacular for awhile, though.

    And I protest on behalf of all boobies everywhere, feathered or not, upstanding or droopy!

  13. I’ve been to Iceland three times–it is one of the most spookily beautiful places in the world. Confusing though, are the souvenirs, which read “Island” (the Icelandic spelling). Seems kind of generic on a tee-shirt.

  14. Okay that picture of the mid-ocean ridges blows my mind. You can actually SEE the outline of Africa in that ridge and realize that that is the point where the earth punched a hole in pangea and said, “everybody back!” Does anybody know what those ridges and hotspots don’t ever seem to move? Why do they only serve to push the plates on top of them? Why is it so hot under the earth in those specific areas?

  15. When we spent a couple of weeks in Iceland several decades ago I was entranced by a road map of the interior. It had some very thin dotted lines, the legend for which was (roughly) “Usually passable in dry weather during summer.”

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