Volcanic gases

As you may well know, there are many volcanic gases. These gases help drive the eruption. Initially dissolved in the magma, they expand as the pressure is released, driving the magma out of the vent and causing explosive eruptions. One should also note that anything that boils below the temperature of magma (600-1200°C) should be considered a volcanic gas. A good example is shown here,

where garbage is thrown into a lava lake and subsequently vaporizes; the garbage has turned into volcanic gases.

The most abundant volcanic gas in most cases is water. Water drives volcanism at subduction zones. The wet oceanic crust is pulled into the mantle where it has several effects. First, water is believed to lubricate the process. This may be through a chemical alteration of the rock called serpentinization. Water also decreases the melting point of rock. This, along with the fact that water is lighter than rock, leads to the buoyant plumes of molten rock that feed subduction zone volcanoes. The good news about water is that it is non-toxic. Steam can burn you, cause explosions, and throw hot rocks at you, but it will not poison you. Other volcanic gases are not so nice. We may, or may not, have to worry about them, but we should understand them if there is any chance of exposure.

Steaing Geyser, Image Wikimedia Commons

Steaing Geyser, Image Wikimedia Commons

Before we go any further, it’s important to understand that different substances have different levels of toxicity. For example, both carbon dioxide and hydrogen cyanide are toxic. The current atmospheric concentration of CO2 is close to 400ppm, a level which is absolutely harmless, at least in terms of breathing it. Hydrogen cyanide, in the same concentration, would kill us all in less than an hour. For toxic gases, a good measure of toxicity is the LC50. The definition of the LC50 is the concentration that causes death of half of the exposed critters over a certain period of time. This value is determined experimentally, in a controlled lab setting. For obvious reasons, this is usually tested on rodents, rather than humans. Time is important here, because longer exposures may be deadly with a much lower dose. These numbers are usually geared to occupational exposure, and may not reflect constant exposure volcanic gas over hours or days, but it’s good enough to get some idea of the toxicity. It is important to note that the LOWER the LC50, the more toxic the gas.

Notably, these are the concentrations that kill HALF of the exposed individuals. Death can result from far lower exposure. A good measure for this is the LCLO, which is the lowest concentration in which death has occurred. Again, lower numbers mean greater toxicity. This data is usually far less available, and is generally based on short, high concentration exposures that would occur in an industrial setting. This is an uncontrolled environment, so this data is less reliable than the LC50, and the hazard of longer exposures, such as would occur during a volcanic eruption, are difficult to judge by this metric. Usually, this data tells a similar story to the LC50, but not always. For example, the lowest exposure of hydrogen fluoride known to cause death was 50 ppm for 30 minutes, while hydrogen sulfide has a much higher LCLO, around 600 ppm for the same time frame. The LC50 shows the opposite pattern, with hydrogen sulfide seeming to be much more toxic. Based on this, it seems that sulfur dioxide is more uniformly toxic to all individuals, while some individuals are more susceptible than others to hydrogen fluoride exposure. It’s also important to know that this does not tell the whole story. Hydrogen fluoride, for example, has significant, dangerous effects with long term, low level exposure, and it has ways to get into you other than by breathing.

In addition to these data points, there is another standard of safety that is often encountered. This is the IDLH concentration, which stands for “Immediately dangerous to life or health.” This is the level that is “likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment” according to the NIOSH, or National Institute of Safety and Health, here in the United States. This standard attempts to address additional concerns. A person who is unable to see, unconscious, disoriented, or struggling to breathe is not going to be able to escape a dangerous situation. For example, exposure to concentrations of carbon dioxide far below the lethal level can lead to unconsciousness or disorientation. Hydrogen chloride is also dangerous because it can cause severe tearing up of the eyes, along with severe respiratory irritation significantly below lethal levels, which could lead to incapacitation. While this number is based on scientific information, it is not determined by objective data collected in a controlled lab testing, but rather by regulators looking at data. Therefore, it is far more arbitrary, and may not be as accurate as the other numbers.

Toxicity data for various volcanic gases:
Gas LC50 (ppm)/exp. time (minutes) LClo (ppm) / exp. time IDLH (ppm) Typical % of volcanic gas^
Carbon dioxide 470000A ppm /
30 min
90000H / 5 min 40000 ppm 1-50%
Sulfur dioxide 2520 ppm / 60 min 611 / 300 min
1000H / 10 min
100 ppm 1-50%
Hydrogen sulfide 444 ppm / 240 min
713 ppm / 60 min
600H / 30 min
800H / 5 min
100 ppm 0-3%
Carbon monoxide 1784 ppm / 240 min 4000H / 30 min 1200 ppm 0-2%
Hydrogen fluoride 1276 ppm / 60 min 50H / 30-60 min 30 ppm <0.3%*
Hydrogen chloride 3124 ppm / 60 min 1300H / 30 min 50 ppm 0-1%
Data for LC50 and LCLO is for rats unless otherwise noted. IDLH is always for humans.
LC50, LCLO, and IDLH from http://www.cdc.gov/niosh/idlh/intridl4.html
H: Human data
A: Data from https://www.airgas.com/msds/006598.pdf
*: Volcanoes in Iceland typically give much more, though I can’t find reliable data.
^: There are plenty of exceptions.

There is additional information that we need to take into account when judging the danger of volcanic gases. Looking at the table, it would be easy to assume that hydrogen sulfide would be the biggest danger, since it is the most toxic (on the LC50 scale). However, while it is roughly 4 times as toxic as sulfur dioxide, there is typically at least 10 times as much sulfur dioxide. While carbon dioxide is comparably non-toxic, it is often the most abundant toxic volcanic gas. It also is dense, and settles into low-lying areas. Recently, near Mount Nyiragongo, it resulted in the deaths of several children in a low-lying area of a playground. (http://www.pbs.org/wgbh/nova/transcripts/3215_volcanoc.html) It can also concentrate, dissolved in the water at the bottom of a lake, until the water turns over and spills its deadly contents over the landscape. This happened at Lake Nyos in 1986, killing 1700 people. (http://en.wikipedia.org/wiki/Lake_Nyos)



Notably, hydrogen fluoride has the lowest LC50 on the list, but it usually makes up only a tiny fraction of the volcanic gases emitted by a volcano, and so it is rarely a big risk. This is not the case in Iceland, though, where eruptions are known to emit a lot more hydrogen fluoride. I don’t have reliable data for Icelandic eruptions, but Laki is estimated to have emitted 120 million tons of sulfur dioxide, and 8 million tons of hydrogen fluoride. If we assume that only 10% of Laki’s emissions were sulfur dioxide, then that means that hydrogen fluoride emissions were more than double its normal percentage of volcanic gas. If there was more sulfur dioxide, the portion of hydrogen fluoride would have been even higher. That being said, based on toxicity data, sulfur dioxide would have been a serious inhalation hazard long before hydrogen fluoride presented the same danger.

This leads me to the last point on toxicity. There are many factors that affect the concentration of toxic gases. The total amount of emissions, not just the percentage of each gas, is important. A large fissure eruption, like Laki, is going to put out a lot more gases than a small central volcano eruption such as what happened at Eyjafjallajokull. Heavier gases, such as sulfur dioxide and carbon dioxide can settle in low-lying areas, while higher areas may be safer. Wind direction and speed is important. People downwind from a volcanic eruption will face much higher concentrations than those upwind. A fast wind will actually dilute the gas more, and will help keep heavy gases from settling in low areas, but will increase concentrations further downwind.

That is a lot of data, but what does it all mean? Which of the volcanic gases were listed in the table above actually pose a threat? The main risks are from sulfur dioxide, carbon dioxide, and hydrogen fluoride. The rest are dilute enough that they rarely pose a threat. Sulfur dioxide, if present, clearly lets you know it’s there. It is a pungent, choking gas that irritates the nose, throat, and eyes long before it reaches dangerous concentrations. Carbon dioxide should only be a threat in low-lying areas, because of its low toxicity. Its symptoms include shortness of breath, dizziness, and rapid breathing. Hydrogen fluoride should have a strongly irritating, sharp, acidic odor at immediately dangerous levels. However, levels that you can’t detect can be a problem over time. There will be more on this later.

Specific advice for Iceland about the volcanic gas hazard can be found here:   http://earthice.hi.is/sites/jardvis.hi.is/files/myndir/Bardarbunga/volcanic_gas_hazard_enska.pdf

Volcanic Ash

OK, volcanic ash is not a gas, but it is an important toxic volcanic emission. In addition to its physical effects, such as weighing down roofs to the point of collapse, smothering crops, clogging car air filters, and contributing to lahars, it also has toxic effects. These are a bit harder to measure and put in a table, though. The first hazard is simply its irritant effect. Ash consists of many sharp-edged rock particles. They can irritate the eyes and respiratory system. As we saw previously, this can pose a danger by hindering one’s ability to escape the situation. With high levels or prolonged exposure, it can clog up the respiratory system in a condition called silicosis. (http://en.wikipedia.org/wiki/Silicosis) While acute symptoms may reside with time, the silica never comes out of the lungs, so this has the potential to be a permanent condition. Silicosis is not a nice way to die. Silica has an IDLH of 3000mg/m3, a concentration that would cause irreversible illness in 30 minutes. Note that this is a different unit that the PPM’s typically used for gases. Also note that ash can contain toxic materials other than just silica.
Upon further review of the information out there, I found that silicosis is unlikely. While volcanic ash is mostly silica, the most toxic form, (fine, crystalline silica,) is rarely abundant in volcanic ash. It would take years of exposure to crystalline silica rich ash to develop silicosis. Those with preexisting lung diseases, such as asthma, may be more prone to problems, up to and including death. Additionally, there is some evidence that children exposed to ash may be more prone to asthma. However, healthy individuals are unlikely to experience anything more than bronchitis-like symptoms.
The pertinent information on volcanic ash toxicity is presented here: http://www.geo.mtu.edu/~raman/papers2/HorwellBaxterBV.pdf



Many eruptions in Iceland, as well as a few other volcanoes, emit high levels of fluoride. Fluorosilicates in ash can be an even more important source of fluoride than hydrogen fluoride gas. Both fluorosilicates and hydrogen fluoride will adhere to surfaces and foods and dissolve into water. Even at low concentrations that would be harmless in the short term, hydrogen fluoride can be absorbed into the body and slowly cause fluoride toxicity. Fluoride anions bind strongly to calcium, and lock it up, keeping it from being dissolved or utilized by the body. We know about the toxicity of fluoride because there are a few regions of the world where ground water naturally contains toxic levels of fluoride.   Although small quantities can harden teeth and bones, too much fluoride starts sucking calcium out of the body, resulting in the opposite effect. This can cause crippling deformities and weakening of the bones. (Here is a link to a picture of individuals suffering from dental and skeletal fluorosis: http://openi.nlm.nih.gov/detailedresult.php?img=3467640_BMJOPEN2012001564f02&req=4) Fluoride toxicity not only affects the bones and teeth, but it can damage the kidneys and interfere with thyroid function. High enough doses can cause vomiting, diarrhea, and cardiac arrhythmia, which sometimes leads to death. Only 1mm of Hekla’s ash, in 1947, was enough to start killing sheep due to fluorosis.

Protecting yourself

Now, I bet you’re asking, “How can I protect myself from volcanic gases?” Well, first and foremost, I’m only giving advice on the toxicity of volcanic gases and ash, not the other hazards they pose. Ash, in particular, can cause a lot of other problems that I won’t cover here. Second, I’m a chemist, not a volcanologist, so I’m not an expert in this area. If my advice is different from the experts’ advice, listen to the experts. However, I can approach the issue like a chemist would approach toxic chemicals. The first line of defense against toxic gases is knowledge. Knowing the toxicity of a chemical and symptoms of that toxicity is important. Knowing what chemicals you and others may be working with is important, so you know when and how to protect yourself. The same approach applies here. Reading this was a nice start, but you’ll need to know more. Read more on toxic volcanic gases. Listen to the authorities, particularly in developed nations. They should tell you when and where volcanic gases will be most concentrated, and where ash will be falling. They will tell you if you should evacuate. They should tell you if your municipal water supply is unsafe to drink. Watch the weather report to know which way the wind is going to blow. Keep up to date on the status of an eruption.

The second line of defense when dealing with toxic substances is engineering controls. For example, chemists work in a fume hood, which ensures toxic vapors blow away from the chemist. As another example, drums of toxic substances are stored over large, empty containers, which would contain a spill if a drum leaked. You may not think you have any engineering controls working in your favor, but you do! Do you use well water? Or does your city use groundwater? If so, volcanic ash cannot easily contaminate your water supply. Your house, workplace, or car (if the vents are set to recirculate air) can provide protection from volcanic gases. If you are outside, one minute the wind could be blowing healthy air towards you, then seconds later, it could blow hazardous concentrations of gas towards you. Since air only slowly moves into and out of buildings and cars, the composition of air inside will be the average composition of the atmosphere over the last several hours. Staying inside will not protect you for long if you are directly downwind from the eruption, but if the wind is alternately blowing toxic and clean air your way, it can prevent exposure to hazardous concentrations.

The third line of defense is personal protective equipment. You probably know that chemists wear gloves and goggles most of the time in order to protect themselves from accidental exposure to toxic chemicals. We try NOT to depend on these items, though. These devices can fail, and are meant only as a last line of defense. They are no substitute for avoiding exposure to toxic substances. However, they do work, and have saved many chemists from injury or death.

One piece of personal protective equipment that chemists use, which is applicable here, is called a respirator. These come in various types.


The dust masks that you often see (which look similar to the one in the middle) are usually the particulate type, although a few offer limited vapor protection. (Read the package!) These protect you from small particles in the air, and should provide protection from volcanic ash. However, most dust masks will NOT protect you from volcanic gases. The type you need for that is one rated for acids and organic vapors. The most effective respirators fit on the face with a rubber seal, and use cartridges to absorb the gases. A respirator of this type will protect from sulfur dioxide and hydrogen fluoride, but not carbon dioxide. Some of these respirators (right) also provide eye protection. The bad news is that these are expensive, and without being properly fitted, they may leak. They also have a finite capacity to absorb toxic substances; the higher your exposure, the quicker they stop working. Additionally, if the respirator is not rated for particulates, volcanic ash could clog it quickly! If you have one of these or can get one, and you are being exposed to volcanic gases, use it! Of course, the better choice is to avoid volcanic gases, but this is not always possible.

If you don’t have a respirator, or the cartridges run out, and you can’t escape the gases, you’re going to need an alternative plan. Sulfur dioxide and hydrogen fluoride are acidic, and can be neutralized by bases. As shown here, http://www.uhh.hawaii.edu/~nat_haz/volcanoes/vog.php .

Hawaiians have found some ways to deal with sulfur dioxide. Towels dipped in baking soda solution, (a mild base), then draped over a fan can remove sulfur dioxide from the atmosphere. (This should work for HF, too!) Dust masks or bandanas dipped in the solution, then left to dry, and used to cover the face should also be somewhat effective. These options should also filter out most ash. (Note: Baking soda is “sodium bicarbonate” or “sodium hydrogen carbonate”. Do not confuse it with baking powder, which will NOT work. Also, do not confuse it with washing soda, which is “sodium carbonate”, as it can cause skin injury. Most other bases are too toxic to use! ) If you have nothing else, a wet rag over the nose and mouth will absorb some of the acidic gases. This is used by Indonesian sulfur miners, whose life expectancy is only 30 years, but that’s a lot longer than those who try to go up without any protection!

Drinking water safety

Now what about volcanic ash emissions contaminating your drinking water with fluoride? First of all, this is rarely a concern unless you are in Iceland, or you are near a volcano known for fluoride emissions. (Remember, information is your first line of defense!) Of course, many of the readers are from Iceland, so we will talk about it here. First of all, while some people may have suffered from fluorosis during the Laki eruption, there is evidence that fluorosis in humans may not have been widespread. (http://www.nabohome.org/uploads/fsi/FS328-04291_Fluorosis.pdf) If you can’t implement any of the techniques to limit fluoride exposure, you still have a good chance of making it out alive. Indeed, famine due to the death of livestock was the main killer, and with modern transportation, you’ll probably still have access to food.

If you have well water, your water should be safe. The same will be true if you have city water that comes from wells. If you get your water from above ground in any other way, and you are near an erupting, fluoride-emitting volcano, then it would be wise to purify your water. If you have a municipal water supply that comes from above ground, your city might monitor for fluoride, but I wouldn’t count on it. This is not a standard test that local treatment plants do in all locations, especially in countries that don’t fluoridate water. Even if they do monitor it, it is unlikely that they will be able to treat it, as this requires specialized techniques that are expensive and not necessary under normal conditions. Municipal water should still be safe for bathing and washing clothing, as long as they are properly adjusting the pH. Other surface water may not be safe for those purposes.

So, what are your options for removing fluoride from the water? Of course, you could use bottled water, but this will run out early during a crisis. Typical commercial water filters do NOT work. Boiling and freezing do nothing. Even reverse osmosis will not remove fluoride unless the water has a high pH. (This means the water must be basic in order for them to work.)   Yet, there are some things you can do. The following link lists several techniques used where ground water naturally contains dangerous levels of fluoride. http://www.samsamwater.com/library/TP40_22_Technologies_for_fluoride_removal.pdf Note that most require lime or other materials, which you may or may not have available. Assuming you don’t, you’ll need an alternative. Distillation is that alternative.

One should be aware that distillation will NOT remove all fluoride if the water that you start with is acidic. Hydrogen fluoride has a boiling point of 19.5°C, so it will readily boil with the water. However, distilled water will be safer than water that has not been distilled. Some fluoride will still be removed, since much of the fluoride emissions from a volcano will be in other forms, such as fluorosilicate minerals. You can decrease the amount of hydrogen fluoride in the distillate by condensing the water above the boiling point of hydrogen fluoride (around room temperature), so don’t use ice or anything cold to condense it. If you want to remove all of the hydrogen fluoride, you need to make the water basic BEFORE you distill it. The safest way to do this is baking soda. A spoonful per gallon should be adequate, as long as you don’t see a bunch of fizzing when you add it. Notice a pattern here? Buy lots of baking soda! There are lots of household uses for it, too, if it turns out you don’t need it. Lime or washing soda should also work to make the solution basic. Lye will work, but it may damage the container and is less safe to handle. Ammonia or bleach will contaminate your distilled water, so don’t use them!

A homemade water still can be made fairly easily. Go ahead and get creative! All kinds of stuff could work. A good video showing a fairly simple design is here:

All you need is a container in which to boil water, which can be sealed except for one opening. That opening should be connected to a long tube, preferably metal, which goes to the container in which you collect your clean water. The end of the tube in the vessel you are heating must be well above the level of the liquid. The collection vessel must NOT be sealed tightly, and the tube must not be clogged, or the steam won’t come over, and you risk an explosion. The longer and thinner the tube, the less water you will lose as steam, but for safety considerations, a wider tube is better. You can also reduce your losses by cooling the end near the collection vessel, (try a damp cloth) and by distilling slowly under the lowest heat that gets you distillate.

There are a few important considerations in operating a still safely. First of all, the pot in which you boil, the tube from that pot, and any steam that comes out of the tube will be dangerously hot! However, burns are not the biggest danger. The biggest danger is if the tube gets clogged. If, for any reason, at any time, the heated vessel is not open to the atmosphere, pressure can build up, causing it to explode. This will result in shards of metal, plus superheated water flying everywhere. In order to avoid this, make sure the part where the water drips out is open to the atmosphere. Do at least a crude filtration before putting water in the pot… no sticks, leaves, or pebbles! Also, do not distill to dryness. It is tempting to try to get all the water out of the pot that you’re heating, but DON’T! Minerals from the water will build up on the inside, and pieces of it may clog the tube. When you finish a batch, be sure to rinse out the pot to get rid of any deposited minerals.

Well, that’s all I have for toxic volcanic gases and toxic ash. Hopefully, you’ve learned a lot. There is a lot more you need to know about safety during volcanic eruptions, most of which deals with the hazards of volcanic ash. However, I think you’ve got toxic gases covered now!




1,843 thoughts on “Volcanic gases

  1. I’ve bee thinking that it would be wonderful if there was some way to get just the latest news, a snapshot as it were, of activity. Sort of like a Wall Street ticker feed. (Maybe such a place already exists). The type of data would be highly summarized and we’d have to look here or at other sites that “flesh” out the details. Things like has Holuhraun activity remained stable / normal, eq activity up/down in past 8 hrs in BBunga, eq activity NE of Askja, have there been updates to main info sites (like this one) in past 8 hrs, … Just a thought for those of us who really, really, really, really should be doing something other than searching comments, etc. for updates all day long. I’d love to do quick checks and stay if something seems highly interesting to me. (Not volunteering, my programming skills are 15 years out of date.)

  2. “Seismometers at the Icelandic Met Office have in recent minutes shown increased low-frequency tremor at stations near the northwest part of Vatnajokull. The Civil Protection Agency has now called everyone back who was near the fissure in Holuhraun, due to concern that the eruption could be getting bigger, or that magma could break the surface at another location. No changes in the eruption have as of yet been confirmed. ”


  3. So the University people are describing the depression as a graben and the western fault of the graben seems to line up, both with the old line of craters in Holuhraun and with the line of the new fissure eruption

    • If that is case, it may have had a couple of burp eruptions on its way north like what started at Holuhraun before the bigger eruption (then the full fissure), and that area the quakes are moving back SW to will be very weak.

  4. I’ve been a few days away, as I was very busy. So I’ve a lot to do to catch up. Maybe an idea for the next post is a timeline of the eruption, with what has happened (so at date x the earthquake swarm began, at date y the tremor went up, at Z we had the first 5M quake etc.) and with graphs, photo’s, tremor charts etc.

    If nobody is doing that already, I want to do that, as I’ve to catch up anyway. But because I’ve had a very busy month I will have to look up nearly everything, so that will take time and any help is welcome.

  5. If what we’ve been witnessing over the last couple of weeks has been the formation of a graben, with two parallel faults, approximately 1 to 1.25km apart, I wonder if it would be possible for some data visualisation genius to replot some of the EQs on a larger scale. If it was possible to select a rectangle running around 10km SSW-NNE by around 4km across, straddling the southern section of Holuhraun and the northernmost few kilometres of the glacier, centred on the graben, to see if the seismic events corresponded with the two faults. The bubble plots did appear to show two separate columns of EQs! (Note: This task is so far beyond my capabilities it’s deep red on the new scale!)

  6. A few days before the eruption, cracks were reported that existed before, although there appeared to be new ones and one big crack seemed bigger, they were there before as shown on Google Earth

    The big crack is located on the red line drawn in the latest radar picture, it is a little jog in the line running through the small hills in the middle of the picture

    It appears this area may have already been ready to slip and has done so due to the rifting

    • It also makes sense that pre-existing crevasses in the glacier would naturally enlarge as the glacier experiences disturbances from below. The glacier will rip apart along the pre-existing faults in its structure.

  7. Plate Tectonics 101:

    The bad news is that Iceland is ripping apart.

    The good news is that America is getting further away.

    (please forgive me, Americans – I’m only joking)

    • There are many American’s like me that are disgusted with the way our country is being managed and where it is heading. It’s slowly being ripped apart like the plates in Iceland. I am looking to leave here eventually before it crashes hard and its only a matter of time.

      So trust, me, your going to want America to be very far from Iceland at that point.

      • You’re just not better than anyone else, but there are worse… 🙂
        It’s not the country and its people, it’s as anywhere else the “classe politique” and the “classe economique” where some disturbed personalities lets the rest of humanity have hard times.
        Let’s see each others for what is good in our countries. American cookies, muffins, cheesecake, Jeep, the Leatherman’s tool are all pretty cool… 😉

        • Wasn’t it Churchill that said
          “Americans always do the right thing – after they’ve exhausted all the other possibilities.” 🙂
          (just kidding…I’m American…agree with Zyfly above…)…

        • Nice! and i agree….. Nice people all over the globe and even if You have a democracy it doesn’t mean You get the activity that You want…. enough politcal talk… back to VOLCANOES! Best!motsfo

      • America has some of the best craughtsmen on the planet. I have a few employed and they always amaze me at how skilled they are.

          • I’m biased, as I lived in Norway for a while. Norway has better scenery and smoe parts have better weather than others. Caveats: I’ve never been to Sweden, so don’t really know the scenery and as the Norwegians say, there’s no such thing as bad weather. Also, the landscape of Norway varies quite considerably. I like the scenery of the Lofotens, but the far north also has dramatic scenery in its own way. Finland is flatter, with lots of forests, similar to parts of southern Norway.

      • Watching the rift eruption I felt like I was going back to a time before the written word, when stories were told in words and music and myths were created. The only other time I felt like that was when I was listening to Norwegian Hardangefele music late at night in the Appalachian mountains. I could hear the snow and the trolls inside the music. … Someday I hope to travel there.

    • Emissions look like they have drastically increased. Valley completely fogged over with smoke the same color as what is coming from vent.

      • Rain interacting with the fissure emissions, perhaps? Weather was crummy earlier this morning and there are trails from the clouds on the B1 cam that look like rain.

  8. Is there any information yet about HREEs in the lava that was analysed recently – sorry if I’ve missed this in an earlier post

    • No there was not, but it should be in the Bárdarbunga line of things.

      This is not an area I am at liberty to talk about due to being under a secrecy agreement.

      • Just read this:

        “The magma intrusion which feeds the Holuhraun eruption comes from the south, from the Bardarbunga volcano. Most of the intrusion lies deep beneath the Vatnajokull glacier and Dyngjujokull outlet glacier, so a subglacial eruption is a very real possibility, says Dr. Hoskuldsson. “We know where the magma is coming from, and in episodes like this, experience has shown that eruptions can occur near the source. Given that the current eruption is quite near the edge of the glacier, we would expect a subglacial eruption.” ”


      • Like LREE, but heavy, rather than light….
        (REE = rare earth element, and the LREE/HREE ratio is diagnostic of something to do with the magma’s origin.)

    • Makes sense – they don’t know where a new fissure eruption could form from, and if you’re in the middle of a field when one pops up, things can get dangerous. Last thing people want is a situation like Galeras in the early 1990’s.

      • Yes. I was very aware that there are 4 life dangers:
        Being near Bardarbunga: low risk but a deadly one
        Being near the glacier or glacial rivers, high risk and a deadly one
        Being near to where a new fissure occurs, high risk and deadly one
        Being near gas: high risk and a possibly deadly one

        If one keeps constant updated checks on the harmonic tremor, one could escape on time. But the flood and a new fissure opening can occur without any tremor change, and therefore come without warning,

        How to avoid them?
        Bardar eruption: Stay away from Bardar and rivers coming from the glacier around it
        Flood risk: Stay away from both glacial rivers and the flat sands of major flood pathways
        Fissure opening risk: Stay away from the surface equivalent of the dike. Either to the east or the west
        Gas risk: Stay upwind of the eruption site

  9. Good news.Probably was a good ideas to not have gone. But anyways my plan site for viewing the eruption was way away from the flood zone.

    I think a fissure will open at the edge of the ice cap. Remember yesterday I spoke about this when a swarm was taking place there as our eruption was decreasing. Watch this tomorrow,and watch Askja next week. Those are my bets.

    If I am wrong, then i will dance bare ass to the wwebcam while also eating hazelnut/coffee icecream, which is my fav.

    Damn a rift valley, that’s something big.
    Definitively this event is the LARGEST rifting event happening since Askja 1875.

  10. Rain driving the the lower airborne volcanic junk down to the surface? Barder 1 has water droplets on its lens and Barder 2 is seeing nothing but dark smoke/haze.

  11. Truck! I saw a truck up close on Mila 1. Soooo excited. If only there was some other way I could get the same excitement. Seeing them outside is not the same as seeing them one a web cam!! 🙂

  12. The 30 evacuated scientists and others are now in the Drekagil mountain hut, near Askja. “We are at 800 meters above sealine; about 200 metres above the potential reach of a glacial flood, quite safe and sound.”

        • One of the dance moves is called hallingkast. In this move, a girl has traditionally held a hat high using a stick or something similar, and the dancer is supposed to kick down the hat. Kast is seen as the test of strength, which involves kicking a hat that is held about 230 to 280 cm above the floor. Some girls have been able dancers themselves, and known to be as agile as any man. The agility of the female dancers may have been even greater, considering they danced in their skirts.[2]

          Baggy I hold the hat 😀 (Not willing to actually DO the dance…..I tend to trip over my skirt when just walking upstairs.)

          • Yes, I suppose I should have explained. But I was positive at least one person knew what I was talking about. 🙂 … I know it is very OT, but test of strength? The entire dance tests strength; I would think that part would be testing “spring”, technique, coordination, aim and endurance (because it comes at the end of the dance.) (My husband, being a mathematician who dances Halling, says it would be testing the strength-to-mass ratio rather than simply strength.)

  13. I suspect that this is a medium size eruption which will cause a large flood, and possibly a minor ash cloud, but I am not sure about the second part yet. Only DYNC seems to show a big increase. So this is definitively an event local to Dyngjujokull!

    I think we will see something happening until midnight. It shouldn’t take long for a flood there, to come out.
    It will totally flood the new fissure site and create a phreatic event there too.
    An ash cloud if it occurs under the ice age, could show this dawn.

    We might have very interesting hours ahead!

      • Eheheh!

        as much as it sounds a fantastic idea, it can’t never happen.

        Iceland hotspot, or whatever lies beneath it, makes it go upwards and also grown downwards.
        So, any rifting forming might sink, but any magma erupting or intruding can re-fill the void and increase it upwards. Unless there is a magma-starved rift, which we don’t there. So, while you see this rifitng now, in the future,magma from eruptions will cover it and grow above it.

        Maybe a rift valley and a shield volcano next door. Just like in Thingvellir.

        • I seriously laugh when I re-read my comment of 18:17 “An ash cloud if it occurs under the ice age, could show this dawn.”
          Obviously I meant an eruption happening under the ice cap, not ice age.

          But I enjoy saying: there is a certain part of Iceland still stuck on the ice age, and that is Vatnajokull. It’s freezing there when there is 17º in the lowlands.

    • Difference is that Irpsit actually was right on the Graben possibility.
      Irpsit have been following Icelandic volcanoes for years, read a lot about them, and been to most of them…

      Now, who would you think would have the larger credibility, Irpsit or a random person on a chat-stream.

      Seriously Andrew in Finland, do you ever think before you sprout snark?

      • In my experience… they don’t. Typically they are the most likely to “hoist on their own petard”, or suffer from a tendency to self immolate. {figuratively}

  14. Didn’t know Bárðarbunga had a bit more shady past, from Wikipedia:

    6600 BC Þjórsá Lava, the largest holocene lava flow on earth, originated from Bárðarbunga about 8,500 years ago, with a total volume of 21 to 30 cubic kilometres and covering approximately 950 square kilometres.

    And just for completion on ” Þjórsá”:

    The Great Þjórsá Lava is the largest lava flow in Iceland (by both area and volume) and the largest lava that is known to have erupted in a single eruption in the Holocene. It belongs to a group of lavas known as the Tungná lavas. It was erupted in the Veiðivötn region, Central Iceland, 8600 years BP (6600 BC).

    • Yes, if that would happen at least I wouldn’t have to worry driving to the lava. The lava would “drive” until me. All the way 200km to the southwest. Amazing no?

      From Bardarbunga almost to Hengill.!

  15. Maybe this has been addressed already but reading through almost 1800 comments is just too much so I´ll ask here.. 🙂

    What would make the 1-2 Hz band behave like this? It is extremely high.

      • Well yes I do understand that much.. 🙂

        Looking at the cam there isnt too much activity on the surface so this should mean that there is a rapid increase in pressure? Looks very steep..

    • When the 1st fissure eruption outside the icecap occurred, it was the first one that was visually seen/confirmed and could be directly correlated (time-wise) to spikes in the lower frequencies on the tremor plots. As a result, we can now assume with high confidence that spikes like these in the low and mid-frequencies at DYNC (and other stations) were/are revealing the start of actual eruptions. From this new DYNC plot, it would appear likely there is either a new eruption is taking place somewhere nearby, or there has been a marked change in the ongoing fissure eruption. As previously noted, only DYNC is showing this signal strongly, although a few other nearby stations are picking it up albeit at a weaker level…and in general, tremor at most of the stations around Iceland is in decline. Right now, my bets are that a significant local event is taking place, which is what the experts are now saying. And, if the expected flood does occur, we’ll then we’ll get a confirmation of what a large flood looks like on the tremor charts (If anything?)

    • Could someone please direct me to the website where I might be able to see the DYN plot? I can’t find it on en.vedur.is!

  16. I’ve been watching that cloud over the mountain for a few minutes now, and my wishful thinking continue to tell me that its fed from the mountain/glacier…. Oh well….

    • Has the main fissure expanded its activity south/left slightly? Looks like somewhat more ground hugging emissions there. Not sure if the angle is right for just wind.

    • I think the glacier is on the far left, possibly out of the picture, but I’m not sure about that. I think they set up Mila1 to get as broad a picture as possible initially, including the glacier, but they may have moved it when the eruption started.

    • i could be totally wrong but that’s Kistufell pretty much dead quake wise or anything.
      *angle not entirely correct still trying to figure out exact location.

  17. Not sure if this was already posted but from RUV:

    “Geologists working near the Holuhraun eruption north of Vatnajokull have been called back, as increased volcanic tremor has been detected in the vicinity. GPS measurements show that the magma intrusion has increased since the beginning of the current eruption and a rift valley has formed.

    Seismometers at the Icelandic Met Office have in recent minutes shown increased low-frequency tremor at stations near the northwest part of Vatnajokull. The Civil Protection Agency has now called everyone back who was near the fissure in Holuhraun, due to concern that the eruption could be getting bigger, or that magma could break the surface at another location. No changes in the eruption have as of yet been confirmed.

    According to the conclusions of the latest Scientific Advisory Board of the Civil Protection Agency, posted at noon today, the volume of the dike intrusion from Bardarbunga volcano towards the north has increased since the beginning of the current eruption in the Holuhraun lava field. This is taken to signify that more magma is entering the dike than is being erupted.”

    • Would not it be better to evacuate to the south of the volcano considering the activity is happening on its north side?Not thinking specifically of flood threat.

  18. Evenin’ All,
    Though I am a dragon and an volcanoholic; this is my first “live” Icelandic eruption. I must admit I am a little overwhelmed with all the coverage and instrumentation available. I have followed VC every day for nearly 3 years and never really felt like I had a working mental model of the Icelandic situation. The interaction of the MAR, Mantle Plume and Tectonics is beyond my grasp…
    My first “live” eruption was BoB, off the southwest tip of El Hierro int Canary Islands, where the instrumentation was/is minimal. While it is complex, the geologic setting is somewhat understandable to me; I’ve spent a month of every year there for 9 years. So understandable, (that after some intensive reading) I was able to cobble together some halfway decent articles.
    I guess this is a message for our new friends; please, if you have time, submit an article, the dragons will review and edit it… The VC email address can be found int sidebar above. If your piece is published, it could be read by thousands!!!

  19. I popped quickly to look at Barda 2 web cam, but it is still so madly zoomed in it’s out of focus. I can almost see Reykjavik and possibly the USA on this camera. It’s a shame they can’t pull it back a tad and get better focus / definition. Anyone from Mila reading this – hint hint pretty please!

  20. congrats carl and the dragons,
    this post has already 1.15 post per minute at the moment

    previous post was about 0.63 ppm

    Good job! that’s a good sign if you ask me 😛

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