Bardarbunga and SO2 emissions: comparison with Laki 1783

Bardarbunga spewing gas from Nature/News
Arctic-Images/Corbis

"Gas-spewing Icelandic volcano stuns scientists". So reads the headline in Nature/News on October 28. Bardarbunga, about 250 km from Reyjkjavik, has been erupting for over two months (see previous posts on this blog here and here). The reason that scientists were "surprised" is that they had been expecting Bardarbunga to mimic the 2010 Eyjafjallajokull eruption that spewed ash high into the flight paths of airplanes, and instead, they are getting lava flows and gas.

Over a period of about two weeks in August, magma moved underground (in a configuration called a dike by volcanologists) approximately 45 km to the edge of an ice cap. There it began erupting into a barren plane called "Holuhran". Along with the lava, SO2 has been erupting in such quantities that Austria is recording more sulphur in its air than anytime since the 1980's when industrial pollution was still at high levels in Europe.

NASA Earth Observatory image in early September

How much sulfur dioxide is being emitted? Estimates are about 35,000 metric tons (tones) per day, and the Nature/News article uses the comparison that this is about twice the amount spewing from all of Europe's smokestacks. In the town of Hofn, sulfur spikes as high as 21,000 micrograms per cubic meter have been measured, more than 40 times the recommend maximum 10-minute exposure of 500 micrograms per cubic meter, according to the WHO. Hofn lies southeast of Bardarbunga (about 250 km as far as I can estimate) across the entire expanse of Vatnajokull. In early September, people in Norway 800 miles away reported smelling sulfur from the volcano.

The eruption site is remote, winter is setting in making logistics difficult, and the darkness of winter at such high latitudes will limit the amount of data that can be collected. The limited ground observations will be supplemented by satellite observations.

In 1783-1784, a fissure eruption similar to this one, known as the "Skafta fires" or the 1783 Laki eruption, spewed forth about 14 cubic kilometers of lava, nearly 1 cubic kilometer of ash, 8 million tons of hydrogen fluoride, and 120 million tons of sulfur dioxide, producing the "Laki haze" across Europe.  In Iceland, this is known as the "Mist Hardships," killing 20-25% of the population by famine and fluoride poisoning, 80% of the sheep, 50% of the cattle and horses. It is speculated that the eruption weakened the African and Indian monsoons, causing low flow on the nile and a famine in Egypt that killed 1/6 of the population. In Europe, the weather became hot through the summer of 1783, the winter was also severe, and the weather disruptions continued for several years. In North America, the winter of 1784 was miserable, with the Chesapeake freezing over at Annapolus, the Mississippi froze at New Orleans, and there was ice in the Gulf of Mexico. Benjamin Franklin made observations of the fogs in Europe and in North America and speculated that it was due to Hekla in Iceland, not knowing about the Laki eruption.

Assuming that the 120 million tons of SO2 in the 1783 eruption was degassed uniformly over 8 months, the rate averaged about 500,000 tons per day. Ignoring the 10% difference between metric tons (tonnes) and short tons, the Laki degassing was about 15 times as intense as the Bardarbunga. The last event similar to the current eruption began in 1975, the so-called Krafla fires, and lasted until 1975. Freysteinn Sigmundsson, a volcanologist at the University of Iceland and co-leader of the FUTUREVOLC project, suggests that the current eruption could continue for months or years if, as it appears, magma deep in the crust is being tapped.

1859 Solar Superstorm

"The Northern Lights"
Frederick Church, American painter
painted in the 1960's,
perhaps inspired by the 1859 superstorm

I had an earlier post on a the current solar activity in the context of a concern of Newt Gingrich who has made it a political issue. NASA has an interesting blurb today that lays out some of the concerns, and this blog is a summary of that article which puts "The Great Solar Superstorm of 1859" in perspective of the events of the last half of the 20th century.  It includes the following collage of events from past descriptions of superstorms:

"She ran screaming down the street, unable to contain her terror as night was turned into hideous crimson daylight…communications networks failed and equipment burst into flame…a bustling city lost power, trapping thousands of people inside elevators…satellites malfunctioned and in an instant millions of people lost touch with critical services, doctors and children."

From the NASA report cited. Based
on the work of Smart et al.

The 1859 superstorm lasted for 10 days, and is deemed one of the most spectacular solar storms in the past 450 years.  The basis for saying this comes from work by Michael Smart and colleagues who discovered that nitrate concentrations in trapped gases in the Greenland and Antarctic ice crystals rise and fall with solar activity. The graph to the right shows atmospheric nitrate (NOx) abundances from Galileo's time to the present, with the 1859 event highlighted in red.  The article calls attention to the time period during which the satellite industry has based their estimates of "worst case" scenarios: the last part of the 20th century in which there were only two major events, August 4, 1972 and March 1991.  In contrast, since 1561, there have been 19 events more intense than these two, with an average (though nonuniform) interval of 23 years. "The current 40-7ear-0eriod has been the least productive in generating large [events] as far back as 1670 during the Maunder Minimum.  If you wanted to build satellites that endure the rigors of the space environment, Cycle 23 [our last one] and some of the severe storms during the last 50 years, were probably the wrong examples to use as a 'tall pole' for how bad things can get." (I need to update my NASA jargonese, never heard the 'tall pole' analogy before; wonder if goes with their newly discovered sense of drama (the collage above, and sunspot description mentioned below!).


Nevertheless, during Cycle 23, there were satellite outages and losses totaling nearly $3 billion, and commercial satellites collectively lost about 3 years of lifespan at an estimated eventual cost of tens of billions in lost profit.  There were also several near-misses with US electrical grid blackouts.  Those in Quebec who remember the day that the power grid went down in March in Quebec, or those of us who are here in a deep freeze in the midwest this December shudder (literally) at the thought of a length power outage.


If Cycle 24 (the one we have now begun) were to have such a storm, it would be close to sunspot maximum, sometime between 2010 and 2012, likely in March or September during the Equinoxes. If astronomers notice a "large, angry-looking" sunspot (when did NASA start writing poetically?!!) crossing the solar meridian, time to look out.  It is predicted that all satellites on the daylight side of Earth would be blacked out by an intense blast of X-rays and energetic particles.  The X-rays would destroy the D-layer and cause shortwave blackouts; ozone would be depleted by 5-10% causing a spike in skin cancer events.  Auroras would dazzle us around the world. Computer systems on earth would crash as the integrity of their binary information systems is compromised.  Satellite losses and malfunctions would run up to $20 billion losses, Defense Department satellites would be blinded in some ways, and GPS systems would report inaccurately. This would affect precision navigation, oil drilling, search and rescue, and military targeting. 150 million people in north America would suffer a blackout without any precedent. Components of transformers for which there are no replacements would be damaged and have to be manufactured overseas.  The daily cost could be $30 billion in lost salaries, spoiled food, and closures--a larger scale example of the danger of global interconnectedness that the Icelandic volcano Eyjafjallajokull showed us earlier this year.

Eyjafjallajokull is Quieting Down

According to the Icelandic Meteorological Office, the activity at Eyjafjallajokull has diminished in a number of significant ways, although it is not clear whether this is "the end" or just a lull. The plume is "only" 10,000 feet high and is composed of steam only. There are no reports of ashfall, and no lightning strikes have been detected (lightning strikes indicate significant ash concentration). Meltwater from ice surrounding the volcano is small, temperatures from a heat camera are "almost 100 C". Volcanic tremor is decreasing to levels prior to the eruption, except in the frequency band 1-2 Hz which may be due to rising steam. I published a paper ages ago regarding seismicity of a very similar nature at Old Faithful, see Figure 1, reproduced here. It had been noted by scientists studying Karkar Volcano in Indonesia that there was banded harmonic tremor that suggested underground geyser eruptions, and the similarity of the two seismograms (Karkar and Old Faithful) is amazing.

You can get a higher resolution look at the figure by clicking on it, but it's not a high-quality image to start with! I look fondly at the low-quality reproduction of the seismic record (it isn't much better in the pdf of the original article). 1984--before PDF, WWW, and low-quality scanning to make the PDF. Young(er) geophysicists will be laughing--this seismogram was obtained by the now-lost-art of smoked drum seismographs. The art is to take the drum off the case, wrap it in special white paper, and then hold and rotate it over a smoking kerosene lamp. Since I had to do all of my seismic work in Yellowstone during the winter in 1976 (approximately when this record was obtained), we did all of the smoking in an unheated garage in Yellowstone. Kudos to my colleagues at the time, Rick Hutchinson (now deceased) and Gonzalo Mendoza!

Volcanic Mesocyclones and Lightning

Mount Pinatubo erupted in 1991. Nearly 20 years later, scientists made careful measurements of the position of the top of the eruption column, the "umbrella", and noted that it rotated (see Chakraborty, P., Gioia, G., and Kieffer, S., Volcanic Mesocyclones, Nature, 458, 497-500, 2010). The rotation induced an instability manifested as waves or lobes on the edge of the umbrella, as shown in the attached figure (from the Nature paper). The image shows a satellite view of the umbrella of Pinatubo. The graph shows rotation rate and growth rate of the umbrella.

The two sketches above show the outline of the edge at different times as documented by satellite photos, and the graphs in the lower left show measured rotation rates. Details are in the Nature paper.

By analogy with meteorologic cyclones, Chakraborty et al. called the eruption plume a "volcanic mesocyclone". Three key elements interact to produce tornadic structures such as dust devils and waterspouts: updraft in the center, downdraughts, and the rotating mesocyclone. Chakraborty et al. proposed that the mesocyclone pulls the ash radially outwards from the core of the updraught, gathering it in an outer sheath where it discharges to produce the spectacular lightning displays that can accompany volcanic eruptions. The color image shows such lightning in the current eruption of Eyjafjallajokull in Iceland. It was taken by Marco Fulle. The other image shows (a) waterspouts spawned during the eruption of Surtsey volcano on November 14, 1963, and (b) the lightning sheath from Mount Chaiten on May 3, 2008.

Contact me at s1kieffer@gmail.com if you would like a PDF of the Nature paper.