A. Iceland volcano: and you thought the last eruption was bad…
10 Apr 2012, The Telegraph, By Andy Hooper (Dr. Hooper is an assistant professor at Delft University of Technology)
On the second anniversary of the ash cloud that grounded Europe’s flights, Iceland is facing further volcanic havoc, warns Andy Hooper .
This month marks the second anniversary of the eruption of Eyjafjallajökull that left millions stranded across Europe, and cost airlines an estimated €150 million a day for six days. But alarmingly, there are signs of high activity beneath the much larger, neighbouring Katla caldera in Iceland – a possible sign of an impending eruption. This should prompt extensive high-level contingency planning across Europe, as Katla has the potential to be much more damaging than Eyjafjallajökull.
Since Iceland was settled in the ninth century, Katla has erupted on average every 60 years, but has not had a significant eruption since 1918. Ominously, eruptions of Eyjafjallajökull in 1821-23 and 1612 were followed within months by eruptions of Katla. Judged by the historical calendar, an eruption is overdue.
Last July, a flood of water burst from beneath the ice cap on top of Katla, washing away a bridge. This indicates that an extra pulse of heat reached the base of the ice. Since then, there have been erratic movements of the surface of the volcano, measured by precise GPS instruments, and bursts of high earthquake activity beneath Katla’s caldera. These observations imply that magma has risen to shallower depths.
Katla’s eruption in 1918 produced five times as much ash as the 2010 Eyjafjallajökull one. A major eruption could result in large parts of Iceland being flooded as snow and ice melted; significant poisoning of Icelandic agriculture; destruction of property; and, of course, the grounding of aircraft across Europe.
If enough material is ejected it could even have a cooling effect on the global climate for a few years. A precedent for that would be the 1783-84 eruption from the fissure of Laki, which is part of the same volcanic system, Grímsvötn, that erupted last year. This was a very large eruption of 15 cubic kilometres (3.6 cubic miles), compared to the fraction of a cubic kilometre ejected in 2010, and had a huge impact on the northern hemisphere, reducing temperatures by up to 3 C. This had catastrophic effects far beyond the shores of Iceland (where at least a fifth of the population died), with thousands of recorded deaths in Britain due to poisoning and extreme cold, and record low rainfall in North Africa.
Large eruptions such as this occur only every few hundred years on Iceland, but the potential for danger is significant. Even if deaths from famine are less likely today, a recent study of the potential effects of the air pollution caused by such an eruption estimates that it could lead to between 52,000 and 228,000 fatalities throughout Europe.
Meanwhile, nearby Hekla has erupted about once every 10 years in recent times, with the last being in 2000. Similarly, volcanoes beneath the largest ice cap, Vatnajökull, are entering a period of increased volcanic activity – the peak of a 140‑year cycle.
This trend is being exacerbated by climate change. Vatnajökull has lost an estimated 400 billion tonnes of ice since the end of the 19th century. This has reduced the pressure on the hot mantle material beneath the crust, leading to increased magma generation. At the end of the last ice age, this same effect led to eruption rates some 30 times higher than at present. The current rate of ice loss is much lower than then, but we can still expect the formation of extra magma equivalent to that which erupted from Eyjafjallajökull in 2010 every 10 years or so.
There is a question mark over whether and when all this extra magma will erupt, however. Studies indicate that the timelag between generation and eruption could be as much as a few hundred years. In the meantime, the shrinking of the ice cap also causes stress changes in the crust that can encourage, or discourage, capture of the magma on its way up, depending on the path it takes.
The scale of the chaos that an eruption could cause is difficult to estimate. Partly it would depend on which way the winds are blowing but also on the style, size and duration of the eruption. Perhaps surprisingly, the magnitude is less important than the type of eruption.
While the Eyjafjallajökull eruption was relatively small, it caused such havoc because the materials ejected had the perfect make-up to ground flights: fine ash was deposited high enough to remain airborne for days, affecting the airspace of continental Europe. An eruption of Katla is likely to have a similar explosive style, due to the interaction of the magma and the overlying ice cap – the heat of the magma causes the transformation of ice to steam, which expands and fragments the magma.
A key goal for scientists and aviation authorities must be to develop predictive capability as to the nature of forthcoming eruptions. We would then be able to construct better plans for dealing with the impact, including the threat to agriculture and air travel.
To this end, my group at Delft University of Technology is working with the University of Iceland and others to develop more accurate models of volcanic plumbing systems. Using GPS receivers, satellite-borne radar, and advanced algorithms, we have been able to track the movement of magma and create maps of magma storage.
Just as importantly, the risks associated with the largest Icelandic eruptions, such as that which occurred in 1783-84, need to be thoroughly assessed. Even though these events occur only every few hundred years, the potential for widespread loss of life means we need to be properly prepared.
[The 6 mile diameter caldera of Katla volcano has an ice cap cover with a depth of 660-2,300 ft. In the past 1,000 years, all three known eruptions of Eyjafjallajökull have triggered subsequent Katla eruptions. From Wikipedia]
B. Iceland volanco eruption could affect global environment
2 Dec 2011, The Telegraph, By Matthew Day
Scientists in Iceland have warned that one of the world’s largest volcanoes could soon erupt with such force that it could affect the global environment.
Monitoring devices on the massive Katla volcano, which has a crater 6.2 miles in diameter, have detected an unusual amount of activity prompting experts to issues warnings that Iceland could soon witness its biggest volcanic eruption in a 100 years.
“There have been more than 500 tremors in and around the caldera of Katla just in the last month [Nov 2011], which suggests the motion of magma. And that certainly suggests an eruption may be imminent,” Ford Cochran, National Geographic’s volcano exert on Iceland, told the BBC.
The volcano is also due a major eruption, having last blown its top in 1918.
A powerful eruption could have serious consequences for both Iceland and the world.
In 1783 an eruption on the volcanic system to which Katla belongs to killed one fifth of the Icelandic population and half the island’s livestock. It also managed to change the world’s climate. “Folks talk about a nuclear winter, this eruption generated enough sulphuric acid droplets that it made the atmosphere reflective, cooled the planet for an entire year or more and caused widespread famine in many places around the globe,” said Mr Cochran.
An eruption could also trigger significant flooding in Iceland as it would melt the huge glacier that now covers the volcano. But scientists also said that despite its increased activity Katla may remain dormant as predicting an eruption remains an inexact art.
Straddling two tectonic plates Iceland lies in one of the world’s most active volcanic areas.
In 2010 a huge cloud of ash dispersed by the Eyjafjallajokull volcano brought severe disruption to European air traffic.
C. Katla Volcano 10X or 100X Eyjafjallajokull
June 18, 2010, Modern Survival Blog, Submitted by: Ken
When Iceland’s Katla volcano erupts next, could it be 100 times as powerful as the recent Eyjafjallajokull eruption?
Maybe, yes. Hopefully not. Probably not, but, let me explain…
The current thinking and assumption is that Katla will possibly be as powerful as ten times that of the recent eruption of Eyjafjallajokull, which is a reasonable expectation given the fact that the 1918 Katla eruption was indeed almost ten times as powerful as Eyjafjallajokull.
Volcano explosiveness is ranked on a scale from 0 to 8 (Volcanic Explosivity Index – VEI), and each increase in number represents a ten times increase in explosiveness (logarithmic scale). The total volume of ejected material also known as ‘tephra‘ (the fragmental material, regardless of size, produced by volcanic eruption), as well as plume height are the most important criteria factored in to VEI.
The recent Eyjafjallajokull volcano eruption in Iceland was ranked on the low end of VEI 4 and released about 140 Million cubic meters of material , of which about 80 Million cubic meters went into the atmosphere by way of the ash plume. It affected aviation in the region for weeks, translating to global transportation issues of both human and cargo, and had a measurable negative economic impact.
Imagining the impact of a Katla eruption on a scale of ten times worse than Eyjafjallajokull is bad enough, but when considering an impact of one hundred times worse, one begins to cringe…
VEI 4 (ejects .1 – 1 Billion cubic meters of tephra, plume height 10 – 25 km)
VEI 5 (ejects 1 – 10 Billion cubic meters of tephra, plume height >25 km)
VEI 6 (ejects 10 – 100 Billion cubic meters of tephra, plume height >25 km)
The 1918 Katla eruption has been ranked VEI 4+ and VEI 5, ejected 700 Million cubic meters of material, was about ten times the explosive power as Eyjafjallajokull, and nearly comparable with the 1980 eruption of Mount St. Helens.
The fact is, the magma chamber beneath Katla is large enough to produce a VEI 6 eruption. The chamber has a volume of about 10 Billion cubic meters and the caldera has an area of about 42 square miles (108 square kilometers). The total volume within the magma chamber, if completely filled and ejected, could touch the bottom range of a VEI 6.
When Katla erupted in 934 AD, it produced one of the world’s largest known lava flows which amounted to 18 Billion cubic meters while also ejecting 5 Billion cubic meters of tephra. This put it solidly within VEI 5 and would certainly have been VEI 6 if some of the enormous amount of lava had ejected as tephra instead.
History often repeats itself
Whether Katla goes off as a VEI 4+, 5, or 6, it will have a significant impact on today’s world. Regardless of the scale, air travel will be severely impacted, particularly in Europe, which will ripple down through the economies of the world. Localities in the path of the ash plume will likely endure regional crop and livestock failure from ash fallout, as well as the threat of poisoning from inhalation.
History favors a probable VEI 4+, maybe VEI 5 type of event, however a VEI 6 worst case scenario will bring significant devastation in that it will be much wider spread. It will surely have a global impact as temperatures could drop enough to cause wide spread crop failures while our weather is effected from such a large volume of ash ejected into the stratosphere. Having said that, even a VEI 5 could also cause a world wide temperature drop depending on which end of the VEI ’5′ scale.
Katla historically erupts following the eruption of Eyjafjallajokull (which erupted 14-April and went on for 10 days). Katla’s volcanic eruptions have ranged in duration from 13 days to as long as 120 days, while the last three Katla eruptions have been between 20 and 28 days.
We will not know the answer to the question of 10x or 100x until it happens, but in the mean time, if I lived nearby, I would stock up with some extra food and water just in case the disruption is bad enough. We all know that it will happen, it could be tomorrow or months from now, but the clock is definitely ticking.
[End of post.]