Some Katla Volcano Q and A
July 22, 2010, Submitted by: Ken
Questions and Answers
I sometimes get some great questions and observations from our readers. Here are a few questions from Fred regarding the Katla volcano, which historically erupts following that of its neighbor, Eyjafjallajokull. I’ve answered them with my own opinion as an observer of the situation.
When Katla follows Eyjafjallajokull, is the time frame based on when Eyjafjallajokull erupts or when the eruption ceases ?
You can look at it either way.
Keep in mind that Katla has erupted many more times than Eyjafjallajokull. Katla has had 38 explosive eruptions as of 30 AD whereas Eyjafjallajokull has had only 4 explosive eruptions in that same time frame.
The interesting thing is that it appears not to be a coincidence that each of the four times that Eyjafjallajokull has erupted, Katla has followed very quickly (relatively speaking). Katla’s average time between eruption is 52 years. Eyjafjallajokull was 692, 209, and 189 years between eruptions.
Other than correlating the known year in which Eyjafjallajokull erupts and then Katla, the only specific month and day dates for Eyjafjallajokull are the following.
Eyjafjallajokull (1821)
START: 19-Dec-1821 STOP: 1-Jan-1823
383 day eruption
Katla (1823)
START: 26-Jun-1823 STOP: 23-Jul-1823
27 day eruption
Katla erupted 554 days (1.5 years) after the 1821 eruption of Eyjafjallajokull. You can also say that Katla erupted only 176 days after Eyjafjallajokull stopped.
We do know that Katla followed Eyjafjallajokull within one year of the other known Eyjafjallajokull eruptions (920 and 1612), but the month and day are not recorded for Eyjafjallajokull.
What is the time-frame relative to a Katla eruption as it pertains to Eyjafjallajokull?
Based on history, the longest time-frame was 1.5 years. So based on the 14-Apr-2010 eruption date of Eyjafjallajokull, that would put the Katla eruption to occur no later than October, 2011. It could also be as soon as tomorrow.
What would be the best indicator on an imminent eruption – if earthquake clusters , how many per min / hour / day ?
I believe that seismic activity and surface deformation are good indicators of an imminent eruption. When magma moves within the crust it usually is noticed by earthquakes or earthquake swarms. Although the presence of signature earthquakes may indicate magma movement, it doesn’t necessarily tell us how much magma is moving. It could be just a little, or it could be a lot. I’ve read articles that support this point of view and there are many factors to consider.
A tip-off would be a rapid change in what was considered normal activity. There is not a strict definition of an earthquake swarm that I know of because they are often different from each other. In the case of Katla over the past several months, based on my own observations I have calculated the average number of earthquakes to be around 2 per day, so we might say that normal activity right now is 2 earthquakes per day.
However, lately there have been as many as 5 to 10 in one day. If this activity were to continue at this pace or to increase in frequency of occurrence, I would venture to say that there is an earthquake swarm going on, many of which have been on the northwest side of the caldera, as of this post. I believe that Eyjafjallajokull was swarming with many more earthquakes leading up to its eruption.
If based on strength of seismic activity , what would be the tipoff ?
Another tip-off could be a larger magnitude earthquake than those that have been regularly occurring, or several of them. That is, above magnitude 3.0 in this case. Several higher magnitude quakes might indicate that something is very imminent.
Katla historically erupts following the eruption of Eyjafjallajokull (which first erupted April 14). Katla is about 10 times more powerful, and has the potential to cause worldwide disruption.
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Katla Eruption History
July 11, 2010, Submitted by: Ken
The average time between Katla eruptions since 80 BC is 52 years. The Icelandic volcano has pretty much followed this average time between eruptions except for a few instances, one of which extended 190 years leading to the eruption of 1150. However there is some controversy regarding an eruption in the year 1000 (which would have followed the ongoing average) in that the tephra / ash of that time was credited to a different volcano.
Two simple statistical observations why Katla could be ready to erupt once again…
- 92 years have ticked by since Katla’s last explosive eruption, nearly twice the average 52 years between historical eruptions. We are overdue in 2010.
- Eyjafjallajokull, Katla’s nearest neighbor volcano has erupted four times, while each eruption has occurred immediately preceding a Katla eruption. As you can see in the time-line above, it seems more than just coincidence that these two volcanoes have erupted together during the past 2,000 years.
Now that Eyjafjallajokull has erupted (14-Apr-2010), the clock is set and ticking for Katla (assuming history repeats itself). The Katla volcano, which hides beneath the Myrdalsjökull icecap, has the potential explosive power of perhaps up to ten times that of Eyjafjallajokull, and is currently awake with regular earthquakes popping underneath it.
There are additional and more scientific ways to predict the eruption (monitoring tremors and frequencies, earthquake swarms, GPS movements, expansion – contraction, etc..) however in this example, I thought I would simply look at history, knowing that it truly does often repeat itself.
So, why is any of this important? The Katla variety volcano is large enough to cause significant disruption in today’s modern society which depends on unobstructed air travel, and whose population lives on food that is grown on highly leveraged super-farms that in turn depend upon nature to provide adequate sunlight, weather, and temperatures to maintain their output. If Katla’s ash plume is large enough and explodes high enough, it could potentially cause great local damage while lowering global temperatures and blocking some percentage of sunlight from reaching the ground for a period of time. Are you prepared?
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Katla Volcano Caldera Earthquakes
July 9, 2010, Submitted by: Ken
Since 17-May-2010 until this post 9-July-2010, there have been approximately 96 earthquakes at the Katla volcano site within the region of the Myrdalsjokull glacier. Of the 96 earthquakes, 27 have been within the Katla caldera. The image shows the earthquake locations with respect to the past volcanic eruption sites of 1755, 1823, and 1918. There was also a suspected region of eruption during 1955 which never broke through the ice glacier. It is located on the eastern edge of the caldera.
As you can see, only a few of the earthquakes occur directly underneath a previous eruption location, while the majority occur around the perimeter, particularly the east-northeast perimeter. Several others are scattered in other locations within the caldera.
It is interesting to note that of the approximate 96 Katla earthquakes since 17-May, the majority have occurred just off of the northwest rim of the caldera as you can see in the image above.
Katla has been fickle during the past number of weeks in that there have been days when hardly an earthquake has appeared, while there have been other days that have been fairly active. There was one stretch of several weeks that was very quiet, while during the past several days there has been quite a lot of activity, much more than average since I’ve been watching this.
Katla historically erupts following the eruption of Eyjafjallajokull (which first erupted April 14). Katla is about 10 times more powerful, and has the potential to cause worldwide disruption.
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Katla Volcano 10X or 100X Eyjafjallajokull
June 18, 2010, 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.
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Katla Volcano 3 Earthquakes in Seconds
June 11, 2010, Submitted by: Ken
Friday, 11-June-2010, 07:03 this morning, an earthquake shook at the Katla volcano in Iceland.
10 seconds later, a slightly larger magnitude earthquake struck.
10 minutes later another earthquake trembled followed by yet a fourth earthquake hours later.
As I was writing this, a fifth earthquake just popped off!
Update: Now a sixth earthquake has gone off – this one though, way over on the western edge of the glacier area – lots of excitement today…
2nd Update: There goes number seven!
Having been monitoring the earthquakes at Katla since mid May, these seven earthquakes are the most in one day so far. This is just my observation as an interested independent amateur, and there is no evidence of swarming at this time (could this be the beginning of a swarm?), but it is interesting to note today’s occurrence. The situation would potentially warrant the term, swarm, if the number of earthquake occurrences continue at this pace or if it increases over the coming days, in my opinion.
Map source data captured from Icelandic Meteorological office – rolling 48 hour Seismicity map
(While tracking the Myrdalsjokull map and table, the Katla-specific earthquakes are differentiated by observing the map and longitude while ignoring those beyond approximately -19.45, which are over on Eyjafjallajokull)
We must keep our eyes on this potential disruptive volcano, Katla, that historically erupts following the eruption of Eyjafjallajokull (which first erupted April 14). Katla is about 10 times more powerful, and has the potential to cause worldwide disruption.
I’ve been keeping a map record of the Katla earthquake locations since 17-May. It is interesting to note the buildup of earthquakes on the East-Northeast rim area. Time will tell. Stay tuned…
Update, Saturday, 12-June
Apparently 3 additional earthquakes registered between yesterday and today as Katla remains shaky so far this morning as of 0730 Pacific Time. Then quiet for most of the day.
Update, Sunday, 13-June
Again, 3 additional earthquakes leading into this morning, although this time followed by a fourth – the past several days have certainly been the most active.
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