Katla Reported To Be Melting Ice

A report from the Iceland Volcano and Earthquake Blog by Jon Frimann seems to suggest that Katla volcano in Iceland has been experiencing some ice melt and creating some jökulhlaups (glacier outburst floods). Jon suggests that a geologist who is close to the monitoring efforts on the volcano is recording harmonic tremor since April 28th, which suggests magma is on the move, and possibly making contact with the base of the glacier.

The months of April and May have so far been pretty quiet for the volcano when it comes to seismicity. While there have been many small earthquakes, they are few and far between. Tremor is not necessarily registered as an earthquake by seismometers, but is picked up by waveform monitors designed to listen to this type of tremor. Harmonic tremor typically denotes the movement of magma within a system, and is typically seen as a precursor to a potential eruption...

But then again, oftentimes (a recent figure from the USGS states something more like 90% of the time) harmonic tremor and magma intrusion doesn't lead to an eruption. Personally I would not go ringing the alarm bells yet on Katla volcano. If it was actually gearing up for an eruption, it is highly likely you would see many more rock fracturing earthquakes, followed by land swell indicated by GPS measurements. This would most likely take at least 1-2 weeks given the history of many Icelandic volcanoes, and would give us plenty of warning ahead of time.

Indeed, there has not been a recent eruption in Iceland that did not give off some fairly obvious warnings before the main event. The eruption of Eyjafjallajökull was preceded by GPS measurements that indicated the mountain was swelling outwardly, then harmonic tremor/volcanic quakes, ultimately resulting in the fissure eruption at Fimmvörduhals, and finally the main caldera eruption at the summit. Katla, despite its ongoing geothermal action, has not yet displayed the sequence of events that suggest an eruption is imminent.

Katla volcano will erupt in the future. Maybe even the very near future. But right now, I wouldn't hedge any bets on this being really soon. As the summer months warm Iceland, ice will most certainly melt, and it will be easier for geothermal heat to assist in this process. There will undoubtedly be adjustments to the earth's crust when the level of ice falls, and seismicity will probably pick up a little bit. For now, I (and I'm sure Jon Frimann) will be watching Katla a bit more closely. 

Katla Volcano Has Another Quake Swarm

Katla volcano in Iceland is having another quake swarm today, during what some say is supposed to be a quiet time geologically for Iceland, during the harsh Winter months. Seismicity is elevated today at the Mýrdalsjökull glacier, with some quakes even occurring at the neighboring Eyjafjallajökull volcano. Eleven tremblors struck within the Katla caldera within the last 24 hours. As I write this, the swarm is ongoing. Most of the quakes except for two were below 2.0 in magnitude, with the largest being a 2.5. Many smaller >1.0 quakes occurred.

This again is probable dike intrusion into Katla, which has seen elevated seismicity and geothermal activity since its very small eruptive event last year (which produced a glacier outburst flood, and caused minor damage to bridges and roads). 

Image from Iceland Met Office showing today's quakes at Katla/Mýrdalsjökull 

Katla has been seismically active for months, with most scientists expecting an eruption soon.When is impossible to say, however this will likely be larger than last time due to the amount of magma intruded into the system. Swarms have occurred at the volcano at least a few times in any given month since June of 2011, but so far has not resulted in a large eruptive event like its neighbor Eyjafjallajökull, who's eruption in April 2010 produced a large ash cloud, carried by the jet stream, and stranded millions of travelers in Europe as airliners were grounded due to ash concerns.

Europeans fear a repeat of this event should Katla erupt, however it is anyone's guess whether an ash cloud from Katla would even follow the same pattern. It is entirely possible that the ash cloud going go East, and give the United States East Coast a taste of the headaches that Europeans suffered. Or the ash could simply blow South, into the ocean, harming no one. In any case, Katla rumbles on, gearing up for its inevitable show. 

Another Quake Swarm At Katla And Whispers Of Impending eruption [UPDATED 3-5-2012]

Katla volcano has had over 16 quakes in the caldera area in the last 36 hours. 11 of these were in the last 12 hours as of this writing, with most a bit under mag 1.0, but some almost to a 1.9 magnitude. The largest eent was a 2.1 mag quake slightly outside the caldera. Harmonic tremor is also being detected at the volcano, again raising the specter of a Katla eruption. Whether or not it's going to be a small event like the 2011 minor eruption remains to be seen, but one thing is becoming abundantly clear. Katla is waking up, and it will erupt soon.

My guess based on constant observation of this volcano and reading Icelandic blogs and media reports is that Katla will likely have an eruption either this year, or sometime next year. As there are no instruments that can tell us the location of the magma in the chamber, or how much is being injected, it is very hard to tell, if not impossible to predict what will happen. If history is any guide, we might be expecting a very large eruption sometime soon. But then again, looking to history for apparent patterns in volcanic activity is something we humans do, even if it truly means nothing in reality.

A large Katla eruption has been expected after its neighbor blew up in 2010. Eyjafjallajökull has been characterized by some volcanologists as being slightly connected to Katla's magma chamber via a lateral dike-like structure. Historically speaking, each recorded eruption at Eyjafjallajökull was followed usually within months by a Katla eruption. But this sort of proves how historical "patterns" may not always be so. It has since been almost two whole years since Eyjafjallajökull erupted, and despite the tiny eruption from Katla (which may have been a result of left over magma from Eyjafjallajökull's eruption via the lateral dike I mentioned), Katla has remained restless, but non-eruptive as some people predicted.

Time will tell, but it's probably a good time to start really keeping a close eye on what's going on at Katla, especially for Iceland and Europe. Due to its location next to Eyjafjallajökull, it is quite possible that a large ash producing event from Katla would have very similar effects on the Eurozone that Eyjafjallajökull did when it exploded. This could easily cause more economic hardship to Europe, at probably the worst time to do so if it were to erupt rather soon.

I'm going to be keeping my eyes peeled on Katla this week, and if more activity occurs, you'll hear about it here!

*****UPDATE*****

Another swarm of quakes were recorded today at the Katla caldera. 4-5 quakes ranging from less than 1.0 to around 1.5 occurred within an hour period. Again, this is most likely more magma dike intrusion into the caldera system.

Katla Volcano Showing More Tremor

Katla volcano in Iceland has been showing more harmonic tremor pulses as well as minor earthquake swarms within the caldera. This has been typical of Katla for almost a year now ever since it's very minor eruption in mid 2011. Icelandic scientists are quite sure this is minor magma dike intrusion into the caldera system. Katla will erupt in the future, however when is anyone's guess, but it will be sooner rather than later.

The winter in Iceland usually calms geological processes while the ice accumulates, but during spring/summer, the massive amounts of ice start to disappear, making it easier for gases to escape and making the potential for volcanic activity a bit higher. Some scientists believe that melting glaciers on volcanoes can initiate a 'rebound' effect on volcanoes that were covered in ice, resulting in a volcano that is able to erupt more easily. The rebound effect can be seen in the USA's Great Lakes region, an area of former glaciation that is rising geologically very fast (around a couple of cm a year) after the ice sheet retreated following the last ice age. This leads scientists to assume that in Iceland, volcanic activity can actually be affected by the seasons. While this has not been 100% proven and made scientific cannon, it is a compelling theory. Scientists have long theorized that the continent of Greenland might be hiding 'suppressed' volcanoes under the vast plains of ice that make up most of the continent. Again, this has never been proven as the ice is far too thick for a geological readout.

But Katla doesn't seem to mind the ice and snow. Last year it had a minor subglacial eruption (or what is firmly believed to be one) that resulted in glacier outburst floods and damage to a bridge and road. This occurred despite the massive glacier on top, and has erupted before through many meters of ice. I'm not entirely sure Icelandic volcanoes are affected much by being capped with Ice. Grimsvotn volcano doesn't seem to mind the ice either.

The swarm today was particularly strong at Katla, with over 15 quakes within the last 24 hours, all under magnitude 1.5. but clustered very close to each other in the caldera. Check out the swarm below.

New Earthquake Swarm in Katla Volcano

Katla volcano in Iceland had a swarm of quakes within the caldera region today, with the largest magnitude hovering around 2.5. Quake swarms have been a common occurrence in the volcano since its small, but damaging eruption in 2011 where a glacial outburst flood (jokullhlaup) destroyed some public infrastructure (bridges).

Blogger Jon Frimann, who is typically the best direct source for Icelandic volcanic events, has been monitoring what he considers to be magma dike intrusion beneath Katla since this eruption. Katla volcano was expected to have a large eruption after the eruption of Eyjafjallajökull in 2010, but has since proven that attempting to predict volcanic eruptions of any kind is a foolish endeavor. Many Icelandic scientists have been quoted as saying, "It's not a matter of if, but when". We are on the "when" stage of an eruption for Katla now.

Katla has the potential of generating huge eruptions (of a probable VEI 3) if it was to get a large injection of magma into its chamber. Currently, it appears that if this is indeed magma dike intrusion (which is definitely a strong possibility with this volcano), the intrusion appears to be quite minor. It is probable that any eruption from Katla at this time may be very small, as larger magma intrusions generate much larger quakes.

However, if magma is able to create a solid and consistent channel to the surface, there is the possibility for a stronger eruption. Katla volcano is overlain by the Mýrdalsjökull glacier, many meters thick. So an eruption of Katla would likely be a repeat of the Eyjafjallajökull conditions where hot magma/lava hits glacial ice and creates a large and fine ash cloud. This of course waits to be seen.

Below is the tremor graph for today's quakes, showing both the location and timeline for the quakes.

Image copyright Iceland Met Office.

An earthquake swarm also occurred at the Hengill volcanic area, but this is mainly due to geothermal power development in the area. This is quite similar to the seismicity at the Clear Lake volcanic field in California, USA.

Tremors at Eyjafjallajökull and Katla (Iceland) Today

Several small quakes struck Eyjafjallajökull today, as the seismic swarm continued at Katla caldera in Iceland. Two small flank tremors and one at the summit hit Eyjafjallajökull within the last 12 hours. Numerous other small tremors have also continued under the Mýrdalsjökull glacier capping Katla's caldera system. Several volcano moitoring scientists, agencies, and bloggers have noted the unrest under Katla, and suspect that minor dike intrusion is occurring under the volcano.

The quakes and tremors under Eyjafjallajökull are small, but four have occurred within the last 12 hours. Numerous tremors can be seen under Katla. None of these quakes exceed magnitude 3.0.

In the case of Eyjafjallajökull, it is entirely possible these are not volcanic quakes, rather they could be structural adjustments to the volcano due to it having had a recent eruption (April 2010), and further settling of the volcano on the crust. GPS deformation charts are not available to look at at this time, so it is unclear if inflation or deflation is occurring. Looking at the Iceland Met Office website, all GPS data looks flat on all sites, so their equipment may not be functional at this time (I blame the weather). It will be interesting to keep an eye on, nonetheless.

Eyjafjallajökull caused havoc for air travel to and from Europe during its eruption that began in April of 2010. It was a fascinating eruption to watch, as it started out with a somewhat benign and beautiful fissure eruption on its NE flank (in an area known as Fimmvörðuháls) between the main summits of Eyjafjallajökull and Katla. This eruption lasted around a month, and became quite a tourist attraction, with a great webcam view for a time. After the cone ceased to erupt, there was a short lull in activity from the volcano, before it erupted suddenly and powerfully from its main summit caldera. The eruption was actually rather minor for an Iceland volcano, but due to prevailing winds, and the latitude of the eruption, Europe and Europe's airspace was choked with ash.

This resulted in a months long ban from air travel, while Europe and other parts of the world bemoaned Eyjafjallajökull and the severe inconvenience it brought upon them. Celebrities were stranded, industries were paralyzed, and in the end, Eyjafjallajökull caused billions of dollars to be lost due to economic damage.

Iceland volcanoes have a violent history. Some of its eruptions have been devastating on a global scale, especially the famed Laki fissure eruption that covered a large part of Iceland in volcanic basalt lava, and unleashed incredible amounts of sulphur dioxide into Earth atmosphere for years. This caused a worldwide famine, global cool down, and some say it was actually responsible for sparking the French Revolution! And eruptions from Hekla are famed for the terror they caused to ancient Vikings, who referred to it as "The doorway to Hell".

This has made any news about Iceland volcanoes hot topics for tabloid news, and the usual rabble like Fox or the BBC/Daily Mail. Eyjafjallajökull is NOT currently erupting, nor is it expected to again any time soon. However, volcanoes do have a habit of reminding us that they cannot be predicted in the first place, so vigilance is important with volcanoes, especially the ones that have erupted in historical time. So to be clear, there are NO eruptions currently going on in Iceland, and nothing is imminent. It looks like Katla might be reloading, as well as Grímsvötn (American name). But neither has erupted yet this year.

Possible Dike Intrusion at Katla Volcano, Iceland

Seismographs are recording a large amount of small quakes beneath the Mýrdalsjökull glacier in Katla's caldera in the past 48 hours. Over 20 small quakes have so far hit a concentrated area, which usually indicates slow dike intrusion under the volcano. Katla, next door to the now infamous Eyjafjallajökull volcano which caused massive transportation disruptions in April of 2010, is far larger and has been known to erupt with much more fury than Eyjafjallajökull.

Katla may have had a minor eruption earlier in 2011, when a glacial outburst flood (jökullhlaup) came suddenly and destroyed a small bridge with debris in a lahar-like surge. This was considered by some to be a small eruption, possibly preceding future stronger activity.

While many Icelandic volcanologists have expected Katla to blow shortly after Eyjafjallajökull, it has yet to occur. This new intrusion could be the start of more activity, but it will likely be small. It could be Katla might just have a few small eruptions rather than a large one, but it's anyone's guess at this time.

                                           

Image from Icelandic Meteorological Office website showing current quake swarm at Katla.

Katla has not had a major eruption in quite some time. Some of Katla's previous eruptions have been record setting events that produced some of the largest amounts of tephra and basaltic lava flows that Iceland has ever witnessed (except for of course the famed eruption of the Laki fissure system, credited for worldwide famine and the straw that broke the camel's back for France preceding the revolution). While Katla's future is highly uncertain, the only certain thing that can be said about it is that it is active, it will erupt again, and probably soon.

Other than this, speculation is always useless with Icelandic volcanoes. The media like BBC and DailyMail will no doubt hype this up tot he point people are hysterical... while those of us who know better will sit back and wait for the show with the knowledge that this is probably going to be a non event.