Volcano and earthquake activity in Iceland
Yesterday (29-August-2016) an magnitude 3,4 earthquake took place on Reykjanes Peninsula, this earthquake was felt due to how close it was to populated area.
Green star shows the location of the earthquake. Copyright of this image belongs to Icelandic Met Office.
No other earthquakes have followed this earthquake. Some minor earthquake happened before the main earthquake, no other activity has happened after the main earthquake.
This is not going to be a too long update about the activity in Katla volcano. Since I fear that this article might become outdated rather quickly.
Currently there is no eruption in Katla volcano. At the moment only earthquake activity has happened. Latest information shows that hydrothermal water has entered Múlakvísl glacier river from Mýrdalsjökull glacier and that is making the air nearby possibly toxic and dangerous. The two largest earthquakes had the magnitude of 4,5. One earthquake had the depth of 3,8 km while the one that happened 20 seconds later had the depth of 0,1 km. Other earthquakes had magnitude around 3,0 and above and below.
Green star show where earthquakes with magnitude above 3,0 took place in Katla volcano. Copyright of this image belongs to Iceland Met Office.
It is not know how and eruption starts in Katla volcano, since no historical recordings exist when last eruption took place in the year 1918. Making ideas on how an eruption in Katla volcano start mostly guesswork. Current earthquake activity is the strongest since 1977, in 1955 there was some strong earthquake activity but magnitude of those earthquakes is not known. It is my idea that Katla volcano erupts when a rift zone activity takes place in this area, since it is on the eastern volcano zone (EVZ) in Iceland, it is currently expanding south of Vestmanneyjar and American plate and Euroasian plate is around 1cm/year.
The main 4,5 earthquake in Katla volcano. This image clearly shows a long period earthquake. This is my station in Heklubyggð. This image is under CC Licence, please see CC Licence page for more details.
The main 4,5 earthquake as it appeared on my geophone in Böðvarshólar. The earthquake signal is clear. This image is under CC Licence, please see CC Licence page for more details.
It is difficult to know what happens now. The signs are not good, but Katla is an active volcano with regular eruption cycles so this is only matter of time now. As mentioned above, the reason is lack of data on how the eruption process starts in Katla volcano. All that can be done now is to wait and see what happens next.
This article is going to be updated in the next 24 hours if needed. Details are few at this moment.
A magnitude 3,6 earthquake (automatic magnitude estimate) has happened in Katla volcano. Few other earthquakes happened before the largest earthquake and few minor earthquakes took place after it. At the moment activity has dropped down (as it appears on my geophone) to nothing. That might change without warning.
Earthquake activity in Katla volcano. This image does not have the magnitude 3,6 (automatic magnitude estimate) in it. Copyright of this image belongs to Iceland Met Office.
At the moment no harmonic tremor has appeared on the SIL stations around Katla volcano. This means that eruption has not started. Until an harmonic tremor appears, this is just an earthquake activity.
This article is going to be updated if needed in few hours (around 16:00 GMT/UTC due to my current day plan).
Today (26-August-2016) a minor earthquake swarm started on TFZ. This is currently not a large earthquake swarm and only around 50 earthquakes have happened so far. More earthquakes might happen if this earthquake swarm continues.
The minor earthquake swarm is shown by the cluster of red dots. Copyright of this image belongs to Iceland Met Office.
This area has seen several earthquake swarm since July and is a high chance earthquake activity is going to continue in this area for the next few days to weeks. Earthquakes with magnitude above 3,0 cannot be ruled out.
Today (19-August-2016) a magnitude 3,5 earthquake took place in Katla volcano. It was followed by several earthquakes, both before the strongest earthquakes and after it.
The earthquake activity in Katla volcano. The green star shows the location of the magnitude 3,5 earthquake. Copyright of this image belongs to Iceland Met Office.
This doesn’t seems to be an activity connected directly to magma movements. This might however be a gas under pressure breaking rock, since clues this summer suggests that heat is now increasing in the caldera. At least for now, it might cool down again in coming months. The most common months for Katla volcano to erupt are from July until November, eruptions in other months are less common, they do happen every few hundred years.
The magnitude 3,5 earthquake as it appeared on my geophone in Heklubyggð. This image is under Creative Commons licence. Please see the CC Licence page (above) for more details.
Today (05-July-2016) at 05:56 UTC an magnitude 3,4 earthquake took place between Bárðarbunga and Grímsfjall volcanoes.
The green star is the magnitude 3,4 earthquake between Bárðarbunga and Grímsfjall volcano. Copyright of this image belongs to Iceland Met Office.
This earthquake suggests that an complication is on the way. The question here is if an interaction between Bárðarbunga volcano and Grímsfjall volcano is on the way. Since both volcanoes are preparing for an eruption. [Speculation!] All that I get from my models (in my mind, since I don’t have the computer power or the skills to make them PC friendly at the moment) is confusion. At worst a magma dyke from either Bárðarbunga volcano might enter Grímsfjall volcano or an dyke might come from Grímsfjall and enter Bárðarbunga volcano (hint: A result of either of such event is rather catastrophic eruption, even if just for a short time). What can also happen is nothing, just earthquakes and nothing more. However, increase in the earthquake activity at this location suggests that no such luck is on the way. When and if such event happens is impossible to know, what can be done is to keep monitoring, day and night. This is going to happen the when and the way it wants to happen, all that can be done as humans is to wait and see. [/Speculation!]
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Today (05-July-2016) an earthquake swarm took place far north of Kolbeinsey Island. Earthquake activity in this area of the ocean has been increasing over the past few months. It’s unclear what is going on at the moment.
The earthquake activity north of Kolbeinsey Island. Copyright of this image belongs to Iceland Met Office.
Largest earthquakes in this swarm had the magnitude around 2,9 – 3,4. Good magnitude estimate is not possible due to the distance from the SIL network. What exactly is going on at this location is unclear. I do not rule out any eruption activity at this location when earthquake swarms take place. This might also just be normal earthquake swarm without any eruption connection. The depth of the ocean at this location is around 3 – 5 km.
Today (30-June-2016) three earthquakes took place in the root system of Eyjafjallajökull volcano I think. The most depth for those earthquakes was 14,3 km and the most shallow one 1,3 km. The largest magnitude was 1,1 the other two earthquakes had the magnitude of 0,7. Nothing to worry about magnitude wise.
The earthquake activity close to Eyjafjallajökull volcano (three yellow dots). Copyright of this image belongs to Iceland Met Office.
Eyjafjallajökull volcano extends to this area, however at this area there are no surface craters. If there where they are long lost due to erosion. Unlike many other volcanoes, Eyjafjallajökull volcano does not have an extensive fissure swarm extending outwards for it, that should limit the path the magma can travel in theory. While I am not expecting any type of eruption from Eyjafjallajökull volcano in near future. If this earthquake activity continues I might have to review that outlook. I don’t expect this earthquake activity to continue, since next eruption in Eyjafjallajökull volcano won’t happen (based on my model) until the year 2199 at the earliest.
It is also question of this earthquake activity belongs to Vestmannaeyjar volcano system. Over the past few years deep earthquakes have been taking place there at regular time. Not many, just one or two at the time.
Few days ago an earthquake swarm started deep on the Reykjanes Ridge, this is as far as the Reykjanes ridge extends at the end of it. After that the north Atlantic ridge starts. It is close to impossible to know for sure what is going at this location, however the data suggests that an eruption is taking place there and it appears to be a big one. How big I don’t know and I’m not willing to guess it due to lack of data.
The earthquake activity has been interesting, with the largest earthquake having a magnitude 5,5 (EMSC info). Other earthquake magnitudes are 4,9 (EMSC info), magnitude 5,0 (EMSC Info), magnitude 4,9 (EMSC Info).
This earthquake activity is currently ongoing, since the distance from land is ~1100 km it is impossible to know for sure what is going on. There is also around 4 km deep ocean at this location. If an eruption is taking place at this location, it is not going to show in the surface of the ocean. I’m sure a lot of smaller earthquakes are taking place, they are just not being recorded by any seismic detecting network due to distance.
This is little short on details as of yet. There is clearly something going on in Bárðarbunga volcano. I don’t know what at the moment, several earthquakes have appeared, the strongest one with the magnitude of 4,0 so far. I’ll post more updates soon as I know more.
The earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Icelandic Met Office.
No volcanic harmonic tremor has been seen as of yet. That means no eruption for the moment.