Wednesday, July 26, 2017

Katla Volcano Has Strong Quakes {UPDATED}

Katla volcano under the Myrdalsjökull glacier just had a magnitude 4.4 quake with many smaller tremors. This is the strongest quake at Katla in the latest unrest which has seen swarms occurring weekly. Katla is thought to be primed for an eruption at any time. Webcam views of Katla are not clear at this time due to fog, so it's impossible to see what is going on. Since this quake sequence just now occurred, it will take some time for Iceland Meteorological Office to give any statement.


Screenshot from Iceland Meteorological Office showing large quake swarm at Katla.


I will update this post as the sequence continues.

*****UPDATE 7/28/2017 *****

After a 3.0 magnitude quake at Katla, harmonic tremor (read: fluid movement and/or magma) is on the rise. You can track the tremor here: http://hraun.vedur.is/ja/Katla/ 
Tremor is continuing to rise and so far is not showing signs of stopping. This could very well lead to an eruption within hours (or days). Now is a good time to keep your eye on Katla, you can watch the webcam feed of it here (note, you may need to use an older browser such as Internet Explorer to view the cam feed as newer browsers have ceased to support Flash): http://www.livefromiceland.is/webcams/katla/ 



Large Earthquake Swarm In Iceland's Reykjanes Peninsula {UPDATED}

A large and somewhat powerful earthquake swarm is currently underway in Iceland's Reykjanes Peninsula in the area of the Krysuvik volcanic center. According to blogger Jon Frimann and the Icelandic Meteorological Office, this swarm is partly tectonic and magmatic in nature. At the time of this writing there have been 9 earthquakes above magnitude 3.0, with one 4.0 tremor so far in the sequence, and dozens of lower magnitude quakes.

Screenshot from en.vedur.is detailing current quake swarm at Rykjanes Peninsula.


Krysuvik volcano last erupted in 1340 CE, according to the Smithsonian Global Volcanism Program. It is unknown whether or not this could lead to an eruption. Reykjanes volcano however last erupted in 1926 CE, but this was a submarine eruption, not on the main island.

If this does end up as an eruptive event, it could put thousands of Icelanders at risk as the area is close to the towns of Volgar, and Grindavik. Previous eruptions of Krysuvik and Reykjanes have been fissure and flood basalt driven, which would mean that large lava flows and gas release would be the biggest hazards. It is still too early in the sequence to tell if this will end up being just a rumble, or develop into an eruption.


Google Earth screenshot showing satellite view and location of volcanic centers. The swarm is occurring between Reykjanes and Krisuvik volcanic centers. 


At current, the Icelandic Meteorological Office has not raised the alert level for the region, which might suggest that they are not anticipating this to develop into an eruption. This could change at any time based on how long this swarm continues for. Since the Krysuvik volcano has not erupted for around 700 years, it is more probable that this swarm is related to the Reykjanes system.

If anything further develops I will update this post.

*****UPDATE 7/27/2017*****


The vigorous quake swarm continues:
                                                  

Second picture is showing increased harmonic tremor which could indicate magma movement. 





Wednesday, June 21, 2017

Katla and Bardarbunga Rumble In Iceland

Katla volcano, and its neighbor Bardarbunga are putting on quite a seismic show in Iceland as of late. Weekly to monthly quakes above magnitude 3.0 have been occurring at both volcanoes, raising anxiety about if or when both of the giant volcanoes will blow. The 2010 eruption of Eyjafjallajökull still fresh in the memories of Europe, when it paralyzed national airports and cost billions to various economies.

Katla volcano is stealing the show today, with large earthquake sequences pulsing now almost daily (which is rather unusual behavior in recent times). It is probable that this is related to magma movement under the crust, and the depths of these quakes are getting shallower. Katla has long been thought 'overdue' for an eruption, although no volcano is ever truly 'overdue' as they do not have scheduled eruptions.


Screen capture from en.vedur.is - Iceland Met Office showing Katla earthquake activity

Katla is thought to be connected in some way to its neighbor Eyjafjallajökull via a magma sill, but the two magma chambers are considered separate. Historically (according to evidence) Katla typically erupts soon after Eyja. This has not occurred yet, although it is suspected a minor subglacial event took place in the year after Eyja's eruption, which was indicated by harmonic tremor and glacier outburst flooding. If there was an eruption, it did not breach the icecap.

Bardarbunga is also rapidly inflating, and has regular quakes within its caldera, and along the old fissure from the Holhuraun lava field eruption. During Bardarbunga's last eruption, the caldera floor dropped many meters, indicating magma chamber drainage via the fissure to its NNE. Current activity has resulted in weekly quakes within the caldera with one or two quakes over 3.0 per pulse. The depths of the quakes and continued deformation indicate that Bardarbunga is far from done with its currently active cycle. 


Screen capture from en.vedur.is - Iceland Met Office showing Vatnajökull earthquake activity

For now nothing seems imminent, but it is especially prudent to keep up with Katla at this time.