Magma – Page 77 – Iceland geology

January 21, 2014

Waiting for the eastern Skaftá glacier cauldron

The glacier flood in Skaftá glacier river is almost over or is over at present time (21-January-2014). This however does not mean that everything is over. Since there are two cauldrons in the Vatnajökull glacier in the Hamarinn volcano it means there is more water stored there now then has now flooded from the glacier. It is now clear that the eastern Skaftá glacier cauldron in Vatnajökull glacier has not emptied it self in this flood from the western Skaftá glacier cauldron.

The eastern (Eystri) and western (Vestari) cauldrons in Vatnajökull glacier. Copyright of this image belongs to Icelandic Meteorological Office.

When the eastern glacier cauldron empties it self they are expecting a lot larger glacier flood to take place. Since there is a lot more water holding up in the eastern Skaftá glacier cauldron. It is also longer since it flooded and emptied it self. Last glacier flood from the eastern Skaftá glacier cauldron was in the year 2010. More information on how this flood system works can be found here (in Icelandic) on Icelandic university website geology department.

January 19, 2014January 19, 2014

Glacier flood started in Skaftár glacier river

It was announced today (19-January-2014) that glacier flood has started in Skaftá glacier river (or connected rivers) from Skjaftár cauldrons in Vatnajökull glacier. Currently the water is discharging from Skaftár cauldrons at the rate of 370 m3/s according to Icelandic Meteorological Office. So far no changes have taken place in harmonic tremors close to Hamarinn volcano where the Skaftár cauldrons lie within Vatnajökull glacier.

Smell of hydrogen sulphide has been detected by people living close the rivers that the glacier flood is discharging into. There is a considerable risk of poisoning if people get to close the rivers that hold the flood water. It is currently believed that it is the western Skaftár cauldron that is now emptying, that one did empty it self back the in the year 2012. That is however not going to be confirmed until the area can be checked by flying over it and see what is taking place at this location. That might take few days since it is dependent on weather when it is possible to do such flight.

Location of Skaftár cauldrons in Vatnajökull glacier. Copyright of this image belongs to Icelandic Meteorological Office. Picture is taken from Icelandic Meteorological Office Facebook page.

The current flood in Skaftár glacier river. The water monitoring stations around Vatnajökull glacier. Red stations are monitored for floods, black ones are normal flow stations. Copyright of this image belongs to Icelandic Meteorological Office. Picture is taken from Icelandic Meteorological Office Facebook page.

Uncertainty level has been declared in the area do to this glacier flood by the Civil Protection and Emergency Management in Iceland. It is advised against people travelling in the area while this glacier flood takes place. On Vatnajökull glacier there is also a risk of new cracks forming in the glacier was the cauldron is emptied of water in the next few days. This cracks are dangerous and really deep and wide on the top, but get narrower closer to the end of them. It is possible to monitor the glacier flood here on Icelandic Meteorological Office website.

Icelandic news about this. Some English text is in some of the news. It is possible to use Google Translate on this, but result can be unreliable.

Skaftárhlaup er mjög líklega hafið (Rúv.is, maps, English text)
Skaftárhlaup hafið en það vex óvenju hægt (Rúv.is, Icelandic, maps)
Óvissustig vegna Skaftárhlaups (Rúv.is, Icelandic, maps)

Skaftárhlaup er hafið (mbl.is, English text)
Óvissustig vegna Skaftárhlaups (mbl.is, Icelandic)
Fundað um næstu skref (mbl.is, Icelandic)

Post updated at 20:34 UTC on 19-January-2014.

December 20, 2013

Earthquake activity in Esjufjöll and Kverkfjöll volcanoes

Earthquake activity started again in Esjufjöll volcano today (20-Desember-2013). The largest earthquake had the magnitude of 2,9 and had the depth of 5,0 km. So far only two earthquakes have been recorded, but it is not uncommon that earthquake activity in Esjufjöll volcano starts slow before it picks up. Earthquake activity remains low in Esjufjöll volcano, but there is now more earthquake activity in Esjufjöll volcano for the past few years then in past several decades (perhaps, recording is missing in the past)

Kverkfjöll volcano

Earthquake activity continued in Kverkfjöll volcano today. None of the earthquake did reach the magnitude of 3,0. The largest earthquake had the magnitude of 2,0 and the depth of 5,3 km.

Earthquake activity in Esjufjöll volcano and Kverkfjöll volcano. Copyright of this image belongs to Icelandic Meteorological Office.

I am expecting more earthquake activity in Kverkfjöll volcano. But I expect it to remain small as it currently is at least I do not expect any earthquake above the magnitude of 3,0 to take place as is.

November 27, 2013November 27, 2013

Harmonic tremor detected in Þórðarhyrna volcano

On the 21-November-2013 there was an earthquake swarm in Þórðarhyrna volcano (part of Grímsfjall volcano). This was not large earthquake swarm or a strong one. With the largest earthquake just having the magnitude of 1,9. While I did just suspect it I did not have it confirmed until today that following this earthquake swarm was an harmonic tremor pulse. This harmonic tremor lasted from 03:30 to 06:10 UTC. Based on nearby SIL station this was not a strong harmonic tremor, but this is important because it suggests that something is taking place in Þórðarhyrna volcano. If this is going to lead to an eruption is unknown at current time. This might be a dike intrusion into the volcano at depth, but that has not been confirmed.

The harmonic tremor pulse can be seen at 21-November date on this tremor plot from Icelandic Meteorological Office. Copyright of this image belongs to Icelandic Meteorological Office.

The harmonic tremor pulse as it did appear from Grímsfjall SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

Harmonic tremor pulse as it did appear on Jökulsel SIL station. Copyright of this image belongs to Icelandic Meteorological Office.

This activity might not lead to an eruption, but given the past history of this area and the eruption in Grímsfjall volcano in the spring of 2011 I find it to be highly likely outcome that eruption is going to take place in Þórðarhyrna volcano in near future, it is not possible to know when such eruption might take place. Last eruption took place in Þórðarhyrna volcano in the year 1902, it is not known if any later eruptions have taken place in Þórðarhyrna volcano.

Blog post updated at 14:47 UTC.

November 24, 2013November 24, 2013

Earthquake swarm in Tungnafellsjökull volcano

There is currently ongoing interesting earthquake swarm activity in Tungnafellsjökull volcano. This earthquake activity appears to be taking place due to magma injection at depth into the volcano. Currently the earthquake activity doesn’t appear so clearly on the Icelandic Meteorological Office earthquake maps. I am not sure why that is, the largest earthquake so far has had the magnitude of 2,3 at the depth of 0,5 km so activity is already rather shallow, deepest activity had the depth of 17,5 km. Earthquake activity started in Tungnafellsjökull volcano in the year 2012, before that earthquake activity had taken place in Tungnafellsjökull volcano following an eruption in Bárðarbunga / Grímsfjall volcano in the year 1996 [map here of Week 41 – 1996]. Current earthquake activity is not based on any such event.

Earthquake activity in Tungnafellsjökull volcano. Copyright of this image belongs to Icelandic Meteorological Office.

Tremor activity showing minor earthquakes taking place in Tungnafellsjökull volcano (most likely) over the past few hours. Copyright of this image belongs to Icelandic Meteorological Office.

I am not sure yet what is happening in Tungnafellsjökull volcano. But data in mounting and suggesting that magma is about to start flowing into the volcano at faster rates then before (via dike intrusions). Tungnafellsjökull volcano has not erupted in historical times (at least no eruption is documented) so it is impossible to know for sure what happens next in this volcano. If an eruption where to take place it would be mostly basalt based on post sub-glacier eruptions (when they erupted is not known). Current earthquake activity might die down as it did in the year 2012 when (and earlier this year [2013] also) this swarm like activity at depth (15+ km) started to happen.

Blog post updated at 04:36 UTC.
Blog post updated at 04:46 UTC.

November 21, 2013November 21, 2013

Minor earthquake swarm in Katla volcano

On the 20-November-2013 an minor earthquake swarm took place in Katla volcano, it started at 06:21 UTC and was over by 08:54 UTC. This earthquake swarm was minor one, with the largest earthquake having the magnitude of 1,2. The deepest earthquake had the depth of 26,1 km. That means this earthquake swarm was due to magma changes in Katla volcano at depth.

Earthquake swarm in Katla volcano. This was a minor earthquake swarm. Copyright of this image belongs to Icelandic Meteorological Office.

No further activity has taken place in Katla volcano following this earthquake swarm since it took place. Future activity cannot be ruled out since Katla volcano is highly active when it comes to earthquake activity.

November 17, 2013November 17, 2013

Minor earthquake swarm in south-east of Katla volcano

Today (17-November-2013) a minor earthquake swarm took place in Katla volcano at 06:21 UTC and it lasted to 07:09 UTC. The largest earthquake has the automatic magnitude of 1,8 with the depth of 18 km. This earthquake swarm took place under an former island in the area called Hjörleifshöfði (in Deutsch, English is not available). It is possible that this former island has it’s origin is in an volcano activity in the area, while I do not have it confirmed it is at least an idea. The deepest earthquake in this area had the depth around 22 km according to automatic results from Icelandic Meteorological Office.

131117_1815 — The earthquake activity in the east part of Katla volcano system. *Copyright of this image belongs to Icelandic Meteorological Office*.

Based on the depth of this earthquake swarm, the origin of this earthquake swarm was in magma movement or dike intrusion. It is not a tectonic activity, since such earthquakes are not so common in this part of Iceland, but they do happen. I am not sure what this means for activity in Katla volcano since I have not seen this before as it appeared now. This area of Iceland can be viewed in Google Maps and with Street View here.

October 13, 2013October 13, 2013

Earthquake swarm on the Reykjanes peninsula

Today at 01:11 UTC (13-October-2013) an earthquake swarm started on the Reykjanes peninsula. Early in this earthquake it was just minor earthquakes until 07:34 UTC an earthquake with magnitude 4,8 took place on the Reykjanes peninsula. Before the strongest earthquake took place, an magnitude 3,4 and 3,5 took place. Several earthquakes with magnitude above 3,0 took place following the main earthquake. The strongest earthquake was felt over an wide area, from Vík í Mýrdal to Hólmavík in north-west Iceland. Far as I know no damage did take place following this earthquake.

The earthquake swarm on the Reykjanes peninsula. Green stars mark earthquakes with magnitude above 3,0. Copyright of this image belongs to Icelandic Meteorological Office.

This earthquake did appear clearly on all of my geophone stations in Iceland. They can be viewed here.

The magnitude 4,8 earthquake on the Eyrarbakki geophone station. The earthquake signal is strongest on this geophone station and clearly tops the sensor it self, it can be seen how the signal goes above the maximum line on the geophone image. This image is released under Creative Commons licence. Please see CC Licence page for more details on this licence.

The magnitude 4,8 earthquake at Heklubyggð geophone station. This image is released under Creative Commons licence. Please see CC Licence page for more details on this licence.

The magnitude 4,8 earthquake at Böðvarshólar geophone station. This image is released under Creative Commons licence. Please see CC Licence page for more details on this licence.

The magnitude 4,8 earthquake at Skeiðflöt geophone station. The earthquake did appear clearly even if the noise level is high on that station. This image is released under Creative Commons licence. Please see CC Licence page for more details on this licence.

It is impossible to know for sure if this earthquake swarm is going to increase again. For the past few hours activity has been dropping, there is however nothing that says activity is not going to increase again. Such activity is common in this area, but it’s impossible to know for sure what happens next. At the moment there is nothing to suggest that volcano activity is the source of this activity. That might change but I think it is unlikely to be the case at the moment, regardless of what the future has in store.

October 11, 2013October 12, 2013

Source of the glacier flood in Hofsjökull volcano found

In August-2013 there was an glacier flood from Hofsjökull volcano, this glacier flood was minor and did not cause any damage. The source of this glacier flood has now been found according to Icelandic Meteorological Office. A new glacier cauldron has been found in Hofsjökull glacier, where none was before. The cauldron is around 700 meters long and about 30 – 50 meters deep. The glacier is cracked a lot around the cauldron and it’s dangerous to travel to this area because of that. The hight of this cauldron is around 1700 meters above sea level.

Hofsjökull volcano and glacier. The new glacier cauldron is located at ~64°49,5‘N; 18°52‘W. Click on the image for full resolution. Image from NASA/USGS/Icelandic Meteorological Office/Geological Department of University of Iceland (Jarðvísindastofnun Háskólans).

According to Icelandic Meteorological Office this part of the glacier has not had any glacier cauldrons before that they know of. This cauldron has the volume of 1 million cubic meters (10⁶ m³) according to Icelandic Meteorological Office. This area now has highly active hydro-thermal area and hot-springs. What formed this glacier cauldron is unclear at the moment, it was not an eruption since no such signals have been recorded from Hofsjökull volcano before or after the glacier flood in August-2013. It is also unclear if this glacier cauldron is going to create new glacier flood in the future.

Icelandic Meteorological Office announcement

Hlaup úr Hofsjökli í ágúst 2013 (vedur.is, in Icelandic)

Icelandic News

Fundu sigketil á Hofsjökli (mbl.is, Icelandic)

Blog post updated at 21:02 UTC on 11-October-2013.
Blog post updated at 01:45 UTC on 12-October-2013.

October 10, 2013October 11, 2013

Earthquake swarm in Eyjafjallajökull volcano

Today (10-October-2013) an minor earthquake swarm took place in Eyjafjallajökull volcano. This is the first earthquake swarm in Eyjafjallajökull volcano since the eruption stopped in May-2010 [link, Wikipedia]. This just appears to be an earthquake swarm, currently there are no signs of new magma getting into Eyjafjallajökull volcano. I am uncertain on what is creating this earthquake activity, but this might be old magma starting to move again or just stress changes in the volcano, the reason remains unclear as is. It is also important that this earthquake activity is minor, none of the earthquakes so far has reached the magnitude 2,0. The largest earthquake recorded had the magnitude 1,0 at 4,3 km depth.

Earthquake swarm in Eyjafjallajökull volcano today (10-October-2013). Copyright of this image belongs to Icelandic Meteorological Office.

There are no signs that any volcano activity is about to take place in Eyjafjallajökull volcano. So far it’s just earthquakes and nothing else. If this is old magma on the move there is a slight chance it might reach the surface via old transport tubes , such events would never be anything more than just minor explosion. It would not be anything like what happened in the year 2010. The only reason why this earthquakes are being detected today is because there is now a dense SIL network around Eyjafjallajökull volcano that measure it’s every earthquake and change that takes place. At the moment I doubt this is going to be anything like what happened in the 19th century eruption of Eyjafjallajökull volcano [link, wikipedia]. Currently there are no signs of such event is about to take place at current time. There are also no signs that show an imminent or possible eruption in Eyjafjallajökull volcano.

I do not expect anything more to happen in Eyjafjallajökull volcano. It might, but I am not expecting anything at this time of writing.

Blog post updated at 23:12 UTC on 10-October-2013.

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