Update Fri 19 Sep 17:12No significant changes have occurred at the ongoing fissure eruption in Holuhraun. The lava effusion rate seems to remain stable, according to IMO.
Subsidence, or slow caldera collapse, of the Bárdarbunga caldera continues at rates of approx. 50 cm per day.
Seismic activity remains elevated. The largest earthquake yesterday and today was a magnitude 5.3 event at 14:21 local time and a magnitude 4.7 this morning.
Irregular horizontal displacements of the crust revealed by GPS stations probably indicate that magma movements underground are changing, but it is impossible to predict what the consequences will be.
Scientists concluded from chemical analysis and modelling that the magma currently erupted has been coming from a storage area below 10 km depth. This is another indicator that the eruption could be a long one, as the reservoir that has been feeding it is likely to be a large one.
Eruption continues with little changes
Update Thu 18 Sep 21:32IMO reports that the eruption continues at similar intensity as during the past days. Fog prevented visual observations at the fissure eruption today.
The Bárdarbunga volcano's caldera continues to sink at a rate of approx. 50 cm per day. Earthquakes continue to occur at the northern caldera rim and - lesser and much smaller, below magnitude 2 - along the northern part of the dyke, mostly under the Dyngjujökull glacier.
The largest quake had a magnitude 5.3 at the northern rim of Bárðarbunga caldera at 14:22. This quake was associated with a drop of 15 - 20 cm of the caldera floor.
Continuing fissure eruption, caldera subsidence, seismic unrest and sulphuric gas emission
Update Thu 18 Sep 17:38Both the fissure eruption at Holuhraun and subsidence of the Bardarbunga caldera continue at similar rates as yesterday.
Seismic activity has however been rather intensive today with already 7 earthquakes larger than M 3.0 detected so far since midnight (local time) - the biggest of which was as strong as M 5.2 and occurred at 14h21 UTC. Smaller earthquakes also continue to shake up the ground along the Bardabunga caldera and the subsurface dike intrusion. GPS monitoring of the last few days shows irregularity in the crustal movements which could be a sign for a change in the magma movement under Bardarbunga.
The Icelandic Met Office considers the following two scenarios to be most likely:
-The eruption on Holuhraun declines gradually and subsidence of the Bardarbunga caldera stops.
- Large-scale subsidence of the Bardarbunga caldera occurs and results in either an eruption at the edge of the caldera or southwards lengthening of the now active Holuhraun eruptive fissure. Both scenarios would place active vents directly beneath the glacier and lead to significant melt water floods and the production of volcanic ash.
For now, however, the main warnings involve the migration of volcanic gasses rich in sulphuric acids from the eruption site towards the northern parts of Iceland. The Icelandic Met Office offers continuously updated maps of the prediction of such gas pollution and advises people that detect these gasses to stay indoors, close the windows, turn up the heat and switch of the air conditioning.
The main vent with 100-200m tall lava fountains feeding the large river of glowing hot lava. Photograph taken by Tom Pfeiffer on the 13th of September.
eruption and deformation of volcano's caldera continue
Update Wed 17 Sep 16:47The eruption at Holuhraun continues. According to the Icelandic Met Office, there are no signs of decreasing magma output. The lava flow field continues to spread.
At the Bárdarbunga caldera, subsidence of 50 cm / day continues. GPS measurements show irregular deformation patterns, but it is not completely clear what these mean except that the magma movements underground are probably changing their paths.
Seismic activity today and yesterday has been rather intensive, IMO wrote in its latest update:
"Yesterday 7 earthquakes larger then M3,0 were detected in Bardarbunga. The biggest were M5,4 and M4,8 last night. Smaller earthquakes were detected in Dyngjujokull glacier and in north part of the dyke."
Fissure eruption decreases, but seismic activity continues
Update Tue 16 Sep 16:25
The lava flow field at Holurhaun on 13 Sep
Lava fountain from Holuhraun on 13 Sep
We have posted sets of photos from our recent visit during 12-13 Sep.
Seismic activity continues at reduced rate, with a few 100 events detected daily, mainly below magnitude 3. Most of them have now been under the Bárðarbunga volcano caldera and the ring fault that has formed there, producing subsidence at a rate of approx. 50 cm per day. This process has been referred to as a slow caldera formation.
It has been one month since the seismic crisis at Bárðarbunga volcano started. So far, around 20.000 earthquakes have occurred since a month ago - compared to Iceland's normal yearly average of 12,000 earthquakes. More than 200 quakes had magnitudes larger than 3.
It is expected that the current rift episode continues in pulses for possibly months to even years. New fissures could open up, in particular once the Holuhraun fissure closes down and allows for pressure build-up. The risk of a subglacial eruption and associated floods and ash emissions remains high.
Pollution by SO2 in downwind areas in eastern Iceland has become a serious problem.
Holuhraun eruption and subsidence of Bardarbunga caldera continue
Update Sun 14 Sep 23:40
Lava fountains on the main fissure at the Holuhraun eruption this evening (Mila webcam)
The following is adapted from the most recent update of the Icelandic Met Office (IMO):
Earthquake activity has been stable compared to recent days. Approx. 140 events were detected since midnight (until 18:50 local time). The quakes concentrate in the northernmost part of the dyke intrusion, from the eruption site to about 6 km into Dyngjujökull glacier.
Earthquakes in the intrusion hardly exceed magnitude 2: as the magma has an open way to the surface now, no new fractures need to be broken, and earthquake activity has dropped as a result.
There are still several earthquakes located on the Bárðarbunga caldera rim, one of magnitude around 5 today at 14:06 on the northern rim, five of magnitude 3-4. A small series of events occurred around 17:00 close to Dreki (east of Askja), all events lower than magnitude 1.5.
Stable subsidence is seen on the GPS in the Bárðarbunga caldera, crudely 50-60 cm since midnight. A short step of 10-15 cm lowering might be associated with the 14:06 earthquake. (IMO)
Lava flows and subsidence at Bardarbunga caldera continue
Update Sat 13 Sep 15:10The eruption continues at similar levels as during the previous days. IMO estimates the volume of lava erupted so far to be at least 200 million cu m, and the surface covered by it 24.5 square km. The lava flows continue to travel eastwards into Jökulsá á Fjöllum river.
At the caldera of Bárðarbunga, subsidence continues at a speed of more than half a meter per day.
"Gas cloud from the eruption drifts to the east. High level of SO2, sulphur dioxide, was measured at Reyðarfjörður last night around 10:00 o'clock. The highest value measured were just under 4000 micrograms per cubic meter. These are the highest values measured in Iceland. High level, 685 micrograms per cubic meter, was also measured in Egilsstaðir." (IMO)
Photos of lava fountains
Update Fri 12 Sep 20:06
IMO reported that the lava erupted seems to be slightly less than the lava intruded at depth, as slight ongoing deformation revealed by GPS suggests.
Threat from eruption due to toxic gasses?
Update Fri 12 Sep 13:10The short answer is that most likely, the gasses released by this eruption will not present a big threat except in near downwind areas of the eruption.
For a more in-depth discussion of this topic, please have a look at this post on all-geo.org.
Eruption continues, satellite images
Update Fri 12 Sep 13:00No changes have occurred. The eruption continues at similar levels as during the past days. The flows are now more than 16 km long.
NASA Earth Observatory published satellite images showing the extent of the flows on 6 Sep:
Landsat-8 image of the area of the eruption (NASA)
Enlarged part of the image showing the active lava flows (NASA)
Eruption continues, small earthquake swarm under Tungnafellsjökull volcano
Update Thu 11 Sep 19:30The eruption at Holuhraun continues at similar intensity. It appears that the lava output is now balancing the magma influx at depth, most of which seems to be draining from the reservoir underneath the Bárdarbunga caldera, which reacts by subsidence.
Lava flows from the main fissure expand east and north. The main lava flow now follows the river bed of Jökulsá á Fjöllum, but no explosive activity due to the lava and river water interaction has been observed.
IMO warns of high concentrations of sulfuric gases that reach dangerous (even life-lethal) levels near the eruption site and are likely to affect the downwind areas including the northern part of the Eastern fjords, Fljótsdalur, Hérað, Jökuldalur, and Vopnafjörður.
Earthquake activity in the caldera of Bárðarbunga remains similar to that of the last days. Epicenters are distributed along the northern and south-eastern caldera fault. An earthquake of M 5.3 occurred at 00:07 h. Earthquake activity at the dyke tip has decreased. More than 30 events have been detected since midnight. Low frequency tremor is similar to what has been observed in the last few days. (IMO)
Earthquake swarm in Tungnafellsjökull
A smalll earthquake swarm has been occurring under the Tungnafellsjökull volcano located to the NW of Bárdarbunga since yesterday. According to scientists from the Iceland university we talked to today, this was likely a result of an intrusion from magma from Bárdarbunga which disturbed the other volcano's own volcanic system.
In a similar way, all surrounding volcanoes (including Askja, Kverkfjöll and Grimsvötn in particular) have been disturbed by the ongoing activity.
Updated map of the lava flows from the eruptive fissures (triangle) (IMO)
Earthquakes around Bárdarbunga today so far (IMO)
Update Thu 11 Sep 02:03The flight from Copenhague to Reykjavik took us approximately 100 km south of the Holuhraun eruption site, yet the red glow of the fountain(s?), a thin lava flow and the billowing eruption plume were clearly visible in the light of dusk.
Eruption continues with little changes
Update Wed 10 Sep 16:51No significant changes have occurred. The eruptive activity at Holuhraun continues at similar levels as during the previous days. Lava fountains were strong from the central vents on the main fissure this morning.
Adapted from IMO's latest status report:
Lava flows continue to travel east and north, where lava is flowing in the river bed of Jökulsá á Fjöllum. No explosive activity due to the lava and river water interaction has been observed, but steam rises from the lava.
The eruption is producing significant amounts of SO2 gas, dangerous for people if caught in the plume near the eruption site. Smell of sulfur has been reported as far as Norway.
Earthquake activity has continued to slow down. Only around 80 earthquakes have been recorded during the first half of the day. The largest two earthquakes, M 5.5 and M 4.9 occurred on the northern rim of Bárðarbunga caldera. Low frequency tremor is similar to what has been observed in the last few days.
GPS observations show insignificant crustal movements supporting the assumption that the amount of magma flowing into the dyke continues to be similar to the magma erupted to the surface.
Three scenarios are still considered most likely:
1 Subsidence of the Bárðarbunga caldera stops and the eruption on Holuhraun declines gradually.
2 Large-scale subsidence of the caldera occurs, prolonging or strengthening the eruption on Holuhraun. In this situation, it is likely that the eruptive fissure would lengthen southwards under Dyngjujökull, resulting in a jökulhlaup and an ash-producing eruption. It is also possible that eruptive fissures could develop in another location under the glacier.
3 Large-scale subsidence of the caldera occurs, causing an eruption at the edge of the caldera. Such an eruption would melt large quantities of ice, leading to a major jökulhlaup.
Other scenarios cannot be excluded
Eruption continues, earthquake swarm in Herðubreið
Update Tue 09 Sep 08:03The fissure eruption at Holuhraun continues, although it appears that only the main fissure is still producing lava fountains and flows, while the smaller fissures south of it became inactive and only emitted steam yesterday.
The intensity of the eruption, i.e. the average output of lava, seems to be stable. Lava flows have been reaching the waters of Jökulsá á Fjöllum river, without producing explosive activity, only steam. The lava flows now cover almost 20 square km.
Earthquake activity has decreased at the intrusion, but continues at the caldera of Bardarbunga volcano, which has been subsiding.
Another swarm is in progress north of Herðubreið, an impressive tuya volcano in the midst of the Ódáðahraun desert close to Askja volcano.
It is impossible to predict how the situation will evolve. Scenarios such as the propagation / opening of new fissures under the ice, potentially explosive subglacial eruptions at Bardarbunga and/or Askja volcanoes, or simply a gradual ceasing of activity are all realistic scenarios.
Lava fountains at the main fissure this morning (Mila webcam)
Earthquakes in the Vatnajökull area during the past days (IMO)
Update Mon 08 Sep 08:59Activity at the Holuhraun fissure eruption continues with little changes. The lava fountains from the main fissure seem even to have increased in strength again.
Eruption continuing with little changes
Update Sun 07 Sep 17:19
Lava fountains at the Holorhaun fissure eruption yesterday (image: Uni. Icelande / @uni_iceland / Twitter)
The eruption sites are the same as before. The eruptive intensity on the southern fissure that opened on Friday is much less than on the northern fissure that has been active since the beginning of the eruption.
The lava tongue now extends 11 km to the north and has reached the western main branch of Jökulsá á Fjöllum river. However, no explosive activity due to the lava and river water interaction has been observed, but steam rises from the lava. A white eruption cloud rises 3 - 4 km and is directed to the north and northeast.
Seismicity in the area is similar to yesterday. Around 140 earthquakes have been recorded since midnight. At 03:30 this morning, a magnitude 4.6 earthquake occurred at the rim of the Bárðarbunga caldera. Shortly after 07:00, a magnitude 5.4 earthquake occurred on the rim, one of the largest recorded since the start of the present activity. The amount of magma flow into the dyke seems to be similar to the magma erupting from the fissures."
Update Sun 07 Sep 09:17 / 09:51The eruption continues at similar levels as during the previous days. At the eruptive fissures, most lava emission in the form of lava fountains is now concentrated from the central vent on the main fissure.
Lava flows have reached the Jokulsa a Fjollum glacial river, where "steaming occurs" (IMO). It could include phratomagmatic explosive activity. Access to the area is strictly restricted and Iceland police has arrested several people who entered the area on their own, according to RUV.
Magnitude 5.7 earthquake
The intensity of the continuing seismic swarm has been decreasing, but continues both at the intrusion near the glacier's edge, under the Bárdarbunga caldera and NE of Askja. A magnitude 5.7 earthquake, one of the largest in the ongoing seismic crisis so far, occurred this morning under the northern caldera rim. Deformation as revealed by GPS measurements has slowed down considerably.
Earthquakes in the Vatnajökull area during the past days (IMO)
Map showing the subsidence measured at the Bárdarbunga caldera (IMO)
Eruption update, record subsidence detected in Bárdarbunga caldera
Update Sat 06 Sep 17:07
Updated map of the lava flows from the eruptive fissure and location of the new fissure that opened yesterday (triangle) (IMO)
Earthquakes around Bárdarbunga today so far (IMO)
Record subsidence in Bárðarbunga caldera
The ice-covered caldera of Bárðarbunga volcano has subsided by as much as 15 meters, an aerial radar survey of the ice surface yesterday showed. This is the largest ever measured subsidence in Iceland since precise deformation measurements have been done (approx. 60 years)!
The volume of subsidence in the caldera corresponds to a volume change of 0.25 km3. This volume likely corresponds to magma that has drained into the intrusion & erupting dyke to the NE.
There are no signs of eruption or increased geothermal activity in the Bárðarbunga caldera at the moment, but an eruption at the caldera can not be excluded as possible scenario for the near future.
Depressions in Dyngujökull glacier
In the surveillance flight yesterday a shallow, wide depression was observed on the surface of Dyngujökull, 10 km from the glacier edge. Another depression 6 km from the Dyngjujökull ice edge, which has been monitored over the last few days has deepened and is now 35 m deep.
It is likely that these depressions are sings of small and short sub glacial eruptions.
Seismic activity decreases
Seismic activity has decreased since yesterday. Approximately 90 earthquakes have been detected since midnight. One earthquake, of magnitude 5 was located in the Bárðarbunga caldera at 05:40 UTC. 14 earthquakes of magnitudes greater than 5 have been located since 16 of August.
Deformation changes since yesterday, measured with GPS north of Vatnajökull are small.
Update Sat 06 Sep 10:26Activity at the fissures continues at similar levels as yesterday. Civil Protection has again closed the area for all access.
Scientists from the University of Iceland who monitor the eruption posted an impressive picture of the newly formed graben in Holorhaun north of the glacier on their twitter site. The graben is being formed as magma intrudes into a fissure (dyke) beneath the surface. Chances it will erupt towards the surface in this and other locations (as it did at the active vents) are high. If this happens under the glacier, there is a high risk of potentially large floods.
The newly formed graben (image: Univ. of Iceland/Thor Thordarson / twitter)
View of the eruption this morning
Activity update - subglacial eruption expected
Update Fri 05 Sep 23:37
Activity at the main fissure this evening (Mila webcam)
One of the ice cauldrons in Dyngjujökull glacier this afternoon (Icelandic Civil Protection)
View of the new eruptive fissure north of the glacier (Icelandic Civil Protection)
The new fissures, first observed early this morning, are approx 1-2 km long and there are some indications that some activity could have started beneath the Dyngjujökull glacial ice (perhaps increased gas emissions only at the moment); the observed depression on the glacier have deepened - as a result of melting beneath, likely from new (eruptive?) fissures developing there.
The smell of rotten eggs (H2S gas) has been reported coming from the water of the Jökulsá á Fjöllum river, indicating contamination with volcanic gasses.
Civil Protection and IMO warn about toxic gasses released from the eruptive fissures, very dangerous if you are downwind: these include high concentrations of SO2, CO, CO2, fluorine gases and others. A steam plume is rising approx. 5 km above the eruption.
As of tonight, the lava flows have come within 1 km from the Jökulsá á Fjöllum river; once the lava meets the river, explosive interaction of lava and water will generate small to medium-sized explosive activity and produce ash plumes. However, the latter will be small compared to what is now expected to occur in the near future if an eruptive fissure opens under and the eruption breaks through the ice of the Dyngjujökull glacier.
Update Fri 05 Sep 21:26
Updated map of the lava flows and the location of the new eruptive fissures (triangle) (image: IMO)
"- The eruptive fire fountains from the new fissures are substantially smaller than in the older fissure. Steam and gas rises in a south eastern direction from the fissure.
- The cauldron in Dyngjujökull seems to have grown deeper since the last observation.
- No changes are visible in Bárðarbunga.
- Substantial amounts of SO2 are still being released to the atmosphere in association with the eruption.
- Conductivity measurements show a slight increase in conductivity in Jökulsá á Fjöllum.
- Some tremor was detected on seismometers shortly after 3:00 UTC last night. It decreased at about 6:00 UTC this morning.
- Considerable activity is in the northern fissure (fissure 1) and the height of the steam cloud is about 15,000 feet. There are no indications of the eruption in Holuhraun being in decline. The lava from fissure 1 continues to flow to the east north east and has grown in area since yesterday.
- Seismicity in the area is similar to yesterday's activity. About 170 earthquakes were detected since midnight. Two earthquakes of magnitudes 4,4 and 5,3 were detected in the Bárðarbunga caldera region at around midnight UTC.
- GPS displacements have continues to decrease and are now within uncertainty limits."
Eruption migrates towards glacier, new fissures open
Update Fri 05 Sep 11:06
The new fissures south of the previous eruption in Holuhraun. (Picture: Lara Omarsdottir/RUV)
Volcanologist Thorvaldur Thordarson said to the national televion that the eruption is changing and seems to be spreading towards the glacier, where already a graben (depression bounded by 2 parallel extension faults) ahd been observed during the previous days. Part of this structure is under the glacier.
Icelandic Civil Protection plans to undertake another surveillance flight to evaluate the situation. According to the news, the area around the Holuhraun eruption is now closed to all traffic.
Source: New fissures erupting in Holuhraun (RUV)
eruption continues, access restriction lifted
Update Fri 05 Sep 09:20The eruption continues with little changes.
Earthquake and deformation activity also continue, but on a decreasing trend. Two earthquakes of magnitude 4.3 and 5.2 occurred on the rim of the Bárðarbunga caldera during the night.
Civil Protection decided to lift the restrictions on traffic in the area for scientists and journalist with special permissions.
Webcam view of the eruption this morning (Mila webcam)
Depth vs time of earthquakes near Bárdarbunga over the past days
Deformation at Dyngjuhals (DYN GPS station, IMO)
Update Thu 04 Sep 22:21
The eruption at the Holorhaun fissure continues with little changes and at similar intensity as yesterday.
The ongoing eruption this evening (Mila webcam)
Map of the lava flows as of 4 Sep (image: Univ. Iceland / @uni_iceland /Twitter)
The northernmost vent along the fissure morning. (image: Þorbjörg Ágústsdóttir / @fencingtobba /Twitter)
Seismic activity has decreased, probably as a result of magma being able to be erupted with less obstacles. However, continuing deformation, although slower now than before, indicates that more magma is being intruded into the dike than what is erupted on the surface.
IMO estimates that by now 10-11 square km have been covered by the lava flows of an estimated total volume of 40-70 million cu meters.