Category Archives: Reykjanes Peninsula

Seismic and volcanic activity on the Reykjanes Peninsula.

Reykjanes Peninsula, Spain

Updates on Activity at Fagradalsfjall, Cumbre Vieja, and Askja as of October 2021

We are no longer updating this post; future updates will be included in new posts.

Update 2 12.10.2021: Plots of the Earthquake Swarm SSW of Mount Kelir, 27/09/2021 to Date

Fig 16: Mount Kelir, cropped from an image by Michal Klajban, published under CC BY-SA 4.0.  Source: Wikimedia Commons

Mount Kelir is at the northern end of the earthquake swarm which started on 22 February 2021. In that swarm, earthquakes started near Mount Kelir and migrated towards and beyond Fagradalsfjall prior to the eruption at Geldingadalir on 19 March 2021.

The current swarm which started on 27 September 2021 near Mount Kelir is ongoing at the time of writing.  Over 10,000 earthquakes have been recorded, of which IMO have confirmed c. 1,245.  It is thought that an eruption may ensue near Mount Kelir.

We have plotted the earthquakes and made a video of the geoscatter and scatter plots.

Fig 17:  Analysis of the swarm by depth and magnitude by the author.  © Copyright remains with the author; all rights reserved, 2021.
Fig 18:  Video of geoscatter plots and scatter plots of the current swarm by the author.  © Copyright remains with the author; all rights reserved, 2021.

Whether or not a new eruptive site emerges, magma migrates to the existing site at Fagradalsfjall, or, it all quietens down, only time will tell.  At the moment the swarm is migrating SSW. 

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Source for raw earthquake data:  Icelandic Met Office: IMO

12.10.2021 1: Update on La Palma Seismicity

Good Morning!

Let’s take look at status of the eruption and seismicity at La Palma.

The eruption is still going strong.  The cone has grown substantially, despite partial collapses.

Fig 11: Cone growth.  On the left, the new cone on 20 September, 2021, cropped from an image by Eduardo Robaina, published under CC BY-SA 3.0; on the right, screen shot earlier today from RTVC

The following was reported earlier today:

  • The lava reached the cement works, Callejón de la Gata, today.  Local residents were confined to their homes due to the risk of toxic fumes from burning chemicals.
  • A  large volume of lava was emitted after the wall of the lava lake [cone?] was destroyed.
  • The northern arm of the lava flow is now 300 metres from the sea and expected to make a new lava delta near the beach of Perdido.
  • 591.1 hectares have been affected by lava.  This includes 132 hectares of crops , of which 70 hectares were banana crops; 33 hectares vineyards; and, 8 hectares avocado crops.
  • The maximum width of the lava flow is 1,520 metres.
  • 1,281 buildings have been impacted, of which 1,186 have been destroyed.
  • The lava delta is now 34 hectares.
  • Seismicity remains high.  To  date, over 35,000 earthquakes have been recorded.  The most recent earthquakes remain below 10km, with depths reaching more than 20km.

The high level of seismicity is thought to indicate rising magma because there have been spasmodic tremors and a strong volcanic tremor at 18 Hz; the latter may be from depressurisation of magma at a depth of c. 10km.  In the absence of increased ground deformation, it is not known when or how magma may reach the surface.  If it reaches the surface, it may follow the current conduit or emerge at new fissures.

Fig 12:  Amplitude of seismic signal, source: IGN.  Green line denotes onset of the eruption.
Fig 13:  Seismic signal, source: IGN

We have updated our earthquake data and have plotted the swarm from 27 September 2021to present.  The results are shown in the video below.

Fig 14: Analysis of the earthquake swarm from 11 September 2021 to present by the author.  © Copyright remains with the author; all rights reserved, 2021.
Fig 15: Video showing geoscatter plots and scatter plots by the author of the swarm from 27/09/2021 to present

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources:

El Mundo: www.elmundo.es

VolcanoDiscovery:  www.volcanodiscovery.com

IGN: www.ign.es

04.10.2021: Update Fagradalsfjall Seismic Swarm near Kelir

The swarm near Mount Kelir is ongoing.  IMO report that 6.200 earthquakes have occurred in the swarm, although c.624 have been confirmed at the time of writing (Sources:  IMO_Earthquakes and  Skjálfta-Lísa (vedur.is)).

Fig 8: Geoscatter plot of the current swarm SSW Mount Kelir by the author. Colour denotes time (using earthquake number), red is the oldest and yellow the youngest.  © Copyright remains with the author; all rights reserved, 2021

We have analysed and plotted the swarm.  It would appear that the swarm is ascending but still in the crust. The largest earthquake with a magnitude of 4.16 had a depth of 5.669 km. 

Fig 9: Numerical analysis of the swarm by the author.  © Copyright remains with the author; all rights reserved, 2021.

The possible ascent of the swarm is more visible in the scatter plot looking at it in an easterly direction.

Fig 10: Scatter plot of the swarm by the author.  Colour denotes time (using earthquake number), red is the oldest and yellow the youngest. © Copyright remains with the author; all rights reserved, 2021.

04.10. 2021: Update on the Cumbre Vieja Eruption

Fig 6: Plot of earthquakes from 11/09/2021 to 04/10/2021 10:13:11 by the author.   © Copyright remains with the author; all rights reserved, 2021
  • Part of the main cone collapsed at c. 9:10 pm last night; some vents have now merged.
  • Effusive activity has increased.  Lava flows have merged; the flow is 1km wide at its widest point.
  • The lava delta is now 29.7 hectares.  This has impacted the surfing beach at Los Guirres.
  • 400 hectares of land has been covered by lava and 4,819 hectares covered by ash.  1,047 buildings have been damaged, including 947 destroyed.
  • 20% of the banana crop has been lost. The village  of La Bombilla, built for banana plantation workers, is now under threat.
  • The seismic swarm is ongoing, with most recent earthquakes between 7km  – 14km depth.

We have updated our earthquake plots for the most recent swarm (11/09/2021 to 04/10/2021 14:30:59).  The swarm reactivated on Day 17.

Fig 7: Earthquake  plots by the author for the swarm 11/09/2021 to present. © Copyright remains with the author; all rights reserved, 2021

Sources for updates as before: El Mundo and IGN.

01.10.2021 (original post)

Good Morning! Today we provide an update on Fagradalsfjall, Cumbre Vieja (with video of earthquake swarms) and Askja.

Fagradalsfjall, Iceland

Fig 1: Mount Kelir, cropped from an image by Michal Klajban, published under CC BY-SA 4.0.  Source: Wikimedia Commons

Fagradalsfjall celebrated the six-month anniversary of the start of the eruption, which occurred on 19 March 2021, by taking a break.  Low level activity has been observed since 18 September 2021.

An earthquake swarm stared on 27 September 2021 south of Mount Kelir.  This is located near the northern end of the earthquake swarms earlier this year which preceded the eruption at Geldingadalir.

We have plotted the swarm to see what is going on.

Fig 2a: Plots by the author of the earthquake swarm from 27/09/2021 to present. Geodensity plot on the left and geoscatter plot on the right.  The colour code in the geoscatter plot is time: red is the oldest, yellow the newest. Time is approximated by earthquake sequence.  © Copyright remains with the author; all rights reserved, 2021.
Fig 2b: Plots by the author of the earthquake swarm from 27/09/2021 to present. Scatter depth v longitude plot on the left and scatter depth v latitude plot on the right.  The colour code is time: red is the oldest, yellow the newest. Time is approximated by earthquake sequence.  © Copyright remains with the author; all rights reserved, 2021.

While it is not clear what the cause of the swarm is (new magma or the crust adjusting to changes in tension), people are advised to avoid the area for the time being.  If an eruption does occur near Kelir, it is expected to be similar to that at Fagradalsfjall.   The aviation code is still orange.

Cumbre Vieja, Canary Islands

Fig 3: Cumbre Vieja eruption on 20/09/2021, cropped from an image by Eduardo Robaina, published under CC BY-SA 3.0.  Source: Wikimedia Commons

The eruption is still going strong.  The vents have produced ash columns, jetting lava and effusive lava flows.

Lava reached the sea, following the opening of a new vent earlier this week, which emitted more effusive lava. The lava travelled at 300 m/hr, crossing the coastal road and cascading over 100m high cliffs at Los Guirres. The lava is forming a delta, which has reached an impressive size 21 hectares. 

There are now four eruptive vents: a new effusive vent opened 400m north of the main vent on Thursday; and, two more opened on Friday 15 metres apart and 600m north west of the main cone.  Lava from Thursday’s new vent also made it to the sea via a flow parallel to the original one.  A fumarolic field has developed on the north side of the main vent.

Over 80 million cubic metres of lava have been erupted.  Sadly, this has damaged 1,005 buildings, of which 870 have been destroyed.  30.2km of road has been impacted, of which 27.7km have been destroyed.  Ash now covers 3,172.9 hectares of land.

SO2 levels are higher but not considered a risk for the population at the moment.

Earthquakes are occurring near the area start of the swarm which preceded the eruption.  They are deeper than the earlier swarm leading to concern that lava may be fed from a deeper reservoir.   We have plotted the current swarm and previous swarms from 2017 to date. 

Fig 4: Plots by the author of the most recent earthquake activity at Cumbre Vieja.  For plotting purposes, the activity has been labelled as a new swarm, which started on 27 September 2021. Green circles are the current swarm earthquakes < 3.0M; red stars are current swarm earthquakes ≥3.0M; grey circles are earthquakes < 3.0M from 2017 to 26.09.2021; and cyan stars are earthquakes ≥3.0M from 2017 to 26.09.2019 (all are in fact from the previous swarm starting 11 September 2021).  © Copyright remains with the author; all rights reserved, 2021.

We have compiled a video of the earthquake swarms from 2017 to present.

Fig 5: Video by the author showing the progress of the earthquake swarms from 2017 to present. © Copyright remains with the author; all rights reserved, 2021.

Askja

Seismicity is still occurring.  The Icelandic authorities are continuing to monitor this.  The aviation code is still yellow. 

We have not had time to update our earthquake plots, but will do so in due course.

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021

Sources:

Plots are the authors own work.

Information and raw earthquake data:

Fagradalsfjall: Home-page – Icelandic Meteorological Office | Icelandic Meteorological office (vedur.is)

Cumbre Vieja: Instituto Geográfico Nacional (ign.es) & EL MUNDO – Diario online líder de información en español

Caribbean, Iceland, La Soufrière St. Vincent, Reykjanes Peninsula

Update on the eruptions at Fagradalsfjall and La Soufrière St Vincent, and status of Mount Pelée

Good Afternoon!

Fig 1: Image from Civil Protection / Webcam 11.05.2021

Fagradalsfjall

At the time of writing the eruption at Fagradalsfjall is not only continuing unabated but getting stronger.  After the opening of five new fissures, eruptive activity has focused on one crater, fissure 5. Lava now covers the Geldingadalur valley floor and threatens to engulf the first cones; lava has been flowing steadily into Meradalir since 24 April 2021.

Eruptive activity changed from continuous fountaining with effusive lava flows to periodic jetting after midnight on 2 May 2021. The change is thought to be due to degassing of the magma in the upper part of the eruption channel where a small chamber may have formed.  Each jet is now accompanied by strong gas emissions.  Lava flow, itself, is mostly being carried in lava channels under the crater rim, rather than ejected in the current jets so periodic jetting has not adversely impacted the output.

The onset of jetting can be seen in the tremor plots from local stations. We have included KRI because, being further away, we can see more of the lower frequency lines.

Fig 2: Tremor plots for KRI and MER showing the onset of jetting on 02 May 2021. Source: IMO
Fig 3: Unrest seen on seismometers near the eruption sites with pulses in volcanic activity from midnight on 2 May 2021.  Source: IMO
Fig 4: This image shows the unrest on days 8-9. May. Source:  IMO

Some stats as at 10 May 2021 (Source: Institute of Earth Sciences (hi.is))

  • Area of the Geldingadalsgos lava field: 1.78 Km2 (1.41Km2, 03 May 2021)
  • Volume of erupted lava: 30.7 million m3 (23.0 million m3, 03 May 2021)
  • Lava discharge rate: 12.9m3/s, (7.5m3/s, 03 May 2021)
  • Mg0: varies from 8.5 to 9.8
  • K20/Ti202 ratio: increasing from 0.1 to 0.3

In the first two weeks of the eruption lava flow decreased steadily from 7-8m3/s to 4-5m3/s.  In the second two weeks, five new fissures opened with lava flow varying between 5 – 8m3/s.  In the two weeks to 3 May 2021, one crater dominated with lava flow increasing.  In the week to 10 May 2021, there has been a large increase in the output of lava to 12.9m3/s; the lava field now covers an area of 1.78km2 with a volume of 30.7 million m3.  It is thought that the increase in output reflects changes in the lava channel from the mantle to the surface; it has widened over time.

Changes in chemical composition may mean that materials are mixing in the upper mantle before ascent or there is less partial mantle melt in the magma.  If the latter, the eruption will end when the mantle source is sufficiently reduced.

Geldingadalsgos is still a toddler compared to Holuhraun; Geldingadalsgos’ eruption rate is 5% – 10% of the average eruption rate at Holuhraun between September 2014 and February 2015. Let’s hope it stays that way as it is a lot closer to residential areas.

La Soufrière St. Vincent

The alert status was lowered to orange after a period of relative quiescence on 6 May 2021; only a few long period events and volcano-tectonic earthquakes are occurring each day.  People are allowed back into the orange zone but the red zone remains an exclusion zone.

The last explosive event was on 22 April 2021.  However, a possible lava spine was spotted on photos on 27 April 2021.  Tephra fills the crater, increasing the risk of pyroclastic flows should eruptive activity pick up again.  In the meantime, lahars are the main hazard.

Mount Pelée

Mount Pelée remains on alert level yellow.  Volcano tectonic events are occurring and seismic activity remains at above baseline level.  An area of brown and dead vegetation was confirmed on 8 February 2021 caused by diffuse CO2 emissions; the vegetation has not recovered.   The volcano is slowly reawakening.

Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources and Further Reading:

In the text and:

Iceland

Icelandic Met Office: https://en.vedur.is/ (English site)

Icelandic Met Office: https:// vedur.is/ (Icelandic site)

Reykjavik Grapevine: https://grapevine.is/

Department of Civil Protection and Emergency Management | Almannavarnir

La Soufrière St. Vincent

St Vincent and the Grenadines:  https://news784.com/

Barbados: https://www.nationnews.com/

Mt Pelée

Observatoire volcanologique et sismologique de Martinique (OVSM – IPGP): http://www.ipgp.fr/fr/ovsm/observatoire-volcanologique-sismologique-de-martinique-ovsm-ipgp

Iceland, Reykjanes Peninsula

New Fissures Open Near Geldingadalur, Fagradalsfjall, Iceland

Updated earthquake density video added (uses satellite image as background). 12.04.2021

Good Morning!

Geldingadalur – Where Are We at Now?

Since we last wrote, the new volcano at Geldingadalur has continued to erupt with a lava output rate between 5 m3 per second and 10 m3 per second, filling the Geldingadalur valley with more lava.  The University of Iceland has confirmed that the early lava erupted has a magnesium content of 8.5%, a low titanium dioxide content and is more depleted in rare earth elements (low HREE to LREE ratio) than earlier historic lavas, indicating that it is a more primitive lava sourced from the lithospheric mantle at a depth of between 17 km and 20 km.

On 5 April 2021 at around midday, a new fissure opened up about 700 m north east of the original eruption site.  The fissure, spotted by a sightseeing helicopter, was quickly confirmed by the RUV.is webcam monitoring Geldingadalur. Fortunately, no-one was in the vicinity at the time due to bad weather and sheer good luck; the site had been open to visitors at the time. The fissure is around 200 m long.  Lava from the fissure is flowing into the Meradalir valley. 

Fig 1: New fissure on 05.04.2021 in the foreground with lava flowing to Meradalir on the left of the image.  The original Geldingadalur eruption is on the right of the image.  Photo IMO.
Fig 2: Lava from the first new fissure entering Meradalir at 15:00 06.04.2021. The fissure itself is on the ridge in the background (Photograph: Public Protection/Björn Oddsson).

At around midnight on 6 April 2021, a second fissure opened up between the earlier fissure and the original eruption site.  This had been preceded by a landslip earlier in the day. Lava from this fissure is now flowing into both the Geldingadalur and Meradalir valleys, linking the eruption sites.  It is believed that the three eruption sites belong to the same fissure.

Fig 3:  Photograph from Public Protection/Björn Oddsson showing the three eruption sites and lava flows.
Fig 4: Map showing the location of the three eruption sites from IMO. The fissures are shown as red lines and dots; and, lava flows are based on photography.

Unfortunately, one of the webcams set up by mbl.is to monitor the Geldingadalur cones was lost; its last image is shown below.  We thank mbl.is for providing the webcam; we viewed its images with a lot of interest.

Fig 5: Screenshot from the mbl.is webcam.is set up to monitor the cones at Geldingadalur.  This may be this webcam’s last image. The lava flow to the lower left of the image is from the newest fissure. 

Like the original eruption site, neither fissure opening was heralded by an increase in seismicity in the immediate vicinity. 

Seismicity Post the Initial Eruption

We have updated our earthquake plots for the period 19.03.2021 to 06.04.2021.  We can confirm that there is very little earthquake activity in the vicinity of Geldingadalur.  The fissures are not giving any seismic warning; seismic activity near Keilir dominates.  It is perhaps surprising that magma has not made its way to the surface north east of Fagradalsfjall; does magma finds it easier to make its way through older fault-ridden Pleistocene rock that has not been covered in tougher historic lavas?

Fig 6: Earthquake density plot of the earthquake swarm post eruption (19.03.2021 20:45 to 06.04.2021) by the author. © Copyright remains with the author; all rights reserved, 2021.
Fig 7: Scatter plot of the earthquake swarm post eruption (19.03.2021 20:45 to 06.04.2021) by the author. © Copyright remains with the author; all rights reserved, 2021.

We have also tried our hand at making a video of the earthquake density plots by month from 2008 to 6 April 2021.  Months are numbered from January 2008 (Month 1) to April 2021 (Month 160, which only has 6 days).   If you make it all the way through, you will see that Fagradalsfjall has had several swarms, albeit much smaller than the current one. Enjoy!

Fig 9: Earthquake density plots by the author from Jan 2008 to April 2021. © Copyright remains with the author; all rights reserved, 2021.

As noted in earlier posts, for up-to-date advice and status, check out IMO or the Department for Civil Protection and Emergency, links below. 

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources: 

Icelandic Met Office: https://en.vedur.is/ (English site)

Icelandic Met Office: https:// vedur.is/ (Icelandic site)

Reykjavik Grapevine: https://grapevine.is/

Department of Civil Protection and Emergency Management | Almannavarnir

MBL webcams: Livestream of Fagradalsfjall Eruption  and New Webcam

Iceland, Reykjanes Peninsula

An Introduction to The New Volcano, Geldingadalur, Fagradalsfjall, Iceland

27 March 2021

Good Morning!

The eruption at Geldingalur, Reykjanes, Iceland, which started on 19.03.2021 at 20:25, is continuing unabated as I write.  The volcano is happily bubbling away building somewhat unstable but impressive looking cones and covering the Geldingadalur valley floor with lava.

Fig 1: Cones of Geldingadalur, cropped from an image by Berserkur, published under CC BY-SA 4.0

The eruption is steadily increasing at the time of writing; it has a lava output of 5 -7m3 per second.  IMO have estimated that the valley would fill enough for lava to overflow into the neighbouring valley, Meradalir, in a matter of days at the current eruption rates.

Fig 2: Image by IMO.  Expected path of the lava over the next few days at the current eruption rate.

Scientists at the University of Iceland are analysing the lava.  To date, they have reported that the lava is a primitive one (i.e. little magma evolution in the crust), indicative of a mantle source at a depth of 17 km to 20 km.  

Geological Setting

The Reykjanes Peninsula lies on oceanic crust created by the Mid Atlantic Ridge.  The Peninsula, itself, straddles the Ridge.  The crust here is 15 km thick, which is unusual so close to a spreading ridge.  However, Iceland is a basaltic plateau overriding a mantle plume. Both the mantle plume and the Mid Atlantic Ridge influence formation of the crust.  There are no magma chambers / reservoirs in the crust on the Peninsula; magma tends to ascend directly from the mantle. 

The Peninsula is made up of lava shields, móberg hills, table mountains and fissure-fed lava flows and crater rows.  The shield volcanoes on the Peninsula formed at the beginning of the Holocene between 10,000 and 7,000 years ago.  Shield volcanoes form from hot picrite or olivine tholeiitic basaltic lava flows with rates of c . 5m3 per second.  The móberg hills formed from submarine fissure eruptions and consist of pillow lavas, breccias and tuffs.  The table mountains were formed from subglacial activity, which had the activity not been constrained by the ice cap, would have resulted in shields.  Later Holocene activity has comprised effusive tholeiitic fissure eruptions which formed crater rows and produced large lava flows that now cover some of the earlier formations.  Historic activity has been between 940 AD and 1340 AD, including the Reykjanes Fires of 1210 AD to 1240 AD; and, the Krýsuvík Fires of 1151 AD to 1188 AD. 

Geldingadalur, itself, is a small valley to the south east of the summit of Fagradalsfjall, a 385m high hyaloclastite subglacial Pleistocene table mountain formed during the Weichselian glacial period, with a subaerial lava cap on its northwest part.  It is currently classified as part of the Krýsuvík Volcanic System.

The Fagradalsfjall area is seismically very active, with large earthquake swarms, notably in 1998, 2000, and 2004, and again now as part of the new volcano-tectonic episode on the Reykjanes Peninsula that started in December 2019.  Various studies from previous seismic activity have noted extensive faulting under the south west part of Fagradalsfjall; these faults strike N-S and NE -SW. In addition, there are two clusters of faults under the eastern part.

Earlier swarms in the current volcano-tectonic episode have resulted in magma intrusions, such as the one at Mt Þorbjörn which we discussed last year, but no eruption.  The latest earthquake swarm which started on 22 February 2021 is the only one to result in an eruption at the time of writing.

Seismicity in the Current Swarm

We have updated our plots for the Reykjanes Peninsula and dividing them between the run up to the eruption on 19 March 2021 at 20:45 and after the eruption to 26 March 2021 15:55.

The plots preceding the eruption repeat the ones shown earlier  so we are just showing the geodensity plot for comparison.  You will note that the earthquakes do not reach down to 15 km in the current swarm to date.  However, there were one or two deeper earthquake in some of the earlier episodes.

Fig 3: Geodensity plot by the author of earthquakes occurring between 63.83314°N, 22.55148°W and 63.96605°N, 21.85666°W from 22.02.2021 to 19.03.2021 20:45.  © Copyright remains with the author; all rights reserved, 2021.

The plots for the period after the onset of the eruption (19.03.2021 20:45 to 26.03.2021 15.55) show that activity is concentrated on Geldingadalur and two spots north east of Fagradalsjall.  Seismic activity has also extended further south.

Fig 4: Geodensity plot by the author of earthquakes occurring between 63.83314°N, 22.55148°W and 63.96605°N, 21.85666°W from 19.03.2021to 26.03.2021.  © Copyright remains with the author; all rights reserved, 2021.
Fig 5: Scatterplot by the author of earthquakes occurring between 63.83314°N, 22.55148°W and 63.96605°N, 21.85666°W from19.03.2021 to 26.03.2021 20:45. Colour denotes earthquake number since the onset of the eruption (red earliest; yellow latest).  © Copyright remains with the author; all rights reserved, 2021.

Whether the earthquake hotspots will lead to new eruption sites, only time will tell. 

For the current status, please consult IMO (link below).

If you wish to watch the eruption , there are local webcams. The link to one is given below.

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources:

Earthquake raw data: IMO:  https://en.vedur.is/

Status reports: https://en.vedur.is/

Webcam link

RÚV.is : Geldingadalur – Volcano (livefromiceland.is)

Iceland, Reykjanes Peninsula

Alert Level for the Krýsuvík Volcanic System Lowered to Orange; the eruption is contained in Geldingadalur for now

20.03.2021

Good Evening!

Fig 1: The eruption at Geldingalur earlier today, 20.03.2021.  Image from IMO.

For this update, our information comes from IMO and the Department for Civil Defence.  We will update our earthquake plots later on.

The eruption which started yesterday on a ridge in Geldingadalur has been assessed as a minor one, contained in the valley; the eruptive fissure is around 500m to 700m long; and, there is no ash or tephra.  Levels of S02 are low, except near the eruption site; gases can accumulate in the valley or other depressions. The main road to Keflavík from Reykjavík has been opened.  However, the road between Grindavík and Þorlákshöfn is closed.  The aviation code has been lowered to orange. 

The eruption may change without notice.  The Department of Civil Defence warn of the potential for new fissures opening either at the current site or elsewhere from the dyke near Fagradalsfjall.  Large earthquakes are considered unlikely at the eruption site but the risk for a magnitude 6.5 still remains for Brennisteinfjöll.  At the moment seismicity on the Reykjanes Peninsula is much reduced.

Fig 2: Map of earthquakes in the last 48 hours on the Reykjanes Peninsula by IMO.

Hazards for those visiting the site are getting too close to the lava flow and not being able to outrun any lava that breaks off it; the craters are unstable and may break, releasing a lava flow; and explosions where hot lava meets water-logged ground.  The Department of Civil Defence advises observers to keep to the hills surrounding the site.  Not that it is easy to get to without a helicopter!

Local webcams have been set up from which the rest of us can watch; one is:

https://www.livefromiceland.is/webcams/geldingadalur-volcano/

For up-to-date advice, please consult IMO or the Department for Civil Defence.

The Armchair Volcanologist

©Copyright remains with the author; all rights reserved, 2021.

Sources:

IMO: https://en.vedur.is/

Department for Civil Defence: https://www.almannavarnir.is/

Iceland, Reykjanes Peninsula

Krýsuvík Volcanic System, Aviation Code Red; A Volcanic Eruption Has Started Near Fagradalsfjall, Iceland

1 Comment

Good Evening,

19.03.2021

Fig 1: Eruption at at Geldingadalur. Image from IMO: A volcanic eruption has begun | News | Icelandic Meteorological office (vedur.is)

This was going to be a post with an update on the earthquake swarm on the Reykjanes Peninsula, but the magma beat me to it!  IMO has just confirmed that a volcanic eruption is underway near Fagradalsfjall at Geldingadalur.  The eruption started at 20:45 19.03.2021. It has been named as Geldingadalsgos, after the valley.  At the time of writing, the eruption is a small fissure eruption; the fissure is c. 0.5km long.

Fig 2: Hópsnes Lighthouse, Grindavik looking towards the Fagradalsfjall system.  Image cropped from one by Martin Morris, published under CC-BY-SA 2.0

The public have been  advised not under any circumstances go close to the eruption site or on Reykjanesbraut. First responders need to be able to drive freely to assess the situation. Scientists are working on assessing the eruption, the site and possibilities.

People living nearby in Þorlákshöfn have been instructed to stay indoors, close windows and turn up their heating to avoid exposure to any volcanic gases.  The Reykjanesbraut has been closed – the main road from the capital region to Reykjanesbær and the international airport at Keflavík.

Fig 3: Aviation code red; source IMO.
Fig 4: IMO’s confirmation of the eruption (third warning down). This is an extract from a screenshot of the page.

Here are the updated earthquake plots by the author, anyway.  The raw earthquake data has been obtained from IMO; this is confirmed earthquakes to date (19.03.2021 15:00). IMO’s page above gives the more recent earthquakes.

What we see from the plots is that seismic activity has now extended beyond Reykjanes to the west and the swarm is still active.  Activity in the swarm is densest to the NE and SW of Fagradalsfjall.   The depth plot shows that earthquakes in the swarm are tending to be smaller and shallower.

Extension of the swarm to the west is in keeping with the swarms which have occurred since December 2019. 

Fig 5: Geoscatter plot of the earthquake swarm by the author from 22.02.2021 to 19.03.2021 (15:00).  Colour indicates earthquake number from 22.02.2021. © Copyright remains with the author; all rights reserved, 2021.
Fig 6: Geodensity plot of the swarm between Svartsengi and Krýsuvík. by the author from 22.02.2021 to 19.03.2021 (15:00).  © Copyright remains with the author; all rights reserved, 2021.
Fig 7: Scatter plot of the earthquake swarm by the author from 22.02.2021 to 19.03.2021 (15:00).  Colour indicates earthquake number from 22.02.2021. © Copyright remains with the author; all rights reserved, 2021.
Fig 8: Scatter plot of earthquake depth v time (earthquake number in the swarm) by the author from 22.02.2021 to 19.03.2021 (15:00).  © Copyright remains with the author; all rights reserved, 2021.

Let’s hope that this is a “tourist eruption”; our thoughts are with anyone affected by this eruption.

For more up to date information, please consult IMO or the Department for Civil Protection.

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources:

Plots by the author.

Source for raw earthquake data: IMO

Icelandic Meteorological Office – IMO (@Vedurstofan) / Twitter

Department of Civil Protection and Emergency Management | Almannavarnir

Iceland, Reykjanes Peninsula

Aviation Alert Level for The Krýsuvík Volcanic System raised to Orange

3 March 2021 (Updated 07.03.2021 – new plots added).

The earthquake swarm which started on 24 February 2021 between Kleifarvatn and Svartsengi on the Reykjanes Peninsula is continuing.

This image has an empty alt attribute; its file name is capture-keilir.png
Fig 1: Keilir.  Image cropped from one taken by Michal Klajban, published under CC BY-SA 4.0.  Keilir is the dark cone in the background; Spákonuvatn lake is in the foreground.

IMO have raised the aviation code for Krýsuvík to Orange and report a tremor pulse south of Keilir.  At the time of writing, no eruption has been confirmed; however, visibility of the area is hampered by weather.

Fig 2: Drumplot showing the onset of the tremor pulse.  Source: IMO.

If magma does reach the surface, the most likely scenario is a fissure eruption, which would produce effusive basaltic lava flows and toxic gases, rather than an explosive ashy eruption.  If lava meets a significant amount of water, some tephra may be produced.

The likely impact from any eruption is expected to be disruption of air traffic and also road traffic access to and from Keflavík International Airport, if lava flows cross the access road.

Keilir, itself, is a subglacial mound near Krýsuvík formed during the Pleistocene during a fissure eruption.  The mound is built of tephra formed when melting ice met magma, topped by lava. Fagradalsfjall, another location associated with the earthquake swarm, is a Pleistocene table-mountain.  As lava prefers to take the easy route out, it is unlikely to emerge via these two volcanoes whose lavas would be fairly solid – hence the expectation of a new fissure swarm.

Fig 3: Current aviation codes for Iceland.  Source: IMO.

For status updates, please consult IMO.

A local news service that is also providing updates in English is the Reykjavik Grapevine.

Life is not easy for the research scientists monitoring events.  Two had to be rescued after having been separated from the main party while studying gas emissions.  Spare a thought for the risks they take. 

The public have been advised to stay clear of the area at least until it is known where and how lava emerges and where it would be safe to observe the eruption.

In our excitement at the thought of a possible eruption we overlooked the very real risk of larger earthquakes, if the intensity of the swarm continues: up to 6.0 M near Fagradalsfjall and up to 6.5 M in the Brennisteinfjöll range. Be careful if you are in the area.

Update 05.03.2021 23:29

We have plotted the earthquakes with a quality of 99.0 from IMO’s page showing the earthquakes for the last 48 hours for the Reykjanes Peninsula for the period 2 March 2021 to 5 March 2021 (23:29) (we were too slow to capture 1 March 2021).  Here are the results.  Colour coding in the scatter plots is by day and size reflects magnitude.  The geodensity plot is weighted by magnitude.

Fig 4: Geoscatter plot by the author of the earthquake swarm on the Reykjanes Peninsula for the period 2 March 2021 to 5 March 2021 (23:29).© Copyright remains with the author; all rights reserved, 2021.
Fig 5: Depth scatterplot by the author of the earthquake swarm on the Reykjanes Peninsula for the period 2 March 2021 to 5 March 2021 (23:29). © Copyright remains with the author; all rights reserved, 2021.
Fig 6:  Geodensity plot by the author of the earthquake swarm on the Reykjanes Peninsula for the period 2 March 2021 to 5 March 2021 (23:29). © Copyright remains with the author; all rights reserved, 2021.

Update 07.03.2021

Here are plots for the entire swarm from 24.03.2021 to 07.03.2021

Fig 7: Geodensity and geoscatter plots by the author of the earthquake swarm from 24/02/2021 to 07/03.2021. © Copyright remains with the author; all rights reserved, 2021.
Fig 8: Scatter plots by the author of the earthquake swarm from 24/02/2021 to 07/03/2021. © Copyright remains with the author; all rights reserved, 2021.

As noted above, for the latest status please consult the experts: IMO.

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021,

Sources:

Icelandic Met Office: https://en.vedur.is/

IMO: Aviation colour code map

Reykjavik Grapevine: https://grapevine.is/

Iceland, Reykjanes Peninsula

Seismic Activity on the Reykjanes Peninsula

1 Comment

28 February 2021 (updated 2 March 2021 with the addition of earthquake plots showing rifting / dike formation)

Good Evening!

A large earthquake swarm started on 24 February 2021 on the Reykjanes Peninsula in the vicinity of the Krýsuvík volcanic system between Kleifarvatn and Svartsengi.  At the time of writing the swarm is still ongoing with over 7,200 earthquakes record by Iceland’s SIL system.  Three earthquakes of 5.0M or more have been recorded: 5.7M and 5.0M on 24 February and a 5.2 on 27 February 2021. 

The alert level for the Krýsuvík volcanic system has been raised to yellow following sightings of steam jets in geothermal areas in the region after the 5.7M and 5.0M.

The Icelandic Met Office have attributed this swarm to the recent re-awakening of volcano-tectonic activity on the Peninsula.

We downloaded the confirmed earthquakes from IMO’s site to take a look. We plotted earthquake density for Week 8, 2021, earthquake locations for February 2021 and earthquakes by month from January 2009 to February 2021.

From our plots we can see the awakening of the volcano-tectonic activity with the upkick in number of earthquakes from December 2019.  The current swarm is part of this activity.

Fig 1: Geodensity plot by the author of the earthquakes occurring on the Reykjanes Peninsula for Week 8 2021.  The locations of the earthquakes of 5.0M and more are shown by black stars. Blue triangles denote volcanoes.  © Copyright remains with the author; all rights reserved, 2021.
Fig 2: Earthquake plot by the author of earthquakes occurring on the Reykjanes Peninsula in February 2021. Yellow stars denote earthquakes over 3.0M, orange stars over 4.0M and red stars over 5.0M. Blue triangles denote volcanoes.  The rectangle shows the area plotted.  © Copyright remains with the author; all rights reserved, 2021.
Fig 3: Plot by the author of number of earthquakes by month occurring on the Reykjanes Peninsula from January 2009 to February 2021.  © Copyright remains with the author; all rights reserved, 2021.
Fig 4: Geodensity plot by the author of earthquakes on the Reykjanes Peninsula between 1 December 2019 and 28 February 2021. © Copyright remains with the author; all rights reserved, 2021.

At the time of writing, it is not possible to predict whether or not this activity will result in a local eruption in the near future.  Only time will tell.

Update 1 & 2 /03/2021

Since writing the swarm has continued, with more than 15,000 earthquakes since it began last week.

The Department for Civil Protection has advised on 1 March 2021, that satellite images show deformation in the area has increased more than expected, indicating possible magma inflow.

We can see from the local GPS stations that there has been significant uplift near Krýsuvík.

Fig 5: Composite GPS plots for KRI, SENG and THOB.

We have also produced scatter plots by day for the swarm in week 8, 2021 which show possible rifting or dike formation.

Fig 6: Lat v Lon Scatter plot by the author of earthquakes in the swarm in week 8, 2021 on the Reykjanes Peninsula.  Red is day 1 (22/02/2021) yellow is day 7 (28/02/2021).  © Copyright remains with the author; all rights reserved, 2021.
Fig 7: Depth v Lon Scatter plot by the author of earthquakes in the swarm in week 8, 2021 on the Reykjanes Peninsula.  Red is day 1 (22/02/2021) yellow is day 7 (28/02/2021).  © Copyright remains with the author; all rights reserved, 2021.
Fig 8: Depth v Lat Scatter plot by the author of earthquakes in the swarm in week 8, 2021 on the Reykjanes Peninsula.  Red is day 1 (22/02/2021) yellow is day 7 (28/02/2021).  © Copyright remains with the author; all rights reserved, 2021.

IMO are updating the list of earthquakes for week 8, 2021, at the time of writing. For up-to-date information, please consult IMO.

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2021.

Sources:

Raw earthquake data and status: the Icelandic Meteorological Office:  www.en.vedur.is

Department of Civil Protection and Emergency Management | Almannavarnir

GPS: http://gps.vedur.is/mapGPS.php

Grímsvötn, Iceland, Mýrdalsjökull Region, Reykjanes Peninsula, Tjornes Fracture Zone, Vatnajökull Region

A Quick Look at Iceland: Total Earthquakes by Year 2009 to 23 October 2020

Good Morning!

While we are waiting to see if there is any volcanic activity at Grímsvötn or her neighbours, let’s take a look at how the current seismic activity in Iceland compares to previous years. 

Our database, comprised of earthquake data downloaded from IMO (see Sources below), now goes back to 29 December 2008 and extends to 23 October 2020, although we may reupload the last week soon because IMO may have been in the process of updating the record when we downloaded the data. 

Fig 1: Iceland: Total Earthquakes by Year and Magnitude by the author, using data downloaded from IMO (see Sources below).  © Copyright remains with the author; all rights reserved, 2020.

From our graph, we can see that the total number of earthquakes was up in 2010, 2014, 2017 and 2020.  In 2010, Eyjafjallajökull erupted, in 2014, Barðarbunga erupted at the Holuhraun fissure; in 2017, there was no subaerial volcanic activity, although Katla may have had some subglacial activity, and, in 2020, there is rifting both in the Reykjanes Peninsula and Tjörnes Fracture Zone but we have yet to see what, if any, volcanic activity emerges.  Interestingly, the 2011 eruption of Grímsvötn did not push the total earthquakes up in 2011.

Let’s take a look at activity by region. Here we look at the four main volcanic regions: the Tjörnes Fracture Zone, Vatnajökull, Myrdalsjökull and the Reykjanes Peninsula, where there is most seismic activity.

Fig 2: Iceland Total Earthquakes by Region and Year by the author, using data downloaded from IMO (see Sources below). Note: not all regions

Fig 3: Iceland Total Earthquakes > 2.0M by Region and Year by the author, using data downloaded from IMO (see Sources below). Note: not all regions are shown.  © Copyright remains with the author; all rights reserved, 2020.

We see that the eruption of Eyjafjalljokull increased the number of earthquakes in Myrdalsjökull but not to the extent that the eruption of Barðarbunga at the Holuhraun fissure and subsidence in the caldera pushed up the earthquakes for Vatnajökull in 2014 and subsequent years.  In fact, the total number of earthquakes in all regions, except Myrdalsjökull, has remained elevated since Holuhraun.

Our database does not extend back far enough to draw any firm conclusions, however, it would appear that rifting events such as Holuhraun produce far more earthquakes than volcanic activity on its own. 

Tjörnes Fracture Zone and on the Reykjanes Peninsula

This rather begs the question as to what is happening this year with the large earthquake swarms both in the Tjörnes Fracture Zone and on the Reykjanes Peninsula.  Unless our database does not go back far enough, neither the 2011 Grímsvötn nor the 2014 Barðarbunga eruption was preceded by such large earthquake swarms in other regions.

The fact that there is significantly raised activity this year in both regions suggests to us that we may be witnessing the normal plate separation on the Mid Atlantic Ridge (it is not entirely smooth), possible local magma ascent, and / or the plates accommodating an ascending blob of magma from the mantle plume, which is believed to be under the Vatnajökull icecap. There is ground deformation at several spots under the Vatnajökull icecap which points to magma ascent. 

IMO have reported that there could be a magmatic intrusion at depth on the Reykjanes Peninsula; this is supported by ground deformation. 

Gas measurements, ground deformation and recent seismic activity at Grímsvötn (not enough to show in our graphs but above the background levels for the volcanic system) have led to the Icelandic authorities to consider that an eruption is possible there in the not too distant future and to raise the alert level a notch (see earlier article). 

It is too soon to tell whether or not the rifting events, themselves, will result in eruption(s); it is possible that it is just a coincidence that we are seeing two large rifting events at roughly the same time – both areas are seismically active.  Time will tell. 

In the meantime, we will continue to watch.

The Armchair Volcanologist

© Copyright remains with the author; all rights reserved, 2020.

Sources:

For raw earthquake data and updates:

Icelandic Met Office: https://en.vedur.is/

Iceland, Reykjanes Peninsula

Quick Update on the Earthquake Swarm on the Reykjanes Peninsula

A large earthquake swarm started on the morning of 19 July at around 1:30 am at Fagradalsfjall on the Reykjanes Peninsula.  The largest earthquake had a magnitude of 5.1M.  At the time of writing, there had been 1,635 earthquakes in the last 48 hours recorded on IMO’s website (note that not all of these have been confirmed). IMO’s map and breakdown of the swarm are shown below:

Fig 1: Map of earthquakes in Iceland over the past 48 hours.  Source: IMO

Close up of the Reykjanes Peninsula:

Fig 2: Map of earthquakes in the Reykjanes Peninsula over the past 48 hours.  Source: IMO
MagnitudeNumber
< 1.0720
1.0-2.0723
2.0 -3.0162
>3.030
Fig 3: Breakdown of earthquakes by magnitude

This swarm is occurring on the east side of the swarms on the Reykjanes Peninsula which started late last year.  IMO have reported that these swarms (still ongoing) are associated with multiple magma intrusions.  The aviation code for the area is still green (IMO). IMO are in the process of evaluating the Fagradalsfjall swarm. 

The swarm at the Tjörnes Fracture Zone is still ongoing.

The eagle-eyed amongst you will note that there is some seismic activity at Katla.  Whether this will result in anything is anyone’s guess at the moment. 

We have not yet updated our earthquake data-set for the current swarm.  We will wait until IMO has had a chance to confirm more earthquakes

Update 24 July 2020

The swarm at Reykjanes is now less intense. In the meantime, Katla produced a shallow 3.0 M. IMO have remarked that earthquakes in the summer at Katla are not uncommon.

From memory, Katla was seismically active before the intense swarms started in August 2014 at Barðarbunga in the run up to the eruption at Holuhraun. This may have been a coincidence.

Fig 4: Map of earthquakes in Iceland over the past 48 hours.  Source: IMO

For further updates, please consult IMO.

The Armchair Volcanologist

21 July 2020

© Copyright remains with the author; all rights reserved, 2020.

Source and Further Reading

“An earthquake swarm in Fagradalsfjall”, 20.07.2020  https://en.vedur.is/about-imo/news/an-earthquake-swarm-in-fagradalsfjall