Stronger harmonic tremor reported in Fagradalsfjall mountain eruption

Yesterday (15-April-2021) it was reported (late) that harmonic tremor seems to have been increasing in the eruption since midnight. This normally happens if new craters have opened up. The weather is really bad at the eruption site currently so viewing the eruption with any web camera is difficult if not impossible. Rúv web cameras failed last night because of the weather that has been seeing wind peaks up to 41 meter/second with heavy rain. Current weather forecast is that the weather is not going to start improving until late today (Friday 16-April-2021). The increased tremor might be weather but weather is in general easy to filter out and doesn’t affect the lower bands (0.5 – 1Hz) that much as it does higher bands (2 – 4hz). What is happening won’t be clear until the weather starts getting better.

Information about the volcano Krýsuvík.

News and web cameras that might work

Órói auk­ist en aðstæður óljós­ar (, Icelandic)
Gosið í Geld­inga­döl­um í beinni (web camera, – The fog cover sometimes breaks a little on this web camera.

Long eruption is now expected in Fagradalsfjall in Geldingadalir valley (soon a former valley) based on lava chemical details

This is not a update on the eruption. There has not been any major change in the eruption at the writing of this article.

University of Iceland has released a report that can be read here (pdf) showing that the magma that is now erupting comes from the depth of 17 to 20 km. Crust at this location on the Reykjanes peninsula is around 17 km deep. A 3D map can be found here of the eruption. I think it is going to updated regularly by ÍSOR. The lava that is now erupting is part of Tholeiitic magma (Wikipedia). The lava is 1180C when it erupts from the ground.

What seems to be now happening is that a shield volcano is forming. It is a question if this is going to result in a formation of new magma chambers along the dyke where it formed. There is continued risk that new vents and fissures eruptions opens in this change can happen without warning. Based on earthquake activity it seems that the dyke continues to be active rather than having turned into rock by cooling.

The eruption is also high in the following gases, CO (Carbon monoxide), CO2 (Carbon dioxide), SO2 (Sulfur dioxide) and other dangerous gases.

It is now estimated that the Geldingadalir valley is going to overflow in 8 to 18 days and currently a lava pond is forming at this location. Once that happens the lava is going to flow into nearby valley (I can’t find the name of it). One of the valley the lava is in the end going to flow into Nátthagi valley if the eruption lasts long enough.

Update on the eruption in Geldingadalur on 22-March-2021

This is a short article about the eruption in Geldingadalur. The volcano that is erupting continues to be Krýsuvík-Trölladyngja volcano system. This might change at later date. This article is written on 22-March-2021 at 17:30 UTC.

  • The eruption is now mostly just in one crater. There is some activity in two other craters but it seems to be getting smaller as the eruption goes on.
  • This eruption is tiny and one of the smallest eruption observed in Iceland.
  • There is risk of new eruption opening up once this eruption ends or starts to get close to ending.
  • There is a fissure in the ground on the right side of the main crater (as seen on the web camera). A lot of volcanic gas comes from that fissure but no eruption has taken place so far.
  • There has not been any noticeable deflation according to GPS data from today (22-March-2021).
  • The main crater is now estimated to be 30 meters high but it is unstable and collapses often.
  • The lava is estimated going to fill Geldingadalur valley in 10 to 14 days if the eruption continues this long.
  • Earthquake activity has almost stopped on Reykjanes peninsula after the eruption started. Once the eruption stops earthquake activity might increase again.


The Geldingadalur valley seen from above with Google Earth. Small valley with small mountains on most sides.
This is a image from Google Earth and shows Geldingadalur valley that is now being filled slowly with lava. Copyright of this image belongs to Google Earth/Google and other companies that Google has made this image available with its Google Earth program.

The last eruption period on Reykjanes peninsula lasted from the ~700 to the year ~1400. It can be estimated that current eruption period that has now started on Reykjanes peninsula is going to last until the year ~2400 to the year ~2600. During this time shortest time between eruptions is 1 year but the longest time between eruptions might be up to 10 years. How this going to be exactly is a big question but this estimate of mine is based on the limited historical data that I have read somewhere (I no longer remember where that was).

News items with videos

Tower breaks again, lava gushes forth (Rú

Web cameras now with English text

Live feed from Iceland volcano (Rú
Live from Geldingadalir volcano, Iceland (YouTube)

Rúv has moved the stream to YouTube only.

Beint: Eld­gosið í Fagra­dals­fjalli (, this camera is on the other side compared to the Rúv camera)

Update at 23:57 UTC

According to the evening news on Rúv the lava and magma that is now flowing into the valley of Geldingadalur is around 1200C and is a primitive magma of Tholeiitic magma series (Wikipedia). The source of this eruption is a magma chamber with the depths of 17 km to 20 km and the origins of the magma it self is far deeper into the hotspot below Iceland. This magma has a lot of CO and CO2 gases that are highly dangerous. There is also a lot of SO2 gas in the eruption and that is dangerous gas.

News in Icelandic about this

Hraunkvikan sýnir beintengingu við miðju möttulsins

Rate of updates

Since the eruption is now in stable activity I am going to limit update to if anything major happens. Next update about the eruption should be on Friday 26-March-2021. Other activity in Iceland is going to be reported as normal if anything happens.


Please remember to support my work with donations. Google Adsense remains limited on my website and I don’t know when it might get back to normal. Thanks for the support. 🙂

Article updated at 18:32 UTC. New web camera added.
Article updated at 20:50 UTC. Web camera information updated.
Article updated at 23:57 UTC. Information added about the eruption.

Update on Geldingadalur in Fagradalsfjall mountain eruption on 21-March-2021

This information is going to get outdated quickly. This article covers Krýsuvík-Trölladyngja volcano. This article is written on 21-March-2021 at at 00:40 UTC.

  • This eruption is tiny. The amount of magma erupted is now around 0.02km3 but this number might not be fully accurate since I’ve not seen any published number about of volume of lava erupted so far.
  • This is unconfirmed but it is possible that an new fissure opened up under the lava field next to the hill side (seen on the web camera, this is on the left side).
  • The current erupting fissure is now about 200 meters long and might be getting shorter.
  • Earthquake activity has almost stopped at the writing of this article.
  • This eruption might only last 1 to 3 days before it stops.
  • There is no sign of deflation in the GPS data at the writing of this article.

There are no other reports about this eruption at current time. This might change without warning.

Web cameras

Beint vefstreymi frá eldstöðvunum – Rú – Live from the eruption.

Beint vefstreymi af eldgosinu – Vogastapi (Rú – Added 22-March-2021. View from a distance. Should show a red glow from the eruption if the weather isn’t too bad. – This web camera is no longer active!

Update at 15:28 UTC – One side of the main crater collapses

Here is a video of the main crater collapse on one side and give lava a new path for short period of time. At the writing of this update that path for the lava has closed down again.

Gígbarmurinn gefur sig og ný hraunrennslisæð myndast (Rú

Update at 21:21 UTC

Kvikustreymið braut sér nýja leið (Rú – This is a new video of the crater collapse that took place at 14:20 today (21-March-2021).

Article updated at 15:29 UTC. New information added.
Article updated at 21:21 UTC. New information added.
Article updated at 03:06 UTC on 22-March-2021. Web camera added.
em>Article updated at 16:34 UTC on 22-March-2021. Web camera has been removed by Rúv – comment added to that web camera.

Overview of the eruption in Geldingadalur in Fagradalsfjall mountain

This is a short overview of the eruption that is now ongoing in Geldingadalur in Fagradalsfjall mountain area. This is part of Krýsuvík-Trölladyngja volcano system according to latest information. This information might change as the time and more information is collected. This article is written on 20-March-2021 at 02:58 UTC.

  • This is the first eruption in Krýsuvík-Trölladyngja volcano system since the year 1340.
  • The eruption started at 20:45 UTC according to Icelandic Met Office.  The harmonic tremor from the eruption is almost invisible.
  • The fissure is at the writing of this article estimated about to be 1 km long with the direction south-west and north-east.
  • Currently the eruption is small and there is no risk of damage to any infrastructure. Next road (currently closed because of earthquake damage) that might get damaged is 2,5 km distance from the eruption site.
  • This eruption suggests that more eruption might start in different fissures once this eruption is over.
  • The valley that the lava is flowing into might get filled with lava if the eruption lasts long enough. The valley next to it is equally deep so there is no danger of this lava flow.
  • The eruption is in a area that is difficult to access even by a car.


The earthquake activity in the dyke between Fagradalsfjalls and Keili. Mostly just minor eartquakes show by red dots
The earthquake activity in the dyke. Copyright of this image belongs to Icelandic Met Office.

The eruption might only last for two to three days as it currently looks but that might change without warning since it is impossible to know for sure what is going to happen next with this eruption.

There are no good web cameras of this eruption since it is remote and started late on Friday night and the weather on Reykjanes peninsula is not good for today (20-March) or tomorrow (21-March).

Updated at 04:49 UTC. Web cameras added to this article.

Rúv – Beint vefstreymi af eldgosinu – Vogastapi
Beint vefstreymi frá eldstöðvunum – Rú – New! This web camera is closest to the eruption.
Road camera 1
Live from Iceland – Keilir
Live from Iceland – Reykjanes

Article updated at 03:49 UTC. Information added. Spell check fixes.
Article updated at 04:52 UTC. Web cameras added.
Article updated at 14:44 UTC. New web camera added from Rúv.

Update on Fagradalsfjall volcano activity on 10-March-2021

This is a short update on the activity in Fagradalsfjall volcano. This article is written at 21:08 UTC.

Since Monday 8-March-2021 there has been a lot going on and there are no signs of this activity slowing down. Currently it seems that the volcano dyke is expanding to the south and that is more into Fagradalsfjall mountain that is a earlier eruption structure from maybe few million years ago. This expansion of the magma dyke is resulting in strong earthquake activity and during the night the strongest earthquake had a magnitude of Mw5,1 at 03:15 UTC. Second largest earthquake had a magnitude of Mw4,6 at 08:50 UTC. Over the last 48 hours 68 earthquakes with magnitude above Mw3,0 have taken place. Smaller earthquakes are happening with the rate of 1 to 5 or more earthquakes at every minute. Since 24-February-2021 over 34.000 earthquakes have been recorded by Icelandic Met Office.

Dense earthquake activity on Reykjanes peninsula. Dense location of green stars that shows the location of the main active area. A lot of red dots showing smaller earthquakes
Earthquake activity on the Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

The chance of an eruption are increasing according to Icelandic Met Office in the news this evening. While the magma dyke has space to expand it is going to do so. The magma in the dyke is now at the shallowest only at 1 km depth or less. Exact depth has been problematic to get information about. Eruption can happen without much earthquake activity because how shallow the magma is to the top of the crust. There remains a high risk of an earthquake with magnitude Mw6,0 to Mw6,5. Both in the fracture areas on both ends of the dyke and in Brenninsteinsfjöll volcano.

Next update is going to be on Friday (12-March-2021) unless something major might happen.


Please donate if you can. Everything is still locked down with Google Adsense that doesn’t seems to have liked the traffic increase my website got when the Fagradalsfjall volcano started going active on 24-February-2021. There is nothing I can do about it since there are exactly zero person to contact with Google Adsense and I just have to hope this is somehow resolved if that is what happens (it might not because Google placed their eggs in the automation basket and that’s not a good thing). Thanks for the support. 🙂

Harmonic tremor pulse during the night until morning in Fagradalsfjall volcano (9-March-2021)

This is a short article on the activity in Fagradalsfjall volcano. This situation is developing quickly and it is impossible to know what happens next.

During the night of 9-March-2021 from 05:20 UTC until around 07:00 UTC an harmonic tremor pulse was detected by Icelandic Met Office. This shows that the magma is still expanding into the Earth crust below Fagradalsfjall mountain and according to Icelandic Met Office it looks like the dyke is expanding in south direction but it is going to take a day or two to confirm that with GPS data.

Earthquake activity in the volcano Fagradalsfjall. Dots on a generated map my a program called Skjálfta-Lísa shows the most recent earthquake activity from midnight until 16:18
Earthquake activity in Fagradalsfjall volcano. This shows the possible location of the south end of the magma dyke. Copyright of this image belongs to Icelandic Met Office.

There have been fewer stronger earthquakes in last few days. While the there are fewer strong earthquakes the amount of earthquakes has not really dropped in any number, most earthquakes are small in magnitude and only few reach magnitude above Mw3,0. This quiet period is not expected to last for any amount of time while magma continues to be injected into the crust of Fagradalsfjall volcano. There continues to be a high risk for earthquake with magnitude Mw6,0 to Mw6,5 along with risk of Mw6,5 earthquake in Brennisteinsfjöll volcano. Currently no magma movement is being detected in Reykjanes volcano, Krýsuvík volcano or Brennisteinsfjöll volcano.

New information about the situation in Fagradalsfjall volcano

This is a short article about the new information published today (8-March-2021) by Icelandic Met Office and Department of Civil Protection and Emergency Management.

New measurements of the situation in Fagradalsfjall volcano show that the dyke intrusion continues to grow and as at its shallowest point at 1 km depth. Possible eruption is expected at the south end of the dyke intrusion (closest to Fagradalsfjall mountain). Earthquakes are going to happen at the south-west end of the dyke and north-east of the dyke because of the inflation the magma is creating in the area.

The dyke shown with dotted line and circle shows the most effective area. Gray areas at both ends shows earthquake effected area
The earthquake areas at the ends of the dyke intrusion, shown in gray areas on this map. The dyke is shown within the line with dot lines. Copyright of this image belongs to Icelandic Met Office.

There are going to be quiet times between high period of activity according to the news about this activity. There is also ongoing risk of a earthquake with magnitude of Mw6,5 in Brennisteinsfjöll volcano and according to Icelandic Met Office that risk has not been reduced in recent days. Outside of the Fagradalsfjall volcano magma dyke, no magma movement has been detected in Reykjanes (Svartsengi?) volcano and in Krýsuvík volcano.

Sources (Icelandic)

Áfram má búast við að virknin á Reykjanesskaga verði kaflaskipt (Iceland, English, Polish,
Kvikan er á kílómetra dýpi (Rú, Icelandic)

Strong earthquake activity in Fagradalsfjall volcano

This article is short because the situation is always changing. Article is written at 07-March-2021 at 23:10 UTC.

At 00:22 UTC and until around 00:42 UTC an harmonic tremor was detected in Fagradalsfjall volcano. While this harmonic tremor only lasted for 20 minutes it started an earthquake swarm around 01:00 UTC that lasted until around 04:00 and the largest earthquake in that swarm had a magnitude of Mw5,0 to Mw5,2 (USGS/EMSC) at 02:01 UTC. Every day from 2500 to 3000 or more earthquakes are being recorded. Since 24-February-2021 over 24000 earthquakes have been recorded in this earthquake swarm. There is a massive inflation happening from Fagradalsfjall volcano and that is what is causing the earthquakes west and east of the dyke location between Fagradalsfjall mountain and Keilir mountain. Resulting in large earthquakes like the Mw5,0. Many of the earthquakes are happening close to the town of Grindavík and people there can’t sleep due to earthquake activity and the ongoing earthquake activity that is now happening at every minute.

Heavy earthquake activity on Reykjanes peninsula. Total of 68 green stars on the map and over 2600 other earthquakes of smaller magnitude are shown on the map at different age
Heavy earthquake activity in Fagradalsfjall volcano. Copyright of this image belongs to Icelandic Met Office.

It is now possible to check the inflation by viewing this GPS data website. Another website with GPS data can be found here and its is called Crustal Deformation.

More strong earthquakes are expected. If anything major happens I’ll post update soon as possible.

Web cameras directly streaming

Beint vefstreymi af skjálftasvæðinu – Efstaleiti
Beint vefstreymi af skjálftasvæðinu – Vogastapi (Rú
Keilir í beinni (
Óróasvæðið í beinni útsendingu (Ví
Live from Iceland
Keilir og skjálftasvæðið (YouTube)
Road camera 1
Road camera 2 (night vision/infrared)

Update 8-March-2021

A news article has been published showing the road damage from the recent earthquake activity. This is close to the HS Orka energy plant on Reykjanes peninsula.

Mal­bik sprungið við HS Orku í Grinda­vík (, Icelandic, Pictures)

Article updated at 01:31 UTC.
Article updated at 04:36 UTC. Fixed web camera link that was broken (YouTube)
Article updated at 16:58 UTC on 8-March-2021. Fixed Rúv web camera link.

Katla volcano update article of 29-July-2017

This article is going to be updated as activity continues in Katla volcano today on 29-July-2017. If an eruption starts (big one) a new article is going to be written for that event.

Overview of the activity during the night and today

It seems that during the night a minor eruption took place (this is just my view). This based on harmonic tremor pulse that appeared in Katla volcano after midnight, the source of the activity seems to be north-west part of the caldera. Possibly where a magnitude 3,0 earthquake had taken place at 00:48 UTC. Harmonic tremor remains unstable and above background levels, at the moment however it seems that current harmonic tremor when this is written is due to glacier flood pushing it self from under the glacier. The water that is moving under the glacier is few hours away from (at best) from appearing in glacier rivers that come from Katla volcano.

The earthquake activity in Katla volcano during the last 48 hours. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor in Austmannsbunga in Katla volcano at 12:09 UTC. It clearly shows the minor eruption and ongoing harmonic tremor pulse. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor in Austmannsbunga in Katla volcano at 13:04 UTC. This image shows ongoing activity in the tremor. This is mostly high frequency tremor and that is interesting. What that is not known. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor in Goðabunga at 12:09 UTC. It clearly shows the night minor eruption and ongoing harmonic tremor. The harmonic tremor is however a lot less visible now on Goðabunga. Copyright of this image belongs to Icelandic Met Office.

Harmonic tremor as it appears on Rjúpnafell (SIL station). This station is at more distance from the source of the harmonic tremor pulse and shows a weaker signal as a result. The night minor eruption is also clear on this SIL station but current harmonic tremor is less visible, it does appear but at much lower level. Copyright of this image belongs to Icelandic Met Office.

Katla volcano has been moved to yellow alert. It is now possible to watch the glacier flood live from here (Rú Currently the glacier flood is getting smaller, but that might only be a temporarily thing if more water is on its way from Mýrdalsjökull glacier. There has also been a drop in conductivity for now in Múlavísk glacier river.

Announcement in English on Rúv

People advised to stay away from Múlakvísl (Rú

This article is going to be updated as needed today.