Fewer earthquakes close to Keilir, no eruption in Fagradalsfjall mountain for almost one month

Earthquake activity continues close to Keilir mountain. But it remains at depth of 5 to 6 km and doesn’t show any sign that it is about to move to the surface. More than 10000 earthquakes have been recorded and 18 earthquakes have been recorded with magnitude above Mw3,0. This is according to Icelandic Met Office.

Earthquake activity close to mountain Keilir marked by a green star close to it of the map on Reykjanes peninsula
Earthquake activity close to Keilir mountain on Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

The eruption in Fagradalsfjall mountain (more information at Krýsuvík-Trölladyngja website at Global Volcanism Program) has not been active since 19-September-2021 and there are no signs that the eruption is about to restart soon. Global Volcanism Program no longer updates its information for this volcano as an active eruption. Icelandic scientists in eruptions have not declared the eruption over. It should be expected that the eruption in Fagradalsfjall mountain is over for now, but it can start again at the same location or at new location in few weeks time or maybe even few years from now.

Ongoing earthquake swarm close to Keilir mountain

The earthquake swarm with Keilir mountain continues today (2-October-2021) and largest earthquake at the writing of this article had a magnitude of Mw4,2. This might change without warning.

Green stars on Reykjanes peninsula close to the mountain Keilir. Shows where the current activity is.
The earthquake activity close to Keilir mountain. Copyright of this image belongs to Icelandic Met Office.

Based on what I am seeing it is my view that magma is the reason why this earthquake activity is happening. The magma seems trapped, based on the earthquake activity and that is interesting. This suggest that the feeder channel, that possibly started at this location has closed up and that is the reason why the eruption in Fagradalsfjall mountain stopped. At least that is the working idea, if it is true I don’t know.

Department of Civil Protection and Emergency Management and Icelandic Met Office has warned people against going to Keilir mountain because of risk of volcano eruption or large earthquakes.

It is unclear at the writing of this article if there are changes to hydrothermal activity close to Keilir mountain. There have been reports about it, but they remain unconfirmed at the writing of this article.

There is now a risk of an earthquake with magnitude of Mw6,0 in the area of Keilir mountain. The earthquake activity shows a pattern of high and low activity every few hours. Why this happens is not well understood at the writing of this article.

Earthquake activity south of Keilir mountain

On Saturday 25-September-2021 an earthquake swarm started close to Keilir mountain, at the writing of this article this earthquake swarm is ongoing.

Red dots on Reykjanes peninsula show the location of an ongoing earthquake swarm that is now happening.
Earthquake swarm on the Reykjanes peninsula. Copyright of this image belongs to Icelandic Met Office.

The eruption in Fagradalsfjall mountain has been having its longest quiet period since 19-March-2021 and at the writing of this article that is ongoing situation.

This earthquake activity suggest that the eruption time period in this part of the Reykjanes peninsula is not over, even if nothing is happening at the moment.

Krýsuvík-Trölladyngja is a volcano system is currently erupting in this area.

Article updated on 29-September-2021 at 11:49 UTC. Correct date of the earthquake swarm start added to the article.

Massive lava cave opens up, results in lava flood down to Nátthagi

Yesterday (15-September-2021) around 11:10 UTC a large lava cave just south of the crater in Geldingadalir had a roof collapse in a small area or a lava breakup in the surface. This resulted in the lava flow down Geldingadalir into Nátthagi. The flow covered Geldingadalir in less than 20 minutes. After that it did reach the barrier that stops it from going into Nátthagakriki, if that happens both walking path A and B are going to get closed forever or having to be redrawn from their current locations. Lava down that path also allows the lava flow to go in the direction of Grindavík town and nearby roads.

The lava flow yesterday did go down into Nátthagi but didn’t get far into there compared with the older lava it was flowing on top of. This sudden lava flow did put people in danger and shows that the lava field is full of dangerous caves that can collapse or burst open at any time without any warning. The lava flow that started yesterday is ongoing best to my knowledge. But the view has been limited due to fog and bad weather in Fagradalsfjall mountain this evening.

One or two idiots where seen walking on the crater rim yesterday and I think this are the same people that Icelandic coast guard had to transport from Gónhóll since they where unable to get back because of the new lava flow that had happened when they where there.

The crater is now ~334 meters above sea level high. Currently the crater is now growing in height but that can change without warning.

Pictures of this new lava flow are on social media. I can’t use them because of copyright but if searched they can be found and viewed. There are also some amount of videos of this lava flow on YouTube.

Fagradalsfjall mountain is part of Krýsuvík-Trölladyngja volcano system.

Unconfirmed activity in the area of Keilir in Fagradalsfjall mountain eruption

This is unconfirmed so there might be number of other reasons why this is being observed. This also might be wrong reporting but based on web cameras that might not be the case. There has been some visual view of this on web cameras. Here are two pictures that I was able to screen grab from two of those cameras.

Thermal black and white image showing a bright spot on the centre of the image suggesting a strong heat source.
There is a heat source in this image. Where it is located is currently unclear. Copyright of this image belongs to Míla and Securitas.
Black image showing two light dots. With the dot on the left being a car or some human made noise. While the dot on the right might be a small eruption that is unconfirmed.
The light on the right of this image might be the an unconfirmed eruption. Copyright of this image belongs to Míla.

It is unclear what is going on and this might all be wrong. But I am also seeing this new light source on the web camera from mbl.is on YouTube as it peaks a little from behind the large crater in Fagradalsfjall mountain. That crater is not active at the moment.

I don’t know when confirmation is going to appear. If this is an eruption. If this is not an eruption, then there is going to be a confirmation of that too. I’ll post update here is I learn anything more in the next few hours.

Update 03:07 UTC 7-September-2021

The light on the second picture (on the right) is a human made light. I think it is the lighthouse. What is appearing on the thermal camera has not been identified.

Update 13:36 UTC 7-September-2021

This is wrong reporting that happened here. Nothing happened and what was seen on the thermal camera is most likely the heat from the crater. This type of wrong information happens every once in a while. Currently the main crater remains inactive and sulphur colours have started to appear on him from the sulphur outgassing that is now happening.

Article updated at 03:08 UTC on 7-September-2021

Article update at 13:39 UTC on 7-September-2021

Update on the eruption in Fagradalsfjall mountain on 19-August-2021

This is a short update on the five month eruption day in the Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngja volcano system.

  • The eruption continues its strange cycle of not erupting for few hours and erupting for few hours.
  • The consequence of this type of eruption is that the lava doesn’t flow that far from the crater. It just piles up next to the crater making the structure ever higher. I am currently estimating (this is a guess and might be wrong) the crater at 200 meters high (-+ 50 meters).
  • The eruption has now been going on for five months. Holuhraun eruption in Bárðarbunga volcano in 2014 to 2015 lasted for six months.
  • At the writing of this article there are no new craters open but it doesn’t rule out that new crater might have opened but are hidden under the amount of lava that is around the main crater. As there are some extreme large caves in this lava field. Allowing for a lot of space for new crater to form and start erupting unnoticed.

There are no more updates of the eruption at the writing of this article. That might change without warning but I don’t know if that is going to happen.

Update on the eruption in Fagradalsfjall mountain on 16-August-2021

This is a short update on the eruption in Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngja volcano system.

  • New crater has been confirmed in the eruption in Fagradalsfjall mountain. This crater started to form few days ago. It follows the activity in the largest crater and remains inactive during the time period when there is no activity in the large crater.
  • This new crater is going to change lava flows in the eruption and restart lava flows in the south-Meradalir and Geldingadalir.
  • Current the new crater is building up. It is on the larger crater rim and might be unstable and collapse are likely to happen.
  • Formation of new craters following the formation of this crater is likely. When and where new craters form is impossible to know in advance.
  • It is a question if this is a new phase of the eruption. I currently don’t have an answer.
  • The new crater is visible on all the web cameras.

Fog has been blocking the view of the eruption today and I expect that is going to be the case tomorrow (17-August-2021) and maybe next few days. This fog makes it difficult to see what is going in the eruption.

Update on the eruption in Fagradalsfjall mountain on 10-August-2021

This is a short update on what is going on the eruption in Fagradalsfjall mountain that is part of Krýsuvík-Trölladyngja volcano system.

  • The eruption continues as before with few hours of eruption and few hours of no activity. (This is my personal view of the situation) Each event is an active eruption as it would happen with any other volcano. The time between eruptions now is just shorter than in any volcano in Iceland. Its hours, not decades between eruption. I don’t know why this is happening like this.
  • Cracks have appeared in the viewing area hill closest to the erupting crater. Why this is happening is unclear. There are two explanations for this. The first one is that this are tension cracks because of the eruption and lava flows nearby to this hill . The second explanation is that this is deformation cracks because magma is about to start erupting in this part of the hill. Formation of new cracks was observed early on in the eruption in Fagradalsfjall mountain few days before an eruption started in that area.
  • There is now slightly less lava flowing from the crater. Current flow is up to 9m3/sec according to latest reports about the lava flow. This studies are done by Earth Science of University of Iceland and Icelandic Metrology Office.

This eruption remains small. Currently it is even smaller than Hekla volcano 2000 eruption that was the smallest eruption in Hekla in recorded history (according to the news). While the eruption remains this small the lava is not going to flow far or is going to do so slowly. Most of the lava is just going to build up next to the crater and next nearby area.

People continue to walk out in the lava and that is extremely dangerous. The lava field, where it is deep enough has large caves full of 1100C hot lava and if the roof breaks and people fall into it there is no saving anyone from this. Just break in the lava field crust allows for lava flows to break out with same deadly consequences.

Unconfirmed report about ash cloud off the coast of Krýsuvík-Trölladyngja volcano (Krísuvíkurberg)

This is possible mistaken reporting. There have been reporting of ash clouds or steam clouds off the coast during the evening of 7-August-2021. This would be in the volcano system Krýsuvík-Trölladyngja.

The ash cloud or steam cloud would indicate an activity off the coastline or possible eruption activity in the ocean. Explosive events like that appear a lot more clearly as harmonic tremor on SIL stations and according to news reports nothing has been seen so far in the harmonic tremor data. There have been no earthquake activity in the area where the clouds are supposed to have been seen.

The coast guard has been sent to this area, as they where nearby anyway. I don’t know if anything has been reported so far. The weather is fine in south Iceland and I don’t think there is a lot of ocean waves, but as this is the Atlantic ocean there can be ocean waves even if there is no wind, since the ocean waves can arrive from parts of the ocean with bad weather thousands of kilometres away.

If anything new is reported I am going to update this article or write a new one.

Short update on the eruption in Fagradalsfjall on 7-August-2021

This is a short update on the eruption in Krýsuvík-Trölladyngja volcano system on 7-August-2021.

Over the last few weeks there has not been a lot to report about the eruption in Fagradalsfjall mountain. That changed tonight. The eruption seems to have entered a new stable phase. With constant eruption, rather than erupting every few hours and nothing happening for several hours after that. I don’t know if that is going to continue for long, but that is the situation at the writing of this article.

Red glow from the crater lights up the nearby lava field that has three gas funnels rising up from it. Lava is flowing from the crater down into nearby Meradalir and some of the lava is flowing underground
The eruption in Fagradalsfjall mountain. Copyright of this image belongs to Rúv ohf.

Most of the lava flow is going into Meradalir at the writing of this article. Some of the lava flow is happening underground and that lava flow is going into south-Meradalir that is just above Nátthagi valley. That can be seen as gas is now coming from that lava field and increase in gas emission shows that fresh lava is flowing under the crust of the lava. Surface lava paths can change without warning at any time.

Tourist continue to place them self in great danger by walking out in the lava field. If there is an accident there won’t be any recurse because it is going to be already too late anyway.

Update on 7-August-2021 at 13:48 UTC

Today (7-August-2021) at 08:00 UTC the eruption stopped. The harmonic tremor dropped quickly as the stop in the eruption was quick after going on for two and half day. Why this happens remains unclear. At the writing of this update at 13:49 UTC the eruption remains inactive.

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