Category: Harmonic tremors

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Update on Grindavík 17. November 2023

This is a short update on the situation in Grindavík on 17. November 2023. Information here can go outdated quickly and without warning.

Daily updates

  • Grindavík town continues to sink as the rift valley continues to move. The speed of sinking has slowed a little according to the news today.
  • Earthquake activity has slowed down in last few hours (this is written around 22:51 UTC). What that means is unclear.
  • Some houses in Grindavík town have been completely destroyed. Iceland has a natural disaster fund for this type of situation and that is going to cover the owners loss according to the news.

General update

It took me a week. But it seems that this dyke intrusion under Grindavík town is because of the magma sill (dyke) under Svartsengi. That area has inflated around 110mm in a week. That is a inflation of 15mm/day based on my best calculations. That is a lot of inflation, since before 10. November the inflow of magma into Svartsengi was at most 8m3/sec according to measurements of Icelandic Met Office.

The sill in Svartsengi created a lateral dyke in Sundhnúkar and nearby areas. When the pressure in the sill is high enough again it is going to push the magma into the dyke at Sundhnúkar again with the same force as it did before. How long that takes I don’t know. Last time this was from 25. October to 10. November. That’s seventeen days, but there was a lot of deeper sills in Svartsengi and its impossible to know much, if anything flowed form them into the dyke. This is my personal view, it might be wrong. But this is what I am reading from the data.

Risk of the eruption remains high because there’s a ongoing inflation at Svartsengi. When a eruption starts is impossible to know.

If anything happens. I’ll post update soon as I can.

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Update on Grindavík on 16. November 2023

This is a short update on what is happening in Grindavík on 16. November 2023. Information here can go outdated quickly and without warning.

The situation is mostly the same as yesterday (15. November 2023), but few things have happened and that is enough for me to publish this article.

  • Sulfur dioxide has been detected in a drilling hole in Svartsengi. This drilling hole is such that it end point is close to Hagafell mountain  east to Svartsengi power plant. I think this might be a cold water hole. It has a depth of 2,5 km. This means that magma is at or close to that depth. Ground water in this area doesn’t go deeper than 1,9 to 3 km I think (I am not sure on how the fresh water ground level works in this area).
  • Eruption is expected from hours to day based on most recent measurements from Icelandic Met Office.
  • Grindavík town continues to sink according to news today (16. November 2023). Difference between days can be as much as 25 cm.
  • Mbl.is (Morgunblaðið) has a video of the damage done by this sinking on their website here. Its in Icelandic.

The situation for now is quiet, but that might only last for few hours to days longer before an eruption starts. Since earthquake activity strongly suggests that magma is looking for a way to the surface. While some magma is at shallow depth of 400 to 500 meters. There’s not enough of it to start an eruption. That can change without any warning at any time in this situation.

I’ll write updates if anything more happens here as quickly as I can.

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Update on Grindavík 15. November 2023

This is a short update on what is happening in Grindavík on 15. November 2023. Information here might go outdated quickly.

In general, not much has changed since yesterday (14. November 2023).

  • There’s no change in earthquake activity. Strong wind in the Reykjanes peninsula might be masking some of the smaller earthquakes.
  • Part of the harbour area has started to sink according to news. I am not sure how much, but I think it might be considerable sink.
  • Speed of the sink in some areas of areas inside Grindavík has increased from 7 cm for each 24 hours to 12 cm for each 24 hours since yesterday. Some areas inside Grindavík have lowered as much as 2 meters or more.
  • Inflow of magma into the dyke continues to be at 75 m3/second according to news reports today. This is a lot of magma inflow into the dyke. The eruption in Holuhraun in 2014 and 2015 had an flow of 90 m3/sec when it was the most.
  • It is reported on mbl.is that it is now considered that magma might be flowing directly from the main magma chamber at 20 km to 40 km depth under this location in Reykjanes peninsula. That news is in Icelandic here.
  • Parts of Grindavík town has lost power, hot and cold water because of sinking of the ground and movements. Emergency repair is going to be attempted tomorrow if it is safe.
  • Eruption might happen at Sundhnúkar and Hagafell, where the highest flow of magma is happening according to Icelandic Met Office and the news.
  • Eruption at many craters at the same time is what is going happen here. Based on what I am seeing. That means more lava covering larger area quicker than the small eruptions in Geldingadalir, Meradalir and at Litli-Hrútur. Where it was just one crater and a small eruption.
  • Something is holding back the magma from reaching the surface. What that is unclear. But magma is at shallow 500 meters or less according to measurements done by Icelandic Met Office. This shallow depth means that magma can start erupting without much warning or notice in the dyke.

There is a chance that parts of Grindavík town might sink under the ocean because of the ground sinking. When eruption starts, what goes under lava depends on where the eruption is going to start and where the lava is going to flow. Both are random events that is impossible to know anything about.

If anything happens. I’ll post update soon as I can. If anything happens tomorrow I’ll write about it. Otherwise I plan on publishing next article on Friday 17. November 2023. Since changes at the moment are not that big changes between days currently.

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Update on Grindavík on 14. November 2023

This is a short update on the situation in Grindavík and nearby area. Information here can go outdated quickly and without warning.

For the press media. Please contact Icelandic Met Office or Department of Civil Protection and Emergency Management for any important information or interviews. I already write everything I know here on this website as needed. Thanks.

  • The magma is at 400 meters depth, where it is at its most shallow.  I am not sure on location, but I think it is just north-east of Grindavík town.
  • There is strong wind on Reykjanes peninsula. That normally hides some of the smaller earthquakes happening. Icelandic Met Office continues to record 700 to 3000 earthquakes each day. Most of them are along the dyke and most of them are in the magnitude range of Mw0,0 to Mw3,1. With the stronger ones happening least often.
  • Inflow of the magma into the dyke is at the writing of this article around 73 m3/s to 75 m3/s. On Friday 10. November that inflow was 1000 m3/s.
  • Sulfur dioxide was detected today north of Grindavík. That suggests that magma might be at shallow depth in the dyke area.
  • News reports today did say that the area in Grindavík and nearby continues to sink around 7 cm over 24 hour time period. This might be uneven process depending on the area.
  • Lakes south of Grindavík have been seen growing, as the area continues to sink and get lower. It is a question of parts of this area is going to get flooded by the ocean soon. This is reported on Facebook by Eldfjalla- og náttúruvárhópur Suðurlands.
  • The GPS station just north of Grindavík has lowered by 1400mm since Friday 10. November 2023. The stations on the east are going up, some much as 1 meter. While the GPS stations on the west side are lowering.
Line of red dots shows all the small earthquakes, along with one green star on it. This show all the 15 km of the dyke.
The dyke as it appears on the earthquake map. Copyright of this image belongs to Icelandic Met Office.

This situation changes quickly and often from hour to hour. I’ll post new updates if something major happens, quickly as I can.

Article updated on 15. November 2023 at 00:21 UTC. – Removed information that might not be correct.

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Update on the situation in Grindavík on 13. November 2023

This is a short update. Information here can go outdated quickly and without warning. I am sorry for the Google Adsense popup ads. They turned them on without telling me and I can’t turn it off. I never run this type of ads because this is just annoying pop-up and I don’t allow that on my website. Google Adsense ads are going to be gone by the end of this month anyway (regardless of anything else).

The situation is similar to yesterday. Earthquake activity continues to drop for now. But that might be a short quiet because the dyke and the rift valley continues to grow. Inflow of the magma continues, at slightly slower rate than on Friday 10. November 2023.

  • The inflow of magma on Friday 10. November 2023 was 1000 cubic meters per second according to Icelandic Met Office and experts.
  • The rift zone that is lowering is on the western side of the Grindavík town. The east side is rising up to almost the same amount. Parts of Grindavík have lowered around 1 to 2 meters. Some of the cracks in the grounds are up to 20 meters deep or deeper.
  • There is a lot of damage in Grindavík to many houses. If not from earthquakes, then from the formation of the rift valley.
  • Eruption risk remains high and the dyke seems to holds its length at 15 km. This can change without warning.
  • The rift valley is now around 2 km wide according to the news. The rift valley continues to get wider according to measurements.
  • There has not been any drop in harmonic tremor on SIL stations next to the dyke, even if earthquake activity has lowered. This is because of the ongoing inflow of magma into the dyke.
A line of red dots shows the dyke formation that goes under Grindavík town and goes north-east of the town.
The earthquake activity in the dyke appears clearly. Copyright of this image belongs to Icelandic Met Office.

It is not possible to know what happens next. It is my view that an eruption is going to start in this area. This is a start of a activity that is going to last for a while until it quiets down.

This dyke activity might also upset the volcanoes Fagradalsfjall and Reykjanes and what is happening in them. Anything can happen in them without warning. If not eruption, then earthquake activity.

I’ll post update when I have some new information about this situation.

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Update on the situation on Grindavík dyke intrusion

This is a short update, since the situation is changing quickly and without much warning. This just looks like it is quiet, it is not.

  • Grindavík town is sinking and parts of the town have lowered by as much 1 meter when this article is written. This is a large area, large enough to be called rift valley. This was reported by mbl.is here in Icelandic. This was just discovered today when some measurements where taken.
  • Magma might be as shallow as few dozen meters under the surface where it is the most shallow. This has been reported by mbl.is here in Icelandic. This is a live link and the news item in question might be removed or gone in few hours.
  • This is a event that was not expected. Most of the inflation until Friday 10. November 2023 had happened in Svartsengi (Reykjanes volcano) and in Fagradalsfjall volcano. There had nothing been happening at Sundhnúksgígar to the north-east of Grindavík. Until Friday 10. November at around 08:00 when a earthquake swarm started in that location. Originally it was though those where just tension related earthquakes, but that view (according to reports) changed early in the morning at Icelandic Met Office. Everything did go crazy in earthquakes between 16:00 until 19:00 on Friday. This earthquake swarm was really dense and many earthquakes with magnitude Mw4,0 took place inside Grindavík town.
  • There is damage in Grindavík, both roads and houses because of the displacement. Damages to pipes, electricity wires and other infrastructure.
  • The dyke seems to be few dozen meters wide and up to 1 meters deep. It might be different wide and deep at its 15 km length. I have not found any useful information about this. Just information on its length that was last time I checked, 15 km long.

This is not a small volcano event. What I don’t know and this doesn’t seems to be known. What volcano is causing this. This might be Fagradalsfjall volcano or this might be Reykjanes volcano.

String of earthquakes reaching from the ocean and under Grindavík town and to the north-east. This is the dyke that is causing a lot of problems in Grindavík. A lot of earthquakes to the west of this location. That is also having magma inflow. This is a map over seven day time period.
The earthquake activity over the last seven days. Copyright of this image belongs to Icelandic Met Office.

I’ll post more information about this when I know more or if anything more happens if I can.

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Update on the Sundhnúka / Kálffellsheiði / Reykjanes volcano / Fagradalsfjall volcano / Grindavík dyke intrusion

This is a short update. Information here might go outdated quickly and without warning. This update is written on 11. November at 22:42 UTC.

  • The dyke is 15 km long at the writing of this article. It might be extending both north-east and south-west. Earthquake activity remains heavy but the magnitudes have dropped for now.
  • The inflation in the area is around 120 cm or more since start of this yesterday (10. November 2023).
  • The dyke now extends into the ocean and the part in the ocean is around 3 to 5 km. At shallow depth, this is going to result in explosive eruption for the first few hours to days.
  • The magma is now at depth of 800 meters, where it is the most shallow. That might not result in a eruption at that location.
  • Eruption is going to start without warning. Since Icelandic Met Office has issued that they can’t see the harmonic tremor start because of heavy earthquake activity in the dyke.
  • There is now a major risk of large earthquakes both east and west of the dyke because of all the displacement resulting from him. Those might happen days or even weeks in the future.
  • Icelandic Road Administration published pictures on Facebook here, showing the damage from the displacement and from the earthquakes. The ground is falling apart and opening up.

 

Image of the dyke in direct 15 km line from north-east to south-east.
The dyke location. Copyright of this image belongs to Icelandic Met Office.

It is difficult to know what happens next and this eruption is not going to be small or tourist friendly.

Hundreds of green stars showing earthquakes larger than magnitude 3,0 next to Grindavík and nearby area.
The insane amount of earthquake activity next to Grindavík town in last 48 hours. Copyright of this image belongs to Icelandic Met Office.

I’ll post updates once I know more.

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Dyke has formed or is forming under Grindavík town, mandatory evacuation ordered

This is a short article. Its going to outdated quickly.

  • Dyke has or is forming under Grindavík town. This dyke starts at Sundahnjúkar in north-east of Grindavík town and is going to down to Grindavík. This is at the moment around 4 to 7 km long dyke. It might get longer and reach the ocean.
  • There’s a mandatory evacuation order in place. Everyone in Grindavík town has two hours (from around 23:00 UTC) to leave the town. Many people had already left because of the heavy earthquake activity today (10. November 2023).
  • Earthquake activity remains heavy, but is lower than it was at around 17:00 to 19:00 UTC. This might change again without warning.
  • GPS data suggests this is more magma than in all of last three eruptions combined.
  • This magma might be from Fagradalsfjall volcano. This is currently only an idea. That means the magma in Reykjanes volcano has not started to move to the surface. That might also happen without warning at any time, since that inflation continues.

I’ll post more information when I got them. The situation is unclear and there’s a lot of wrong information out there so check your sources.

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Update on the eruption at Litli-Hrútur on 10th July 2023 at 18:41 UTC

This is a short update because events are changing quickly.

  • Length of the eruption fissure is uncertain, reports are conflicting. The numbers I’ve seen are from 200 meters to 900 meters long. This also might be a case of growing fissure eruption.
  • Harmonic tremor on the SIL station Fagradalsfjall continues to grow. Suggesting that the eruption is increasing in power since it started. This sometimes happens in lava eruptions.
  • The lava is flowing to the south. It might reach Meradalir valley in about one  week to three weeks. Some of the lava is flowing to the north, but a lot of less of it and is only expected to flow in the nearby area. There is no risk at current time for any damage to infrastructure or property.
  • There’s a risk of new fissures opening up in this area without warning.
  • This area is remote and difficult to go towards. Police has closed roads for the time being for safety reasons.

I’ll post new update soon as I have any new information or if anything changes. Experience has shown that this type of eruptions are rather uneventful for a longer time periods. I’ll adjust my updates in accordance with that.

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Update on the activity in Fagradalsfjall mountain on 7th July 2023 at 14:28 UTC

This is going to be a really short article. Because an eruption might be about to start. Difficult to be sure, but there’s a chance. Eruption has not started at the writing of this article.

  • Largest earthquake in the last 24 hours seems to be a magnitude Mw4,3. I no longer can keep up with all this earthquake activity.
  • Inflation in area close to Keilir has reached 200mm (20cm) in less than 48 hours when this started.
  • Inflow of magma is estimated to be 88m3/s and that is a lot of magma moving and moving fast.
A lot of earthquakes in Fagradalsfjall mountain. Too many earthquakes too count and too many green starts.
Heavy earthquake activity in Fagradalsfjall mountain. Copyright of this image belongs to Icelandic Met Office.

It is unclear where the eruption is going to happen. But there has been a drop in earthquake activity that strongly suggest that magma is close to finding a path to the surface. According to measurements, the magma is now less than 1 km away from the surface.