Anxious period on Iceland is going on once again. A LOT of earthquake activity has been going on in Iceland's Reykjanes peninsula. In this post I want to discuss what's going on and the dangers that currently make some fears in people.
This post is not really related to weather but I decided to expand my weather community and now I edited it to be a Geoweather community which now includes everything involving geology too, so overall all forces of our planet. There is no other community for this and I need someplace to add this kind of content too!
Earthquakes on Iceland are a normal ocurrance and is usually not cause for alarm. However, over the past week, over 10 thousand earthquakes occurred on a couple of specific places on Reykjanes peninsula. On this map you can see all the earthquakes for the past 24 hours. It only shows verified earthquakes and not all that are recorded.
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You can clearly see two obvious areas on the photo below where the activity happens. The strongest one today was 4.25 magnitudes which is greatly felt in nearby areas. Over 10 quakes have been recorded to be over 3 in magnitude. When you see something like this, it clearly indicates that something abnormal is happening under the ground.
Here is a bit closer view of the area.
Ground is rising! GPS measurements indicate that over the past week the ground near the mountain Thorbjörn has risen up to 6 centimeters. This map shows well where the land rise is taking place. Note the red area. Its at the same location where most of the tremors are happening. In fact, a couple of days ago the fastest land rise of 3 cm in a day was recorded. Reportedly this has never happened that fast before, at least not recorded before.
Im just getting the facts out of the way, I will explain more below what it all means.
Where Lies the Danger ?
Past 3 eruptions have not been dangerous that happened in 2021, 2022 and 2023 August. For one very simple reason... The eruptions happened in an uninhabited areas of the Reykjanes peninsula. Lava flows never really posed any danger to houses or infrastructure.
Now the earthquakes and land rise does not happen in the same Fagradallsfjall volcanic system as before but in another one Eldvörp/Svartsengi system on the west.
Eldvörp/Svartsengi system unfortunately is close to settlements and infrastructure. First of all, there is a geothermal power plant right next to where the land rise and tremors are happening. This power plant supplies heat, water and electricity to nearby town Grindavik and parts of Reykjavik. If the power plant went offline or get destroyed then its a BIG problem.
Right next to the power plant is the very famous Blue Lagoon spa where you can take a swim in warm mineral rich waters. Here is a poor photo from 2018 when I visited the place. At the background is mount Thorbjörn where majority of the current quakes happen.
Here I have a photo from the maps where I have circled a few locations to give you a picture.
Red circles are current earthquake hotspots
Purple circle is a town of Grindavik with ca3000 people.
Black circle is the area of previous 3 eruptions, red dots inside the eruption craters.
Source: Google Maps
When the eruption would come up in the red circle near the town, it would be a worst case scenario. The power plant and Blue lagoon would get destroyed and lava would most probably start to flow towards the ocean in the south and Grindavik.
If the eruption happened in the bigger red circle then it would be a better scenario. It would flow to the ocean but most likely skip Grindavik but still bury the road in the south.
Google street view of the hotspot location where a ton of earth quakes are happening and the land rise. You can also see the mount Thorbjörn and the power plant.
I have driven this road a lot of times during my trips to Iceland
Source: Google Street View
Current status of possible eruption
At the moment consensus is that the eruption is not imminent. At least nothing indicates that the magma will rise to surface at this moment. Earthquakes indicate that magma is on the move yes and most probably finding new paths to flow.
Land rise indicates of rising pressure underground. Magma is accumulating at about 5 to 4 kilometers in depth, the inflow is creating pressure and therefore the land above rises. The earthquakes happen due to the tension release when rocks break apart and magma finding a new opening to flow into. At the moment at least, the magma is not rising vertically therefore not going to erupt in the coming days but nobody knows if/when it will start to rise near the surface. Most likely most magma flow happens horizontally and moves from place to place.
To me, the earthquakes swarms seem too inconsistent for eruption to happen at the moment. You can see this graph below.
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EQ swarm comes and then goes. Before the last eruptions the quakes were constant and not much quiet periods in between. Right now the magma probably finds a new opening to flow into and then the tremors calm down. When a new area get full and the pressure builds, rock layers will break again and new eq swarm comes. Thats's my theory but im no scientist, just have been following iceland geology and volcanoes for a long time.
Anyway at the moment Iceland has announced a state of uncertainty and they are closely monitoring what happens because conditions can take a turn very fast and with little warning. At least for the moment being there is no imminent eruption danger.
It can also happen that that things will quiet down and absolutely nothing comes out of it. It has happened before in 2021 and can happen again. In 2021 though the land rise was not that fast and much.
Here is a random photo I have taken in Grindavik
Icelandic government is developing measures in case the worst case scenario happens. How to get power, heat and water back fast if the power plant were to go offline. Also what to do if lava starts to flow towards the Grindavik. It would be a catastrophe if the town would get caught in Lava. Reportedly they are prepared to try to divert lava flow with huge barriers and gravel hills if it were to come to that.
This is the first time I am hoping that the eruption will not come due to it possibly being in a very bad location. If the eruption would happen in an uninhabited place where the last three happened then why not, its a sight like no other.
If there is any major developments in the situation then I will make another update. Overall its extremely interesting for me to follow this.
