Volcano and earthquake activity in Iceland
This evening on 16-October-2022 an strong earthquake swarm started close to Geirfugladrangur and Eldeyjarboða on the Reykjanes ridge. At the writing of this article the strongest earthquake had a magnitude of Mw4,4 but that might change without warning.
It is difficult to know how this earthquake swarm is going to evolve but there are clues in this activity that this might be a large earthquake swarm. However, activity in this area is also known to just stop without warning.
The police and Icelandic Met Office have now advised people not to go to Mýrdalsjökull glacier. This is after the earthquake swarm earlier today. According to Icelandic Met Office this earthquake swarm is similar to what happened before the minor eruption in Katla volcano in July 2011 that resulted in a glacier flood down Mýrdalssand and destroyed the bridge over the glacier river in that area. All trips to see ice caves in Mýrdalsjökull glacier have been temporarily forbidden by the Icelandic Police.
In July 2011 it took around 24 hours from the start of the earthquake activity then until something happened. If that is going to be case now I don’t know. That this activity is similar to July 2011 eruption is worrying. The eruption in July 2011 was minor and didn’t break the glacier, but it resulted in damage in that area from the glacier flood.
Largest earthquakes now have the magnitude of Mw3,8 and Mw3,0 (few of them). Other earthquakes have been smaller in magnitude but that might change without warning.
Today (16-October-2022) an earthquake swarm started in Katla volcano in Mýrdalsjökull glacier. Largest earthquake at the writing of this article had a magnitude of Mw3,8. I don’t know if it was felt in nearby towns and farms. Second largest earthquake had a magnitude of Mw3,0.
This earthquake swarm is ongoing at the writing of this article and the situation can change quickly. This might be a normal earthquake swarm and nothing more might happen. This type of earthquake swarm is not uncommon and I am not sure what is required for an eruption to start in Katla volcano.
This is a tricky thing to write about. Because nothing has started on the surface and might not start on the surface. It seems that something is going on in Grímsfjall volcano. Since the glacier flood is almost over or has finished the harmonic tremor level should have started dropping, it has not done so and I am not sure why that is. This might be boiling of the hydrothermal systems in Grímsfjall volcano when the pressure on the suddenly drops. Currently the harmonic tremor doesn’t look like it has reached eruption levels, that might change without warning.
It is difficult to know what is going on. Since there seems to have been a change in Grímsfjall volcano after the big eruption in May 2011. What that change is I don’t know. It seems to have slowed down Grímsfjall volcano eruption rate from what it was, its been 11 years since last eruption. It might continue if no eruption starts now following the small glacier flood that just ended.
Yesterday (12-October-2022) an earthquake swarm started south and east of Grímsey island. This is in the same area as an earthquake swarm took place few weeks ago. Largest earthquakes so far in this swarm had a magnitude of Mw3,5. Larger earthquakes remain a possibility. Largest earthquakes have been felt in nearby populated areas.
This area has frequent earthquakes. This earthquake swarm might grow as sometimes happens. It might also equally just stop, since that is also something that earthquake swarm in this area do.
Today (12-October-2022) at 14:18 UTC an earthquake with magnitude of Mw3,5 took place in Krýsuvík-Trölladyngja volcano. This earthquake was followed by few smaller aftershocks. This earthquake seems to be happening because of a inflation that is taking place in Fagradalsfjall volcano and this strongly suggests that inflation in Fagradalsfjall volcano is slowly reaching critical levels. There is no eruption expected from Krýsuvík-Trölladyngja volcano as is.
This earthquake activity suggests that more stronger earthquake activity is possibly on the way. When it might start is difficult to know for sure. This has been the pattern in recent months. Earthquake activity starts to appears like this and then one day a major earthquake swarm starts. What happens now is a wait and see as before.
Since yesterday (06-October-2022) the earthquake activity has been increasing in the volcanoes Fagradalsfjall and Reykjanes volcanoes. Please note that Global Volcanism Program has updated the informations regarding Fagradalsfjall mountain and now classifies it as its own volcano, this is after a new report and information from Icelandic Met Office. From now on I am going to use that classification when updating on activity in Fagradalsfjall volcano. I’ll not update older articles (too much work), but this also applies to them as such.
This also means that Fagradalsfjall is a new volcano in Iceland.
Earthquake activity at start of an eruption cycle in Fagraldsfjall volcano are not large. They grow larger once magma has started to push into the crust, until then the earthquake activity only seems to happens with minor earthquake swarms.
Article updated with new information.
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This earthquake swarm is around 1330 km away from Reykjavík and in the North Atlantic ocean. What is going on here is unclear, but this is probably an earthquake swarm before an eruption or during an eruption in that area. The ocean depth at this location is between 3 to 4 km so nothing is going to appear on the surface.
Total of 61 earthquakes have been recorded since 26-September-2022 when this activity started. Largest earthquake so far had a magnitude of Mw5,7 but several earthquakes with magnitude of Mw5,0 appears to have taken place. Because how remote this area is only the largest earthquakes are being recorded. It is possible to monitor the earthquake swarm here on EMSC website.
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This is a short update on the earthquake swarm that is ongoing east of Grímsey island.
The earthquake swarm that started on 8-September-2022 east of Grímsey island is ongoing. Over 6000 earthquakes have been recorded at the writing of this article. Largest earthquakes in recent days have had a magnitude Mw4,2 and have been felt over a wide area. People living in Grímsey island and tourists in Grímsey island feel this earthquake swarm clearly.
There are no signs of an eruption is about to start. That might change without warning, but I don’t know likely an eruption is in this location because there’s no good data on possibility of an eruption. There’s also no clear reading from any nearby GPS station. This most likely is just an earthquake swarm. The risk of a magnitude 6 to 7 earthquake in this area remains high and such earthquakes can happen without warning.
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During the night of 8-September-2022 at 04:01 UTC an earthquake with magnitude of Mw4,9 took place east of Grímsey island. According to news reports this earthquake did wake up people in Grímsey island and was felt over a wide area in north-eastern Iceland. Over 22 earthquakes with magnitude above Mw3,0 have taken place since this earthquake swarm started. Over 700 earthquakes have been recorded at the writing of this article. This earthquake swarm is ongoing and number of earthquakes and possible stronger earthquakes might happen after this article is published.
Earthquake swarms like this are common in this part of Tjörnes Fracture Zone and happen every 2 to 3 years, it is longer between large earthquakes in the magnitude range of 6,0 to 7,0, but they do happen. This area has an volcano, but there are no signs that is currently active and remains dormant.
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