During the night of 30-August-2019 an earthquake swarm took place on Reykjanes ridge. Close to 69 earthquakes took place and largest earthquake had a magnitude of 3,0. Other earthquakes were smaller in magnitude.
The earthquake swarm on the Reykjanes ridge. Copyright of this image belongs to Icelandic Met Office.
Earthquake swarms are common in this area. This might result in a bigger earthquake swarm later or a new one at nearby location, that is also happens sometimes in this part of the Reykjanes ridge. This earthquake activity doesn’t appear to be connected to any volcano activity.
At 01:27 UTC on 24-August-2019 an magnitude 3,4 earthquake took place in Krýsuvík volcano. This earthquake was felt in Hafnafjörður, Garðabæ and Kópavogi. This earthquake started a minor earthquake swarm in Krýsuvík volcano.
Earthquake swarm in Krýsuvík volcano. Copyright of this image belongs to Icelandic Met Office.
This earthquake swarm seems to be over when this article is written. Earthquake swarms like this are regular at this location.
A minor earthquake swarm took place in Bárðarbunga volcano today (21-august-2019). Largest earthquake had a magnitude of 3,5 and other earthquakes that happened are smaller in magnitude.
The earthquake in Bárðarbunga volcano (green star). Copyright of this image belongs to Icelandic Met Office.
This earthquake was in the north-east part of the caldera. In last few months earthquake activity has been increasing in that part of the caldera. Earthquake activity in Bárðarbunga volcano is due to magma inflating the volcano.
Over the last few days there has been increase in earthquake activity in Hamarinn volcano (Bárðarbunga volcano). In Global Volcanism Program record this area is known as Loki-Fögrufjöll. Largest earthquakes today (12-August-2019) had a magnitude of 2,8 and 2,5 and other earthquakes have been smaller in magnitude.
The earthquake activity in Hamarinn volcano (red/blue dots at the edge of the glacier). Copyright of this image belongs to Icelandic Met Office.
Last time Hamarinn volcano had this type of earthquake activity it erupted for few months after it had started. That was on 12th July 2011. I wrote about those events here and here (glacier flood that followed, July 13th 2011). There were minor additional eruptions in August and November in 2011 according to the tremor data, those eruptions only lasted for ~4 hours at most. Since then this area has mostly been quiet and did drop down in activity after the eruption in Bárðarbunga volcano in 2014 to 2015.
It is unclear what is going on in Hamarinn volcano, for now there is no eruption taking place and any eruption is going to appear clearly on harmonic tremor data on the SIL network. It seems that eruptions in Hamarinn volcano start without any earthquake activity, I don’t know why that is. Last major eruption in Hamarinn volcano took place in the year 1910 from June 18 to October.
It was announced today (8-August-2019) that gas has started to appear from Öræfajökull volcano. It is not clear from the news when this gas was discovered but it might have been just few days ago. Icelandic Met Office has already made attempts to collect the gas for analyse, last attempt failed due to how little gas is coming from the ground. That might change as this situation changes. What type of gas is leaking out is not known but there is a good chance that this is mostly CO2, SO2. It has been quiet in Öræfajökull volcano in recent weeks. It is a question if this lack of activity is what happens with some volcanoes just before an eruption as is indicated by a study that was done few years ago (information about the study can be found here).
What this means is unclear. Earthquake activity remains at minimum in Öræfajökull volcano. There is a chance this gas is a signal for more earthquake activity even if an eruption doesn’t happen. It is unclear what happens before an eruption in Öræfajökull volcano since last eruption took place in 1727 3rd of August to 1728 1st May.
Earthquake activity in Öræfajökull volcano today. Quiet volcano at the writing of this article. Copyright of this image belongs to Icelandic Met Office.
Loftbólur á yfirborði Kvíárlóns (Rúv.is, Icelandic, picture, map)
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