Earthquake swarm north of Herðubreið mountain

Yesterday (5. March 2023) at 18:00 UTC an earthquake with magnitude Mw3,4 took place north of Herðubreið mountain. This is a small earthquake swarm and is part of an ongoing earthquake swarm in this area that has been going on since October 2022 (or in around that month).

Green star and red dots north of Herðubreið mountain, that is located north-east of Askja volcano. Smaller earthquakes in Askja volcano shown with blue and yellow dots.
Earthquake activity north of Herðubreið mountain. Copyright of this image belongs to Icelandic Met Office.

Depth of this earthquake was only 4,2 km and earthquake activity in this area has been getting shallower with time. If this is magma, then there’s not a lot of it at this depth. Earthquake activity is small compared to the earthquake swarms that happen just before an eruption. It is clear that, if this is magma, it is not pushing its way up the surface at this point in time.

2 Replies to “Earthquake swarm north of Herðubreið mountain”

  1. Hi thanks for this Jon
    Looks like a swarm there today and I noticed a 4.1 this evening your time. Is this a start of something at Askia? Are there any web cams in that area?

    1. This is ongoing swarm in this area. I am not sure what’s going on. If this is magma, there doesn’t seem to be a lot of it, at least close to surface. Interestingly, this area seems to have a fault line at this location, with Herðubreið mountain being the largest volcano crater on that line. There is a chance this might be a second, unrelated magma movement not connected to Askja volcano. There’s a small mountain south of Herðubreið mountain, also seems to be made from an eruption sometimes in the past.

      The earthquake magnitude is now reviewed at Mw3,3. This area is extremely remote and there are no nearby web cameras. There might be some at distance of 100 to 200 km away. I don’t think those are going to help if an eruption happens in this area.

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