Category: Swarm

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Minor earthquake swarm on Hekla – SISZ boundary

During the night of 9-April-2015 an earthquake swarm started on Hekla volcano – SISZ boundary. This has been for most part a minor earthquake swarm so far. With largest earthquake only having the magnitude of 2,8. This earthquake activity has appeared clearly on my Heklubyggð geophone.

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The earthquake swarm is located north of Mýrdalsjökull and Eyjafjallajökull. South of Hekla volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake swarm appears to be tectonic in nature. This means there is a higher chance it might be related to stress changes in SISZ (South Icelandic Seismic Zone), rather then any activity in Hekla volcano. There is little chance in my view that this activity is going to trigger any eruption in Hekla volcano, I just can’t rule it out at the moment. Currently it appears that this earthquake swarm is ongoing. This earthquake swarm doesn’t appear to be moving quickly at the moment, that might change but I am doubtful that is going to happen while minor earthquakes are just taking place. If stronger earthquakes start to happen this minor earthquake swarm might grow into a middle sized one or a big one. Largest known earthquakes in this area have reached magnitude Mw7,0. Such earthquake has not taken place in this part of SISZ for the past 103 years. Currently there is nothing indicating that earthquake with that type of magnitude is about to take place.

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Article updated at 00:20 UTC on 10-April-2015.

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Earthquake swarm in Krísuvík volcano

Today (31-March-2015) there has been a minor earthquake swarm in Krísuvík volcano. Total number of detected earthquakes was 27 so far.

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The earthquake swarm in Krísuvík volcano today. Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this swarm had the magnitude of 2,6 according to reviewed results from Icelandic Met Office. Other earthquakes where smaller in magnitude. This is just tectonic activity at the moment. There has been inflation and deflation taking place in Krísuvík volcano for past several years and such activity is known to start strong earthquake activity in both deflation and inflation stage. At the moment there is nothing suggesting there is an eruption imminent in Krísuvík volcano.

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Deep earthquake activity in Bárðarbunga and Öræfajökull volcano

Today (28-March-2015) there has been deep earthquake activity in Bárðarbunga volcano. This suggest that there is a fresh injection of magma into Bárðarbunga volcano system. If this is going to result in new eruption remains to be seen. It is not impossible at current time to happen. So far however nothing has happened. Deepest earthquake had depth of 21,1 km, others earthquakes are shallower.

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Earthquake activity in Vatnajökull glacier today. Copyright of this image belongs to Icelandic Met Office.

Öræfajökull volcano

Today (28-March-2015) there has also been deep earthquake activity in Öræfajökull volcano [Wikipedia link here]. This activity is not new and has been taking place every few months for the past 10 years or so. Quiet times are different in length. Each earthquake swarm that takes place is different in both magnitude and length, current activity appears to be deep, but mostly small earthquakes, less then magnitude 1,5 for most part. Deepest earthquake in this swarm had the depth of 25,0 km. This earthquake activity is only due to fresh magma entering Öræfajökull volcano system, not tectonic activity in this area due the depth of the earthquakes are taking place.

Based on historical accounts of earlier eruptions (1362 and 1728). It appears that eruptions in Öræfajökull start with powerful earthquake swarm (magnitude 4,0+ earthquakes). The following eruption is an ash cloud one with glacier floods taking place, with that phase lasting up to 48 hours. What happens after that is unclear, since it was not documented properly by historical records (at least not properly mentioned or lost due the old age of the historical records in question). Eruptions can last for up to 45 days, based on earlier documented eruptions. Current earthquake swarm is inside Öræfajökull volcano, since it is not round volcano, but goes a little to north where the earthquake swarm is taking place. There is no fissure swarm connected with Öræfajökull volcano, it does not rule out that one exist, it is at least not known at the moment. At the moment there are no clear sign that there is increased eruption risk from Öræfajökull volcano. That might change without warning, as is always the risk with volcanoes.

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Minor earthquake swarm in Hekla volcano

Since yesterday (26-March-2015) a minor earthquake swarm has been taking place in Hekla volcano. This has not been continuous earthquake swarm and there has not been huge number of earthquakes taking place. Largest earthquake had the magnitude of 1,4.

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The earthquake activity in Hekla volcano. Copyright of this image belongs to Icelandic Met Office.

This earthquake activity took place deep inside Hekla volcano, with the deepest earthquake being on 17 km depth (mag 1,4). Other earthquakes took place on shallower depths, but all depths where greater then 10 km. What exactly is happening I do not know, at this depth it is possible the earthquake activity taking place is due to magma movement rather then tectonic changes. I don’t expect any eruption to take place in Hekla volcano at current time.

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Minor earthquake swarm close to Eldeyjardrangar on Reykjanes ridge

During the night (on 21-March-2015) a minor earthquake swarm took place close to Eldeyjardrangar on Reykjanes ridge. Largest earthquake in this swarm had the magnitude of 3,2. Total number of earthquakes in this swarm was around 30.

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Earthquake swarm close to Eldeyjardragnar. The green star shows the magnitude 3,2 earthquake. Copyright of this image belongs to Icelandic Met Office.

Earthquake swarms like this are common in this part of the Reykjanes ridge. It is difficult to know if more earthquake activity is going to take place soon.

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Article updated at 20:01 UTC.

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Minor earthquake swarm on the Reykjanes ridge

Today (19-March-2015) at 15:24 UTC a minor earthquake swarm started on the Reykjanes ridge. This earthquake swarm was minor, it however might be clue that more activity might happen soon in this part of the Reykjanes ridge.

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The earthquake activity on the Reykjanes ridge today (19-March-2015). Copyright of this image belongs to Icelandic Met Office.

Largest earthquake in this swarm had the magnitude of 3,5 and other earthquakes where smaller. Last earthquake swarm in this area took place on 3-March-2015 and I did write about it here.

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Minor earthquake swarm on the Reykjanes ridge

During the night (3-March-2015) there was a minor earthquake swarm on the Reykjanes ridge. Largest earthquake had the magnitude of 3,1. Other earthquakes where smaller.

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Earthquake activity on the Reykjanes ridge during the night. Copyright of this image belongs to Icelandic Met Office.

Most of this earthquake activity was deep, with most depth being at 16,0 km. This suggest that this earthquake swarm happened mostly due to magma movement at depth. There is nothing suggesting that eruption is imminent in this area. Depth of the ocean at this location is around 400 – 1000 meters, this means that any signs on the surface are going to be hard to detect or not detected at all.

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Article updated at 18:44 UTC.

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The eruption in Holuhraun has ended

The eruption in Holuhraun ended yesterday (27-Februar-2015) it seems. Current status of Bárðarbunga volcano is now yellow. While the eruption is over the area continues to be closed for public due to danger of new eruptions in the area, both outside the glacier and inside it. It is unclear what is going to happen next in Bárðarbunga volcano. There is also a considerable gas emission from Holuhraun crater at the moment and that gas is toxic.

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Current earthquake activity in Bárðarbunga volcano and for the past 48 hours. Copyright of this image belongs to Icelandic Met Office.

What happens next is not known. There is a high risk of new eruption taking place under the glacier. I don’t know if subsidence of the caldera is going on at the moment or has stopped. It might take days, weeks or months until inflation starts again in Bárðarbunga volcano. This is a rifting event and that means this is far from over. For the moment however it is going to be a little break (at least, it can be hope) in the activity in Holuhraun or Bárðarbunga volcano. The lava and the crater continue to be extremely hot (~800C) and are going to remain hot for many years (5 years?).

Since the eruption in Holuhraun is over I won’t post any update next Wednesday. Next update is going to be when something happens.

Icelandic News

Icelandic Met Office information website
The eruption has come to an end (Icelandic Met Office)

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Article updated at 16:59 UTC.

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No lava flow visible in Holuhraun main crater

Today (27-February-2015) there was no visible lava flow from the main crater in Holuhraun. The eruption is not officially over, this however seems to be the end of this eruption in Bárðarbunga volcano. It appears that gas emission continue from the crater and Holuhraun at the moment, it can be expected those are going to end in next few weeks to months.

New video of the crater in Holuhraun can be found here.

Ekki glóð í gígnum í Holuhrauni – Myndband (Rúv.is, video)

It is not known what happens next in Bárðarbunga volcano or when it is going to happen. All that can be done is to wait and see.

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Bárðarbunga volcano weekly update for 25-February-2015

There hasn’t been a lot of new information about the eruption in Holuhraun this week. Earthquake activity continues in Bárðarbunga volcano as before, but at slower rate and earthquake with magnitude 3,0 and larger have almost stopped at the moment.

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Earthquake activity in Bárðarbunga volcano for the past 48 hours, no earthquake above magnitude 3,0 has been recorded for the past few days. Copyright of this image belongs to Icelandic Met Office.

Earthquake activity continues in Bárðarbunga volcano, but at far lower level than just few weeks ago. Subsidence has slowed down considerably at the moment. It has not stopped. There are earthquakes along the dyke from Bárðarbunga volcano, suggesting that pressure might be increasing in it. That in it self might not lead to a new eruption.

The eruption in Holuhraun continues, but at low level. The only remaining vent that is now open is building a new crater inside the big crater that has now stopped erupting. The eruption might continue at this low level for many more months. Current status of the eruption is not known due to extremely bad weather in Iceland at the moment. The eruption is not over, it is however really small at the moment.

Due to bad weather I am expecting that my geophones might go offline due to loss of power or other connection problems that might happen due to this bad weather. Information about the storm can be found here. This is not a weather to travel outside. If you are in Iceland, stay where you are and don’t travel until the weather has passed over Iceland.

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Article updated at 16:35 UTC.