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Harmonic tremor in Katla volcano

At the moment there is an ongoing harmonic tremor going on in Katla volcano. It is just an small one, just above the background level noise floor. This is most likely an small dike intrusion. But nothing in the data from Icelandic Met Office suggests that an eruption has started in Katla volcano at this stage. But that might change without an warning, since this is an volcano after all. This change in harmonic tremor does not seems to be created by an glacier flood of some type. What is interesting is that this harmonic tremor pulse looks like an harmonic tremor pulse detected in the year 1999, just before an small eruption took place in Katla volcano southern caldera rim.

This harmonic tremor is in the high frequency range at the moment. But no change has been seen in the low frequency range at the moment. This is the same thing that did happen in the year 1999. At the moment however it is too early to know what is going to happen in Katla volcano for sure. All that can be done is to watch and wait. This might quiet down, or it might not. Only time is going to tell us what happens next. At the moment the harmonic is falling at fast rate, so this might be over.

Before the harmonic tremor pulse there was an earthquake swarm in Katla volcano caldera. The largest earthquake was ML2.1 and that was an long period event, but that tells me that magma was the source of this earthquakes in Katla volcano caldera. There where two earthquake swarms in the caldera today, but that makes total of three earthquake swarms in the Katla volcano caldera since the beginning of June.


The two earthquake swarms that took place in Katla volcano caldera today. Copyright of this picture belongs to Icelandic Met Office.


The only earthquake that I did record out of this earthquake swarm. This earthquake was ML2.40 with the depth of ~400 meters. This plot is filtered at 1Hz . This picture is released under Creative Common licence. See Licence web page for more detail.


Spectrogram of the ML2.4 earthquake in Katla volcano from this morning. This is filtered from 1Hz. This picture is released under Creative Common licence. See Licence web page for more detail.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can be seen at the end of this tremor chart from the Icelandic Met Office, but it is not clear at this SIL station. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can be seen (not clearly) at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.


Harmonic tremor can clearly be seen at the end of this tremor chart from the Icelandic Met Office. Copyright of this picture belongs to Icelandic Met Office.

The harmonic tremor is strong enough on many SIL station to go above the background noise level on the SIL stations (wind, ocean waves etc..). But this is not an strong harmonic tremor. They can be stronger.

This does NOT mean an eruption is imminent in Katla volcano. What this does mean that is an magma is on the move inside the Katla volcano. What happens at later time is something that nobody can guess at current time. But it is now time to watch Katla volcano even closer.

It is also important to notice that nobody really knows how Katla volcano behaves before an eruption. We only get those answers after an eruption in Katla volcano. For the moment we can only wait and see what happens in Katla volcano.

I am going to post more updates if anything interesting happens. Also, there seems to have been an Long period earthquake at 22:14 UTC, most likely in Katla volcano. It appeared on my geophone close to Hekla volcano. I am guessing the size of this earthquake is ML2.0+.

Blog post updated at 22:39 UTC. Spectrogram picture added.

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Last update on Hekla volcano (for now). Correction on mobile emergency SMS. Earthquake swarm at Reykjanes Ridge. The media hype. Help needed!

Here is an short update on few things.

Hekla volcano: Everything is quiet at Hekla volcano. Movements of magma deep down in the crust have not changed that fact. Nobody knows when it is going to stop begin quiet. Until it does. There is no need to worry about it. Update 2: The movement on the GPS instruments was most likely an deep dike intrusion in Hekla volcano. It was not followed by any earthquakes for some reason.

Correction: I did say that in my earlier post that if there was an emergency in regards to Hekla volcano due to an eruption. The Public Emergency Authority in Iceland would send out an SMS to everyone in the local area. This is half wrong and half correct. They are going to send an SMS, but apparently only to registered locals in the area. Few years ago there was talk of setting up an system to send SMS to everyone around Hekla volcano if an eruption would start. But that system appears not to have gone past the idea stage. I do not watch the changes in this field, so I did miss that. For that I am sorry.

Earthquake swarm at Reykjanes Ridge: Few days ago there was an minor earthquake swarm at Geirfulgasker on the Reykjanes Ridge. This was normal tectonic activity for this area. But it has been having earthquake swarm every few months now for an long time. This earthquake swarm was an small one compared to many other earthquake swarms that have been taking place there.

The media hype: To Daily Mail in the UK. I am not an volcano expert. I also don’t claim to be one. You can’t find that claim on this blog. Because I am not an volcano expert. You also got an wrong volcano in your news and you spelled the name wrong on Hekla volcano. You should correct your news if you want to call your self an newspaper. Also, nobody sad anything about possible size of an ash cloud from Hekla volcano. You just made that up. The media should also relax, drink less coffee. There is nothing going on at the moment. You can hype all you want when something interesting is going on. If the media doesn’t get what I am saying, this here (Youtube, Newswipe) should help you get the clue. I at least remain hopeful, or something.

Help needed!: I need help. I am broke again (demit!). I might be having an low paying job. But my pay goes mostly up to my debts and July was an bit harder then I expected (I try to leave something for food, but this time around it did not work out as I planned it). But that was due to the last VISA payment that I am ever going to make. I am going to get paid on the 1 of next month at least. I am now only left with 2500 ISK (€15) and €24 (182 DKK) to buy food (total 39€) for the rest of the month or until I get paid from my job. My social welfare (that I working toward getting off one day) is always paid on the 1st of every month. My rule about asking for donations is that it is the only option that I have left. Besides not eating anything. But I don’t really regard that as an good option. My status is that the worst is most likely over now, since no more surprise VISA bills (I closed it and I am glad!) and now it is just steady payments of the overdraft until it is finished. But that going to take about 6 to 11 months to finish. Depending on the work income that I have until the end of October this year. If anyone wants proof of how broke I am, I can provide it.

So I once more ask again for donations so I can eat something this month. I am living cheap, but at the moment it did not work out as I planned. Thanks for the help in advance! 🙂

Other: I cancelled going to school this autumn. I am going to work more to pay down my debts faster. Then I plan moving to Denmark in the year 2012, when I have the money to move again. But from end of October I am going to provide regular and good updates in regards to volcanoes and earthquakes, since I won’t be working from that time in companies. But I am going to be working on a book that I am going to publish early 2012 (I hope).

Update 1: For everyone how donates there is going to be an e-book (pdf format only from me) about Icelandic volcano eruption for anyone how wants a copy. But I plan on writing book about volcano eruptions in Iceland soon after they happened. I finally made up my mind on how to write that type of book. It won’t take me an long time write those books, since it is just facts and details about the eruption. I am also going to sell those books on Amazon Kindle and web page named Smashwords. I hope to release the book about Eyjafjallajökull volcano eruption 2010 in December 2010 or January 2011.

Blog post updated at 00:27 UTC on 8. July 2011.
Blog post updated at 07:19 UTC on 8. July 2011.

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Update on Hekla volcano status

Here is an update on Hekla volcano. First of, for the moment the inflation in Hekla volcano is deflating at the moment. This is following the same pattern as before last time this did happen. But that does not mean this might not happen again soon. For the moment, nobody knows what exactly is going on inside Hekla volcano as there are no earthquakes following this inflation period. The magma that is on the move down there is most likely moving deep down in the crust also, as Hekla volcano does not have shallow magma system that I know of (or is known of anyway).

What did happen inside Hekla volcano was most likely an dike intrusion somewhere in the volcano system. This dike intrusion did not create any earthquakes, that suggests to me that it was travelling trough an old dike system already in place inside Hekla volcano system. This is most likely to happen again in Hekla volcano, if that starts an eruption is hard to know for sure.

In regards to possible ash cloud from eruption in Hekla volcano is impossible of know for sure now what happens in next eruption. There might be an ash cloud, but then again there might not be. All that can be done is to wait and see what happens in the next days, weeks or years.


The GPS movement of Hekla volcano. The inflation and the deflation can clearly be marked here. There is an inflation spike around 2011.45 on this plot. But this did also happen in April/May I think (but it might be wrong). Daily updated chart can be found here. Copyright of this picture belongs to Icelandic Met Office.

It is also important to notice that Civil Emergency Authority (Almannavarnir) in Iceland advice against it travelling up to Hekla volcano at current time. Since an eruption can start in Hekla volcano without any warning at all and the maximum time that people have evacuate the mountain is from 1 hour and up to 1 hour and 30 min. No more then that. Being on top of Hekla volcano when an eruption starts is deadly to everyone. If you want to go up to Hekla volcano. Please let somebody know about and have an fully charged mobile phone with you at all times. As the Civil Emergency Authority send out an SMS message to all mobile phones in the area around Hekla volcano if an eruption is starting (I think they do that).

Icelandic News.

Almannavarnir: Hekla tilbúin í gos (Rúv.is, Icelandic)
Almannavarnir vara fólk við Heklu (Vísir.is, Icelandic)

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Magma movements under Hekla volcano have been confirmed

According to the news on Rúv the GPS movements that many have been seeing around Hekla volcano in the past few days are real. At the moment the civil disaster authorities have been notified and also local emergency authorities. Nobody seems to know what is going on with this magma moments for the moment. But they can be tracked with the GPS network to some extent. What is more interesting is that this does not seems to have started until few days ago. But first signals of this happening did take place in April and May, but at lot smaller scale. What is interesting is that fact that no earthquakes appear during this magma movements, there is also no harmonic tremor when the magma is moving around in the crust close to Hekla volcano. But if there is any earthquakes, noise or whatever coming from Hekla volcano it is going to appear on my geophone that is located about 16 km away from peak of Hekla volcano. The distance is even less from the actual edge of the Hekla volcano system it self.

Normally, there are no changes in the GPS network before an eruption in Hekla volcano. So this is highly unusual event in Hekla volcano since instrumental monitoring started few decades ago.

It is an question if this means an fissure style of eruption is going to take place in Hekla volcano. But that does sometimes happen, as with any volcano in Iceland. For the moment however the only thing that can be done is wait and speculate (within reason).

No eruption has started in Hekla volcano. But it can be assured that it might start without any warning and I might not be around the computer when that start, since I am working during the day and feeling tiered during the evening. But I am getting slightly better on that front, thankfully.

I am going to post more on this when I do know more, or if anything happens in Hekla volcano related to this.

Icelandic News about this.

Hræringar í Heklu (Rúv.is, Icelandic)

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Still quiet in Iceland

It is continues to be quiet in Iceland in regards to earthquakes. Just small earthquakes swarms have been taking place in Krýsuvík volcano and in Hengill volcano.

Sadly I currently don’t have a time to write an decent blog post about other interesting things in Icelandic geology or historic eruptions in Iceland (translated to english). But if nothing interesting happens, I plan to do so next weekend.

Other: My plans are not going as I planned. I am only going to be in school until the end of this year (starting from August) since I cannot afford it (yea, I am that broke). But school is going to give me more time to write on this blog rather then I am not working. In the new year of 2012 I am just going to do what I do so well now. Write, and write some more on this blog and a book or two. But I don’t think that I can manage to write more then that in one year.

I also want to thank my readers for this patents for the lack of updates and blog post this summer. As I am working all days now, except weekends from 08:15 to 16:15 UTC. It is an hard work that makes me tired, so I don’t have an lot of energy to write after the day.

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Glacier quakes seen in Mýrdalsjökull glacier and Vatnajökull glacier

It seems that there have been few glacier quakes in Mýrdalsjökull glacier over the past few days. This glacier quakes are created by rain or some other movement in the glacier it self. This glacier quakes normally take place when there is heavy rain, or when the glacier is just moving because of water that is flooding below it. Sometimes glacier quakes also appear to happen around hydrothermal areas, but those might be harder to detect due to distance.

While not on the automatic earthquake list due how poor quality the glacier quakes are. It is still possible to see them on the tremor charts that Icelandic Met Office has on-line.

Glacier quakes seen on tremor chart of Icelandic Met Office. The quakes create an pattern of spikes on the tremor chart, it mixes into the other earthquake activity currently taking place in Katla volcano. Copyright of this picture belongs to Icelandic Met Office.

Same as above. Bust just stronger then on Lágu Hvolar SIL station. Copyright of this picture belongs to Icelandic Met Office.

This glacier quake activity has also been taking place in Vatnajökull glacier. But the force for the glacier earthquakes in Vatnajökull glacier seems to be weather (rain and sun), rather then hydrothermal activity.

Glacier quakes can be seen close the 28th June line on the tremor chart. But most of the activity does not get recorded due to strong wind at the same time. Copyright of this picture belongs to Icelandic Met Office.

Other then this, it is quiet in Iceland. Both in earthquakes and volcanoes.

Update: I did update the history list for eruptions in Iceland to include the last eruption in Grímsfjall volcano.

Blog post updated at 22:36 UTC.

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Book about Icelandic geology

It is always good to know more. This book here offers basics details into Icelandic geology and what is the driving force behind it. This book is on my “to buy when I have the money” list. So I am not going to claim that I have read it.

I think that this book is good for people how want to know little more about Iceland and it’s geology. The Amazon review on this book is good.

This is an lame sale pitch in an attempt to earn me some money with Amazon UK sale programs. I get 5% of what the book sells on.

This is an off-topic blog post.

Blog post updated at 09:22 UTC on 26. June 2011.

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Quiet in Iceland. Picture of Grímsfjall volcano new crater lake

It has been quiet in Iceland. Some minor earthquake swarms have taken place. But they where all less then 50 earthquakes with sizes for most part less then ML3.0. So this is going to be an short blog post.

At Eruptions at BigThink Erik did link to an interesting picture of the aftermath of last eruption in Grímsfjall volcano.

Due to how quiet it is in Iceland. I am not going to have this blog post longer. But on other note, I am going to make fewer blog post this summer since I am working during the day and I am really tiered after I finish working. But I am going to due my best in keeping new blog post coming.

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New harmonic tremor spike in Katla volcano

Today around 16:00 UTC there was an new harmonic tremor in Katla volcano. This harmonic tremor has two sources. Hyrdothermal activity under the glacier, or magma moving deep inside Katla volcano (without creating many earthquakes in Katla volcano). It is unclear what is the case at the moment.

This spikes are so far not related to glacier floods from Katla volcano. But that sometimes also happen without an eruption being involved.


The harmonic spike can be seen here. Close the end of the chart. It is different then the background noise as it is more powerful then the background noise. Copyright of this picture belongs to Icelandic Met Office.

It is impossible to know what happens next. But it is also important to be aware of the fact that earthquake season is starting in Katla volcano. But that is normally from end of June to beginning of October (or when it starts to snow again in Iceland). So more earthquakes are going to be seen this summer also because of more SIL seismometers around Katla volcano.

So there is no reason to panic about Katla volcano at current time. But it is worth to keep watch on it anyway.

Notice: Updates might be an little few due the fact that I am now working all day during the week and I am tired in the end of the day with no energy to write new blog posts. But I am going to do my best anyway.

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Earthquake swarm in Presthnjúkar volcano. Update on Katla volcano

Presthnjúkar volcano: Few days ago an earthquake swarm did start in Presthnjúkar volcano. This earthquake swarm is entirely tectonic in nature. There is nothing that suggests that this earthquake swarm is connected to magma movements inside Presthnjúkar volcano system. So far this earthquake swarm has been slow and small. But the largest earthquakes have gone up to ML3.3 in size according to Icelandic Met Office.


The location of current earthquake swarm in Presthnjúkar volcano. Copyright of this picture belongs to Icelandic Met Office.

Katla volcano: Over the last 18 hours it has been quiet in Katla volcano. As no more earthquakes have been detected from it. I would not be surprised if there are more earthquakes swarms in Katla volcano in the next few weeks and months. It is an well known fact that Katla volcano is heading to an eruption. But nobody knows when that is going to happen.


Location of the earthquakes in Katla volcano yesterday. Copyright of this picture belongs to Icelandic Met Office.

Besides this two highlights of earthquake activity in Iceland. It has been rather quiet in the past few weeks. With just from ~100 to ~300 earthquakes during the week.