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.
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.
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.
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.
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.
Around 17:10 UTC an earthquake swarm did start in Katla volcano. This earthquake swarm is focused inside the Katla caldera at small point. The one earthquake that I have so far been able to record was an long period earthquake, but that suggests that this earthquake was created by magma movement. At current time I am not sure from where this earthquake did originate from. But from Goðabunga area in Katla volcano this types of earthquakes are common and no surprise at all.
At current time I do not know what this means for Katla volcano. But so far no increase in harmonic tremor has been detected on the seismometers around Katla volcano. But that might not start at current time, as harmonic tremor is only going to increase when magma starts to move inside the Katla volcano, like did happen in Grímsfjall volcano few weeks ago.
The location of this earthquake swarm strongly suggests that what is going on in Katla volcano is an dike intrusion in the Katla caldera. If that is powerful enough to start an eruption is an question remained unanswered at current time.
Area of activity is marked by the earthquakes. Looks like an dike intrusion into Katla caldera. Copyright of this picture belongs to Icelandic Met Office.
I am going to update or post new blog posts as this continues to develop. I do not think that this events are over. But it is hard to know for sure, since volcanoes are impossible to predict.
Post post updated at 18:39 UTC.
Here is finally an new blog post from me. This week has been busy. As I did move to Hvammstangi again for this summer. But I did move to Iceland on the 5. June 2011. But just for the next 1 to 3 years, depending on how things goes for me. My work is hard, so I might not often have energy to write new blog post during the week. But I am going to do my best.
Now, the earthquake information on what has been going on in Iceland for the past two weeks or so.
Katla volcano: Even after the harmonic tremor pulse last week. Nothing special has been going on in Katla volcano. But it did come to my attentions that Icelandic Met Office did notice that in Week 23 there have been explosions (mine for road work in the area). So when an “earthquake” appears in that area. It means that an mine explosion have taken place in that area. I do not know when they are going to stop mining operations in this area.
Presthnjúkar: There continues some earthquake activity in the Presthnjúkar area. This earthquake activity appears to be tectonic and nothing else. The latest earthquake swarm taking place there appear to be starting tonight. It is hard to be sure how it is going to develop over the past few hours.
Other: There is currently not a lot other thing going on in Iceland.
I hope to make an better post tomorrow. When I am well rested and focused.
There appears to be an harmonic tremor pulse going on in Katla volcano. While I currently do not think that this is going to start an eruption. It is worth watching this harmonic tremor pulse in Katla. But in the year 1999 this type of activity did result in minor eruption in Katla volcano on the 17. July that year (it is believed).
Harmonic tremor pulse can be seen on the SIL station Lágu Hvolar. Copyright of this picture belongs to Icelandic Met Office.
Harmonic tremor pulse can be seen on this SIL station Álftagröf. But it is hard too see it then on Lágu Hvolar. But that suggests that this tremor pulse is in fact quote weak one. Copyright of this picture belongs to Icelandic Met Office.
Harmonic tremor pulse can be seen on this SIL Rjúpnafell. It is more stronger signal then on Álftagröf, so it suggest that the source of this tremor pulse is closer to this station then on Álftagröf. Copyright of this picture belongs to Icelandic Met Office.
All pictures are from 16:28 UTC on 12. June 2011.
On other station around Katla volcano I do not see this harmonic tremor pulse on the Icelandic Met Office on-line tremor chart. But that does not mean that it this tremor pulse is not being detected on other SIL stations around Katla volcano.
The source of this tremor pulse is most likely an dike intrusion at great depth inside Katla volcano that is taking place without any earthquake activity. This has happened before without resulting in an eruption from Katla volcano (besides the event in the year 1999). I do not think that this means an eruption is going to happen soon. But this might signal that Katla volcano is about enter an more activity phase then in last few decades. But if that is going to turn out that way is something that only time can answer.
Here is an picture of how an ~5 million year old extinct volcano looks out. This pictures also show an old dike intrusion that might have gone up to the surface on that time. But I think it is hard to know that for sure, as erosion has changed the landscape a lot over the past 10 million years or so. So it hard to know for sure how deep this magma dike did actually form or if it was connected to an crater on the surface.
About 5 to 8 million years old dike intrusion into sedimentary rock that pre-dates this dike intrusion. I do not know by how much older the surrounding rock actually is. But it has small fossils in them.
The volcano that did create this old dike intrusion. The rocks in the area (old lavas) suggest that this was mostly basalt that did erupt from this volcano. But this volcano was on the old Snæfellsnes-Skagi Rift Zone.
Rift Zones in Iceland. Picture is from Wikipedia. See original copy here along with copyright information. Please note that this picture is NOT completely correct in regards to the facts. But is good for basic illustration of the rift zones in Iceland. Note that this is picture is missing the Skagafjörður Rift Zone (failed rift zone).
Picture of what can be seen of the Snæfellsnes-Skagi rift Zone. (I think it is the correct name for it). The mountain behind it is also an massive old volcano that was active at the same time as this rift zone. The houses there belong to my mon and dad (also on the picture below this one). They run an sheep farm.
Picture of Snæfellsnes-Skagi rift Zone to the north. The same volcano as on picture above can also been seen on this picture. But what is not seen is the third volcano that is in this area (also extinct). But glacier activity did remove all major traces of that volcano long time ago.
I am going to post more pictures of this area during the summer. Even if it is just small part of Iceland, it has an lot of geological history to show. All of it is connected to volcanism and glacier activity over the past 8 million years (or about that) time. Too see full size of the pictures, just click on them.
Summer: I am now going to start working in few days. I think that this work is from 08:00 to 17:00 every day. So updates might be an bit few while I am working. But I am going to do my best to cover what happens in earthquakes in volcanoes while I am working. But I am working so that I can pay down my debt faster then I normally would have done with just my welfare benefits that I get in Iceland. I need to pay down my debt, as it has gotten quite high since I was unable to make my living in Denmark at current time.
Denmark: I plan to moving back to Denmark in about 2 to 3 years time. But Iceland is not my place in terms of culture and people. That is just the way it is. While Iceland is my place in terms of geology that is just not enough for me. But before I move back to Denmark, I am going to have the income that supports my living in Denmark. My plan is that I am going to move to Copenhagen and live there for infinite amount of time. I might move to Portugal at later date (10 years later?), but at the moment that is just an idea that I am exploring for the moment. Nothing might happen with that idea when it comes down to it.
PayPal: I have given up on having credit card in Iceland. So I am closing it down from July. This means that I also am going to close down my PayPal account, as it is connected to my Icelandic credit card. But do not worry about this. I plan to open up an new PayPal account and connect it to my danish card. That is more easy, as it is technically not an credit card. But still can be used on the internet for paying for stuff like normal credit card. If people understand what I am meaning. This process is going to take few days until it is fully completed. When it is done, the PayPal donations buttons are going to appear again on this web site.
Other: I don’t think that there is other information. I forgot what I was going to write here, so it cannot have been important for me. But if it, then I am just going to post update here about it.