Volcano and earthquake activity in Iceland
According to the automatic SIL system that IMO runs there was a ML3.9 magnitude earthquake about 18.3 km north of the island Grímsey, this earthquake happened at 09:00 UTC. The automatic depth was 14.7 km. This numbers are expected to be changed as the earthquake get reviewed by seismologist at Icelandic Met Office.
No damage is expected from this earthquake. But there is a good chance that it might have been felt in Grímsey Island.
I have added a new geophone station to the webicorder web page. The station name is Þorgrímsstaðir (Thorgrimsstadir). Tomorrow the station is going to it’s correct location. But for the next few hours I am going to run it at home for some testing and set-up proposes. At current time it does not have a GPS clock, so I won’t use the data from it until I have a GPS clock to get both location and time with atom accuracy.
This station is going to replace the Hvammstangi geophone in February 2011. But until Hvammstangi geophone goes off-line I am going to have both station online.
I have been viewing data on Krísuvík volcano and what has been happening recently. Out of this checking I have come to a conclusion that a eruption in Krísuvík volcano is going to place in immanent future. When that might happen is impossible to know for sure.
Far as I know there is no written history on the last eruption at Krísuvík volcano that took place in 14th century. Because of this lack of historic witness of the last eruption in Krísuvík volcano it is impossible to know how the Krísuvík volcano is going to behave before it starts erupting.
It is my un-professional opinion that when a eruption starts in Krísuvík volcano we are going to see something like that took place in Krafla volcano when it erupts. Not exactly like Krafla volcano but something along those lines in eruption style. But Krísuvík volcano is going to have Hawaiian type eruption style when it starts erupting. Unless the eruption takes place under water. Then a Surtseyjan style eruption takes place while a water can get into the crater.
Please note that this is a theory that I am working on. It might work out in part or in full. But then again it might be completely wrong and not work at all. If the second option is true, then I am going to start again and make a new idea on what is going on at Krísuvík volcano.
I got this pictures in a email from a person how wants to remain nameless. Don’t ask me why, it is just a request that I got with the email and I see no reason not to grand it.
The hot springs at the south end of Kleifarvatn lake hot springs. The hot springs there are not new. But they do get lost when the water level rises in Kleifarvatn lake. When the water level dropped after the year 2000 years in the area this hot springs where for the first time visible to humans.
Click on all the pictures to get a full resolution.
The earthquakes swarm at Krísuvík (close to this area) continues with few breaks it seems.
I don’t have a lot to write about the earthquake swarm in Krísuvík volcano that took place there yesterday. But according to IMO the largest earthquake was felt in Hafnafjöður and in Reykjavík.
Here are the wave form data of the largest and the second largest earthquakes. There are no location data in this image. As I have not had time to put them into the wave form data.
From Hekubyggð. This is the ML2.8 earthquake.
From Hvammstangi. This is the ML2.8 earthquake. This one is low-pass filtered at 4Hz.
From Hekubyggð. This is the ML2.5 earthquake.
All pictures can be clicked to see the higher resolution of them.
Here are two earthquakes that I did record yesterday. The earthquakes took place at Arnarvatns highland and in Krísuvík yesterday. The difference between the earthquakes is that one of them took place where the crust is old and carries the earthquake wave well. The second earthquake(s) took place where the crust is young, fractured and does not carry the earthquake wave that well most of the time. If a fracture area is not in-between the epicentre and the sensor in question.
The earthquake at Arnarvatns highland. The earthquake wave clearly shows what type of crust it has been going trough. In this case a old crust that carries the wave well in my direction. I cannot tell what way the crust fractured in this case, as I need a minimal of three geophones to do so.
The Krísuvík earthquakes. This is actually a string of many earthquakes. When this happens the SIL system that IMO has major issues with locating the earthquakes. As the S wave often get absorbed by the next P wave that follows the next earthquakes. Sometimes however the waves get separated at some distance. That often helps to figure out how many earthquakes happened at the same minute. What is also interesting about this earthquake is the fact that it is “noisy”. But a normal earthquakes has a clear P wave and clear S wave. But on Reykjanes and Reykjanes Ridge there are often noisy earthquakes. I do not know why that happens and I don’t think the reasons for noisy earthquakes are not at all understood (far as I know anyway).
This map here shows how warm the hot water is in Iceland. Where I live the hot water is about 66C warm. It is a deep magma that warms the ground water up to this levels. There is a good article on this process at Wikipedia here.
Text updated at 17:15 UTC on the 11th of December 2010. Spelling error fixed and minor text changes.
Time has just put Eyjafjallajökull as the 4th biggest buzzword of the year 2010. The list can be seen on the web pages below.
Top 10 Buzzwords – 4. Eyjafjallajokull
The Top 10 Everything of 2010
Icelandic News about this. Use Google Translate to make sense of the Icelandic news.
Eyjafjallajökull á topp 10 lista (Rúv.is)
In a press release by Almannavarnir (Iceland Civil Protection) it is announced the lowering of the warning level around Eyjafjallajökull from danger area down to uncertainty level. There are also some travel restriction lifted that have been in place around Eyjafjallajökull volcano. The current warning level is the lowest warning level that Almannavarnir has.
The Press release by Almannavarnir in Icelandic. Use Google Translate at own risk.
Lækkun á almannavarnastigi frá neyðarstigi niður á óvissustig vegna eldgossins í Eyjafjallajökli (almannavarnir.is)
Icelandic News about this.
Almannavarnastig lækkað í óvissustig (mbl.is)
Almannavarnir lækka viðbúnaðarstig (Rúv.is)
Almannavarnastig vegna Eyjafjallajökuls lækkað (Vísir.is)
Over the past two weeks there have been signs appearing that a eruption might be close in Grímsfjall volcano. But a GPS station named Skrokkalda. This GPS station has started to move north, but this indicates that inflation has started in Grímsfjall volcano at full power. This did also happen at the same GPS station in 2004 before the eruption in Grímsfjall volcano that same year. But it is debated if this movement was created by ice or by a dike intrusion in Grímsfjall volcano. It is my just my personal opinion on this movement that takes place at the GPS station.
It currently remains to be seen if this northerly movement continues or if it starts to deflate again. So far this is the only indicator that Grímsfjall volcano is getting ready for a eruption. When this did happen in the year 2004 it was almost three weeks after this process started until a eruption took place. But then a glacier flood did trigger the start of the eruption in the year 2004.
For the moment the only thing to do is to wait and see what happens with Grímsfjall volcano. Nobody can tell how long the wait is going to be.
The earthquake swarm that started two days ago at Arnarvatns highlands continues in similar manner as was seen in the earthquake swarm that took place under Blöndulón lake few weeks ago.This earthquake swarm is taking place in a fracture zone known as West Iceland Fracture Zone (WIFZ). But that fracture zone sits between East Iceland Rift Zone and Snæfellsnes volcano zone. This area is known for strong earthquakes, but in the year 1974 there was a magnitude earthquake that had the size Mb5.5 to Mw6.1 (I am not sure on the exact size of this earthquake). According to news there is speculation that this earthquake swarm is somehow connected to the earthquake swarm that did happen under Blöndulón lake few weeks ago. This area is unpopulated and several tens of km to next farm in this area.
Click on the picture of better resolution. Picture is taken from here (Icelandic).
Explanation for the numbers in the picture. The number account for the fracture direction in the area. 1: Northwest-Southwest fracture. 2: West-East fracture. 3: North-South fracture. 4: Northeast-Southwest fracture.
Where the earthquakes are currently taking place are on the west-east fractures in the area. There are no active volcano where the earthquakes take place that I know of. The active volcanoes are south and west (Snæfellsnes volcanoes) of the current location of the earthquakes.
Currently is unclear if this activity did trigger earthquakes in the rift zone. That is Thingvellir and nearby areas that show earthquakes on IMO maps. This might just be poor locations from the SIL system. It is also a question if this earthquake activity is the reason for earthquakes close to Geysir (volcano) geothermal area.
Click on the picture for a full resolution. Picture is from Icelandic Met Office web site.
The earthquake swarm at 13:10 on the 6th of December 2010. Picture is from the IMO web site.
At current time is remains unclear if this earthquake activity is a pre-events before a bigger earthquake in this area. But about ten years ago there was a earthquake swarm south of this location with many earthquakes reaching ML4.0+ in size. But in any case it is worth keeping tab in this earthquake activity, as it might signal more interesting times ahead in this area. But that is just speculation on my part. Earthquake activity might fall down to nothing (normal for this area) in a short time span.
Due to how fractured this area appears to be. I am not recording the earthquakes in this area properly, as the energy of the earthquake wave appears to vanish rather quickly due to the fractures that are between me and the earthquakes that take place (the wave energy that goes north in this case). But this was not the case with earthquake swarm that took place in Blöndulón lake.
Icelandic News of this earthquake swarm. Use Google Translate at own risk.
Skjálftahrina stendur enn yfir (Rúv.is)
Skjálftavirkni á Arnarvatnsheiði (mbl.is)
Text updated at 13:57 UTC on 6th of December 2010. Minor error fixed.
Text updated at 08:33 UTC on 9th of December 2010. Error fixed.