Iceland Civil Protection Service has declared “uncertainty phase” at Mount Hekla!!! UPDATES!!!

Thanks once again for the updates!

[link to volcanocafe.wordpress.com]
Inge B. says:
April 2, 2013 at 05:50
Runup to the quake swarm? This is at Theystareykir: [link to hraun.vedur.is]

And strangely, the graph at the northern Langjökull system shows it with a red component: [link to hraun.vedur.is]

[link to volcanocafe.wordpress.com]
Spica says:
April 2, 2013 at 05:19
Quite an earthquake swarm started in Iceland´s north
from [link to en.vedur.is]
Please VCers keep an eye on this for our Icelanders and me while i am at work!

[link to volcanocafe.wordpress.com]
Inge B. says:
April 2, 2013 at 05:59
The big quake was felt in different parts of the north, but strangely not everywhere even not in the next bigger town, Akureyri. Though one man reports, that he had a feeling like a big car had collided with his house, other people there say they felt nothing.

Civil protection says that there will be a lot of follow quakes during next days to weeks, but not possible to say if there also will follow big ones.
[link to www.ruv.is]

WOW thank you so much for the updates! Just see the big quakes in Hekla stain [link to hraun.vedur.is]

islander on slopes of Hekla* says:

April 2, 2013 at 11:41


Thank you. Swarm seems more intense this morning (more on “órói” plots), so this seems far from over. In fact there is Cvil Warning in effect since this morning.

already marked in "Monsters..." thread

Sa'ke says:

April 2, 2013 at 11:43


And here is a plot of the last registered earthquakes (> 0.5) from 28 maa 2013 till now (2 apr 2013 13:33) in kopasker-area: [link to www.ijsland-enzo.nl]
Unfortunatly their map goes only till 20 km deep so a few earthquakes aren’t show

Christina says:

April 2, 2013 at 12:22


[link to strokkur.raunvis.hi.is]

The gps is going up..

[link to hraun.vedur.is]

Irpsit says:

April 2, 2013 at 12:52


Spica, perhaps consider my comment as part of the next post.

How rifting occurs in Iceland:

Iceland sits in both in the rifting area between two tectonic plates.

The North American and European drift apart in opposite directions. One towards east-southeast, the other towards west-northwest.

However the rifting is not homogeneous. It occurs differently in different sections of the rift area.

Please have a look at the following picture:
[link to images.sciencedaily.com]

Over the area between Hekla, Katla and Vatnajokull, the rifting occurs almost perfectly at angle perpendicular to the direction of the plate movement. The rifting opens aligning volcanic fissures from the NE to SW, while plates drift towards the NW and SE respectively. This means the earth rips easily open in those regions and this allows for large volumes of magma to erupt. Of course, earthquakes do happen in these regions, and they happen constantly (nearly every day – more than in any other region of Iceland) and therefore they are mostly small sized earthquakes. These are the daily earthquakes at Katla, Vatnajokull and Askja.

However in two sections of Iceland, the southwest seismic zones, and in the north, in Tjornes seismic zone, the plates move apart each other in a almost sideway motion. This creates notorious strain in the rocks, and creates much larger earthquakes. These are called transform seismic zones; regions where motion is sideways.

Daily, they are only very tiny earthquakes, but occasionally, every few decades, strain accumulates and then these areas experience large 6.5 earthquakes. Once they come, they occur in clusters, with every few years a larger earthquake (just like the south Iceland earthquakes of 2000 and 2008), and then reverting to calm decades again.

Moreover, these two regions, experience mostly their plate movement through large earthquakes and do not allow much for volcanic eruptions. Yes, they do occur, but more rarely and smaller. Volcanic eruptions have known to occur in Tjornes and SISZ, but last one in the SISZ was 3000 years ago, in the Grimsnes volcanic system, and it was very small.

It has been confirmed that every major tectonic episode is joined by magmatic intrusions at deep, but rarely they come near the surface. To understand why, just imagine the two plates drifting side by side; this does not create much fracture space in the rocks to allow magma to move upwards, magma would move easily laterally than upwards. However, in the rifting regions near Vatnajokull, like the dead zone, rifting is perfect, and when the crust rips open, large volumes can move upwards!

In other regions of Iceland, rifting occurs at different angles, like Reykjanes, where plates create a rift area about 45º angle from the plate movement. Like results it seems in a “middle ground way” between the two former situations. Eruptions are mostly medium size and occasionally large but rather rare, and strain does accumulate and is released in larger earthquakes, but not as large as the two transform zones of Iceland (mostly up to 5.5).

Furthermore, it seems that rifting activity in the north has been occurring in recent decades. In 1975 Krafla began several episodes of fissure rifting eruptions. This lasted until 1984. Also further north, in Tjornes, there was a large and damaging earthquake (almost up to M7) in 1976. Probably this was a consequence of the rifting process extending further north. So, now it is mostly natural that we are experience another series of major rifting episodes, mostly tectonic, even further north.

Recently, also another volcano has shown signs of uplift and more earthquakes, the Theistareykjarbunga volcano. While still unlikely to erupt, this shows how activity in the rifting regions seems to propagate further north or south over the decades, as strain is released and triggers other nearby regions.

I could almost say that the whole of this could have started back in 1874, when there was a very large rifting episode in Askja, which extended further northwards, and culminated in an eruption very large in 1875.

In Tjornes, there is still the potential for a large earthquake, up to 6.8.

Likewise, we have been experiencing what seems in recent decades an increase of rifting activity in south Iceland. Hekla has been erupting regularly, the Westman islands erupted in recent decades, and Eyjafjallajokull also, as well as two large earthquakes in the south seismic zone. It is natural to expect further movements in neighboring seismic fractures and volcanoes in south Iceland.
[link to volcanocafe.wordpress.com]

how much fresh ideas!!! only one misterious and a long time called by fans "to rise again" man able to write such !

swarm continues in full force [link to en.vedur.is]

[link to www.youtube.com]

Thanks Luisport!

Information on the magnitude 5.5 earthquake in TFZ
Posted on April 2, 2013 by Jón Frímann
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This is a short blog post about the earthquake swarm in Tjörnes Fraction Zone.

The largest earthquake so far is a magnitude 5.5. The largest aftershocks so far are magnitude 4.4 that took place at 01:14 UTC and 4.7 that took place at 08:55 UTC this morning. This earthquake swarm is taking place on a complex fault area that is highly active. There is also big question what effect this earthquake swarm is going to have on other faults in the area. There is a risk that this earthquake swarm is going to start other earthquake swarms in nearby faults. Uncertainty level has been declared for area from Sauðárkrókur to Raufarhöfn at least. This is the largest earthquake in this area since the year 2002 and 2005. But both this years there was a magnitude 5.0 earthquakes in this area.

There have been over 500 earthquake recorded since this earthquake swarm did start. It is impossible to know for sure when this earthquake swarm is going to stop, or if it is going to pick up again. But the earthquake swarm is already starting to shown signs of dropping activity. But that might change again if there is new larger earthquake in this area, or swarm of larger earthquake.

I am going to post update of anything major happens in this earthquake swarm. It is possible to monitor the current status of this earthquake swarm here on my geophone web page.

[link to www.jonfr.com]

to put in my active threads to read later.

How rifting occurs in Iceland, explanations regarding the recent earthquake swarm.

Posted on April 2, 2013by Spica


How rifting occurs in Iceland:

Iceland sits in both in the rifting area between two tectonic plates.
The North American and European drift apart in opposite directions. One towards east-southeast, the other towards west-northwest.
However the rifting is not homogeneous. It occurs differently in different sections of the rift area.

Please have a look at the following picture:


image [link to images.sciencedaily.com]

Over the area between Hekla, Katla and Vatnajokull, the rifting occurs almost perfectly at angle perpendicular to the direction of the plate movement. The rifting opens aligning volcanic fissures from the NE to SW, while plates drift towards the NW and SE respectively. This means the earth rips easily open in those regions and this allows for large volumes of magma to erupt. Of course, earthquakes do happen in these regions, and they happen constantly (nearly every day – more than in any other region of Iceland) and therefore they are mostly small sized earthquakes. These are the daily earthquakes at Katla, Vatnajokull and Askja.

However in two sections of Iceland, the southwest seismic zones, and in the north, in Tjornes seismic zone, the plates move apart each other in a almost sideway motion. This creates notorious strain in the rocks, and creates much larger earthquakes. These are called transform seismic zones; regions where motion is sideways.

Daily, they are only very tiny earthquakes, but occasionally, every few decades, strain accumulates and then these areas experience large 6.5 earthquakes. Once they come, they occur in clusters, with every few years a larger earthquake (just like the south Iceland earthquakes of 2000 and 2008), and then reverting to calm decades again.

Moreover, these two regions, experience mostly their plate movement through large earthquakes and do not allow much for volcanic eruptions. Yes, they do occur, but more rarely and smaller. Volcanic eruptions have known to occur in Tjornes and SISZ, but last one in the SISZ was 3000 years ago, in the Grimsnes volcanic system, and it was very small.

It has been confirmed that every major tectonic episode is joined by magmatic intrusions at deep, but rarely they come near the surface. To understand why, just imagine the two plates drifting side by side; this does not create much fracture space in the rocks to allow magma to move upwards, magma would move easily laterally than upwards. However, in the rifting regions near Vatnajokull, like the dead zone, rifting is perfect, and when the crust rips open, large volumes can move upwards!

In other regions of Iceland, rifting occurs at different angles, like Reykjanes, where plates create a rift area about 45º angle from the plate movement. Like results it seems in a “middle ground way” between the two former situations. Eruptions are mostly medium size and occasionally large but rather rare, and strain does accumulate and is released in larger earthquakes, but not as large as the two transform zones of Iceland (mostly up to 5.5).

Furthermore, it seems that rifting activity in the north has been occurring in recent decades. In 1975 Krafla began several episodes of fissure rifting eruptions. This lasted until 1984. Also further north, in Tjornes, there was a large and damaging earthquake (almost up to M7) in 1976. Probably this was a consequence of the rifting process extending further north. So, now it is mostly natural that we are experience another series of major rifting episodes, mostly tectonic, even further north.

Recently, also another volcano has shown signs of uplift and more earthquakes, the Theistareykjarbunga volcano. While still unlikely to erupt, this shows how activity in the rifting regions seems to propagate further north or south over the decades, as strain is released and triggers other nearby regions.

I could almost say that the whole of this could have started back in 1874, when there was a very large rifting episode in Askja, which extended further northwards, and culminated in an eruption very large in 1875.

In Tjornes, there is still the potential for a large earthquake, up to 6.8.

Likewise, we have been experiencing what seems in recent decades an increase of rifting activity in south Iceland. Hekla has been erupting regularly, the Westman islands erupted in recent decades, and Eyjafjallajokull also, as well as two large earthquakes in the south seismic zone. It is natural to expect further movements in neighboring seismic fractures and volcanoes in south Iceland.

Irpsit
———————————————————————————————–

The north of Iceland saw more than 400 quakes today. GFZ lists the strongest one as a 5.3, IMO has it as 5.4. But more than 400 quakes shook the Tjörnes fracture zone today.
Chryphia did an image and explains it:
The Tjörnes fracture zone is really busy again! This is how it looks in respect to all earthquakes from 2011:

The red dots represent (from North to South) Kolbeinsey Ridge, TFZ and Theistareykjarbunga. The current swarm is nicely blending in previous swarms from the past years. They are all very much contorted.

The data are from [link to hraun.vedur.is] and apparently only the earthquakes at 99% find entry there. That´s why here [link to en.vedur.is] they seem to be distributed widely, all qualities are included, when revised they will become more “concentrated” I guess.

This was to been seen on [link to en.vedur.is] this evening.

Chryphia: This 3D video shows the recent swarm in the Tjörnes Fracture zone, but only 99% earthquakes until 7:07 this morning. In the close-up view you can see how twisted (the angle Irpsit was talking about?) the fault zone is and that commonly the swarms happen along a narrow streak.

While i am publishing this post, the swarm is still ongoing.
So for our newbies some links to watch:
[link to en.vedur.is]
[link to en.vedur.is]
[link to en.vedur.is]
Thank you Irpsit for this comment. Used in a post at your request!
[link to volcanocafe.wordpress.com]

M3.7, 10 min ago [link to www.emsc-csem.org]

i think these masses of quakes are happening in this location because all the faults are closing up due to a mass of rising magma in the rift to the east of them, rising from the plume head

this stuff doesn't rise quickly. it moves at the rate your fingernails grow, so all the swarms over the past few years are linked. they are all due to the same mass of magma, slowly, ever so slowly rising to the surface.

one weakness, in the wrong place, and we could all be in a lot of trouble, or, the rock could hold, and the shitstorm won't happen for a few lifetimes yet?

M3.4, 12Km… this is more intense again? [link to en.vedur.is] [link to hraun.vedur.is]

what do you think about?

[link to hraun.vedur.is]

Is there another cam, this one hasn't updated since 12:35, it's so snowy I'm not sure I'm seeing what I think I'm seeing.

Last Edited by alexisj9 on 04/02/2013 05:40 PM

sure? time on cam now 00:40 UTC:tounge:

Ah ok lol, for some reason thought it would be in BST, don't know why lol. I'm not sure I've seen it so pixalated before, don't want to jump to conclusions cause I can't see anything but snowy white dots on black, it sure looks like somethings is happening though.

now long time as the picture with no changes...