Week 41 in Iceland was rather quiet, compared to last two weeks in Iceland. Here is a overview over the highlight in the earthquake activity in Iceland.
South Iceland Seismic Zone (SISZ)
Constant earthquake activity has been in SISZ over the week and it has been ongoing for the past weeks, none of the earthquakes have been large, with almost all of them being less then magnitude 1,0. Largest earthquake in this swarm had the magnitude of 2,5.
The earthquake activity on SISZ. Copyright of this image belongs to Iceland Met Office.
Bárðarbunga volcano
For most part earthquake activity in Bárðarbunga volcano was normal this week, with regular earthquake swarms taking place in the usual places. The most interesting earthquake this week took place under Trölladyngju, it was only magnitude 0,7, but it was on depth of 26,2 km.
Earthquake activity in Bárðarbunga volcano. Copyright of this image belongs to Iceland Met Office.
Herðubreið
Earthquake swarm has been taking place all week in Herðubreið. Earthquake swarms are common in this area and often have magnitude 3,0 earthquakes or larger. The earthquake swarm is ongoing when this is written.
Earthquake activity in Herðubreið/Herðubreiðarfjöll area (north of Askja volcano). Copyright of this image belongs to Iceland Met Office.
Reykjanes ridge
A magnitude 3,4 earthquake took place deep on the Reykjanes ridge this week. The earthquake was not felt and there might have been more than one earthquake. My geophone in Heklubyggð shows more than one earthquake one hour after the magnitude 3,4 earthquake happens.
Earthquake activity on the Reykjanes ridge. Copyright of this image belongs to Iceland Met Office.
A magnitude 3,0 earthquake also took place around 200 km off the coast of Reykjanes peninsula (around 153 km south of Eldeyjarboða). That earthquake location was poor due to the distance from the SIL network.
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Thank you for the update, Jon! It is a very comprehensive summary.
The Katla Area keps going at it, with the onset of some recent tremoring (but not harmonic tremor). Tho I think the activity might be actually closer to Torfajokull than Katla. Considering the recent unrest in that area, I would not be surprised if it would be around Torfajokull.
Looking at the SILs, it looks quite quake-ish, kinda like a small swarm.
http://shrani.si/f/w/lF/mg9Kwj5/sly.gif
And when you look at the drums, that is actually exactly what it is.
http://shrani.si/f/1F/WN/1AXIGaJx/sly-1.png
I do not exclude a possibility of a more like a hydro event, or hydro-thermal. At least no immediate magma is involved, since the low frequencies are more silent for now, and no harmonic tremor was detected whatsoever. Should this continue and increase with time, and the lower frequencies would start to emerge with some HT pulses, than that might be a sign for something more ominous.
A 3.2m at Bunga this morning…is that tetonic or not please ?
I’m going to stick my neck out and say that it looks tectonic to me. I now await correction!
Could it be inflating again after Imo said the next event could come from barda itself ?
Inflation at Grimsjall is gradually on the climb but very slowly. I was told by IMO that the magma chamber of the volcano apparently is not very deep. 1603 days and counting since the end of the last eruption. The higher that number climbs the closer to eruption. I would say the window opens in 2017 for Grimsvotn. That 3.2 at Bardabunga concerned me initially but it so shallow but how deep is the magma? That would be a good question for IMO.
Hallo Jón,
As I’m Dutch, there will be mistakes in my English writing. I’m following your updates already a long time. What a lot of work you are doing. Thanks a lot for this. As I’m interested in geolgy and specialy in vulcanoes, I visited lots of them all over the world,
your bloc is very intereseting. Actualy I’m making a big shield wilt the map of the world, including ” The Ring of Fire”. I’m collecting vulcano ash, – lapili etc. from as many volcanoes as possible and stick it on that map. I show this to children in primary school.
If someone of your followers can help me ………… I’m very interested in some of
Pele’s tears, and Pele’s hair.
I hope you will continue your work a long time
Pele, the football player?
Pele the Hawaiian goddess of fire. Pele’s hair is very fine strands of wind-whipped and cooled lava.
What’s the swarm happening down on the reykjanes peninsula near selfoss? What is there?
com/news/2015/10/21/earthquakes-near-eyrarbakki
Found the answer myself.
http://icelandreview.com/news/2015/10/21/earthquakes-near-eyrarbakki