Magnitude ML4.0 earthquake hits Blöndulón

Over the past few days (since 26th of October 2010) there have been earthquakes happening at Blöndulón. This earthquakes are intraplate earthquakes and it unclear why these earthquakes are happening.

At 02:35 UTC a earthquake with the size of ML4.0 did hit Blöndulón according to automatic SIL system that Icelandic Met Office has. So far this is the strongest earthquake to hit this area since the earthquake swarm did start. This earthquake appears to be a start of new earthquake sequence in this area. But several smaller earthquakes have happened as a result of the ML4.0 earthquake. The depth of the main earthquake was 1km. I do expect that it was felt in nearby farms that are closest to Blöndulón.

I am expecting more earthquakes in this area over the next few days. It remains to be seen if they grow in size or not.

Update!

When reviewed the size of this earthquake was ML3.8 at the depth of 21.1 km.

Text updated at 14:41 on the 31st of October 2010.

More intraplate earthquakes north of Langjökull / Hofsjökull volcanoes

Earlier this night (around 19:19 UTC 28th of October) more intraplate earthquake did start happening north of Langjökull / Hofsjökull volcanoes. The earthquakes are in the same place as before. But please see my earlier post for information about the earlier earthquake swarm at the same location.

Currently it seems that the earthquake swarm is growing in size and frequency of earthquakes. But the earthquakes appears clearly on my Hvammstangi station. The web page for my geophones can be viewed here. The distance of this earthquakes from my Hvammstangi station is about 40 to 80 km. But no more then that I think.

So far all the earthquakes have been less then ML3.0 in size. But if the swarm gets stronger that might change with out any warning. This area of Iceland is unpopulated so it is unlikely that anyone is going to feel those earthquakes at current size levels.

Eyjafjallajökull eruption officially over

According to Iceland Review Online the eruption in Eyjafjallajökull is officially over. But it remains to be seen if the eruption restarts like did happen in 1821 to 1823 eruption in Eyjafjallajökull.

Iceland Review Online news.

Eruption in Iceland’s Eyjafjallajökull Officially Over

Thanks to Chris for pointing this out to me.

Update!

It was brought to my attention that Almannavarnir in Iceland have not declared the eruption over in Eyjafjallajökull. So the news in Iceland Review appears to be wrong in that respect.

Blog post updated at 10:08 on the 29th of October 2010.

Strong earthquake swarm on Reykjanes Ridge

Few moments ago (around 20:15 UTC) a strong earthquake swarm started on Reykjanes Ridge. This earthquake swarm is deep on the Reykjanes Ridge. Strongest earthquakes so far are ML3,1 on Reykjanes Ridge.

I am going to post updates as the swarm progresses. Some of the earthquakes can be seen on my webicoders here. But the distance is great so only strongest earthquakes are going to appear there.

Update at 21:06 UTC.

EMSC reports that the strongest earthquake was Mb4.8 while USGS is reporting that earthquake at Mb4.9 in size. The earthquake activity in this area is ongoing when this is written.

The year 2012 myths – Official blog stand notice from me (Jón Frímann)

I am getting a really tiered of the year 2012 myths that are making there way into discussion here. This nonsense has been outright debunked long time ago as can be seen here.

So this is a official policy notice in regards to this blog of my part. Any comment that refers to the year 2012 myth in part or a whole is going to be removed in all future blog post. If you feel the need to discuses such matters do it somewhere else. This is not the place for it. As this is serious blog about serious volcanoes in Iceland (and sometimes in other part of the world too).

We might put up a idea on volcano activity here. But that is all good. As such ideas can often be wrong. But that is part of the process of learning. But repeating nonsense is not. It is a waste of time and energy to do so. Both mine and other readers and commenter’s on this blog.

Earthquakes in Esjufjöll volcano

There is always surprises in Iceland once in a while when it comes to volcanoes. This evening there was one. This time for a little known volcano named Esjufjöll. But since the year 2002 there have been regular earthquake swarms in Esjufjöll volcano since that year. But this indicates that magma is pushing up the volcano. But it is quite hard to know if that is going to lead to a eruption. It might happen. But so far nothing indicates that it is going to do so at present time.

Here (Week 43 also) are details of the earthquakes in Esjufjöll in the year 2002. But this earthquake activity in 2002 lasted until week 45 (a small earthquake swarm was also in Week 51) before it stopped completely.

So far this are the years that earthquake swarms have happened in Esjufjöll volcano. The year 2002 (swarms, see links above), 2006 (minor swarm, see here), 2008 (small swarm, see here), 2009 (small swarm, see here), 2010 (small swarm ?). Currently the only thing to do now is to wait and see what happens with the 2010 earthquakes in Esjufjöll. But this is unlikely to lead to a eruption. But with volcanoes with rather unknown eruption history it is hard to know for sure.

Last suspected eruption in Esjufjöll took place in 1927 on 5th of September (+- 5 days). But that is unclear eruption as it was not seen and did only create a minor glacier flood. This information is from Global Volcanism Program and can be found in the link at the top.

There is a web camera online that points to Esjufjöll, it can be viewed here.

Deep earthquake in Katla volcano

Yesterday (18th October 2010) at 03:34 UTC there was a deep earthquake under Katla volcano. This earthquake was on a 14,8 km depth and had the size of ML0.7 according to reviewed earthquake data from IMO (this is too small for my Hekla geophone to detect at this distance). This was a single earthquake and does not indicate anything special at current time. However this earthquake might possibility signal a change inside Katla volcano and might be a start of a longer process that is in the end going to lead to a eruption in Katla some time in the future.

Currently it is unclear how the path to volcano eruption starts in Katla. But in 1918 there where no instruments to record that eruption.

This type of deep earthquake have sometimes created harmonic tremor signals in Katla volcano. But that happens due to dike event inside the volcano. This has happened regularly over the last few years. But has not been big enough to start a eruption.


Picture of the earthquake as it appears on IMO web site in the “EWIS (Icelandic)” that IMO has. Currently this earthquake is not on the weekly reviewed charts.

This is not the only earthquake that has been happening in Katla volcano over the past few weeks.


Week 41 earthquakes in Mýrdalsjökull and Eyjafjallajökull volcanoes.

The wait for Katla eruption is going to end one day. But that day is not today far as I know so far.

How to spot a earthquakes on my helicorders

Many people don’t know how to spot a earthquakes on my helicorders web site (you can view it here). Here is a quick how-to. The earthquake used is a Mw6.3 earthquake that did happen in 2008 in Iceland.


The second the earthquake did hit the sensor. The green line is when the power did go down in my apartment, just moment before the earthquake. Before that you can see background noise. That is people, cards and stuff like that. The earthquake is the big black-red line on the helicorder. After that you see smaller earthquakes happening (mag 3+ in size). This Hvammstangi geophone


Same earthquake, different location. This station actually was low-gain at the time of the earthquake. But meant that it was less sensitive to smaller earthquakes then larger. But the aftershock can be seen clearly on the helicorder at the time.


This is how my earthquake computer screen looked like at the time. The top line is currently not in use, as it is for a long period seismometers and I was just testing it at the time (it is also unclear on the signals as can be seen). The second and the third line in use is my geophone. But it clearly showed the earthquake and all it’s waves.


The Mosfellsbær station. That I had connection to at the time. But this is rather crazy view, as this is earthquakes and it is a lot of earthquakes in short space of time. I soon gave up trying to collect them.


This is how I finally work out the earthquakes. I put in location and depth from IMO data, as I can’t plot them my self.

I hope that this examples help people to see when there is a earthquake on my helicorder and just noise from human movement. Harmonic tremors are different and so far I have not been able to get any good example of it. But during the Eyjafjallajökull eruption a wind was problematic and I was unsure if I was recording wind into the harmonic tremors of that eruption or not. So that is going to have to wait a better time.