On the brink? Fifth tremor swarm rattles Iceland’s Katla volcano

September 6, 2011REYKJAVIK, Iceland (AP) — A surge of small earthquakes has been reported around Iceland’s Katla volcano, but scientists said Tuesday there is no immediate concern that the increased seismic activity will trigger a dangerous eruption. Although earthquakes around Katla are common, an increase in cluster earthquakes is not. “It’s one of the most feared volcanos, so we’re closely monitoring it,” said Pall Einarsson of the University of Iceland. “That said, it’s normal for earthquakes to be detected around Katla. What’s a bit unusual is that we’re seeing swarms of small earthquakes, some occurring every 10 minutes or so.” Iceland sits on a large volcanic hot spot in the Atlantic’s mid-oceanic ridge. Eruptions, common throughout Iceland’s history, are often triggered by seismic activity when the Earth’s plates move and when magma from deep underground pushes its way to the surface. Like earthquakes, predicting the timing of volcanic eruptions is an imprecise science. Last year’s eruption of the Eyjafjallajokull volcano forced hundreds of people to be evacuated and paralyzed international air travel for weeks because of a hovering ash cloud. And history has shown that when Eyjafjallajokull volcano erupts, Katla — located under the massive Myrdalsjokull icecap — isn’t far behind. Katla, which threatens disastrous flooding if its ice cap melts, typically awakens every 80 years or so, and last erupted in 1918. Activity around Katla started to increase around July but has since grown even stronger. The strongest earthquake detected so far has been a 3.0 magnitude. There also was flooding that wiped out a bridge in July. Like people, each volcano has a different personality of sorts, says Einarsson. “We look at the behavior, try to analyze patterns and then try to come up with an explanation,” says Einarsson. “This is a bit difficult to interpret so far, but it’s correct to say that it signals some sort of activity in the volcano and some sort of magna intrusions are probably taking place.” Geologists also are worried about the Hekla volcano, which unlike Katla, are not covered by a glacier and produces little seismic activity. During the Middle Ages, Icelanders called the Hekla volcano, the country’s most active, the “Gateway to Hell,” believing that souls were dragged into the fire below. “If we saw earthquakes like this in Hekla, we would immediately signal a warning sign,” Einarsson said. –Times Union
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12 Responses to On the brink? Fifth tremor swarm rattles Iceland’s Katla volcano

  1. luisport says:

    Date Time Latitude Longitude Depth Magnitude Quality Location
    06.09.2011 16:19:11 63.912 -21.995 9.4 km 0.8 53.4 4.4 km NE of Krýsuvík
    06.09.2011 16:18:19 63.933 -21.980 4.2 km 1.3 90.01 6.6 km NE of Krýsuvík
    06.09.2011 16:17:10 63.927 -21.983 7.7 km 2.3 90.05 6.0 km NE of Krýsuvík
    06.09.2011 15:42:00 63.934 -21.982 8.2 km 1.1 90.01 6.6 km NE of Krýsuvík
    Swarm in Krisuvik at same time! Reply
    Carl le Strange says:
    September 6, 2011 at 16:32
    The anomaly at Krisuvik is still going on, and there was a quake, right after it started, in the middle of the bloody lake.
    06.09.2011 15:42:00 63.934 -21.982 8.2 km 1.1 90.01 6.6 km NE of Krýsuvík


    If this is not a kick in mee wee arse it is more energetic than the Godabunga event… Oddness indeed…


  2. luisport says:

    Update 1: The Public Civil Emergency Authority (Almannavarnir) in Iceland has increased monitoring with Katla volcano. But they have not declared any emergency level yet. Announcement about that in Icelandic can be found here. But scientists where flown over Mýrdalsjökull glacier at 18:00 UTC today (6. September 2011).

    According to the news there has been increase in conductivity in Múlakvísl river. But for the moment the water level has not increased. There has been speculation that the tremor was created by water on the move. But that is unclear at the moment, however it is quite possible that more water is on the move under Mýrdalsjökull glacier.

    Currently the harmonic tremor in Katla volcano has dropped back to normal levels. For the moment everything is quiet in Katla volcano. But that can change at any time without any warning.



    • luisport says:

      Update 2: It seems that a new harmonic tremor episode is about to start in Katla volcano. So far it has remained small. But it is impossible to know if that is going to change suddenly or not. Update 2b: There is also some wind noise on the seismometers around Katla volcano. This wind is increasing background noise. It often look like a tremor increase, while in reality it is not.


  3. jonb12 says:

    I know this my be the wrong thing to say, but ive been waiting for this to happen for months, i knew it would eventually come to erupt and im thinking along with many other’s the time has come and past, Its coming people!


    • The problem is a brutal winter is forecasted for Europe already and the last thing you want, in addition, is 10 times the amount of ash ejected from Eyjafjallajökull hanging in the skies over Europe blocking out the Sun from a particularly strong volcanic eruption during the winter. Admittedly, this is a worst-case scenario but Katla has a enormous magma chamber and the historical eruptions tend to be quite large. Let’s hope and pray none of these factors synch into alignment because this could be a nightmare of unrealized scope in the making.



  4. Thank you for keeping us posted on Katla. I will be watching this and waiting for further updates. Too bad that the media doesn’t even mention it. So many people have no idea what is going on.

    Be blessed and Maranatha


  5. luisport says:

    Most likely water creating harmonic tremors in Katla volcano (for the moment)
    Posted on September 6, 2011 by Jón Frímann
    In the news from Rúv at 22:00 UTC it was sad that water is the most likely source of the harmonic tremors in Katla volcano. But it seems that hydrothermal activity in Katla volcano is increasing and melting the glacier. But for the past few hours there have been signs of hydrothermal melt water getting into Múlakvísl glacier river, making the river have more water then normal and increasing conductivity in it. This is not glacier flood as such. The cauldrons that formed in July have not changed according to this news, but it was not reported if they had actually gotten deeper or larger.

    Due to cloud cover it was not possible to explore the north part of Mýrdalsjökull glacier. Just the south part. According to the news on Rúv at 22:00 new small cauldron have formed in the south part of Mýrdalsjökull glacier. They are shallow at present time and may have taken few weeks for form to present size (not sure how big they are), but among this cauldrons is a cauldron that has not been seen for past seven to eight years, cracks have formed around the cauldron and he has gotten deeper and water has collected in the cauldron. But with more earthquake activity and increased hydrothermal activity under the glacier. So more monitoring is needed on Katla volcano according to Magnús Tumi Guðmundsson volcanologist at University of Iceland.

    Note: When I wrote this blog post. It seems that new earthquake swarm is about to start in Katla volcano. At least I think so.

    Earthquake swarm in Krýsuvík volcano
    Posted on September 6, 2011 by Jón Frímann
    Earlier today a earthquake swarm did start in Krýsvík volcano. This earthquake appears tectonic in nature from what I can tell on my geophone. This type of earthquake swarm is common in this area in Krýsuvík volcano. It does not mean that a eruption is about to start. But this area is a rift zone and it has many earthquake swarms during the year. This is just one of them so far. It is impossible to know how large this earthquake swarm is going to be or how long it is going to last.

    The first earthquake swarm did start at 15:42 UTC, the second earthquake swarm did start at 21:53 UTC. That earthquake swarm is currently ongoing with several earthquakes every 2 min or so.

    The current area of activity is a lake named Kleifarvatn lake. But that lake is on top of Krísuvík volcano.

    Current activity in Krýsuvík volcano. This is a tectonic earthquake activity, not volcanic. Copyright of this picture belongs to Iceland Met Office.

    I think that this earthquake activity is going to continue something into the night and next few days at the longest.


  6. luisport says:

    Carl le Strange says:
    September 7, 2011 at 09:58
    Increased risk for eruption at Hekla volcano.
    During the last five days there has been a shift in the movement pattern of both Isakot and Haukadalur.
    Isakot to the NNW of Hekla is showing normal east and north movement patterns, but with a radical sharp uplift for the last five days.
    Haukadalur to the west of Hekla shows normal east/west component, but a burst to the north followin a dip to the south. It is also showing a large lift.
    This leads me to believe there is an enhanced risk of this being a possible hyper-inflation prior to eruption. We are not talking about Campo Flegreii or Mt St Helens here with metres of uplift in a short time period. Just a few centimetres during a few days. If this uplift goes on it will most likely just need a few days of uplift like this.
    Caveat, it might stop or the uplift might “fall down” again.

    Secondly, we have during the last couple of weeks had a large shift in transient directions. Before the transient where at Búrfell which is in line with known eruptive transients of Hekla. But the last couple of weeks we have seen very large transients emanating from the Gledingaá borehole strainmeter.
    And today we have had a small, but significant transient at the HEK station. Hek is not the same as Hel. Hek is located at Hekla proper if I have understood it correctly and show strain in Hekla proper. A transient here is showing pressure buildup under the top of the volcano, and might indicate that the fissure is getting ready to rip open.

    Hek transient:

    If current activity continues I see december as a conservative date for start of eruption. For those that are new here, I did a mathematical modell a month ago that seemed to indicate that Hekla would erupt between december 2011 and may 2012. The changes in the pattern makes me believe it will come sooner.


  7. luisport says:

    This is a new cam pointed at Katla. http://live.mila.is/grimsvotn2/


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