The Iceland Volcano Thread

Young male photographer took this video about five o'clock in the night, which shows clearly the situation at the volcano in Grímsvötn. Gisli went on powerful fjallabíl literally overflowing gigs, as shown in the accompanying video. It shows how one comes blasting from the crater, and scientists say that they can be very powerful and come without warning. Due to the unpredictable explosions, people are encouraged to go no closer than the cabin Glaciological Society is about 6 miles away.

Earthquake swarm in Katla volcano

Posted on June 17, 2011 by Jón Frímann

Around 17:10 UTC an earthquake swarm did start in Katla volcano. This earthquake swarm is focused inside the Katla caldera at small point. The one earthquake that I have so far been able to record was an long period earthquake, but that suggests that this earthquake was created by magma movement. At current time I am not sure from where this earthquake did originate from. But from Goðabunga area in Katla volcano this types of earthquakes are common and no surprise at all.

At current time I do not know what this means for Katla volcano. But so far no increase in harmonic tremor has been detected on the seismometers around Katla volcano. But that might not start at current time, as harmonic tremor is only going to increase when magma starts to move inside the Katla volcano, like did happen in Grímsfjall volcano few weeks ago.

The location of this earthquake swarm strongly suggests that what is going on in Katla volcano is an dike intrusion in the Katla caldera. If that is powerful enough to start an eruption is an question remained unanswered at current time.

It is magma on the move, and it can be signs of an volcano waking up. Katla volcano is somewhat similar to Krafla volcano. But with an glacier. Last eruption was in the year 1918, so we do not know an lot about how Katla volcano behaves before an eruption starts in it.

I did manage to record two earthquakes from the last burst of earthquakes. Both of them where long period earthquakes. That is magma pushing it’s way up the crust. The earthquakes happen at random time, so it is hard to know what is going on.

But I have an bad feeling about this. I must say. But at the moment the best thing to do is to observe what is going on.

So far NO eruption has been detected in Katla volcano. This is just earthquakes at the moment.

Today around 16:00 UTC there was an new harmonic tremor in Katla volcano. This harmonic tremor has two sources. Hyrdothermal activity under the glacier, or magma moving deep inside Katla volcano (without creating many earthquakes in Katla volcano). It is unclear what is the case at the moment.

It is impossible to know what happens next. But it is also important to be aware of the fact that earthquake season is starting in Katla volcano. But that is normally from end of June to beginning of October (or when it starts to snow again in Iceland). So more earthquakes are going to be seen this summer also because of more SIL seismometers around Katla volcano.

So there is no reason to panic about Katla volcano at current time. But it is worth to keep watch on it anyway.

Activity in Hekla Not Necessarily Indication of Eruption

It cannot be stated with any certainty that the recent unusual activity picked up by sensors at the volcano Hekla in south Iceland is a signal of an imminent eruption, according to geophysics professor Páll Einarsson.

Einarsson told ruv.is that the volcano is certainly ripe for an eruption but the sensors are new and there isn’t enough experience with them to draw any conclusive assumptions.

In the past few days the sensors around Hekla have shown unusual movements in the earth’s crust and these movements were picked up by all the sensors.

Scientists aren’t familiar with the volcano’s behavior in this sense as they haven’t had the opportunity to monitor such movements before, Einarsson reasoned.

However, he is not in doubt that Hekla is ready to burst. The volcano has been extending slowly but surely in the past years as magma is accumulating below it. Hekla has been preparing to erupt ever since the last eruption concluded in 2000.

The Civil Protection Department of the National Commissioner of the Icelandic Police was notified of the latest developments yesterday, as were civil protection committees in south Iceland. However, no special action will be taken for the time being.

Hekla will continue to be monitored closely; its eruptions have usually started without much advance warning. In 2000, a series of earthquakes commenced one and a half hours before magma thrust its way to the surface.

Einarsson said this is in fact the longest advance warning Hekla has given; in some cases it is much shorter, only 25 minutes in 1970, for example. The volcano has erupted in approximately ten-year intervals in the past decades.

Harmonic tremor continue to increase in Katla volcano
Posted on July 9, 2011 by Jón Frímann
When this is written around 00:36 UTC on 9. July 2011 the harmonic tremor levels on SIL stations around Katla volcano have continued to increase. The latest spike in harmonic tremor levels happened after an ML1.5 (automatic size) earthquake that took place at 22:13 UTC. There has been an small earthquake swarm in Katla volcano caldera yesterday. But the largest earthquake in that earthquake swarm had the size ML2.4.

The harmonic levels are getting so strong that they have started to appear on stations around Hekla and on my own geophone, even if it is located almost 60 km away from the source of the harmonic tremor. Currently there is little to suggests that this is slowing down at the moment. But that might yet happen. But it is impossible to know for sure at the moment.

The lack of earthquakes tells me that the magma has not yet reached the surface. When or if that might happen is an good question that I do not have the answer to. But this might take several more hours until something happens in terms of earthquakes or other activity in Katla volcano.