Vulkanen IJsland #16 met een Grimmige Grimsvotn.

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Op maandag 14 februari 2011 15:08 schreef Isiolo het volgende:
En het is weer saai in IJsland... zucht..

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New earthquake swarm in Hengill volcano
Posted on February 21, 2011 by Jón Frímann
A new earthquake swarm is currently taking place 2 – 5 km NE of Hellisheiðarvirkun. But that is a geothermal power plant that operates in Hengill volcano.

The largest earthquake so far is a ML1.5 in size when this is written at 03:27 UTC (04:27 CET). There is a good chance that this earthquake swarm is going to continue in the next few hours.

Small earthquake swarm in Krísuvík volcano
Posted on February 20, 2011 by Jón Frímann
Currently there is a small earthquake swarm in Krísuvík volcano. This earthquake swarm is small and is only about 20 or so earthquakes at current time. It is impossible to know if this earthquake swarm is going to continue or grow at present time. But it is not uncommon in this area for a small earthquake swam to be a warm up for a larger one. But as always there is just a wait and see what happens in the area.

The largest earthquakes in this earthquake swarm have reached up to ML2.0 in size so far.

Earthquake swarm at Upptyppingar
Posted on February 18, 2011 by Jón Frímann
I notice that there is a small, yet growing earthquake swarm taking place close to a small mountain named Upptyppingar. This mountain is within the fissure swarm of Kverkfjöll volcano but the area is in it self not active volcanically.

Few years ago (2007) there was a earthquake swarm in this area that did have something about 2000 earthquakes over a 48 hour period. The reason why there is earthquake activity in this area is due to magma being pushed up into the bedrock below. This process is something of the same that took place before the Eyjafjallajökull volcano eruption. But with the major difference that here is no central volcano doing this.

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Bardarbunga volcano in Iceland: a geologist’s analysis
This past spring, while the eruption at Eyjafjallajokull was taking place, there was large scale earthquake activity at Bardarbunga. The increased seismic activity in the area then, and again just a couple of weeks ago, created a lot of discussion and deliberation. Bardarbunga is a big volcano under the Vatnajokull ice cap with a large ice-filled caldera some 6-700 metres deep and a lateral volcano at Hamar to the south of the main crater. Bardarbunga is a central volcano in the Icelandic volcano system. The system’s fissure swarm stretches from the northeast to the southwest from the central highlands under the glacier; all the way from Tungnaa in the south to the lava fields west of Askja in the north. The system is over 100 kilometres long.

The northern part of the volcano lies under the Dyngjujokull outlet glacier and at Dyngjuhals, a ridge with crater rows and lava flow, cutting into the Odadahraun lava fields. The last eruption to take place there was in the second half of the 18th Century, both under Dyngjujokull and at Dyngjuhals. A Jökulhlaup (otherwise known as a glacier meltwater flood) ensued in the Jokulsa a Fjollum river. It is likely that Askja has not erupted in recorded history (since Iceland was settled), but volcanic activity at Gjalp in 1996, near to Bardarbunga, indicates it is part of the Grimsvotn system, according to the lava’s chemical composition

The southern part of the volcanic system is more active than the other half. Many large eruptions took place there in prehistoric times. Around the time of the settlement age in 870 AD, there was a powerful eruption (mainly tephra) and another powerful eruption cycle around 1480, with lava and tephra eruptions. The eruptions took place where there were a lot of lakes and many more were created in the craters, which are now popular trout fishing spots. The eruption fissure is around 40 kilometres long and the amount of volcanic material produced was huge, at some 1,500 million cubic metres. This volcanic activity on both occasions caused eruptions in the Torfajokull system and created, for example, the lava at Landmannalaugar.

It is often forgotten that an eruption took place near the present-day research station close to Tungnaarjokull, to the west of Vatnajokull, in 1862-64 – precisely in the southern part of the Bardarbunga system. It was not a particularly active series of eruptions, but the row of craters with a few separate sections is still 16 kilometres long, with many spatter and scoria craters and the lava field (Trollahraun) is around 30 square kilometres in area.

The next series of eruptions at Bardarbunga could of course happen anywhere, but the recent earthquakes indicate that an eruption could take place in a similar location to in the 18th Century. There are signs that magma is rising at great depth underneath the Bardarbunga volcanic centre. A future eruption under the glacier would be accompanied by a jökulhlaup, most likely in Kreppa and Jokulsa a Fjollum. Tephra would also likely be produced – possibly in large quantities.

There are also other possibilities, for example an eruption in the southern part of the system, but for now geologists at the Icelandic Meteorological Office are stressing that the earthquakes do not mean that an eruption is imminent

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A ML3.3 (EMSC 4.3) earthquake in Grímsfjall volcano
Posted on February 25, 2011 by Jón Frimann
A earthquake with the size of ML3.3 took place at 01:19 UTC in Grímsfjall volcano. At the current moment no other earthquakes have been spotted following this single event. It is also remains unclear at the moment if this is a start of a eruption in Grímsfjall volcano. But at the moment there is nothing that indicates that a eruption is about to start in Grímsfjall volcano. But that can change with out any warning at all.

Note that EMSC is reporting this earthquake with the size of ML4.3. It is unclear at the moment what is the correct size for this earthqua

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Two day long earthquake swarm in Krísuvík volcano
Posted on February 25, 2011 by Jón Frímann
While this earthquake swarm in Krísuvík volcano does not appear to be big in size. It is clear that was rather long and might even be ongoing. But it is interesting how long this earthquake swarm did last. So far the time is about 2 days. It is impossible to know if the earthquake swarm is over or not. Current number of earthquakes is about 60 earthquakes so far.

The earthquakes are on North-South fault line according to the visual evidence. Depth of the earthquakes is from 12 km and up to 3 km at the moment. It is hard to know at the moment if this is due to magma inflow under Krísuvík volcano or just normal tectonic activity along the rift zone in Reykjanes.

Icelandic news about this earthquake swarm.

Hrina smáskjálfta í Krýsuvík (Vísir.is, Icelandic)

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Op vrijdag 25 februari 2011 12:37 schreef kahaarin het volgende:

[..]

Inderdaad, en ik heb het dit weekend weer druk....
_{*tikkie, jij bent em!*}

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Op zondag 27 februari 2011 14:24 schreef zenkelly het volgende:
Ja, ik had t ook al opgemerkt! Spannend! Loos alarm of niet?

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Op zondag 27 februari 2011 14:37 schreef kahaarin het volgende:
De tabel, de score is nu 356 bevingen: http://www.vedur.is/skjal(...)nesskagi/#view=table

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Given the location and how this earthquake swarm is behaving it is my opinion that this is due to a magma is pushing up the crust in this area. But it remains a question of this is going to start a eruption or not. But the chances are growing for as long as this earthquake pattern holds up in Krísuvík volcano. If a eruption starts in Krísuvík volcano it is going to one of Hawaii type eruption, unless it is under water then it is going to be explosive for as long there is water getting into the crater. Last time there was a eruption in this area a 25 km long eruption fissure did form.

For now however all that can be done is to wait and see what happens. This earthquake swarm is going to continue for the next few hours and even days