Moi, Paul Derand

Moi, Paul Derand

bardarbunga eruption update, january 2015

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Saturday 31 January 2015:

 

The scientific advisory board on Friday made a detailed report of the situation and the eruption. You can see it here.

Figure 1 shows the thickness of the lava field in Holuhraun. Because the flow of magma was less strong than at the beginning of the eruption in the past few weeks, the lava field thickened instead of growing horizontally. Its volume is estimated to 1,4 cubic kilometers on January 21.

Figure 2 is made of many cross sections of the Bardarbunga, each one being of a different date. It shows the evolution of Bardargunba subsidence since August 2014. We see that it progressively gets lower.

Figure 3 is a line graph that shows the depth in meters of the subsidence and its evolution during the eruption. We observe that the subsidence's speed is getting slower and slower with time (it was 50 cm/day in September and it is 15-20 cm/day in January). The tendancy curve suggests that the slow decrease in the subsidence's speed would continue until it is so low that the eruption stops.

Figure 4 is similar to figure 3 except that it is not about subsidence but about the speed of the magma flow in Holuhraun. We also see that the magma flow rate is diminishing. "The red dotted line is an exponential curve used to estimate the diminishing flow of lava from the Holuhraun eruption and estimate when the lava flow will go below 5 m3/s. If the diminishing activity follows this trend then the eruption might come to an end anywhere between June 2015 and April 2016"(see report)

Figure 5 is the cumulation of all eathquakes since the eruption is monitored. Most earthquakes concentrate in the Bardarbunga caldera and in Holuhraun.

Figure 7 shows data from the GPS stations. We see slow inflation until August 2014 (it corresponds to the filling of the magma chamber). As soon as the eruption started, significant deflation was observed. However, even though the deflation continues now, it is slower than in the first weeks of the eruption. It leads to think that if it follos this trend, subsidence is going to become slower and slower until it becomes so little that the eruption ends.

In conclusion, it has been observed during those 5 months of eruption, that the intensity has been slowly decreasing. If this tendancy  continues, the eruption will decrease slowly in intensity.

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Friday 30 January 2015:

 

An earthquake swarm occured in the Bardarbunga caldera's east rim at 1km depth between 20:50 and 22:30. UTC on 29-January-2015 according to the Icelandic Met office. Tremor has been recorded from 21:10 to 22:00 (see tremor graphs). According to geologist & volcanologist  Jón Frímann, this tremor and earthquake swarm were associated with a possible minor (only about 30 to 55 minutes) eruption on the caldera's east rim or upper flank. This possible small eruption in the Bardarbunga may have been linked with the increased activity (very high SO2 emissions, earthquake activity at Holuhraun and increased geothermal activty (enlarged geothermal cauldrons) and mainly with the 60 cu m/s magma flow under the Bardarbunga) of last Saturday: January 24. If that subglacial eruption occured, it may have melted small quantities of ice, so there is some possibility for a very little jokulhaup flowing NE and reaching the Jökulsá á fjöllum glacier river.

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Monday 26 January 2015:

 

The rate (intensity) of the eruption is similar as during the past two weeks but lower than at the beginning of the eruption: just under 100 cu meters/second. Earthquake activity is still significant and persistent in the Bardarbunga caldera (a mean of 40 earthquakes/day since last Friday). Slow deflation of the Bardarbunga continues. There is a 65% (high) chance that the eruption continues at a similar rate for the moment. There is a 25% (low) chance of a slow and progressive decrease in activity over time. There is a 10% (very low) risk that the eruption increases in intensity.

Earthquake activity is little in the dyke at Holuhraun (10 to 13 earthquakes/day since last Friday) and the risk that the intrusion lengthens south towards Vatnajokkul is negligible.

Be careful, this is short-term and unaccurate prediction. After that, it is unknown what will happen.

The lava field is now little less than 1.4 cu km and the eruption can go on for many months.

 

See the Iceland met office's updates of the eruption:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

And their "earthquake page":

http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/

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Tuesday 27 January 2015:

 

Activity is similar as in the past two weeks but lower than at the beginning of the eruption. Today I'm not writing an update of the eruption, I'm just informing you that there is a flight report with beautiful photos of Holuhraun here.

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Monday 26 January 2015:

 

The rate (intensity) of the eruption is similar as during the past two weeks but lower than at the beginning of the eruption. Earthquake activity is still moderate and persistent in the Bardarbunga caldera (a mean of 55 earthquakes/day since last Friday). Deflation of the Bardarbunga continues. There is a 60% (moderate to high) chance that the eruption continues at a similar rate for the moment. There is a 30% (low risk that the intensity of the eruption increases.

Earthquake activity came back to "normal" in the dyke at Holuhraun (10 earthquakes yesterday). There is a 4% (extremely little) risk that the intrusive dyke lenghtens to the south toward the Vatnajokul glacier due to the hypothetic increase of the rate of magma flow. IF this occurs, there may be an explosive eruption due to interaction with ice. This situation is, luckily, extremely unlikely.

There is a 10% (very little) chance that the intensity of the eruption decreases significantly immediately.

Be careful, this is short-term and unaccurate prediction. After that, it is unknown what will happen.

The eruption can go on for many months.

 

See the Iceland met office's updates of the eruption:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

And their "earthquake page":

http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/

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Saturday 24 January 2015:

 

The rate (intensity) of the eruption is similar as during the past 10 days. Earthquake activity is moderate in the Bardarbunga (a mean of 42 earthquakes/day since Tuesday). Deflation of the Bardarbunga continues. There is a 50% (moderate) chance that the eruption continues at a similar rate for the moment.

Earthquake activity has increased in the dyke at Holuhraun (a mean of 16 earthquakes/day there), change in the subsidence, very high values of SO2 in the last few days, an increase in geothermal activity (geothermal cauldrons in Bardarbunga have enlarged) and a 60 cu m/s magma flow Under the Bardarbunga suggests that the rate of the flow of magma (the intensity of the eruption) might increase a little (40% of (moderate) likelyhood). There is a 10% (very little) risk that the intrusive dyke lenghtens to the south toward the Vatnajokul glacier due to the hypothetic increase of the rate of magma flow. IF this occurs, there may be an explosive eruption due to interaction with ice. Even if it is unlikely, it is possible and the best is to be careful.

There is a 10% (very little) chance that the intensity of the eruption decreases immediately.

Be careful, this is short-term and unaccurate prediction. After that, it is unknown what will happen.

The eruption can go on for many months.

 

See the Iceland met office's updates of the eruption:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

And their "earthquake page":

http://en.vedur.is/earthquakes-and-volcanism/earthquakes/vatnajokull/

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Thursday 22 January 2015:

 

The power of the eruption is similar as during the past 10 days. Earthquake activity is stable (a mean of 56 earthquakes/day since the last report last Tuesday). Deflation of the Bardarbunga continues. These observations mean that the eruption may continue at a similar pace as in the last 10 days.

Be careful, this is short-term and unaccurate prediction (for the next 36 hours). After that, it is unknown what will happen.

The eruption can go on for many months.

  

The lava field is now 84,7 km².

See a photo of the eruptive site on the Iceland met office website:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

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Tuesday 13 January 2015:

The power of the eruption is now a little weaker but: Earthquake activity is stable again (a mean of 37 earthquakes/day since the last report on Sunday). Subsidence/deflation of the Bardarbunga continues. These observations mean that the eruption may continue at a stable pace, similar as the one of the last 2 days.

Be careful, this is short-term and unaccurate prediction (for the next 36 hours). After that, it is unknown what will happen.

The eruption can go on for many months.

 

See the Iceland met office website:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

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Sunday 11 January 2015:

 

The activity in Holuhraun is still going at the same rate as the preceding weeks. Earthquake activity is still important but it decreased a little (a mean of 31 earthquakes/day since the last report on Wednesday). The GPS station in the Bardarbunga caldera records slower subsidence of the Bardarbunga caldera (rate of 10-15 cm/day. These observations mean that the eruption may continue at a little slower pace in the day or so.

Be careful, this is short-term and unaccurate prediction (for the next 36 hours). After that, it is unknown what will happen.

The eruption can still go on for many months.

 

See the Iceland met office website:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

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Wednesday 7 January 2015:

 

Earthquakes continue in the Bardarbunga caldera and in Holuhraun (a mean of 37 earthquakes/day since the last report last Wednesday). GPS monitoring keep recording subsidence of the Bardarbunga caldera at a rate of 25 cm/day. These observations mean that the eruption is likely to continue at about the same pace in the next several days.

The lava field at Holuhraun is now 83,4 km² and 2,2 cubic kilometers of lava have erupted. The eruption can continue for many months as I estimate that the magma chamber was full of 10,4 cubic kilometres of magma at the beginning of the eruption in August/September 2014. I estimated the volume of magma in the magma chamber at the beginning of the eruption using the time since the last eruption: the last eruption in 1910 (104 years ago) emptied the magma chamber; in 104 years the magma chamber had the time to be filled of approximately 10,4 cubic kilometres of magma.

 

See the Iceland met office website:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

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Wednesday 31 December 2014:

 

Earthquakes have restarted in the Bardarbunga caldera and in Holuhraun (45 earthquakes since yesterday morning). GPS monitoring recorded deflation of the Bardarbunga. These observations mean that the eruption is re-intensifying.

The lava field is 83 km² and 2 cubic kilometers of lava have erupted. It is possible that the eruption continues for many months as the magma chamber was full of 10,4 cubic kilometres at the beginning of the eruption in August/September (it was filling since 1910, 104 years).

 

See the Iceland met office website:

http://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947

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03/02/2015
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