Thnx voor de tip!quote:Op dinsdag 6 januari 2015 21:15 schreef aloa het volgende:
Vanavond in nieuws uur http://nieuwsuur.nl/live/
Morgen ook op de kennis van nu: http://www.npowetenschap.(...)januari-ijsland.html
Toppiequote:Op dinsdag 6 januari 2015 21:15 schreef aloa het volgende:
Vanavond in nieuws uur http://nieuwsuur.nl/live/
Morgen ook op de kennis van nu: http://www.npowetenschap.(...)januari-ijsland.html
quote:There are changes taking place in harmonic tremor on the SIL stations closest to the eruption in Holuhraun. I don’t know what this means exactly, the best idea at the moment is that the eruption is either ending or getting less in power. It is hard to know for sure at this moment due to the bad weather in Iceland. This might also just be part of normal fluctuation of the eruption.
quote:• Insubstantial changes have been in the volcanic eruption in Holuhraun over the last few weeks. The eruption is now well visible on web cameras and the activity appears to be similar to preceding weeks.
• Seismic activity in Bardarbunga continues to be strong, but it has though somewhat decreased. Total number of earthquakes in Bardarbunga from the last meeting of the board, on the 6 of January, is just over 100. Just over 10 earthquakes were between M4,0-5,0. The strongest one was M5,1 yesterday, 8. December, at 18:47. Few earthquakes were detected in the dyke of the same period, all of them smaller then M2,0.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga. The rate of the deflation continues to slow down.
• The GPS station in Bardarbunga caldera show that the caldera continues to subside. The rate of the subsidence continues to slow down and is now between 10-15 cm per day.
quote:• Insubstantial changes have been in the volcanic eruption in Holuhraun over the last few weeks. Although the power of the eruption has diminished, it is still quite forceful. The flow of lava is now largely under the surface of solidified lava.
• Seismic activity in Bardarbunga continues to be strong, but it has though somewhat decreased. The largest earthquake since the last meeting of the Advisory Board was of magnitude M4,7 on Saturday, 10 of January at 18:23. In total 16 earthquakes were recorded of the period between magnitude M4,0-5,0 and 13 between M3,0- 4,0. Over 20 earthquakes were detected in the dyke of the same period, all of them smaller then M2,0.
• Six earthquakes were detected in Tungnafellsjokull glacier since Friday. The biggest was M2,1 tonight, January 13 at 04:21. Around 20 earthquakes were detected around Herdubreid, all smaller then M2,0.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga.
• The GPS station in Bardarbunga caldera show that the caldera continues to subside.
• Indications are of increased respiratory symptoms in Iceland over the period of the volcanic eruption. No serious cases have though been reported.
• High values of sulphuric dioxide are still being recorded. Over the weekend high values were recorded in Hofn (3400 µ/mł) in Reydarfjordur (1000 µ/mł) and in Jokuldal (7800 µ/mł).
quote:• Insubstantial changes have been in the volcanic eruption in Holuhraun over the last few weeks. Volume of the lava flow, over the last few weeks, is estimated 50-70 cubic meters per second.
• Seismic activity in Bardarbunga continues to be strong. Over the last few weeks it has though been quite weaker than in the first months of the event. Three earthquakes of magnitude M4,6 were detected since the last meeting of the Advisory Board on Tuesday, 13. January. Sixteen earthquakes were detected between magnitude M4,0-5,0 during that period and in total around 150 earthquakes were detected.
• Around 40 earthquakes were detected in the dyke during the same period, all of them smaller then M2,0.
• Around 20 earthquakes were detected in Tungnafellsjokull glacier since last Tuesday. The strongest one was M3,1 on January 13 at 13:17. Friday. Around 20 earthquakes were detected around Herdubreid, the strongest one was M2,3.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga.
• The GPS station in Bardarbunga caldera is not transmitting any data at the moment. A repair mission is being organised to get the station back on-line.
• High values of sulphuric dioxide are still being recorded.
Dan moet je kijken of je een heli vlucht kan pakken langs de vulkaan op. Gezien de foto's en filmpjes die ik gezien heb moet dat de moeite waard zijn.quote:
De eruptie zou dus mogelijk mischien in maart zou kunnen ophouden.twitter:
quote:Op donderdag 22 januari 2015 10:24 schreef bwt het volgende:De eruptie zou dus mogelijk mischien in maart zou kunnen ophouden.twitter:
quote:• Insubstantial changes have been in the volcanic eruption in Holuhraun over the last few weeks. The lava field has thickened substantially but activity on the surface has decreased.
• The subsidence in Bardarbunga caldera was measured from air on Wednesday. The volume of the subsidence is now 1.7-1.8 km3. The change in volume from the last measurement corresponds to a flow of magma from underneath Bardarbunga of about 60 m3 per second. The greatest subsidence is now about 61 meters. Over the last few weeks the geothermal cauldrons in Bardarbunga have enlarged.
• Seismic activity in Bardarbunga continues to be strong. Over the last few weeks it has though been quite weaker than in the first months of the event. No earthquake over M5,0 has been detected in Bardarbunga for 15 days, which is the longest period between M5,0 earthquakes since the seismic activity started in August. The strongest earthquake since the last meeting of the Advisory Board on Tuesday was measured M4,7 yesterday at 03:07. Eight other earthquakes between magnitude M4,0-4,7 were detected over the period and about 37 earthquakes between M3,0-4,0. In total around 150 earthquakes have been detected around the caldera since last Tuesday.
• Around 65 earthquakes were detected in the dyke during the same period, the strongest one was measured M1,5.
• Insubstantial earthquake activity was detected in Tungnafellsjokull, Askja and Herdubreid.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga.
• Around 2200 µg/m3 SO2 were recorded on Thursday in Reykjahlid and at lake Myvatn. Very high values of SO2, about 84000 µg/m3, were recorded at the eruption site in Holuhraun on Wednesday, being the highest values recorded at ground level since the eruption started.
quote:• The volcanic eruption in Holuhraun continues. Visible intensity of the eruption was low on last Wednesday while various observations were done at the eruption site. Comprehensive cross-section measurements from air (on 30. December and 21. January) show however that the lava field has thickened substantially during these three weeks and that the volume of the lava field is now little less than 1.4 km3. The flow of magma, during this period, was just under 100 m3 per second. The intensity of the eruption is there for slowly decreasing but hopefully it will be possible to measure the volume of the lava field again later this week, which will give new numbers on the flow of magma.
• Seismic activity in Bardarbunga continues to be strong. Eight earthquakes between M4.0-4.9 have been detected since the last meeting of the Advisory Board on Friday. The strongest one was measured M4.9 on Saturday, 24. January at 07:25. About 40 earthquakes between magnitudes M3.0-3.9 were detected over the period. In total around 150 earthquakes have been detected around the caldera since last Friday. No earthquake over M5,0 has been detected in Bardarbunga since 8. January.
• Around 50 earthquakes were detected in the dyke during the same period. Most of them were under M1.0 but the strongest one was M1.6 on 24. January.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga.
aan hoeveel moet je dan denken?quote:Op dinsdag 27 januari 2015 16:21 schreef 1boefje het volgende:
Ik ga 26 februari, maar ipv een helicoptervlucht heb ik besloten een dag te paardrijden.
De prijzen met een helicopter vanaf Reykjavik zijn abnormaal om het vanuit de lucht te zien.
Ik heb het in Hawaii al vanuit de lucht gezien, dus zie het niet als meerwaarde.
Hoe dan ook, ik ga weer naar mijn geliefde landje, voor de 3e keer
En de feed/viewquote:Op dinsdag 3 februari 2015 09:35 schreef Frutsel het volgende:
'Game of Drones'.... by Ginger Zee
http://hraun.vedur.is/ja/Bardarb/BARC/quote:• The volcanic eruption in Holuhraun continues. A visible reduction has been on the eruption in the last two weeks.
• Seismic activity in Bardarbunga continues to be strong. The strongest earthquake since the last meeting of the Advisory Board on Tuesday was measured M4.9 tonight at 03:48. Two other earthquakes stronger than M4,0 were detected since Tuesday, one was M4,5 and the other M4,0. About 10 earthquakes between magnitudes M3.0-3.9 were detected over the period. In total around 110 earthquakes were detected around the caldera since last Tuesday. No earthquake over M5,0 has been detected in Bardarbunga since 8. January.
• Around 20 earthquakes were detected in the dyke during the same period. The strongest one was M1.8.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga.
• The highest levels of sulphuric dioxide since Tuesday, 3rd of February, 800 µg/mł SO2 was measured in Vopnafjordur on Tuesday.
• A new risk analysis for the area around the eruption site is being conducted. The new risk map for the area will be issued next week.
• A team of technicians from The Icelandic Met Office, Institute of Earth Sciences UI, and The Department of Civil Protection have been working on maintenance on measuring equipment’s on Vatnajokull glacier and in the surrounding area. The GPS station in the Bardarbunga caldera is back on-line and will be visible on the IMO web site as before.
Voor helicoptervluchten askja.nlquote:
• The volcanic eruption in Holuhraun continues. No scientists are in the area because of bad weather.
• Seismic activity in Bardarbunga continues to be strong. The strongest earthquake since the last meeting of the Advisory Board on Tuesday was measured M4.7 tonight at 03:18. Two other earthquakes stronger than M4.0 were detected since Friday, one was M4.1 on Saturday at 07:05, and the other M4.0, also on Saturday but at 04:00. About 10 earthquakes between magnitudes M3.0-3.9 were detected over the period. In total around 60 earthquakes were detected around the caldera since last Friday. No earthquake over M5.0 has been detected in Bardarbunga since 8. January.
• Around 30 earthquakes were detected in the dyke during the same period. The strongest one was M2.0 on Saturday at 20:35.
• The GPS station in the Bardarbunga caldera is back on-line and is visible on the IMO web site.
• GPS measurements near northern Vatnajokull glacier show continuing slow deflation towards Bardarbunga. A detectable errors are in the GPS measurements due to bad weather conditions over the last few days.
• A new risk analysis for the area around the eruption site is being conducted. The new risk map for the area will be issued this week.
• A team of scientists has been monitoring pollution in rainwater, snow and melt water since the eruption started. The team is planning to collect samples on Vatnajokull glacier and on mountain tops in Eastern Iceland. Chemical composition of rainwater around Iceland is also being monitored.
• The volcanic eruption in Holuhraun continues. The eruption is still strong although it continues to diminish.
• Seismic activity in Bárđarbunga continues to be strong. The strongest earthquake since the last meeting of the Advisory Board on Friday was measured M4.5 on Friday, 13th of February, at 21:22. Two other earthquakes stronger then magnitudes M4.0 were detected over the period and three between M3.0-3.9. In total around 70 earthquakes were detected around the caldera since last Friday. No earthquake over M5.0 has been detected in Bárđarbunga since 8. January.
• Around 60 earthquakes were detected in the dyke during the same period. All smaller than M2.0.
• GPS measurements near northern Vatnajökull glacier show continuing slow deflation towards Bárđarbunga.
• About 40 earthquakes were detected around Herđubreiđ and Herđubreiđartögl since Friday. The strongest was M2.0 yesterday at 03:39. About 10 earthquakes were detected around Askja and three in Tungnafellsjökull.
• The volcanic eruption in Holuhraun continues, but it has diminished substantially over the last few weeks. Visual activity in the crater has decreased and the lava field is hardly increasing in size.
• Seismic activity in Bárđarbunga continues to diminish although it can still be considered strong. The strongest earthquake since Tuesday was measured M4.3 at 01:26 yesterday. Two other earthquakes stronger then magnitudes M3.0 were detected over the period. In total around 70 earthquakes were detected around the caldera since last Tuesday. No earthquake over M5.0 has been detected in Bárđarbunga since 8. January. A distinct pulse of earthquakes occurred yesterday between 01:25 and 02:10. Time intervals between such pulses have significantly increased from 2-4 hours in the beginning to 12-24 hours or more at the moment.
• Around 65 earthquakes were detected in the dyke during the same period. The strongest one was measured M1.6 today at 08:24 in Dyngjujökull glacier.
• The rate of the subsidence in Bárđarbunga caldera had decreased substantially. But that is not the whole story. Ice is subsiding into the caldera with the effect that the GPS station does not show any changes. The estimated depression of the rock foundation of the caldera, in the light of the ice subsidence, is about 5 cm per day. The flow of magma from under Bárđarbunga is believed to be 25-30 m3 per second, which is about one tenth of the flow in September last year.
• GPS measurements near Vatnajökull glacier show continuing slow deflation towards Bárđarbunga, indicating a flow of magma from under the volcano.
• About 7 earthquakes were detected around Askja and 15 around Herđubreiđ since last Tuesday. All of them smaller than M1.5.
haha, mooi stukquote:
Voor de videotwitter:
Als het een voorspellende gave is zou ik een hoop wereldproblemen kunnen oplossen .quote:
Ik had niet voor niks afgesloten met een onheilspellende zinquote:
quote:Maar voorlopig lijkt Bárdarbunga zich een beetje te kalmeren. Al kan het natuurlijk ook zijn dat hij druk aan het opbouwen is...
quote:Volcanologist: Bárđarbunga Caldera Starts Rising Again
Volcanologist Haraldur Sigurđsson, who predicted the end of the Holuhraun eruption with remarkable accuracy, wrote on his blog yesterday that there are indications that the caldera of Bárđarbunga volcano, which fed the Holuhraun eruption, has begun rising again.
The rising of the caldera could mean that magma is accumulating in the magma chamber, building pressure, which might eventually lead to another eruption.
“When the subsidence [of the caldera] stopped, the curve of the position of the GPS sensor in Bárđarbunga had become horizontal. In the accompanying graph from the Icelandic Met Office’s website a blue curve shows none or insignificant horizontal movement on the surface of Bárđarbunga from February 7 to March 7,” Haraldur writes.
“I added a red line for comparison [see Haraldur’s blog]. It clearly shows that in the past days, the GPS sensor has started rising again. It can be caused by two things: (A) The ice below the sensor is flowing into the depression … (B) The caldera has started rising again because magma from the mantle is flowing into the magma chamber below Bárđarbunga.”
“I’m inclined to believe the latter explanation, but time will tell. If (B) is correct, it is likely that the flow of magma from the depths into the magma chamber will take many years before it reaches the position which Bárđarbunga had before the eruption which began in 2014,” Haraldur concluded.
Other scientists have predicted that Bárđarbunga will erupt again in the near future and that the eruption in Holuhraun was the first in a series.
The eruption carried on while the caldera subsided and magma flowed out of the magma chamber and into the intrusive dike connecting Bárđarbunga, which lies under Vatnajökull glacier, with Holuhraun north of the glacier.
Using data from a GPS sensor in the caldera, Haraldur and his grandson Gabríel Sölvi calculated the rate of the subsidence and when it would stop, which would mean that magma had stopped flowing into the intrusive dike and hence that the eruption had ended.
They had predicted that this would happen on March 4, while the eruption ended on February 27—they were off by five days.
quote:What is going to happen next in Bardarbunga?
It has been few days since the eruption in Holuhraun has ended and everything is quiet for the moment in Bárđarbunga volcano. What is going to happen next is a big question and nobody has the exact answer. Here are few options.
1.Nothing is going to happen. The rift is going to continue without more eruptions.
2.New magma intrusion is going to start soon in Bárđarbunga volcano. New eruption is going to start days to weeks later.
3.There is also high risk in my view of eruptions in Hamarinn volcano (also called Loki-Fögrufjöll). That volcano system is inside Bárđarbunga volcano and dyke intrusion from Bárđarbunga to the south might start a volcano eruption in it. I don’t know how big such eruption would be, it is my estimate. Dyke to Torfajökull volcano is unlikely to happen. I however cannot rule it out at this point.
What is going happen in Bárđarbunga volcano depends on many factors and not all of them are known. What is known is that heat has been increasing in shallower parts of the crust and caldera for the past six months and those signs are not good. What is not known is the time in question. Next eruption could happen tomorrow or nothing can happen for years. There is no way to know when next eruption is going to happen.
Currently I am just monitoring Bárđarbunga volcano and waiting to see what happens next. The text above is just speculation, not fact. It is not clear what is going to happen next. The only way to know that for sure is to wait until next eruption starts and that might be a long wait.
Zitten een paar interessante commentaren onder het verhaal.twitter:
Laatste uitbarsting van de Kayla is alweer even geleden (1918) Hij is al over tijd dus. (Gemiddeld 40 - 80 jaar een uitbarsting).quote:
Ik moet nog zien wat er bedoeld wordt.twitter:
quote:A series of tremors hit the Tungnafellsjökull glacier in the Icelandic highlands this morning.
A total of eleven tremors over magnitude 2 were felt in the area this morning, with the strongest – a magnitude 2.9 – coming around 11am.
According to Hildur María Friđriksdóttir from the Icelandic Met Office, tremor waves of this kind are common in the area and are no cause for concern.
Tungnafellsjökull is a relatively small (10 x 5km) glacier to the north-west of the mighty Vatnajökull glacier in South Iceland.
quote:Bárđarbunga Volcano Might Erupt Again
Geologists are now investigating data, indicating that magma might be accumulating again under Bárđarbunga volcano in Vatnajökull glacier. The Holuhraun eruption, which took place between August 31, 2014, and February 27, 2015, was part of a series of events which started in the volcano in 1974 and might provide evidence about the behavior of the volcano in the future.
According to Páll Einarsson, professor of geophysics at the University of Iceland, the next few months will determine whether magma is in fact accumulating. “That’s the big question,” he told RÚV. “There are some indications that this might be the case, but we have to investigate it further.”
The signals, gathered by new equipment on location, are not clear and come from a great depth. Geologists are still learning how to interpret such data.
The Holuhraun eruption is now seen as a chapter in a story that began in 1974. That year, a series of large earthquakes began, which hit at regular intervals in Bárđarbunga. The first chapter ended 22 years later with the eruption and glacial flood in Gjálp in 1996.
After the Gjálp eruption, the volcano was silent for many years, but a few years ago, a new series of earthquakes began, culminating in the Holuhraun eruption in the northeastern highlands in August 2014. The magma came from Bárđarbunga and the caldera sank by 60 meters (197 feet) in the course of the eruption.
Páll believes it’s possible that the next eruption might occur in Bárđarbunga itself. “Bárđarbunga is probably the most powerful volcano in Iceland … Bárđarbunga is the center of a volcanic system which often erupts at the periphery, but still more frequently in the volcano itself.”
It is difficult to predict when the next eruption might start and whether previous eruptions can be used as evidence as to what might happen next. Páll concludes: “We have 30 volcanic systems in Iceland and each one of them has its own personality. To predict what is likely to happen in the near future we have to get to know them a bit personally.”
quote:Katla hit by series of tremors
A 3.3 magnitude tremor hit the south-east of Katla, one of Iceland’s most active volcanoes, in the early hours of this morning.
The main tremor was followed by around ten aftershocks, some of which were shallow and possibly connected to geothermal activity, the Icelandic Met Office reports.
No significant changes to nearby rivers have been reported, but the relevant data will be studied more closely.
“Katla sees this type of seismic cycle from time to time – on average 1-3 times a year,” says the Met Office. “We are monitoring the area closely and will keep everybody informed of any changes. At the moment, things appear to have quietened down.”
quote:Earthquake activity in Bárđarbunga and Grímsfjall volcanoes
Yesterday (17-March-2016) an earthquake swarm took place in Bárđarbunga volcano. This is a weekly cycle at the moment in Bárđarbunga volcano so older readers are used to seeing and read about it already. This started in September 2015 (for the new readers) after the eruption in Holuhraun ended in February 2015. This activity suggest that magma has started to flow into the magma chamber in Bárđarbunga volcano again at faster speeds than before the eruption in Holuhraun. The exact rate is difficult to know, since the magma that started the eruption in Holhraun had been building up in Bárđarbunga volcano since 1970-ish and part of that time earthquake recording was poor or did not exist in Iceland or parts of it until 1995 when the SIL network was created by Veđurstofa Íslands.
The largest earthquake this week had the magnitude of 3,4 while other earthquakes that took place had smaller magnitude. The second largest earthquake had the magnitude of 2,8. Other earthquakes where smaller in magnitude. It is also interesting that part of the earthquake swarm aligned it self along north-south fault in the eastern part of the caldera. That is a new feature, either a weakness is forming at this location or something else is up. This area has around 300 – 500 meter thick glacier on top of it and an eruption at this location would be extremely bad. The glacier flood from eruption at this location would mostly go down Jökulsá á fjöllum glacier river. Other flood locations can’t be ruled out (I’m not an expert on glacier floods and I do have limited knowledge of the landscape under the glacier).
It has been five years since Grímsfjall volcano erupted in a largest eruption in 140 years for Grímsfjall volcano. Over the past few weeks there has been a slight increase in earthquake in Grímsfjall volcano. At the moment this doesn’t mean an eruption is imminent, the thing however about eruptions in Grímsfjall volcano is that they happen suddenly and without warning. Normally eruption happens in Grímsfjall volcano every 3 – 5 years on average, sometimes its shorter and sometimes its longer between eruptions.
Notice on Böđvarshólar geophone station
For the longest time now I’ve been having 3G connection issues with Böđvarshólar geophone station. The problems include poor signal, little bandwidth. The poor signal leaks into my recording of earthquakes, making them bad and extremely noisy and that makes them less usable for me. I am going to attempt to improve this situation but if that fails I will have to turn the station down. Since the cost of getting a good antenna for this location is too high and the solution takes too long to implement anyway. I will post a notice if I take down the Böđvarshólar geophone station. If it happens, it is going to happen before I move to Denmark.
Komende week even niet graag. Wil nog wel terug kunnen keren.quote:
Deze gaat over IJsland.quote:
quote:Earthquake Hits Major Volcano Site
There was a major earthquake on the northern edge of the Bárđarbunga volcanic craters at around midnight last night.
The quake measured 4.2 on the Richter scale and is therefore the largest quake to have hit the famous volcano since it stopped erupting in February last year.
According to Bjarki Fries, a naural disasters specialist with the Icelandic met office, the earthquake emanated from 3.5 kilometers underground. Around 15 aftershocks have already been measured, the most powerful of which was a 3.5 quake at 01.00 this morning.
Met office earthquakes specialist Martin Hensch told RÚV that there is no evidence of lava movements or of any eruption activity connected to the earthquakes, but that the situation will be monitored carefully. There were two quakes in the same location on April 3, measuring 3.4 and 3 on the Richter scale.
The recent eruption at Bárđarbunga, often known as Holuhraun, lasted from late August 2014 to late February 2015, and despite not affecting aviation or physically threatening any human settlements, it caused dangerous levels of pollution around Iceland and produced more new lava than almost any other eruption in Iceland since the Vikings first arrived.
Hmmmm... HLNquote:Op dinsdag 21 juni 2016 22:06 schreef aloa het volgende:
Hekla staat op uitbarsten...
Veel linkjes in bovenstaand artikel...quote:Is Hekla really going to blow?
The volcanoes of Iceland are some of the most closely watched on the planet. Not only is there an extensive seismic array that records all the earthquakes that occur on the island nation, but many volcanoes have both GPS monitoring of their shape and borehole strain gauges that measure stresses underground caused by these changes in shape. There have been examples in Iceland where sudden and strong changes in strain in these boreholes came right before an eruption, including the 2000 eruption of Hekla. Volcanologists in Iceland are watching for any signs that an eruption might be in the works so that appropriate measures to protect lives and property can be enacted.
That’s why it is a little peculiar that Dr. Páll Einarsson of the University of Iceland warned people and airplanes to “stay away” from Iceland’s Hekla based on his interpretation of accumulated strain at the volcano. According to reports coming out of Iceland, Dr. Einarsson says that strain measured on these strain gauges is higher than it was prior to the 2000 eruption. Also, it has been 16 years since Hekla’s last eruption and, at least for a brief period from 1970-2000 (mind you, this is a very short time for the lifespan of any volcano), it was erupting about every 10 years. Put those together and he thinks that Hekla is ready for its next eruption, and it could happen soon.
However, I am a little perplexed by this statement from Dr. Einarsson and I wish I knew more about the context in which the quotes were given. Without confirmation from the Icelandic Met Office (the volcano monitoring agency), I don’t really know how to assess the validity of what Dr. Einarsson is saying.
Volcanoes care not for your puny human schedules, so you might expect an eruption soon ... or might not.
Does this mean that doom is coming? Not necessarily. As I said, although Hekla did have a pattern of eruptions every ten years after 1970, prior to that the volcano had no eruption from 1947 to 1970, over 22 years. In fact, if you go back to the 1597 AD eruption (again, be wary of any arbitrary starting point for statistics), Hekla has had eight eruptions separated by anywhere from 32 to 79 years (and if I wanted to choose the most common repose interval, it is ~35 years). That being said, volcanoes care not for your puny human schedules, so you might expect an eruption soon … or might not.
Scientists also don’t have strain data going back further than the 2000 eruption of Hekla, so they don’t have a good baseline for understanding exactly how the strain changes before every eruption—just what happened prior to the 2000 event. That’s not to say that they shouldn’t expect something similar, but the data is somewhat scant.
You can actually see the near real-time strain data coming from around Hekla. Now, I am no expert on these readings, but if you compare them to the readings before the 2000 eruption, there doesn’t seem to be much sign of an eruption coming in the near future (that is, next few hours to days). The five gauges are all roughly the same and prior to the 2000 eruption, they all diverged as the new magma intruded the volcano. You can also check out the earthquakes recorded near Hekla and nothing suspicious appears to be happening either.
For an Icelandic volcano, Hekla has a surprisingly explosive history of eruptions. These explosive eruptions have produced ash plumes that reached over 15 kilometers (~50,000 feet). They are also eruptions that tend to be rich in fluorine, which is especially hazardous to grazing animals as they eat fluorine-contaminated ground cover that leads to fluorinosis (and many times, death). You can imagine the travel ramifications of a large explosive eruption from Hekla—we saw that during the 2010 eruption of Eyjafjallajökull. Hekla has produced some large fissure eruptions as well, with abundant basaltic lava flows, much like what we saw from the Holuhraun eruption in 2014-15.
Now, I’m not saying that Dr. Einarsson is wrong to be point out what he thinks the threat of Hekla right now might be, but without official world from the IMO or emergency management agencies in Iceland, I worry that these statements could be jumping the gun (if Dr. Einarsson was quoted correctly). One of the biggest challenges for volcano monitoring and mitigation is getting people to believe the threat when it presents itself. Too many false alarms, even if they aren’t coming from the official monitoring and management agencies, can make people feel like they can’t trust officials (see: L’Aquila earthquake in Italy). I hope that the IMO releases a statement soon in response to what Dr. Einarsson said so we can know what might be happening at Hekla. Until then, you can watch Hekla on its webcam.
sensatie makenquote:Op maandag 11 juli 2016 23:41 schreef thesiren.nl het volgende:
Ha vandaag bij groeten van Max hadden ze ook een verhaal over de Hekla die op uitbarsten stond. Ze vertellen graag horrorverhalen over vakanties dus nu ook weer, binnen onafzienbare tijd staat het hele vliegverkeer stil. Allemaal omdat 1 professor zegt dat er nu twee maal zoveel druk staat als bij de laatste uitbarsting. Toen namen ze contact op met een Hollandse Fysisch-(geograaf/geoloog) die daar ook reisleider is, die zei dat de professor dat ieder jaar rond deze tijd vertelt! Hij voegde er gelijk aan toe dat het niet zo heftig zal zijn als met de ejafjellajokul, dat was wel een domper voor die presentator.
Vanaf 22:30 Leuk om te zien
quote:Monitoring of Hekla improved
Monitoring of Mt. Hekla has been improved over the past months, Hekla is one of the most active and potentially dangerous volcanoes in Iceland. According to the Icelandic Meteorological Office (IMO) who is in charge of monitoring Mt. Hekla the system should help in sending out timely warnings with the aim of reducing any harm the volcano might cause.
There are several different types of active volcanoes in Iceland and the hazards associated with each volcano are related to the type, location and intensity of an eruption. According to the IMO public vulnerability to volcanic hazards increases as the number of people exposed to the hazard grows.
Mt. Hekla has been getting ready to erupt now for some years and is according to its normal eruption cycle ready to go, the mountain is a stratovolcano in the south of Iceland with a height of 1,491 m (4,892 ft). Over 20 eruptions have occurred in and around the volcano since 874.with the last one happening in the year 2000.
Travelers are warned not to walk the mountain.
According to the IMO, volcanic risk is mitigated by the capability to detect, interpret, and communicate volcanic signals before and during a volcanic eruption.
quote:Scientists Follow Katla Volcano Closely
The water level of glacial river Múlakvísl has risen in line with increased seismic activity in volcano Katla, which lies under Mýrdalsjökull icecap in South Iceland. Scientists are monitoring developments in the volcano closely.
Geophysicist Páll Einarsson finds it likely that melt water from cauldrons in Katla has flowed into Múlakvísl from underneath the glacier. His theory is supported by increased conductivity in the river, mbl.is reports.
At the current stage, the glacial outburst flood is insignificant compared to the massive flood which occurred in Múlakvísl in 2011 and destroyed a bridge on the Ring Road. There are currently no indications of an upcoming volcanic eruption.
Katla last erupted in 1918, causing flooding and ash fall.
Vandaag wat zwaardere aardbevingen. Twee met een kracht van 3.2 op 0.1 km diepte.quote:
iedereen meteen op het randje van hun stoel, valt het stilquote:
en dat klopt dus niet. Het schijnt dat er wel degelijk een kleine eruptie heeft plaatsgevonden van de Katla na de Eyjaflalla in 2010, eentje die niet door de ijskap is gebroken. Dus de laatste eruptie van 1918 zou niet correct zijn.quote:
We wachten het af. kan idd alle kanten op.quote:Op vrijdag 29 juli 2016 23:24 schreef ansitermiet het volgende:
Katla is het rustig.
Vandaag op en.vedur.is toch vooral weer Katla, en Hekla rustig.
En weer een swarm in de buurt van Bardarbunga.
Hekla is onvoorspelbaar. Daarvan weet je pas 2 uur van tevoren of er iets te gebeuren staat.
Katla zou kunnen, ik zie een wijziging in de tremor measurement op en.vedur.is ook al weet ik natuurlijk niet wat dat exact betekent.
Ik verwacht toch echt Bardarbunga en omgeving (Grimsvötn?) als eerste eruptie.
Ook al is Hekla 'over due' sinds 2000 en de trend is elke tien jaar de laatste 100 jaar...
toch hebben we sind Eyjafljalla in 2010 geen serieuze eruptie gehad van de Katla maar wel van Grimsvötn, een van de meest actieve op IJsland momenteel.
Misschien dat Katla alsnog komt als voorspelde reactie op Eyjafjalla ,tenzij die al geweest is en het dus stil blijft.
Is het daadwerkelijk tectonisch of toch magma-gerelateerd?
Grimsvotn en Bardarbunga zijn toch echt de aandachtstrekkers de laatste jaren.
Komt Hekla? Wie zal het zeggen.
Sinds 2010 is het duidelijk dat het vulkaanseizoen weer is aangebroken voor de komende 50-80 jaar.
Dus 'we can eat our hearts out' de komende jaren.
Wat zal het worden?
Of gaan sommige vulkanen ons verrassen, zoals Eyjafjalla dat heeft gedaan in 2010?
En dan maar hopen voor de luchtvaart dat de wind goed staat en dat het magmatype de luchtvaart genadig is, zoals Grimsvötn in 2011.
vandaag op en.vedur.is:quote:
maar wat is 'unusually high'?quote:Remarks of a specialist
According to local reports, the level of the Bláfjallakvísl glacial river is unusually high. Bláfjallakvísl originates from the northern side of Mýrdalsjökull and hikers are advised to show caution if crossing the river.
Water-level and electrical conductivity measurements at the bridge over Múlakvísl show increased drainage of geothermal meltwater from Mýrdalsjökull. Sulfur smell has been reported from the area related to this drainage.
Written by a specialist at 29 Jul 18:08 GMT
Het gaat ook nooit rustig worden op IJsland.quote:Op zaterdag 30 juli 2016 00:02 schreef ansitermiet het volgende:
vandaag op en.vedur.is:
maar wat is 'unusually high'?
Betekent dat meer geothermische energie dan normaal in deze zomermaanden?
Wijst allemaal weer op Katla.
Ja, in de zomer heb je natuurlijk de periodieke afwatering van de caldera door geothermische activiteit... maar als de betreffende website het al 'unusual' noemt, dan is de geothermische activiteit hoger dan normaal.
En wat was dit op 22-24 juli? (tremur measurement)
[ afbeelding ]
Sulphur smell... kan onschuldig zijn.. maar de betreffende verhalen over 'de neus' aangaande vulkaanuitbarstingen...
het kan de jaarlijkse leegloop van de caldera zijn in de zomer... en de ondiepe bevingen misschien de wind...? Maar het gebruik van 'unusual high' vertrouw ik niet.
Ik vertrouw het niet.
Katla zou altijd uitbarsten als antwoord op Eyjafljalla. Heeft ze mogelijk gedaan gezien de historie na 2010, in juli 2011... maar het is niet rustig. Nog steeds niet.
Ik zeg: de herfst is het tijdstip.
In oktober komt de uitbarsting van Katla, Hekla, of toch weer onder de Vatnajokull.
Inderdaad: we wachten af.
op zich wel logisch, voor een hotspot.quote:
quote:Yesterday, August 3rd, there was a seismic swarm in Bárđarbunga. At 16:15, a magnitude 3,9 earthquake, the largest of the swarm, was detected in the northern rim of the volcano's caldera. This swarm is not thought to be out of the ordinary when compared to the activity in Bárđarbunga over the past few months, but nonetheless, the volcano is being thoroughly monitored around the clock.
Written by a specialist at 04 Aug 01:58 GMT
quote:Iceland raised alarm after biggest tremor since 1977 hits largest volcano
Iceland raised the alarm after its largest volcano was hit by the biggest tremors since 1977.
Two quakes larger than 4 in magnitude early Monday rocked the crater of Katla, the country’s Met Office said in a statement. That was followed by at least 10 more tremors at the volcano, which rises 1,450 meters (4,757 feet) into the air on the North Atlantic island’s southern coast.
There were no immediate reports of casualties or damages to property.
Katla last erupted in 1955 and 1999. Neither of those were large enough to break the ice covering its 10 kilometer-wide (6 mile) caldera. Its last major eruption was back in 1918, when it spewed ash for more than five weeks.
An eruption of the Eyjafjallajokull volcano in 2010 caused the cancellation of more than 100,000 flights across Europe on concern that glass-like particles formed from lava might melt in aircraft engines and clog turbines. Historically, Eyjafjallajokull has been known to erupt one to two years prior to Katla.
quote:IJsland vreest voor uitbarsting vulkaan Katla
IJsland maakt zich op voor een mogelijke uitbarsting van de vulkaan Katla, een van de grootste vulkanen van het land. Het gebied is vanmorgen geraakt door twee krachtige aardbevingen, wat mogelijk een uitbarsting kan veroorzaken.
Het gebied werd vanmorgen vroeg getroffen door aardbevingen van respectievelijke 4.5 en 4.6 op de schaal van Richter. Gevreesd wordt dat de trillingen een uitbarsting kunnen bespoedigen. ,,Het is een behoorlijk dynamische situatie op dit moment, en dat zal de komende uren en dagen zo blijven", aldus wetenschapper Matthew Roberts van het meteorologisch instituut van IJsland. ,,Maar op dit moment zien nog we geen direct gevaar."
De 1450 meter hoge vulkaan is voor het laatst in 1918 uitgebarsten. Volgens wetenschappers zou er binnenkort sowieso weer een uitbarsting kunnen zijn, hoewel het ook nog decenia kan duren.
De vulkaan is bedekt met ijs dat de hete lava bij een uitbarsting ruim een uur zou moeten kunnen tegenhouden. Daardoor is er genoeg tijd om het gebied te evacueren en het vliegverkeer in te seinen, licht Roberts toe.
De as afkomstig van de uitbarsting van de dichtbijgelegen vulkaan Eyjafjallajökull legde in 2010 het Europese vliegverkeer nog plat voor zes dagen.
quote:Cluster of Big Earthquakes Rattles Iceland’s Katla Volcano
LAST NIGHT, A brief earthquake swarm rattled the caldera at Katla in southern Iceland. The largest earthquakes were over M4, ranging from a few kilometers deep to near the surface (although the depth locating is likely problematic for many of the smaller earthquakes). These M4+ earthquakes (see below) are the largest temblors to occur to Katla since 1977 (note: those earthquakes did not lead to any eruption). However, although a few of the earthquakes were fairly large, the swarm seems to have petered out quickly as seismicity returned to background levels by Icelandic morning.
The Icelandic Meteorological Office is reporting no tremor recorded currently at Katla, which suggests that at least for the moment, no magma is making its way to the surface. Icelandic officials have not changed the alert status for Katla from normal at this point.
UPDATE 8/29 at 8 PM EDT: The IMO has now reported that flow in the Múlakvísl River, which flows out from under Mýrdalsjökull, has increased and has high concentrations of sulfur dioxide and hydrogen sulfide. Both of these are common gases related to hydrothermal fluids (heated from magmatic sources). This is a common occurrence when earthquake swarms have disturbed the Katla caldera and is not likely directly linked to any change in eruption likelihood.
The earthquake swarm that occurred on the night of August 29 at Katla in Iceland. The green stars are earthquakes over M4.
The earthquake swarm that occurred on the night of August 29 at Katla in Iceland. The green stars are earthquakes over M4.ICELANDIC MET OFFICE
Two big hazards exist at Katla right now. One is obviously that the volcano might have its first eruption since 1918. That lack of harmonic tremor means that the likelihood of an imminent eruption is low. The other hazard might be a jökulhlaup, or glacial outburst flood. Melting from the summer within the Myrdalsjökull icecap and that meltwater can accumulate until it spills over as a flood of water, ice, and debris. These have occurred often and do not need to be associated with any volcanic activity.
Katla has experienced numerous earthquake swarms in the 98 years since its last eruption, most recently in 2011. So this new one, even with its larger earthquakes, is no reason for immediate alarm. Katla does have a history of large, explosive eruptions, which means it makes people nervous. Keeping an eye on any restlessness at the behemoth is vital for both the people of Iceland and for air travel across the North Atlantic.
zou kunnen dat dit de jaarlijkse ontlading van de gletsjermeren is, uiteraard dus vermengd met vulkanische activiteit.quote:
Katla en Hekla staan volgens mijn niet in verbinding met elkaar. De Katla en Laki wel.quote:Op zaterdag 3 september 2016 12:23 schreef ansitermiet het volgende:
zou kunnen dat dit de jaarlijkse ontlading van de gletsjermeren is, uiteraard dus vermengd met vulkanische activiteit.
Hoeft nog niet een bewijs te zijn voor een eruptie, thermisch is het namelijk toch wel daar.
Maar wie weet
Ik zeg: uitbarsting in oktober (Katla of Hekla, of beide als de een de ander triggert... zijn ze onderdeel van hetzelfde systeem?)
quote:Misleading information on Katla
The Iceland Met Office has issued a statement to counteract what they feel are misleading reports on volcanic activity in Katla. Numerous tourists have called the office to ask whether it's safe to fly to Iceland. Many have also called to find out whether their families are safe in Iceland.
As an example, the Crawley News wrote today that a Katla eruption could disrupt flights to and from Gatwick, London citing the effect that the Eyjafjallajökull eruption had in 2010.
The Iceland Met Office has therefore seen reason to issue a summary about the recent increase in earthquake activity in Katla.
"We are aware of inaccurate news in recent days about seismic unrest at Katla volcano, Iceland. To avoid any confusion, we would like to reiterate the current status of Katla."
"Media interest in Iceland's volcanoes has remained high since the Eyjafjallajökull eruption of 2010, hence the summary is intended as an official monitoring statement, in case of diverging media reports."
"Since mid-June, earthquake activity within the caldera of the ice-covered Katla volcano has increased above background levels. More than 100 shallow-seated earthquakes have been detected in Katla caldera since 1 June 2016, which is almost four times the monthly average compared to previous years. Earthquakes occurred mainly in bursts ranging from minutes to hours, often with 20 events or more. The two largest earthquakes since the unrest began occurred on 26 July at 03:42 and 03:50 UTC, respectively, both with a magnitude of Mw3.2.
Such summertime increases in seismicity are common at Katla and the ongoing activity within the caldera is similar to summertime unrest observed in 2012 and 2014. Often this increased seismicity occurred in association with drainage of meltwater from several known ice-cauldrons, formed due to hydrothermal activity, as observed almost annually. Since late June 2016 there have been three small floods in Múlakvísl river, an outlet from Mýrdalsjökull, in addition to a flood from the Entujökull glacier. Presently, water-level and electrical conductivity measurements at the bridge over Múlakvísl show increased drainage of geothermal meltwater from Mýrdalsjökull - the ice-cap overlying Katla. We have received several reports throughout the summer of a hydrogen sulphide stench from glacial rivers around Myrdalsjökull.
Around Katla we are not detecting signs of increased ground deformation or bursts of seismic tremor, which are both signals that might indicate movement of magma. We continue to monitor Katla closely and will issue updates on IMO‘s web-site if the situation intensifies. Our assessment is that the volcano is in a period of summertime unrest and it does not show signs of impending eruption, although we cannot rule-out a sudden escalation in seismicity in connection with a hazardous flood."
quote:Katla teases us once again
Tremors were recorded just south of the volcano Katla yesterday, but it remains decidedly unclear if an eruption is imminent.
Vísir reports that the tremor measured 3.9 on the Richter scale, making it not an insignificant quake, but also not a definitive sign that Katla will erupt.
“There have been some unusually large tremors, and quite a few of them have been over 3 [on the Richter scale],” geologist Magnús Tumi Guđmundsson told reporters. “What that means is another story. They are rather shallow tremors, and you would look for more signs of activity, such as expansion and increasing geological heat. If we saw all these things together, than that would be an obvious sign that the volcano is heating up.”
As reported, Katla has been “overdue” for an eruption for some time now. “On average the time between eruptions is 50 years but now the volcano hasn‘t erupted in 98 years,” earthquake hazards coordinator at the Icelandic Met Office Kristín Jónsdóttir told RÚV. “There will be an eruption, it‘s only a question of when.”
However, the current seismic activity around Katla does not indicate an eruption is imminent, professor of geology Páll Einarsson told RÚV.
“Katla is a powerful volcano and we should never forget that,” he said. “However, there is nothing in this recent series of events that indicates especially that volcanic activity or an eruption is imminent. People ask, when will Katla erupt? My response is it erupted in 2011. We just didn’t notice it.”
Here, Páll refers to the glacial flooding which came from four ice cauldrons in the southeastern part of the Katla volcano that year, resulting in no loss of life but the destruction of a bridge over Múlakvísl.
As such, while technically speaking it is only a matter of time before Katla erupts, the latest recorded activity in the region does not indicate an eruption is imminent at this time. The Grapevine will keep readers updated on any new developments as they arise.
quote:Opnieuw heeft er een golf van kleine aardbevingen plaatsgevonden bij de Katla vulkaan.
Gisteren rond de 50 stuks met als zwaarste een beving van 3.0 en vanmorgen alweer 70 stuks, waarvan 7 groter dan 3.5.
De geleidbaarheid van het rivierwater in de buurt is hoger dan gebruikelijk in deze tijd van het jaar, maar niets duidt op een eventuele op handen zijnde uitbarsting.
In het nabije verleden zijn er vaker dit soort verschijnselen geweest.
nooit geweten dat Napels in IJsland lagquote:Op woensdag 21 december 2016 07:00 schreef Basp1 het volgende:
Misschien in 2020 een grote uitbarsting bij Napels.
Er is een topic over de Campi Flegrei...quote:Op woensdag 21 december 2016 07:00 schreef Basp1 het volgende:
Misschien in 2020 een grote uitbarsting bij Napels.
Sorry ik dacht even dat dit het centrale vulkanen topic was.quote:
quote:Earthquake in Iceland's Katla volcano
An earthquake of magnitude 3,5 took place in the Katla volcano in South Iceland at 7:09 this morning. The earthquake originated in the west side of the volcano’s caldera, underneath the Mýrdalsjökull glacier. Katla is one of Iceland’s largest and active volcanoes with over twenty eruptions documented since the year 930.
From June to September of last year, the volcano was hit with a series of seismic tremors and high level of unrest. For a few days at the end of September and early October, Katla was raised to “yellow alert” by the Icelandic Met Office, roads near the volcano were closed due to eruption warning, and the volcano was under 24 hour watch by the Met Office.
On September 30th over 200 earthquakes were detected in Katla over a period of 24 hours, the greatest frequency of earthquakes in the volcano since 2011.
quote:Strong 4.2 quake in Katla caldera
Icelandic Met Office has detected a strong and shallow M4.2 earthquake in the center of Katla caldera on January 26, 2017. The quake was followed by M3.0 and a series of smaller earthquakes. In total, 28 earthquakes were registered under Katla since late Wednesday, January 25.
The quakes follow a wave of increased activity in the past couple of weeks. On Monday and Tuesday, January 23 and 24, the volcano registered several large earthquakes, following a wave of activity at the beginning of January, IcelandMag reported.
On Monday, January 23, IMO registered two M3+ earthquakes (M3.0 and M3.3) in the eastern part of the caldera, followed by a large swarm of smaller quakes. This activity was followed by a M3.1 earthquake on January 24.
According to the IMO, the volcano is under close supervision and there are no signs of increased volcanic activity.
On September 29, 2016, an intense seismic swarm started under the volcano and intensified on September 30 with several M3+ earthquakes. The Aviation Color Code was raised to Yellow, the second highest level on a four-color scale. On October 3, IMO stated that the seismic swarm was the largest one in decades, though it appeared to be over.
20 eruptions have been documented at Katla between 930 and 1918, at intervals of 13 to 95 years. Since the last eruption took place in 1918, Katla is long overdue for an eruption.
This volcano is known for strong eruptions, with Volcanic Explosivity Index mostly between 4 and 6 (on a scale of 0 to 8).
Its eruption could pose a threat to civilians due to glacial flooding and significant ash generation.
quote:Four Of Iceland's Volcanoes Are Priming To Erupt
As we all know, Iceland is a profoundly volcanic place with a variety of eruption styles – from spewing out a little or a lot of lava, to exploding so violently that Europe gets blanketed in ash.
Well, as reported by the Iceland Monitor, the nation’s soothsaying geophysicist Páll Einarsson claims that four of the country’s angry mountains are exhibiting pre-eruptive conditions. Apart from that, however, little information has been given.
The volcanoes in question are Katla, Hekla, Bárđarbunga, and Grímsvötn. With no data or references given in the post, we decided to do a little digging ourselves.
So what of Katla? Well, it’s a rather sizable volcano that has indeed been showing signs of restlessness recently, with tremors hitting around the 4.6M mark. These quakes are possibly indications of magma ascending upwards through the crust and causing it to violently fracture, but as of yet, there’s no definitive proof of this.
Katla occasionally lets off some steam through minor lava flows, but there hasn’t been a major eruption for several decades. Its average recurrence rate for something significant and potentially dangerous is once every 50 years. The last notable event back in 2011 produced some impressive streams of lava, but it was not enough to smash through the Mýrdalsjökull glacier capping it at the surface.
When it inevitably does, a massive ash plume – akin to the one produced by the Eyjafjallajökull in 2010 – will be generated, and North Europe’s airspace will be immediately shut down. According to a recent study, however, such an epic plume only appears once every 44 years, so we’ve probably got some time before that happens again.
It’s worth noting, however, that the 2011 event produced a “jökulhlaup”, a flash flood caused by part of the glacier melting. It was powerful enough to sweep away a major bridge – although luckily without any accompanying deaths.
Dat was blijkbaar toch in de Bardarbunga vulkaan.quote:Op zondag 12 februari 2017 11:17 schreef Frutsel het volgende:
quote:Earthquake swarm under Bardarbunga volcano, Iceland
An earthquake swarm started under Bardarbunga volcano, Iceland during the early morning hours of Wednesday, March 1, 2017. The swarm started at 08:57 with M4.1 (the strongest) and ended at 10:24 UTC. There were no additional earthquakes registered over the next 24 hours.
Bryndís Ýr Gísladóttir, a specialist in natural hazards with the Icelandic Met Office told media that five powerful earthquakes were detected in the caldera of Bardarbunga volcano on March 1, 2017.
The sequence started with M4.1 at 08:57 UTC at a very shallow depth of 0.1 km (0.06 miles) and continued with M2.3 at a depth of 2.3 km (1.5 miles) within the first minute. In total, there were 5 earthquakes with magnitude above 3.0.
Bryndís insists that there are currently no signs of magma unrest in the area and that earthquakes have been common since the volcanic eruption in Bárđabunga ended in 2015. A similar incident happened in January 2017.
The large central volcano of Bárđarbunga lies beneath the NW part of the Vatnajökull icecap, NW of Grímsvötn volcano, and contains a subglacial 700-m-deep caldera. Related fissure systems include the Veidivötn and Trollagigar fissures, which extend about 100 km SW to near Torfajökull volcano and 50 km NE to near Askja volcano, respectively.
Voluminous fissure eruptions, including one at Thjorsarhraun, which produced the largest known Holocene lava flow on Earth with a volume of more than 21 cu km, have occurred throughout the Holocene into historical time from the Veidivötn fissure system.
The last major eruption of Veidivötn, in 1477, also produced a large tephra deposit. The subglacial Loki-Fögrufjöll volcanic system to the SW is also part of the Bárđarbunga volcanic system and contains two subglacial ridges extending from the largely subglacial Hamarinn central volcano; the Loki ridge trends to the NE and the Fögrufjöll ridge to the SW. Jökulhlaups (glacier-outburst floods) from eruptions at Bárđarbunga potentially affect drainages in all directions
quote:Strong earthquake swarm in Bárđarbunga
During the night of 08-March-2017 a strong earthquake swarm took place in Bárđarbunga volcano. Largest earthquake in this swarm had the magnitude of 4,1 and the second largest earthquake swarm had the magnitude of 3,9. Other earthquakes in this swarm where smaller in magnitude.
Earthquake activity happens in Bárđarbunga volcano mainly due to magma being injected into the main volcano at depth. This goes into magma chambers somewhere in the volcano, current data suggests that the magma chamber that erupted in in August 2014 to February 2015 is currently inflating. The rate of this type of earthquake activity has gone down in Bárđarbunga volcano, this used to be a weekly activity but now only happens every 2 to 4 weeks at the moment. This slowdown in activity is likely to continue if nothing else happens (new eruption or dyke activity).
quote:Bárđarbunga volcano joins Hekla: 3.2 magnitude quake and earthquake swarm over weekend
The 4.5 magnitude earthquake west of volcano Hekla on Saturday was followed up by a 3.2 magnitude quake in the Bárđarbunga caldera later the same evening. The quake, which had its epicenter at a depth of 4.3 km (2.7 miles) in the N.E. part of the caldera was followed by a swarm of smaller quakes, including two 2.1 and 2.5 magnitude quakes, in the N.E. and S.E parts of the caldera.
What is going on?
It is unlikely the two episodes are connected. The earthquakes in Bárđarbunga are caused by magma thrusting its way from the mantle to the magma chambers of the volcano, refilling it after the 2014-15 Holuhraun eruption. Bárđarbunga is preparing for continued volcanic activity.
Volcanic zones and seismic rift zones
The Saturday quake west of Hekla took place in the South Iceland Seismic Zone, a transform fault between offset sections of the Mid-Atlantic Ridge which runs through Iceland. The zone is made up of a series of fracture faults which run from SW to NE. The zone extends from the volcano Hengill, the easternmost part of the Reykjanes volcanic zone to Hekla, which is the westernmost volcano in the East Volcanic Zone.
The massive "South Iceland Quake"
There are no active volcanoes in the South Iceland Seismic Zone, but it is extremely active. The area sits between the two volcanic zones, and is constantly being pulled in two different directions, causing tension to build up in the crust which is then periodically released in earthquakes.
The zone has been the source of the most powerful earthquakes in Iceland, as the most powerful earthquake which has taken place in Iceland since the country was settled took place in the Southern Seismic Zone.
Read more: All of Iceland‘s major volcanoes showing unusually high levels of activity
On 1784 a massive earthquake, which is believed to have been 7.1 magnitude, shook all of southern Iceland, causing widespread damage to farmhouses.
The second largest earthquake, and the largest to be measured with modern equipment, was detected in 1912. This quake was 7.0 on the Richter scale. Both quakes took place close to Saturday's tremor. Quakes of this magnitude are believed to hit once every 100-150 years, and could cause significant damage. Locals in South Iceland are still waiting for the "big one".
quote:Earthquakes and tremors continue around notorious volcano Katla
The past few days have seen a swarm of tremors around Katla volcano, but yesterday they reached over a 3 in magnitude or up to 3.6. According to reports quakes aren’t always signs of looming eruptions although the seismic activity has been frequent of late. The Icelandic Met Office is closely monitoring the volcano and surrounding area.
Katla is a large subglacial volcano in southern Iceland. It’s been dormant under the Mydalsjokull glacier for almost 100 years, but it’s considered a very active volcano with twenty documented eruptions between 930 and 1918, with intervals of 13–95 years.
Katla hasn’t erupted forcefully since 1918, although there may have been small eruptions under the icecap that didn’t break the ice, including ones in 1955, 1999, and 2011. Prior eruptions have measured with a Volcanic Explosively Index of between VEI-4 and VEI-6 on a scale of 0 to 8. In comparison, the infamous 2010 Eyjafjallajokull eruption had a VEI-4. The last major eruption started on 12 October 1918 and lasted for 24 days. It was likely a VEI-5 level eruption.
Katla’s present dormancy is among the longest in known history and many theorize that the current seismic activity is a sure sign of a pending eruption although the Icelandic Met Office assures that there are no definite tell tale signs of a looming eruption.
Volcanologist Jon Friman speculates that the depth of some of the quakes indicates that fresh magma is making its way upward in the magma chamber. One of the quakes was measure on 14.4 km depth and Friman takes that as an indicator of the mountain getting ready to erupt, quakes on such a depth are caused by magma movement rather than movement in the earth’s crust. The greatest depth measured in this series of quakes is 15.5 km and the one closest to the surface was 0.1 km down.
The string of tremors can be observed online with updates of 60 seconds in 3D images in a program developed and made by Baering Gunnar Steinthorsson. The images display the size and depth of the quakes almost in real time. The colour coding for the age of the quakes is the same as the Icelandic Met Office uses, the newest are red, then orange, yellow, blue and the oldest ones are dark blue. The display is based on data from the Met office and it only displayed data which has been overviewed by a Volcanologist.
The 1918 eruption in Katla was major, lasting almost a month and resulting in extending the southern coast by 5 km due to lava flow deposits.