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Eyjafjallajokull is a volcano located in Iceland. The name is a description of the volcano with Eyja meaning island; fjalla meaning mountain; and jokull meaning glacier. You can find out how to pronounce Eyjafjallajokull on the BBC website.
The ice cap covers an area of about square kilometres 39 sq mi , feeding many outlet glaciers. The mountain itself, a composite stratovolcano volcano , stands 1, metres 5, ft at its highest point and has a crater 3—4 kilometres 1.
The two plates are moving apart due to ridge push along the Mid-Atlantic Ridge. As the plates move apart, magma fills the magma chamber below Eyjafjallajokull. Several magma chambers combined producing a volume of magma below the volcano. Eyjafjallajokull is located below a glacier.
It erupted three times in —on 20 March, April—May, and June. The March event forced a brief evacuation of around local people. Still, the 14 April eruption was ten to twenty times more powerful and caused substantial disruption to air traffic across Europe.
It caused the cancellation of thousands of flights across Europe and to Iceland. The eruption was only 3 on the volcanic explosivity index VEI.
Around 15 eruptions on this scale usually happen each year in Iceland. However, in this case, a combination of a settled weather pattern with winds blowing towards Europe, very fine ash and a persistent eruption lasting 39 days magnified the impact of a relatively ordinary event. The eruptions in March were mainly lava eruptions. That led to air traffic disruption in North-West Europe.
The disruption lasted for six days, from April 15th to April 21st, that stranded thousands of travelers. It happened again in May, which resulted in the closure of airspace over many parts of Europe. The eruption also created electrical storms. The volcano continued to have several earthquakes daily, with volcanologists watching the mountain closely.
Today the aftermath of the volcanic eruption can be seen in Thorsmork Glacier Valley, the natural oasis that lies just behind the volcano. You can also see a part of the ice cap is still covered in ash, though that is slowly disappearing under layers of snow.
Perhaps you would like to go on a snowmobile tour on the ice cap and see the crater, which also offers you a great view of southern part of Iceland. Eyjafjallajokull is a strato volcano. It is a conical volcano built by many layers of hardened lava, tephra, pumice and volcanic ash.
Strata volcanoes are among the most common volcanoes. Due to the glacier on top of Eyjafjallajokull eruptions are explosive and contain much ash. A large magma chamber under the mountain feeds Eyjafjallajokull. The chamber derives magma from the tectonic divergence of the Mid-Atlantic ridge. The volcano is a part of the chain of volcanoes that stretch across Iceland , including volcanoes like Hekla , Katla and Grimsvotn. Eyjafjallajokull and Katla , neighbouring volcanoes, are believed to be related.
The eruption continued during March. Click on the index link or scroll down to read the reports. The following was mostly condensed from a multitude of reports on the EIS and IMO websites, and only discusses activity through the start of the explosive summit phase. These vents on the lower E slopes were snow-covered but not under the year-round icecap found at higher elevations. Lava flows filled gullies, and quickly melted adjacent winter snow, creating small steam plumes.
As of late May the eruption continued, with occasional plumes that restricted air travel in parts of Europe. Table 1. Precursory observations. Scientists noticed a trend after 4 March at continuous GPS sites installed within 12 km of the eruptive site; all showed deformation at rates of up to a centimeter a day.
Seismic tremor began around on 4 March, and around that time, signal sources rose slowly towards the surface. Compared to the weeks prior to the eruption, seismicity increased rather slowly immediately prior to the eruption. Before this spring's first eruption GPS stations on the volcano had wandered several centimeters in May of and again in December, signs that rising magma was stretching the skin of the volcano in advance of an eruption. In mid-February But officials didn't order evacuations because the seismic hints weren't that dire.
Although seismic tracking placed magma closer to the surface on 19 March, this low-frequency signal was absent, so civil authorities kept the alert level at its lowest setting.
But the next night, southern Icelanders reported a dark cloud glowing red above the mountain: The volcano had experienced a small eruption, one that led authorities to evacuate farmers living in its floodplains. Initially detected visually, the eruption was seen at that day as a red cloud above the site.
Lava flowed a short distance from the eruptive site and a minor eruption plume rose to less than 1 km altitude and blew W. Eruption tremor rose slowly until reaching a maximum at around that day. No further lengthening of the fissure was detected. Lava was still limited to the immediate surroundings of the eruptive craters runouts of less than few hundred meters. Minor ashfall occurred within a few kilometers W.
On 22 March, observations made from the ground showed lava extrusion from a series of closely-spaced vents. Prevailing E winds led to maximum scoria accumulation on a linear rim W of the NE-trending fissure. A'a lava flowed over the steep Hrunagil canyon rim creating spectacular 'lava falls.
During March, lava steadily issued at the initial craters, with gradual focusing towards fewer vents. Lava descending gullies generated zones of frothy rock. Extensive steam plumes occurred when advancing lava encountered water and snow. Two or three plumes were observed one at the eruptive craters, others more pronounced in front of the advancing lava.
Meltwater descended in batches into rivers valleys, and seismometers recorded relatively steady eruption tremor. On the evening of 31 March, scientists noted the opening of a new short fissure immediately N of the previous one.
This change may have been a response to changes at shallow depth in the feeder channel. Eruption tremor remained unchanged. During 31 March-6 April, lava discharged in both the old and new eruptive craters in a manner similar to before. The FTIR spectrometer uses infrared radiation emitted from the erupting lavas as a source for absorption spectrometry of gases emitted from the explosive vents.
Favorable wind conditions allowed traverse measurements under the gas plume with a DOAS spectrometer for SO 2 flux estimates. On 5 April, eruption tremor at Hz recorded at the nearest seismic station, Godabunga began to gradually decline. By 7 April lava emissions had stopped from the original craters, but continued at the 31 March fissure. When IES surveyed the new landscape on 7 April figure 9 , they found 1.
Another cone with a rim at 1, m elevation was 47 m above the previous surface and the vent area glowed red. By 9 April, after little change in deformation rates during the eruption, time series at continuous GPS stations N of the volcano showed sudden change, partly jumping back to pre-eruptive levels. On 11 April, eruption tremor also approached pre-eruptive levels, but visual observation revealed eruptive activity in late afternoon.
Seismic tremor on 12 April reached a minimum. Eruption from the summit caldera. The second, more explosive eruptive phase, began on 14 April at the subglacial, central summit caldera. This phase was preceded by an earthquake swarm from around on 13 April to on 14 April. Meltwater started to emanate from the icecap around on 14 April and an eruption plume was observed later that morning.
The exact conditions at the summit were unknown due to cloud cover obscuring the volcano, but on 15 April an overflight imaged the erupting caldera using radar figure The 15 April radar image helped depict a series of vents along a 2-km-long, N-oriented fissure. Both on top of and from below, meltwater flowed down the N and S slopes. Jokulhlaups floods of meltwater also carrying considerable debris reached the lowlands around the volcano with peak flow around noon on 14 April, causing destruction of roads, infrastructure, and farmlands.
Residents had earlier been evacuated from hazardous areas. Tephra fall began in SE Iceland. That evening, a second jokulhlaup emanated from the icecap down the Markarfljot valley, which trends E-W along the N margin of the volcano and contains extensive outwash from surrounding glaciers.
On 15 April the ash plume reached a maximum altitude of over 8 km. E-blown ash began to arrive over mainland Europe closing airspace over the British Isles and large parts of Northern Europe. Ash generation continued at a similar level. Meltwater emerged from the glacier in pulses. Debris-charged jokulhlaups were seen in the evening. Burton, M. Sigmarsson, O. Wall, R. Further References. Dahm, T. Hjaltadottir, S. Vogfjord and R. Hooper, A.
Larsen, G. Pedersen, R. Sturkell, E. Vogfjord , Sigurlaug Hjaltadottir , Gunnar B. Gudmundsson , Matthew J. Large explosions from the summit crater; ash plumes close airspace in Europe. After a short hiatus in eruptive activity, an explosive eruptive phase began on 14 April under the ice-covered central summit caldera.
The resulting plume caused an unprecedented disruption of air traffic and closure of airspace over northern and central Europe. In the early morning of 14 April, the ash-loaded eruption plume rose to more than 8 km altitude and blew E.
The eruption plume reached mainland Europe on 15 April, triggering the closure of airspace over large areas. On 16 April some variability occurred in seismic tremor and tephra generation, but overall the eruptive pace remained stable and large closures of airspace continued.
The IES estimated the amount of erupted material during the first 72 hours of the eruption at the summit caldera April Erupted products consisted of fragmental material, the majority being fine-grained airborne tephra. On 17 April the ash plume rose to over 8 km altitude, blowing first to the E, and then, after about that day, blowing to the S. Ash fell around the volcano and there were at least lightning strikes in vicinity of the eruption.
When ash emissions on 17 April figure 12 blew S they created an optically thicker band of ash that appeared to be surrounded by a much wider, less optically dense plume figure NASA analysts determined that the ash plumes were at two different altitudes, the narrow, more concentrated plume was above the more diffuse cloud, casting a shadow on the ash below.
They said that according to the Icelandic Met Office, the upper parts of 17 April ash puffs reached 4. The 17 April example illustrates the difficulty of estimating the critical 'source terms' boundary conditions for modeling ash plume dispersal.
Such models, which are regularly run by groups such as VAACs, volcano observatories, and their associated agencies, help assess where plumes might go in conditions such as darkness and overcast weather. After about on 18 April, tremor intensified beyond levels maintained since 16 April. Daily solutions from continuous, second GPS stations operated by IMO and IES, revealed centimeter-scale horizontal movements toward the center of the volcano, with some stations also registering centimeter-scale vertical elevation decreases.
Tremor with a dominant frequency of 0. Following an initial period of glacial flooding on April, relatively little water drained from the ice cap's N flank. On 19 April the plume rose only m above the volcano's 1. Later in the afternoon reports indicated maximum plume height around 4. Samples collected 19 April show the same composition as early in the explosive phase, but the fluorine content was higher.
Tephra deposited next to the craters was m thick. Analogous conditions continued to exist for the following week.
Although there had been magma spatter at the vent area by 20 April, no significant lava flow had yet been detected. Heavy sound blasts were heard nearby, especially S and E of the mountain.
Radar images acquired that day by the Icelandic Coast Guard showed no changes in the size of the cauldron since 19 April. Latest results from GPS stations showed deflation. On 21 April, the eruption continued with less explosive activity. The northernmost one of two main craters in the summit caldera was active, and phreatomagmatic explosions occurred with some lava spatter at craters. Lava flows towards the N were thought to have begun around noon on 21 April. Beginning about 24 April the IES website contained detailed daily status reports of the eruption.
Over the next few days there was little change, with the N crater remaining active, generating mild explosive activity and spatter. Steam plumes were rising where the N-flowing lava met ice. The eruption site was seen clearly during an overflight on 27 April. The eruptive activity in the N ice cauldron was seen to be similar to conditions during the preceding four days, but a new crater had formed in the cauldron's SW corner.
Erupted material continued to accumulate on the flanks of the crater. Spatter escaped the vent, reaching heights of m. Unstable plumes of ash rose regularly from the vent. After an slight decrease in explosive activity early in May, activity then increased somewhat. The eruption was mixed, with the lava-producing phase being larger than the explosive phase. During this time, the plume was darker and wider than in the preceding week.
Near-source tephra fall-out increased. On 4 May a flight by the Icelandic Coast Guard showed that the crater continued buildup in the northern-most ice cauldron. Lava flowed N and spread at an elevation of m. Increased seismicity up to 13 May suggested that new material was intruding from depth, and GPS observations indicated inflation. Little change in activity was observed during May. Tephra fallout was detected mainly to the NE, with some reaching the coast. Some tephra dispersed towards the W in the afternoon.
By May only a weak plume rose from the W part of the crater; both explosions and lava flows from the crater were absent. During May there was no apparent eruptive activity, though there was still a considerable amount of steam coming from the crater. Aerial observers on 25 May figure 14 saw blue smog sulfuric gases and smelled sulfur.
Scientists who went to the crater on 25 May saw a small blast of ash, but mostly steam. Intense steam rose from the craters, with occasional small ashy explosions. Noise of intense boiling and or degassing came from the craters. Visibility to the bottom was limited due to steam. A strong smell of sulfur came from around the craters. Volcanic tremor was still higher than before the eruption, being rather steady since 22 May, but small pulses, mostly on the lowest frequency, were detected.
Several small and shallow earthquakes under the volcano occurred on a daily basis. No significant GPS deformation was measured.
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