Grímsvötn (; ''vötn'' = "waters", singular: ) is a
volcano
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
On Earth, volcanoes are most often found where tectonic plates are ...
with a (partially subglacial) fissure system located in
Vatnajökull National Park
Vatnajökull National Park ( is, Vatnajökulsþjóðgarður ) is one of three national parks in Iceland. It encompasses all of Vatnajökull glacier and extensive surrounding areas. These include the national parks previously existing at Skaftafell ...
,
Iceland
Iceland ( is, Ísland; ) is a Nordic island country in the North Atlantic Ocean and in the Arctic Ocean. Iceland is the most sparsely populated country in Europe. Iceland's capital and largest city is Reykjavík, which (along with its s ...
. The volcano itself is completely subglacial and located under the northwestern side of the
Vatnajökull
Vatnajökull ( Icelandic pronunciation: , literally "Glacier of Lakes"; sometimes translated as Vatna Glacier in English) is the largest and most voluminous ice cap in Iceland, and the second largest in area in Europe after the Severny Island ice ...
ice cap. The subglacial caldera is at , at an elevation of . Beneath the caldera is the
magma chamber
A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upw ...
of the Grímsvötn volcano.
Grímsvötn is a basaltic volcano which has the highest eruption frequency of all the volcanoes in Iceland and has a southwest-northeast-trending fissure system. The massive climate-impacting
Laki
Laki () or Lakagígar (, ''Craters of Laki'') is a volcanic fissure in the western part of Vatnajökull National Park, Iceland, not far from the volcanic fissure of Eldgjá and the small village of Kirkjubæjarklaustur. The fissure is properly r ...
fissure eruption of 1783–1784 was a part of the same fissure system. Grímsvötn was erupting at the same time as Laki during 1783, but continued to erupt until 1785. Because most of the volcanic system lies underneath Vatnajökull, most of its eruptions have been
subglacial and the interaction of magma and meltwater from the ice causes
phreatomagmatic
Phreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions cont ...
explosive activity.
Jökulhlaup
Eruptions in the caldera regularly cause glacial outbursts known as
jökulhlaup
A jökulhlaup ( ) (literally "glacial run") is a type of glacial outburst flood. It is an Icelandic term that has been adopted in glaciological terminology in many languages.
It originally referred to the well-known subglacial outburst flood ...
. Eruptions melt enough ice to fill the Grímsvötn caldera with water, and the pressure may be enough to suddenly lift the ice cap, allowing huge quantities of water to escape rapidly. Consequently, the Grímsvötn caldera is monitored very carefully.
When a large eruption occurred in 1996,
geologist
A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...
s knew well in advance that a glacial burst was imminent. It did not occur until several weeks after the eruption finished, but monitoring ensured that the Icelandic ring road (
Hringvegur
Route 1 or the Ring Road ( or ) is a national road in Iceland that circles the entire country. As a major trunk route, it is considered to be the most important piece of transport infrastructure in Iceland as it connects the majority of towns ...
) was closed when the burst occurred. A section of road across the
Skeiðará
Skeiðará () is a relatively short glacier river (about 30 km long). It has its source on the glacier Skeiðarárjökull, one of the southern arms of the Vatnajökull in the south of Iceland.
In spite of its short length, this river has a b ...
sandur was washed away in the ensuing flood, but no one was hurt.
Eruption history between 1990 and today
Gjálp 1996
''(See also the main article:
1996 eruption of Gjálp''
The Gjálp
fissure vent
A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive eruption, explosive activity. The vent is often a few metres wide an ...
eruption in 1996 revealed that an interaction may exist between
Bárðarbunga
Bárðarbunga (), is a stratovolcano located under Vatnajökull in Vatnajökull National Park which is Iceland's most extensive glacier. The second highest mountain in Iceland, above sea level, Bárðarbunga is also part of a volcanic system th ...
and Grímsvötn. A strong earthquake in Bárðarbunga, about 5 on the Richter scale, is believed to have started the eruption in Gjálp. On the other hand, because of the magma erupted showed strong connections to the Grímsvötn Volcanic System acc. to petrology studies, the 1996 as well as a former eruption there in the 1930s are thought to have taken place within Grímsvötn Volcanic system.
1998 and 2004 eruptions
![NASA Photo Grímsvötn Nov](https://upload.wikimedia.org/wikipedia/commons/8/8b/NASA_Photo_Gr%C3%ADmsv%C3%B6tn_Nov._2004.jpg)
A week-long eruption occurred at Grímsvötn starting on 28 December 1998, but no glacial burst occurred. In November 2004, a week-long eruption occurred.
Volcanic ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcano, volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used t ...
from the eruption fell as far away as mainland Europe and caused short-term disruption of airline traffic into Iceland, but again no glacial burst followed the eruption.
2011 eruption
Harmonic tremor
A harmonic tremor is a sustained release of seismic and infrasonic energy typically associated with the underground movement of magma, the venting of volcanic gases from magma, or both. It is a long-duration release of seismic energy, with disti ...
s were recorded twice around Grímsvötn on 2 and 3 October 2010, possibly indicating an impending eruption.
At the same time, sudden
inflation
In economics, inflation is an increase in the general price level of goods and services in an economy. When the general price level rises, each unit of currency buys fewer goods and services; consequently, inflation corresponds to a reductio ...
was measured by
GPS
The Global Positioning System (GPS), originally Navstar GPS, is a Radionavigation-satellite service, satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is one of t ...
in the volcano, indicating magma movement under the caldera. On 1 November 2010 meltwater from the Vatnajökull glacier was flowing into the lake, suggesting that an eruption of the underlying volcano could be imminent.
![Grimsvötn August 2011](https://upload.wikimedia.org/wikipedia/commons/a/a5/Grimsv%C3%B6tn_August_2011.jpg)
On 21 May 2011 at 19:25
UTC,
an eruption began, with high
plumes accompanied by multiple
earthquake
An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, from ...
s,
Until 25 May, the eruption scale had been larger than that of the
2010 eruption of
Eyjafjallajökull
Eyjafjallajökull (; ), sometimes referred to by the numeronym E15, is one of the smaller ice caps of Iceland, north of Skógar and west of Mýrdalsjökull. The ice cap covers the caldera of a volcano with a summit elevation of . The volcan ...
.
The ash cloud from the eruption rose to , and was so far 10 times larger than the 2004 eruption, and the strongest in Grímsvötn in the last 100 years.
![Iceland’s Grimsvotn Volcano](https://upload.wikimedia.org/wikipedia/commons/8/81/Iceland%E2%80%99s_Grimsvotn_Volcano.jpg)
Disruption to air travel in Iceland
[Eurocontrol news](_blank)
/ref> commenced on 22 May, followed by Greenland, Scotland, Norway, Svalbard
Svalbard ( , ), also known as Spitsbergen, or Spitzbergen, is a Norwegian archipelago in the Arctic Ocean. North of mainland Europe, it is about midway between the northern coast of Norway and the North Pole. The islands of the group range ...
and a small part of Denmark on subsequent days. On 24 May the disruption spread to Northern Ireland and to airports in northern England. The cancellation of 900 out of 90,000 European flights in the period 23–25 May was much less widespread than the 2010 disruption after the Eyjafjallajökull
Eyjafjallajökull (; ), sometimes referred to by the numeronym E15, is one of the smaller ice caps of Iceland, north of Skógar and west of Mýrdalsjökull. The ice cap covers the caldera of a volcano with a summit elevation of . The volcan ...
eruption.
The eruption stopped at 02:40 UTC on 25 May 2011, although there was some explosive activity from the eruptive vents affecting only the area around the crater.
2020-21 threats of eruption
In June 2020, the Icelandic Meteorological Office
Icelandic Meteorological Office (IMO; is, Veðurstofa Íslands) is Iceland's national weather service and as such a government agency under the Ministry of Environment and Natural Resources. It is also active in volcano monitoring, esp. volc ...
(IMO) issued a warning that an eruption might take place in the coming weeks or months, following scientists reporting high levels of sulfur dioxide
Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...
, which is indicative of the presence of shallow magma. IMO warned that a glacial flood as a result of melting ice could trigger an eruption. No eruption occurred.
In September 2021, an increase in water outflow from under the Vatnajökull ice cap was reported. The water contains elevated levels of dissolved hydrogen sulfide, suggesting increased volcanic activity under the ice. Jökulhlaup (glacial lake flooding) can occur before or after an eruption.
On 4 December 2021, a jökulhlaup occurred from Grímsvötn into the Gígjukvísl river, with an average flow of 2600 m3/s. Two days later, the Icelandic Meteorological Office increased the alert level for Grímsvötn from yellow to orange, after a series of earthquakes was detected. On 7 December, the alert level was lowered back to yellow, after seismic activity decreased and no signs of eruptive activity were detected.
Bacteria in the subglacial lakes
In 2004, a community of bacteria
Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...
was detected in water of the Grímsvötn lake under the glacier, the first time that bacteria have been found in a subglacial lake. The lakes never freeze because of the volcanic heat. The bacteria can also survive at low concentrations of oxygen
Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...
. The site is a possible analogue for life on the planet
A planet is a large, rounded astronomical body that is neither a star nor its remnant. The best available theory of planet formation is the nebular hypothesis, which posits that an interstellar cloud collapses out of a nebula to create a you ...
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
, because there are also traces of volcanism and glaciers on Mars and thus the findings could help identify how to look for life on Mars.
Future trends
Studies indicate that volcanic activity in Iceland rises and falls so that the frequency and size of eruptions in and around the Vatnajökull ice cap varies with time. It is believed that the four eruptions between 1996 and 2011 could mark the beginning of an active period, during which an eruption in Grímsvötn in Vatnajökull may be expected every 2–7 years. Parallel volcanic activity in nearby Bárðarbunga
Bárðarbunga (), is a stratovolcano located under Vatnajökull in Vatnajökull National Park which is Iceland's most extensive glacier. The second highest mountain in Iceland, above sea level, Bárðarbunga is also part of a volcanic system th ...
is known to be associated with increased activity in Grímsvötn. Seismic activity has been increasing in the area in recent years, indicating the entry of magma.
See also
* Geography of Iceland
Iceland ( ) is an island country at the confluence of the North Atlantic and Arctic oceans, east of Greenland and immediately south of the Arctic Circle, atop the constructive boundary of the northern Mid-Atlantic Ridge about from Scotland and ...
* Glacial lake outburst flood
A glacial lake outburst flood (GLOF) is a type of outburst flood caused by the failure of a dam containing a glacial lake. An event similar to a GLOF, where a body of water contained by a glacier melts or overflows the glacier, is called a jö ...
* Iceland hotspot
The Iceland hotspot is a hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland.
Iceland is one of the most active volcanic regions in the world, with eruptions occur ...
* Iceland plume
The Iceland hotspot is a hotspot (geology), hotspot which is partly responsible for the high volcanic activity which has formed the Iceland Plateau and the island of Iceland.
Iceland is one of the most active volcano, volcanic regions in the ...
* List of glaciers of Iceland
The glaciers and ice caps of Iceland cover 11% of the land area of the country (about 11,400 km² out of the total area of 103,125 km²) and have a considerable impact on its landscape and meteorology. Glaciers are also contributing to ...
* List of islands of Iceland
This is a list of islands of Iceland. It includes all islands larger than 1 km2, as well as a number of smaller islands that are considered significant either because they are or used to be inhabited, or for specific historical, geographical ...
* List of lakes of Iceland
This is a list of lakes of Iceland (partially indicating surface, depth and volume).
Iceland has over 20 lakes larger than 10 km² (4 sq mi), and at least 40 others varying between 2.5 and 10 km² (1 to 4 sq mi) in size. This list also in ...
* List of volcanoes in Iceland
This list of volcanoes in Iceland includes active and dormant volcanic mountains, of which 18 have erupted since human settlement of Iceland began around 900 AD.
__TOC__
List
Volcanic zones and systems
Iceland has four major volcanic z ...
* Plate tectonics
Plate tectonics (from the la, label=Late Latin, tectonicus, from the grc, τεκτονικός, lit=pertaining to building) is the generally accepted scientific theory that considers the Earth's lithosphere to comprise a number of large ...
* Timeline of volcanism on Earth
This timeline of volcanism on Earth includes a list of major volcanic eruptions of approximately at least magnitude 6 on the Volcanic explosivity index (VEI) or equivalent sulfur dioxide emission during the Quaternary period (from 2.58 Mya to th ...
* Volcanism of Iceland :''The volcano system in Iceland that started activity on August 17, 2014, and ended on February 27, 2015, is Bárðarbunga.''
:''The volcano in Iceland that erupted in May 2011 is Grímsvötn.''
Iceland experiences frequent volcanic activity, d ...
References
External links
Grímsvötn
in the Catalogue of Icelandic Volcanoes
Update on Grímsvötn Activity
– from the Icelandic Met Office and University of Iceland (updated at least daily)
Current seismology around Grímsvötn
– Earthquakes in last 48 hours
BBC news report of the 23 May 2011 eruption
Report on the 2011 start of the Grímsvötn eruption
from the Icelandic Met Office
Official Website of Vatnajökull National Park
{{DEFAULTSORT:Grimsvotn
Active volcanoes
Highlands of Iceland
Subglacial volcanoes of Iceland
Volcanoes of Iceland
VEI-6 volcanoes
Subglacial lakes
Lakes of Iceland
East Volcanic Zone of Iceland
Volcanic systems of Iceland
Subglacial calderas
Calderas of Iceland