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Grímsvötn Volcano

Updated: Mar 29, 2024 05:41 GMT -
Caldera 1725 m (5,659 ft)
Iceland, 64.42°N / -17.33°W
Current status: normal or dormant (1 out of 5)
Last update: 24 Jan 2024 (Smithsonian / USGS Weekly Volcanic Activity Report)

Grímsvötn is Iceland's most frequently active volcano, probably because it is located on the center of the active NE rift zone of Iceland. Most of the volcano is hidden beneath the giant glacier of Vatnajökull, Europe's largest glacier.

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Typical eruption style: Effusive, explosive magma-water/ice reaction. 
Produces notorious and frequent floods of melt-water bursts from the glacier (jökulhlaups).
Grímsvötn volcano eruptions: ca. 1310, 1332, 1341, 1354(?), ca. 1370, ca. 1390, ca. 1430, ca. 1450, ca. 1470, ca. 1490, ca. 1510, ca. 1530, 1598, 1603, 1619, 1629, 1638, 1659, 1681, 1684-85, 1706, 1716, 1725, 1753, 1768, 1774, 1783-85 (Laki fissure eruption: the largest historically known effusive eruption), 1794(?), 1796(?), 1816, 1823, 1838, 1854, 1861(?), 1867, 1873, 1883, 1887-89, 1891-92, 1897, 1902-04, 1922, 1933, 1934, 1934, 1938, 1939(?), 1941(?), 1945, 1948(?), 1954, 1972(?), 1983, 1984(?), 1996, 1998, 2004 (Nov.), 2011 (21-26 May)

Latest nearby earthquakes

TimeMag. / DepthDistance / Location
Mar 23, 11:20 pm (Reykjavik)
Mar 23, 23:20 GMT
3.5

0.1 km
28 km (18 mi) to the N 5.6 km NE of Bárðarbunga
I FELT IT
Info
Monday, March 18, 2024 GMT (1 quake)
Mar 18, 12:45 am (Reykjavik)
Mar 18, 00:45 GMT
4.4

7.8 km
29 km (18 mi) to the N 3.5 km NE of Bárðarbunga Info
Thursday, March 21, 2024 GMT (1 quake)
Mar 21, 01:48 am (Reykjavik)
Mar 21, 01:48 GMT
2.8

6.5 km
23 km (14 mi) to the N 7.5 km ESE of Bárðarbunga Info
Wednesday, March 27, 2024 GMT (1 quake)
Mar 27, 06:47 pm (Reykjavik)
Mar 27, 18:47 GMT
2.7

1.4 km
28 km (18 mi) to the N 6.5 km ENE of Bárðarbunga
I FELT IT
Info
Sunday, March 24, 2024 GMT (1 quake)
Mar 24, 02:58 pm (Reykjavik)
Mar 24, 14:58 GMT
2.7

6.7 km
29 km (18 mi) to the N 2.8 km N of Bárðarbunga
I FELT IT
Info
Tuesday, March 19, 2024 GMT (1 quake)
Mar 19, 10:40 pm (Reykjavik)
Mar 19, 22:40 GMT
2.6

3.4 km
16 km (10 mi) to the NW 10.1 km ENE of Hamarinn Info

Background

Grímsvötn volcano has a 6x8 km large caldera, whose southern rim is exposed. The caldera contains a lake of liquid water, due to the thermal energy from the volcano. The lake is covered by the ice of the glacier, but during eruptions or times of increased hydrothermal activity from the volcano, the amount of melt water and the pressure of the lake against the ice above becomes strong enough to lift the ice dam and pour out at the South side of the glacier in devastating floods known as jökulhlaups.
During eruptions, the overlying part of the glacier is often melted through, creating a giant hole in the ice permitting breathtaking views from above onto the lake, from where ash and steam can escape.

Fissures and the Laki fissure eruption in 1783:
The volcano's structure seems to be dominated by NE-SW trending fissures that correspond to the rift zone. Eruptions from these fissures can occur well beyond the extent of the glacier, such as the huge eruption in 1783, known as the Laki fissure eruption.
It is the largest known effusive eruption that has occurred on earth during the past millennia. About 15 cubic kilometers of basaltic lava flows were erupted from a 27-km long fissure over a period of 7 months. Accompanied by enormous amounts of suphur dioxide and fluoride gas, the eruption caused wide-spread crop damage, killed a large number of lifestock and caused a severe famine on Iceland. As a result, one fifth of Iceland's population was killed. Some consequences of the eruption were even noticed in other parts of the world: Volcanic fog (the gas cloud from the eruption) was drifting over Europe and parts of Asia, altering summer temperatures. This eruption was the first one that brought some scientists to the idea that volcanoes can impact the world's climate.

Background
Grímsnes is a relatively small volcanic system located SE of Thingvallavatn lake east of an en echelon group of volcanic fields extending across the Reykjanes Peninsula.
Grímsnes lava flows cover 54 sq km and were erupted from a group of 11 fissures that produced a series of NE-SW-trending crater rows. The eruptions of the basaltic Grímsnes lavas were restricted to a relatively short interval between about 6500 and 5500 years ago.

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Source: GVP, Smithsonian Institute

Latest satellite images

grimsvoetn satellite image sat1grimsvoetn satellite image sat2

Wed, 24 Jan 2024, 15:00

Grimsvotn volcano (Iceland) - Smithsonian / USGS Weekly Volcanic Activity Report for 17 January-23 January 2024 (New Activity / Unrest)

IMO lowered the Aviation Color Code for Grímsvötn to Green (the lowest level on a four-color scale) in a Volcano Observatory Notice for Aviation (VONA) issued at 1537 on 22 January. They noted that the jökulhlaup that had begun around 10 January had ended, and that there were no measurable signs of elevated activity. ... Read all
Wed, 24 Jan 2024, 04:52

Grimsvötn volcano (Iceland): water level in Gígjukvísl is stable, alert level returned to Green

The map depicts the location of two ice cauldrons south of Grímsfjall (image: IMO)
Since the glacial flood, forming jökulhlaup (literally "glacial run"), reached its peak in Gígjukvísl river about a week ago, the water level started to decrease and is now at background levels prior to the flood. ... Read all

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