Quiet for 290 years, Iceland’s largest volcano now stirring

Alert code raised to yellow.

The ice-covered Öræfajökull volcano, Iceland’s largest volcano, has lain dormant since 1727.

However, geothermal activity has increased so much since a major earthquake on October 3 that it has  has melted enough ice to form lakes around the volcano. The area also reeks of sulfur, another indication of increasing activity.

“Even in the last few days, there have been tremors, albeit smaller ones. Something is going on there which has not happened before, and therefore the observations about the volcano are increasing,” said seismologist Reynir Bödvarsson of Uppsala University.

“There may be an explosive outbreak of ash, similar to what happened in Eyjafjallajokull, which could affect air traffic,” warned Bödvarsson, adding that such an outbreak could last a lot longer than the Eyjafjallajokull eruption.

An explosive eruption at Öræfajökull in 1362 is considered to have been the second most deadly eruption in Icelandic history.

The 1362 eruption was so big that its ash has been found in Greenland and Western Europe.



Although authorities say there is no sign of imminent eruption (they think a swarm of earthquakes would precede an eruption), Iceland’s Department of Civil Protection has published an evacuation plan just in case.


Thanks to Stephen Bird, Alessandro Decet and Gordon Broussard for these links

5 thoughts on “Quiet for 290 years, Iceland’s largest volcano now stirring

  1. http://oro.open.ac.uk/12911/
    copyright 2008 Elsevier B.V.
    The explosive rhyolitic eruption of Öræfajökull volcano, Iceland, in AD 1362 is described and interpreted based on the sequence of pyroclastic fall and flow deposits at 10 proximal locations around the south side of the volcano. Öræfajökull is an ice-clad stratovolcano in south central Iceland which has an ice-filled caldera (4–5 km diameter) of uncertain origin. The main phase of the eruption took place over a few days in June and proceeded in three main phases that produced widely dispersed fallout deposits and a pyroclastic flow deposit. An initial phase of phreatomagmatic eruptive activity produced a volumetrically minor, coarse ash fall deposit (unit A) with a bi-lobate dispersal. This was followed by a second phreatomagmatic, possibly phreatoplinian, phase that deposited more fine ash beds (unit B), dispersed to the SSE. Phases A and B were followed by an intense, climactic Plinian phase that lasted 8–12 h and produced unit C, a coarse-lapilli, pumice-clast-dominated fall deposit in the proximal region. At the end of Plinian activity, pyroclastic flows formed a poorly-sorted deposit, unit D, presently of very limited thickness and exposed distribution. Much of Eastern Iceland is covered with a very fine distal ash layer, dispersed to the NE. This was probably deposited from an umbrella cloud and is the distal representation of the Plinian fallout. A total bulk fall deposit volume of 2.3 km3 is calculated ( 1.2 km3 DRE). Pyroclastic flow deposit volumes have been crudely estimated to be < 0.1 km3. Maximum clast size data interpreted by 1-D models suggests an eruption column 30 km high and mass discharge rates of 108 kg s− 1. Ash fall may have taken place from heights around 15 km, above the local tropopause ( 10 km), with coarser clasts dispersed below that under a different wind regime. Analyses of glass inclusions and matrix glasses suggest that the syn-eruptive SO2 release was only 1 Mt. This result is supported by published Greenland ice-core acidity peak data that also suggest very minor sulphate deposition and thus SO2 release. The small sulphur release reflects the low sulphur solubility in the 1362 rhyolitic melt. The low tropopause over Iceland and the 30-km-high eruption column certainly led to stratospheric injection of gas and ash but little sulphate aerosol was generated. Moreover, pre-eruptive and degassed halogen concentrations (Cl, F) indicate that these volatiles were not efficiently released during the eruption. Besides the local pyroclastic flow (and related lahar) hazard, the impact of the Öræfajökull 1362 eruption was perhaps restricted to widespread ash fall across Eastern Iceland and parts of northern Europe.

  2. 1362 on the decent into the deep multi cycle Spoorer GSM, a period of high angular momentum and high gravitational effects on the Earth’s crust.
    1727; during the equally deep multi cycle Maunder GSM, on the rise from the depths of the GSM another period of high angular momentum and high gravitational effects on the Earth’s crust.
    More evidence in my lay view on the relationship between GSMs and eruptions on the Mid Atlantic ridge, and volcanic eruptions in general.

    • Hi Ron,
      Several of the Icelandic eruptions during GSMs have done exactly that, with the Laki eruption one of the largest CO2 and SO2 injections into the atmosphere.
      The latter SO2 got trapped into a High pressure system which then moved over Western Europe during the harvest season causing many manual corn cutters to lose their lives due to Sulfuric damage to their lungs. Harvest in the 1700s was a manual affair, no SUV around then or diesel powered combine harvesters.

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