Sunday, 31 August 2014

Eruptions in the Holuhraun lava field.

Lava began to erupt from a fissure in the Holuhraun lava field, no the north of the Vatnajökull Glacier in central Iceland, late in the evening of Thursday 28 August, and has continued to do so for the next three days. The lava field lies to the northeast of  Bárðarbunga, a volcano beneath the Vatnajökull Glacier, which began to undergo seismic activity (Earthquakes) on 19 August, and it is though likely that a magma intrusion has risen through fissures beneath the volcano and now migrated to the lava field.

Fresh lava eruptions in the Holuhraun lava field on Friday 29 August 2014. News Hub.

Seismic activity beneath volcanoes can be significant, as they are often caused by the arrival of fresh magma, which may indicate that a volcano is about to undergo an eruptive episode. Bárðarbunga last erupted in about 1862, and has undergone several periods of raised seismic activity since then, most recently in 1996 and 2010, so there is no reason to believe that this weeks events will automatically lead to an eruption from the volcano itself.

The approximate location of the Holuhraun lava field. Google Maps.

Iceland lies directly upon the Mid-Atlantic Ridge, a chain of (mostly) submerged volcanoes running the length of the Atlantic Ocean along which the ocean is splitting apart, with new material forming at the fringes of the North American and European Plates beneath the sea (or, in Iceland, above it). The Atlantic is spreading at an average rate of 25 mm per year, with new seafloor being produced along the rift volcanically, i.e. by basaltic magma erupting from below. The ridge itself takes the form of a chain of volcanic mountains running the length of the ocean, fed by the upwelling of magma beneath the diverging plates. In places this produces volcanic activity above the waves, in the Azores, on Iceland and on Jan Mayen Island.

The passage of the Mid-Atlantic Ridge beneath Iceland. NOAA National Geophysical Data Center.

See also...

The Icelandic Met Office recorded a Magnitude 5.0 Earthquake at a depth of 3 km beneath the Vatnajökull Glacier slightly before 8.15...

Iceland has evacuated around 300 people from the area around the Bárðarbunga Volcano following a rise in seismic activity this week...

The United States Geological Survey recorded a Magnitude 4.8 Earthquake at a depth of 10.3 km roughly 8 km south of the...

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