THE BLOG

Iceland's Ecological Changes and Geological Disasters

14/04/2016 16:14

Over the past few weeks in Iceland there has been increased volcanic activity from Öræfajökull to Katla and Bárðarbunga volcanos.  While Öræfajökull would not be a major eruption, Katla poses a great threat to the region according to many experts.  Jón Frímann tracks the volcanic and minor earthquake activity in Iceland as the fallout from volcano eruption is well documented from glacier floods which have wiped out vast tracts of agricultural fields in the country to the devastating losses of the glacier and the ecological disaster that ensues.  Iceland's volcanos are part of a larger ecological chain reaction that link ecological change to geological disasters.

The volcano Katla is location is located in the south of Iceland in the Mýrdalsjökull glacier and it last erupted in1918 lasting three weeks with a cubic kilometre of material having exploded through its vent.  Historical records in Iceland show that the Eyjafjallajökull volcano erupted in 920, 1612 or 1613, and 1821-1823. The last eruption of Eyjafjallajökull lasted for 14 months with intermittent bursts throughout this time. In all cases the eruption of Eyjafjallajökull volcano occurred simultaneously to or was followed by the eruption of Katla with is located 25 km to the east.

The volcano Eyjafjallajökull, located under the Eyjafjallajökull glacier, erupted in January 2010 followed by clusters of small earthquakes.  By March 2010 earthquake activity had increased in intensity and frequency such that by 21 March, fountains of lava began exiting the 500-metre-long vent in the Fimmvörduháls Pass which separates the Eyjafjallajökull glacier from an even larger glacier to the east, Mýrdalsjökull.  The heat from the lava melted the glacier above vaporising some of the meltwater while flooding farmland, swelling local rivers and streams, (especially the Markarfljót River), damaging roads, and sending a 30,000-foot-tall plume of ash into the sky as a result of the rapid vaporisation of ice which sparked a series of phreatomagmatic explosions.  Many people remember this event because most of Europe's airports mid-April 2010 were shut down for approximately one week due to an ash cloud in the sky which was driven across the North Atlantic Ocean to northern Europe by prevailing winds.  Then in 2014 there was a similar threat posed by the Bárðarbunga volcano located under the Vatnajökull glacier which ultimately has not yet erupted.

What is worrying to scientists and Icelanders is that the seismic activity beneath the country's volcanoes is significant and there is a causal relational between the arrival of fresh magma and volcanic activity and seismic disturbances or full on earthquakes.  Bárðarbunga last erupted in 2014-2015 and is located at the junction between the eastern and northern rift zones where the centre of the mantle hot spot underneath Iceland is believed to be. One of the  major risks from Bárdarbunga exploding is the jökulhlaup, a glacier outburst flood (GLOFS) that would be hazardous for populations and wildlife as flood waters have been known to carry ice floes that weigh up to 5000 tons with icebergs between 100-200 tons with the ability to strike a tsunami of 4 metres high and 600 metres wide as was the case in 1996 with the eruption of Grímsvötn volcano situated under the Vatnajökull glacier.  The Grímsvötn volcano has erupted several times since in 1998, 2004 and 2011 and the dangers resulting from another such eruption are multiple: an avalanche of rock or heavy snow, an earthquake or cryoseism (and ice or frost quake), volcanic eruptions under the ice leading to jökulhlaup, or if a large enough portion of a glacier breaks off other water bodies can be drastically displaced.

There are recent worries about Bárðarbunga erupting again given that the lava field surrounding this volcano, Holuhraun (originally named Kvislarhraun), is situated at the southern end of Ódáðahraun, one of the largest lava fields in the country.  However, thanks to much scientific research is that there is a confirmed link between climate change and increased volcanic eruptions due to  post-glacial rebound or isostatic rebound whereby the melting glaciers due to the warming Arctic are causing the glaciers to melt where pressure of ice and rocks rocks being released from the underlying volcanos.  There is a chain reaction between Iceland's seismic activity, glacier melt, isostatic rebound, and volcanic activity and the answer to Iceland's geological woes are to be found within ecological change around the globe.

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