Iceland: Volcanic jewel in the ring of fire

Iceland is known as "The Land of Ice and Fire". With a name like Iceland, and it's location near the arctic circle, the ice part might not come as a big surprise. The "fire" nickname comes from Iceland's extensive volcanic activity. Iceland is straddling a divergent plate boundary in the ring of fire called the Mid Atlantic ridge. It is also traveling over a "hot spot" in the mantle, the layer of the earth below the crust. Volcanic History of Iceland. A volcano erupts in Iceland every 3 years, on average.



 The divergent plate boundary accounts for the fissure eruptions (as seen at the right from the 2014 Holuhraun eruption) which are very common on Iceland.









The hot spot, or "plume" in the mantel is responsible for the more classically cone shaped volcanoes, and high volcanic mountains on the island. Kerlingarfjoll: Rhyolitic cinder cone
Snaefellnes: Rhyoltic cinder cone. A geographic position just outside the arctic circle causes glaciers to form on the slopes of these volcanoes. This combination of "fire and ice" is one of the most common features in iceland. These rhyolitc cones are much more dangerous than the fissure volcanoes. The type of magma which erupts from them is much more viscous, or thicker. The additional weight of the glacial ice that forms on top of them also compresses and delays eruptions, making them more violent and explosive.



This also causes extensive flooding when a sub-glacial eruption happens. While Iceland has an eruption warning system, it places much more importance in it's Flood warning system. The volume of water discharged in one of these floods can be greater than that of the flow of the Amazon river.





This combination of volcanic features gives Iceland it's unique terrain. Hot spots alone generally form island chains like Hawaii. It also explains why there is such a high volume of volcanoes on such a small island.