Fire and Ice – Volcano Erupts Under Iceland Glacier

For the second time in a month, a volcano has erupted under Iceland’s Eyjafjallajokull glacier … and lava and ice don’t usually mix. While the volcano that began erupting this morning is in a fairly remote area several hundred people have been evacuated for fear of flooding in rivers which are fed by the glacier.

Iceland is unique geographically. The nation straddles the Mid-Atlantic Ridge, a region that runs down the centre of the Atlantic Ocean marking the boundary between two of Earth’s large tectonic plates. These large plates are separating at a rate of about 1 inch (2.54 centimetres) annually, pushing Africa and South America slowly apart. As the plates push away from each other, cracks and fissures often form, allowing magma from under the Earth’s crust to flow to the surface, forming volcanoes

While most of the Mid-Atlantic Ridge is below sea level, Iceland is one rare instance where the Ridge is raised above the ocean. This helps to explain the unique geography of the country. Iceland is home to over 200 volcanoes, making it one of the most volcanically active regions in the world. In fact, one third of the Earth’s total lava flow over the past 500 years has occurred there.

Most of the volcanic eruptions on Iceland are non-violent. Instead, the lava slowly flows to the surface, hardening into a rock called basalt and adding to the topography of the island. However, when this lava flows out through a glacier, as is the case today, this could spell real trouble for those living down river of the area. Lava is incredibly hot – approximately 1000°C! Something this hot can melt a lot of ice in a short period of time, causing river levels to rise and flash floods to occur. Thankfully, this does not happen instantly.  There is often enough time between an eruption of this nature and any sign of flooding to get everyone away from the dangerous areas and up to higher ground.