Volcanoes or What Lies Beneath…

If you haven’t lived under a rock for the past 12 months you would have heard of the eruption of the Eyjafjallajökull volcanic system in Iceland (a.k.a. Eyjafjöll volcano) in April 2010. The media covered the event mainly due to the considerable disruption of civil and military air traffic. The grounding of the better part of Europe’s fleet for several days led some to speculations about that volcanic eruption being the very first carbon neutral one.

What you probably haven’t heard about is the 60 different volcanoes that erupt over the course of a year. At any moment, some 20 eruptions can be detected, of which 17 are expected from the track records of the past 20 years. These semi-permanently erupting ‘old faithfuls’ are complemented by three ‘surprise eruptions’ like Eyjafjöll, who was dormant since the 19th century. In mid-November, scientists reported on possible magma flows leading to flank (March 20) and summit eruptions (April 14). But how can you be expected to get a grasp of the processes that are beneath the Earth’s crust when mines only explore up to 3 km, and holes can only drill 12 km deep? Contrast that with our planet’s radius just falling short of 6400 km and remember that 1300..1400°C hot magma comes from a zone 100-200 km below the surface!

The key lies in using a number of different measurement methods exploring, for example, the propagation of earthquake waves with seismic stations and surface deformation with satellite radar. The data collected with these methods proved to be amenable to mathematical modelling. As a result of that, one can gain understanding of phenomena which are physically inaccessible and hence prevented from direct observation. Such multidisciplinary efforts can not only bring a better understanding of the Earth itself but also highlight differences to other planets.

Arnd Korn


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