12 | Highlights 2010
Andy Hooper of the Remote Sensing Department: “This eruption will help fill in some of the gaps” The 2010 eruption of Eyjafjallajökull in Iceland was a relatively small volcanic event, but the disruption it caused to European air traffic and the costs involved were huge. Andy Hooper, assistant professor at the Department of Remote Sensing, studies the processes that cause deformation of the earth’s crust: volcanoes, tectonics, earthquakes and post-glacial rebound. For this he uses satellite-based InSAR - Interferometric Synthetic Aperture Radar – a technique first developed in the 1990s. Combining Satellite radar and GPS receivers, deformation can now be determined to within a few millimetres accuracy. “With InSAR we have very good ground coverage, so we have global information, but we have to wait for it until the satellite returns. With GPS we can get data every second, but only at specific points. All in all, we have a pretty good idea of what is going on.” Chain of events Andy Hooper has been interested in Iceland’s volcanoes for years, and spent a year and a half doing postdoctoral research at the Nordic Volcanological Centre of the University of Iceland before joining TU Delft. “We knew Eyjafjallajökull would erupt again, only not when. 13 | Highlights 2010 Looking at its history, this was only the fourth eruption in 1100 years. It could have taken another fifty or a hundred years.” Magma had been moving to shallower depths since 2009, but this had also happened in the 1990s without leading to an eruption. When Eyjafjallajökull did erupt it was the chain of events that surprised scientists, rather than the timing. “In active volcanoes magma typically moves from great depths to shallower depths to form a crustal magma chamber. We observe this as the ground above it stretching and moving upwards. During an eruption the magma moves out of the chamber and the ground moves downwards again. Eyjafjallajökull didn’t follow this pattern. Magma moved up and the volcano expanded upwards, but when the eruption started it stayed like that.” AY-ya-fyat-lah-YOH-kuhtl So why did Eyjafjallajökull behave differently? “Eyjafjallajökull is only a moderately active volcano. The crust is cooler and magma comes up infrequently, therefore no shallow magma chamber forms”, explains Dr Research