Picture this - early warning system
by Elizabeth Willoughby

04 DLR image of Iceland eruption

Iceland's volcano eruptions last spring provided a key testing opportunity for Dr Ulrich Münzer, leader of the LMU Geology Department's Remote Sensing Research team that is developing an early warning system using satellite radar technology.

An all weather camera

On April 11, 2010, Dr Münzer received scheduled TerraSAR-X satellite radar images of the glacial areas of southern Iceland, taken every 11th day as he had requested from German Aerospace Center (DLR). When seismic readings had shown a series of earthquakes earlier that month, Dr Münzer was sure an eruption was coming. He was right – on April 14, he received the phone call from his Icelandic co-investigator – but rain, clouds and spewing ash had grounded local air traffic and obscured the exact source.

Dr Münzer immediately requested daily satellite radar images – they're unaffected by weather – and received data within hours. Only then could the source be pinpointed and potential dangers revealed. The images showed three craters in the Eyjafjallajökull glacier, but would the torrent flow out of the northern side into a valley or would it carry rocks, sediments and giant ice blocks towards the southern coast, wiping out farms, homes and bridges? New images that the LMU team provided from two days later showed that the glacial torrent went north, filling a lake with sediments, ice blocks and basaltic stones. The receipt of those images allowed Icelandic authorities to make informed emergency measure decisions.

Pictures from space

As a principal investigator, Dr Münzer's early warning system development project allowed him to request 130 radar images from the German TerraSAR-X satellite. From 514 kilometers above Earth, nearly real-time space-based radar images provide the highest ground resolution worldwide, able to detect even minimal changes on glacial surfaces, 200 meters thick at the site of the last eruption. Dr Münzer's pictures were targeted at Iceland's subglacial volcanoes because, he says, "subglacial volcanoes provide the most significant indicators in observing volcanoes."

When the wind picked up last April and carried Iceland's ashes into European skies, grounding planes, closing airports and stranding travellers, an early warning system became an obvious priority. At the end of July, Dr Münzer and his team flew to Iceland to work in conjunction with meteorologists, volcanologists and Iceland's own researchers. There was much to be done in the short, 6-week window of potentially good weather and daylight for LMU's team to make preparations for the next stage of the early warning system project, which should begin in October. As a result of the last eruption, new elevation models were needed, the surface of the ice had changed, and some of the 150-kilogram corner reflectors used to geocode radar images were buried under ash.

Exploring the Icelandic volcanoes

Because previous trips have exposed Dr Münzer's teams to whipping sand funnels, sandstorms and August snowstorms on the wasteland terrain, he knew he was at the mercy of weather. Waiting out days of torrential rains, when it wasn't too windy, he zigzagged over glacial surfaces in a Cessna taking photos out of the open window, looking for lines and depressions, marking changes and taking GPS readings. On other days they were on Eyjafjallajökull measuring the ash layer thickness, the ice crystal consistency at different depths, and verifying the radar images. They also had to unbury the reflectors and clean, restore and re-measure them, authenticating each image. The glaciar lake in front of Gigjökull scattered with enormous blocks of ice, sediments and rocks from the recent eruption presented another opportunity for investigation and data collection.

Knowing that there are volcanic eruptions on Iceland every three or four years and that the most active volcanic zone of the Middle Atlantic Ridge runs through this part of Iceland, key factors in the early warning system development, Dr Münzer is now eyeing the Mýrdalsjökull ice cap that lies above Katla, a subglacial volcano 25 kilometres east of Eyjafjallajökull. Dr Münzer thinks it will erupt soon. He was right about it the last time.

Originally published at insightLMU, September 2010

Photos provided by Dr Münzer and DLR 

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