In 2008, an Austrian team including Daniel and Gernot went to Zackenberg within the framework of the International Polar Year. They mainly did ground penetrating radar (GPR) measurements of the Freya glacier and the A.P. Olsen ice cap. You can read about their experiences during this trip in this blog (only in german).
The results of their studies revealed some very interesting englacial features (see figure 1) which are most likely related to the outburst of the glacier dammed lake Lake A.P.Olsen.
Figure 1: GPR crosssection. (source: ZAMG, Daniel Binder)
The Lake A.P. Olsen fills every year during summer and it empties sometime between autumn and spring. The Zackenberg GeoBasis research programme has installed a timelapse camera at the lake which takes an image every day. These photo sequences proof, that the lake empties very fast within one day (see figure 2).
Figure 2: The lake fills up during summer and it empties every year. The time when the lake empties is not fixed. It happens sometime between autumn and spring. (source: GeoBasis)
With this information we planned a seismic- and geodetic monitoring network to be deployed at the A.P.Olsen glacier. The network should be operating one year to catch the whole cycle of the filling and emptying of the lake. Moreover a dense GPR study is planned to further investigate the area of the glacier having the englacial features. Figure 3 shows the monitoring network which we installed at the A.P.Olsen glacier during our stay in 2011.
Figure 3: The Lake A.P.Olsen monitoring network consists of 5 seismic/gps stations (APO1 to 5) and one gps reference station (APO6) at the terminus of the glacier. (orthophoto source: GEUS)
In the next part of this series I’m going to give you some more details on the construction of the stations and how we set everything up at the Zackenberg base station.
