EGU22-5685
https://doi.org/10.5194/egusphere-egu22-5685
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

On-ice seismicity of a rapidly-rising jökulhlaup cycle at the A.P. Olsen Ice Cap, NE-Greenland

Daniel BInder1,2,3, Stefan Mertl4, Michele Citterio5, Signe Hillerup-Larsen5, Kirsty Langley6, Fabian Walter7, and Eva P. S. Eibl1
Daniel BInder et al.
  • 1University of Potsdam, Institute of Geosciences, General Geophysics, Germany (binder4@uni-potsdam.de)
  • 2Climate Research Department, Zentralanstalt for Meteorology and Geodynamics (ZAMG)
  • 3Austrian Polar Research Institute (APRI)
  • 4Mertl Research GmbH, Vienna, Austria
  • 5Glaciology and Climate Department, Geological Survey for Greenland and Denmark (GEUS)
  • 6Greenland Survey (ASIAQ)
  • 7Swiss Federal Institute for Forest, Snow and Landscape Research (WSL)

Rapidly-rising jökulhlaups, or glacial outburst floods, are a phenomenon with a high potential for damage. The initiation and propagation processes of a rapidly-rising jökulhlaup are still not fully understood. Seismic monitoring can contribute to an improved process understanding, but comprehensive long-term seismic monitoring campaigns capturing the dynamics of a rapidly-rising jökulhlaup are rare. In 2012, we installed a seismic network at the marginal, ice-dammed lake of the A.P. Olsen Ice Cap in NE-Greenland. Episodic outbursts from the lake cause flood waves in the Zackenberg river, characterized by a rapid discharge increase within a few hours. We deployed industrial geophones (4.5 Hz) for the five on-ice stations. Two stations were designed as mini-arryas with three vertical sensors, and the remaining were equipped with three-component sensors. All sensors were sunk about 3 m into the ice. Our 6 months long seismic dataset comprises the whole fill-and-drain cycle of the ice-dammed lake in 2012 and includes one of the most destructive floods recorded so far for the Zackenberg river. Seismic event detection reveals periods of high seismicity during enhanced surface melting prior to the outburst flood. During the outburst itself the number of detected events dropped due to the elevated seismic noise level. Furthermore, different beamforming methods were tested to infer back azimuth changes during periods of elevated seismicity. We propose that the changes of back azimuth are related to the subglacial infiltration of water and evaluate the role of the ice-dammed lake within this context.

How to cite: BInder, D., Mertl, S., Citterio, M., Hillerup-Larsen, S., Langley, K., Walter, F., and Eibl, E. P. S.: On-ice seismicity of a rapidly-rising jökulhlaup cycle at the A.P. Olsen Ice Cap, NE-Greenland, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5685, https://doi.org/10.5194/egusphere-egu22-5685, 2022.