G07 Geohazards Monitoring

IAG (Geodesy)



26-Jun-2015, 15:00 - 16:30


 
Abstract content:

Continuous kinematic GPS monitoring of a glacier lake outburst flood

Natural glacier events such as ice avalanches, debris flows or glacier lake outburst floods (GLOF) may have hazardous impacts on the downstream area of the glacier and can cause severe destruction. In Kyrgyzstan, the Inylchek Glacier is the second-largest glacier in the world. In spring, a glacier-dammed lake is formed (Lake Merzbacher) by melt-water which drains suddenly at least once a year within a few days causing a destructive flood. To understand the mechanism of the GLOF, it is essential to study the kinematic behavior of the lake’s ice-dam before, during and after the outburst.

GFZ and CAIAG jointly operate a GPS monitoring network with a base station and a station located directly on the moving glacier adjacent to the ice-dam providing continuous 1Hz GPS data. The GPS data is processed with GAMIT/Track and daily horizontal and vertical positions are estimated. During higher glacier dynamics when the station suddenly moves, shorter time slices are processed.

Irrespective of the general motion of the ice-dam during the year, the GPS time series show a significant change in the ice-dam's behavior shortly prior and after the GLOF. Especially the vertical position increases before the GLOF and decreases rapidly of almost 20m within three days after the GLOF. Additionally, the surface velocities are 3-5 times higher shortly before and up to 16 times higher during the GLOF. These results show a significant change in the movement of the ice dam and can be used to develop a early warning system for the glacier-dammed lake outburst flood.

 
Author(s):
C. Zech1, T. Schöne1, A. Zubovich2.
1German Research Centre for Geosciences, Geodesy and Remote Sensing, Potsdam, Germany.
2Central-Asian Institute for Applied Geosciences, Monitoring Systems and Data Management, Bishkek, Kyrgyzstan.

 

Keywords:
Inylchek Glacier     Kyrgyzstan     kinematic GPS glacier monitoring     glacier lake outburst flood