Ground Penetrating Radar Survey for Risk Reduction at Imja Lake, Nepal
Marcelo Somos-Valenzuela, Daene McKinney, Alton Byers
This study presents observations of the structure of the terminal moraine complex at Nepal’s Imja Lake, a potentially dangerous glacial lake due to the risk that it might flood.
Climate change is increasing the risk of glacial lake outburst floods (GLOFs), which threaten local and downstream communities.
The research team conducted ground penetrating radar (GPR) surveys at the lake with the intent of learning more about the structure of the terminal moraine and the distribution of ice in the core of the moraine. Doing so helps to map out ice thickness in critical areas.
It found that the thickest areas of ice are in the moraine near the western end of the lake on the northern side of the lake outlet. The ice in this region is several tens of meters thick and up to fifty meters thick in some places.
Extensive seepage of water from the terminal moraine was observed in two locations during visits to the lake in September 2011, May 2012, and September 2012. GPR transects above and below the site of seepage show the presence of ice above it and much less ice below. Seepage through the terminal moraine is an indication of its potential weakness.
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