Glacier Tracking with Intelligent Pebbles

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A couple of summers ago I was involved in a project, called Glacsweb, that seeks to discover what happens underneath a glacier (photo above) as it slowly moves downhill. Glacsweb has been subject to a recent BBC News article. Observing what happens to the rocks as they are broken, worn and moved under a glacier presents tremendous technical difficulties. Glaciers often exist in remote places that can be inaccessible for most of the year. Observing the processes under a glacier in “real time” presents an even greater challenge. Sometimes insight can be gained from tunnels created by moving water as it flows underneath the glacier (see photo below) but these are likely to flood and therefore dangerous places for researchers to spend time.

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Glacsweb seeks to address this problem by placing intelligent pebbles (photo below) under the glacier. These pebbles can beam back to the UK, via a base station on the glacier surface, information about their orientation, temperature, approximate location, and pressure they are subject to. In theory they can do this for 10 years (although the pebbles I helped to place have only been running for 16 months so far).

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I joined the Glacsweb team for two weeks in the summer of 2008 where we put the pebbles at the base of the Skalafellsjokull Glacier, to the west of Iceland (photo of the area below, glacier to the left (west)). To get the pebbles under the glacier, bore-holes up to 80m deep had to be drilled using a high pressure hose and boiling water. This proved a very effective method of melting circular holes into the ice down which the pebbles could be dropped. A video of a pebble floating down the hole to the base of the glacier is available here. I hope the results from this research, when they are published, will provide new insights into the many processes occurring in the base of the Skalafellsjokull Glacier.

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