Saturday, 3 November 2007

Fieldwork near Faxe

Two weeks ago I had the opportunity to go to Faxe, in southeast Zealand (Sjælland), to help out with some land seismics. It was really nice to be outside again – to shut down the computer to be outside in the beautiful colours of the autumn. Well is helps when the weather is really nice, as it was.
The project was a collaboration between the University of Copenhagen and the University of Aarhus. The idea was to see the subsurface structures of the chalk and to find coral reefs, just at the edge of Faxe limestone quarry. The main question was: "Why do we find coral reefs here?". A total of about 7 km seismic profile will help answering this question, and the results should be presented at Geomuseum Faxe in a couple of years.The funny white truck in the picture is the seismic vibrator, it sends out a vibration (like a big loudspeaker) that is reflected in subsurface layers (like an echo), the reflection is picked up by the geophones (kind of really sensitive microphones) in the tail behind the vibrator. The method works the same way as the scanning of pregnant women.
It was hard work. In 4 days we worked 52 hours, but well since we had nothing else to do in Faxe, it was OK. The work was to drive the seismic vibrator and to take care that the "tail" was in as straight a line as possible behind the vibrator. It's really easy when the road is straight, but demands a lot of force when the road curves, it's not easy to pull the 6 tons vibrator.

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