Seismic characteristics of an airgun fired over snow

An alternative seismic source was investigated in an experiment conducted near Rothera Station, Antarctic Peninsula. The source was an airgun fired above the snow surface. Comparison shots using explosive and hammer sources were also recorded. A clear reflection was obtained from the ice/bedrock interface 300 m beneath the site on the unprocessed airgun record. On the explosive and hammer records the reflection could only be seen after frequency-wavenumber filtering had attenuated shearwaves and ground roll. The technique has potential use in profiling ice shelf thickness and seabed depth using a single, small airgun.