SEISMIC METHODS ON THE ICE SHELF: A COMPARISON BETWEEN VIBROSEIS AND EXPLOSIVE SEISMICS ON EKSTRÖMISEN

• Main Authors: Hofstede, Coen, Eisen, Olaf, Kristoffersen, Y., Lambrecht, A., Mayer, Christoph, Blenkner, R., Kindermann, Lars
• Format: Conference Object
• Language: unknown
• Published: 2010
• Subjects: Antarc*; Antarctica; Dronning Maud Land; Ice Shelf
• Online Access: https://epic.awi.de/id/eprint/22613/; https://hdl.handle.net/10013/epic.35282

We present first-time-ever results of active seismic measurements on an ice shelf with a vibroseismic source. The measurements were conducted in the 2009/10 field season in Dronning Maud Land, Antarctica. A Failing Y-1100 on skis with a mass of 16 t was used on the Ekströmisen ice shelf where ice is about 100-200 m thick and overlies about the same amount of water. The goal was to investigate the feasibility of vibroseismic operations on a porous firn layer to image the internal structure of the ice and the underlying sediments as well as ice and water column thickness. In comparison with conventional explosive seismics, where explosives are detonated in 20-m deep boreholes, vibroseimics does not require any drilling and can thus be considered a true surface measurements. In combination with a snow streamer the vibroseismic operation would enable long seismic traverses in comparably short time periods. vibroseismics seems a promising site survey method for core drilling campaigns like the ANDRILL project but also to map the nature of the ice bed contact over long traverses. In addition to comparison with conventional explosive shots we also recorded the signals and the PALAOA observatory at two calibrated hydrophones underneath the ice shelf, which enables the determination absolute amplitudes and absorption.