HR: 14:30h
AN: NS43A-05    [Abstracts]
TI: Electroseismic Exploration of Glaciers
AU: * Kulessa, B
EM: b.kulessa@qub.ac.uk
AF: Queen's University Belfast, Shallow Geophysics Laboratory School of Civil Engineering, Belfast, BT9 5AG United Kingdom
AU: Murray, T
EM: t.murray@geog.leeds.ac.uk
AF: University of Leeds, School of Geography, Leeds, LS2 9JT United Kingdom
AU: Rippin, D
AF: University of Leeds, School of Geography, Leeds, LS2 9JT United Kingdom
AB: We report the first electroseismic soundings on a glacier. More than 80 repeat soundings were conducted in four locations using antennas aligned both transverse and parallel to the orientation of a baseline. Strong electrical fields were generated in all cases, peaking early in time, and decaying approximately exponentially over some tens of milliseconds. In some cases much shorter-term electrical fluctuations are superimposed on this long-term decay. Comparison with GPR data reveals that the fluctuations are consistent with the arrival of independently propagating electromagnetic fields, generated by electrokinetic conversion as seismic waves pass (i) the interface between two layers of relatively low and higher water content; and (ii) the interface between relatively clean ice and debris-richer ice, or the interface between ice and bedrock, or potentially both. Electroseismic signatures depended on antenna orientation in all cases. Future work will focus on identifying the exact origin of the electroseismic signatures, and on linking these signatures to physical properties of glaciological interest. Electroseismic methods potentially allow the hydraulic conductivity of snow, ice and subglacial substrate to be estimated, even where substrate layers are thin. This is more challenging to achieve using other surface-based geophysical methods.
DE: 0699 General or miscellaneous
DE: 1827 Glaciology (1863)
DE: 1863 Snow and ice (1827)
DE: 5114 Permeability and porosity
DE: 5144 Wave attenuation
SC: Near-Surface Geophysics [NS]
MN: 2005 Joint Assembly