Comparison of elastic moduli from seismic diving-wave and ice-core microstructure analysis in Antarctic polar firn
2019
We compared elastic moduli in polar firn derived from diving wave refraction seismic
velocity analysis, firn-core density measurements and microstructure modelling based on firn-core
data. The seismic data were obtained with a small electrodynamic vibrator source near Kohnen
Station, East Antarctica. The analysis of diving waves resulted in velocity–depth profiles for different
wave types (P-, SH- and SV-waves). Dynamic elastic moduli of firn were derived by combining P- and
S-wave velocities and densities obtained from firn-core measurements. The structural finite-element
method (FEM) was used to calculate the components of the elastic tensor from firn microstructure
derived from X-ray tomography of firn-core samples at depths of 10, 42, 71 and 99 m, providing
static elastic moduli. Shear and bulk moduli range from 0.39 to 2.42 GPa and 0.68 to 2.42 GPa,
respectively. The elastic moduli from seismic observations and the structural FEM agree within 8.5%
for the deepest achieved values at a depth of 71 m, and are within the uncertainty range. Our
observations demonstrate that the elastic moduli of the firn can be consistently obtained from two independent
methods which are based on dynamic (seismic) and static (tomography and FEM) observations,
respectively, for deeper layers in the firn below ∼10 m depth.
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
63
References
6
Citations
NaN
KQI