Publication Date:
2015-08-08
Description:
Permafrost inundated since the last glacial maximum is degrading, potentially releasing trapped or stabilized greenhouse gases, but few observations of the depth of ice-bonded permafrost (IBP) below the sea floor exist for most of the arctic continental shelf. We use spectral ratios of the ambient vibration seismic wave field, together with estimated shear wave velocity from the dispersion curves of surface waves, for estimating the thickness of the sediment overlying the IBP. Peaks in spectral ratios modelled for 3-layered 1D systems correspond with varying thickness of the unfrozen sediment. Seismic receivers were deployed on the sea bed around Muostakh Island in the central Laptev Sea, Siberia. We derive depths of the IBP between 3.7 and 20.7 m ±15 %, increasing with distance from the shoreline. Correspondence between expected permafrost distribution, modelled response and observational data suggest that the method is promising for the determination of the thickness of unfrozen sediment.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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