Ice shelf structure derived from dispersion curve analysis of ambient seismic noise, Ross Ice Shelf, Antarctica
Bromirski, Peter D.
Stephen, Ralph A.
Anthony, Robert E.
Aster, Richard C.
Nyblade, Andrew A.
Wiens, Douglas A.
MetadataShow full item record
An L-configured, three-component short period seismic array was deployed on the Ross Ice Shelf, Antarctica during November 2014. Polarization analysis of ambient noise data from these stations shows linearly polarized waves for frequency bands between 0.2 and 2 Hz. A spectral peak at about 1.6 Hz is interpreted as the resonance frequency of the water column and is used to estimate the water layer thickness below the ice shelf. The frequency band from 4 to 18 Hz is dominated by Rayleigh and Love waves propagating from the north that, based on daily temporal variations, we conclude were generated by field camp activity. Frequency–slowness plots were calculated using beamforming. Resulting Love and Rayleigh wave dispersion curves were inverted for the shear wave velocity profile within the firn and ice to ∼150 m depth. The derived density profile allows estimation of the pore close-off depth and the firn–air content thickness. Separate inversions of Rayleigh and Love wave dispersion curves give different shear wave velocity profiles within the firn. We attribute this difference to an effective anisotropy due to fine layering. The layered structure of firn, ice, water and the seafloor results in a characteristic dispersion curve below 7 Hz. Forward modelling the observed Rayleigh wave dispersion curves using representative firn, ice, water and sediment structures indicates that Rayleigh waves are observed when wavelengths are long enough to span the distance from the ice shelf surface to the seafloor. The forward modelling shows that analysis of seismic data from an ice shelf provides the possibility of resolving ice shelf thickness, water column thickness and the physical properties of the ice shelf and underlying seafloor using passive-source seismic data.
Author Posting. © The Author(s), 2016. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 205 (2016): 785-795, doi:10.1093/gji/ggw036.
Suggested CitationArticle: Diez, Anja, Bromirski, Peter D., Gerstoft, Peter, Stephen, Ralph A., Anthony, Robert E., Aster, Richard C., Cai, Chen, Nyblade, Andrew A., Wiens, Douglas A., "Ice shelf structure derived from dispersion curve analysis of ambient seismic noise, Ross Ice Shelf, Antarctica", Geophysical Journal International 205 (2016): 785-795, DOI:10.1093/gji/ggw036, https://hdl.handle.net/1912/7902
Showing items related by title, author, creator and subject.
Bromirski, Peter D.; Stephen, Ralph A. (International Glaciological Society, 2012-11-01)Comparison of the Ross Ice Shelf (RIS, Antarctica) response at near-front seismic station RIS2 with seismometer data collected on tabular iceberg B15A and with land-based seismic stations at Scott Base on Ross Island (SBA) ...
Near-surface environmentally forced changes in the Ross Ice Shelf observed with ambient seismic noise Chaput, Julien; Aster, Richard C.; McGrath, Daniel; Baker, Michael G.; Anthony, Robert E.; Gerstoft, Peter; Bromirski, Peter D.; Nyblade, Andrew A.; Stephen, Ralph A.; Wiens, Douglas A.; Das, Sarah B.; Stevens, Laura A. (John Wiley & Sons, 2018-10-16)Continuous seismic observations across the Ross Ice Shelf reveal ubiquitous ambient resonances at frequencies >5 Hz. These firn‐trapped surface wave signals arise through wind and snow bedform interactions coupled with ...
The crust and upper mantle structure of central and West Antarctica from Bayesian inversion of Rayleigh Wave and receiver functions Shen, Weisen; Wiens, Douglas A.; Anandakrishnan, Sridhar; Aster, Richard C.; Gerstoft, Peter; Bromirski, Peter D.; Hansen, Samantha E.; Dalziel, Ian W. D.; Heeszel, David S.; Huerta, Audrey D.; Nyblade, Andrew A.; Stephen, Ralph A.; Wilson, Terry J.; Winberry, J. Paul (John Wiley & Sons, 2018-09-22)We construct a new seismic model for central and West Antarctica by jointly inverting Rayleigh wave phase and group velocities along with P wave receiver functions. Ambient noise tomography exploiting data from more than ...