A Surface Wave Study of the Greenland Ice Sheet

Thursday, 18 December 2014: 3:10 PM
Anatoli L Levshin, Weisen Shen, Mikhail P Barmin, Lili Feng and Michael H Ritzwoller, University of Colorado at Boulder, Boulder, CO, United States
Since 2009, the seismic stations as part of the Greenland Ice Sheet Monitoring Network (GLISN) have become available for broadband seismology on Greenland. Using this network, seismic surface waves can be exploited to study the structure of Greenland’s crust and ice sheet and to investigate whether time variations in ice properties can be discerned. Methods include innovations developed using Earthscope/USArray data (e.g., the ambient noise cross-correlation techniques, Rayleigh wave H/V observations). In this presentation, the preliminary results of surface wave investigations utilizing the GLISN network are presented with four principal aspects. First, we measure the Rayleigh wave dispersion from ambient noise cross-correlations and explore their use to derive the information about the structure of the uppermost mantle, crust and icesheet. Second, we made measurements of the Rayleigh wave H/V ratio from teleseimic earthquakes and investigate their use to quantify the physical-state of the ice-sheet. Third, using the surface wave dispersion information and Rayleigh wave H/V ratios, we perform a Bayesian Monte Carlo inversion to infer the shear velocity structure of the ice-sheet, crust and uppermost mantle of Greenland. Finally, we explore time variations in the surface wave dispersion and H/V ratio to determine whether such variations can be observed and used to constrain seasonal and perhaps secular changes in the structure of the ice sheet.