An application of a seismic nodal system with seismic ambient noise near Kunlun Station, Antarctica: estimating ice thickness and firn structure

The thickness and upper densification structure of an ice sheet are important parameters for dynamic ice sheet modeling and glacier mass balance studies. Seismic ambient noise methods, such as the horizontal-to-vertical spectral ratio (H/V) method and ambient noise cross-correlation method, are becoming increasingly popular in glacier structure investigations. During China’s 39th expedition to Antarctica, seismic ambient noise experiments were conducted to investigate the structure of the ice sheet at Kunlun Station, Dome A, using a seismic nodal system. We obtained a broad band (0.1–10 Hz) H/V curve with a 1-hour noise record from a seismic node. In addition, we extracted the Rayleigh wave dispersion curve with 5-day noise cross-correlation functions from a linear dense seismic array. Three clear peaks were observed in the H/V curve — a lower peak at ~0.17 Hz and two higher frequency peaks at ~3 Hz and ~6 Hz. We inverted the ice sheet thickness using the lower frequency portion of the H/V curve and inverted the upper structure of the ice sheet using the higher frequency portion of the H/V curve jointly with the dispersion curve. Our estimations from ambient noise observations were consistent with those derived from the BedMachine ice sheet thickness dataset and the density profile determined by ground-penetrating radar investigations at the same site.