Antarctic ice sheet thickness estimation using the horizontal-to-vertical spectral ratio method with single-station seismic ambient noise

Abstract

Abstract. We report on a successful application of the horizontal-to-vertical spectral ratio (H / V) method, generally used to investigate the subsurface velocity structures of the shallow crust, to estimate the Antarctic ice sheet thickness for the first time. Using three-component, five-day long, seismic ambient noise records gathered from more than 60 temporary seismic stations located on the Antarctic ice sheet, the ice thickness measured at each station has comparable accuracy to the Bedmap2 database. Preliminary analysis revealed that 60 out of 65 seismic stations on the ice sheet obtained clear peak frequencies (f0) related to the ice sheet thickness in the H / V spectrum. Thus, assuming that the isotropic ice layer lies atop a high velocity half-space bedrock, the ice sheet thickness can be calculated by a simple approximation formula. About half of the calculated ice sheet thicknesses were consistent with the Bedmap2 ice thickness values. To further improve the reliability of ice thickness measurements, two-type models were built to fit the observed H / V spectrum through non-linear inversion. The two-type models represent the isotropic structures of single-and twolayer ice sheets, and the latter depicts the non-uniform, layered characteristics of the ice sheet widely distributed in Antarctica. The inversion results suggest that the ice thicknesses derived from the two-layer ice models were in good concurrence with the Bedmap2 ice thickness database, and that ice thickness differences between the two were within 300 m at almost all stations. Our results support previous finding that the Antarctic ice sheet is stratified. Extensive data processing indicates that the time length of seismic ambient noise records can be shortened to two hours for reliable ice sheet thickness estimation using the H / V method. This study extends the application fields of the H / V method and provides an effective and independent way to measure ice sheet thickness in Antarctica.

Antarctic Ice Properties Revealed From Teleseismic P Wave Coda Autocorrelation

“…It is interesting to comment on the similarity between the autocorrelation and the spectral ratio (H/V) methods (e.g., Seht & Wohlenberg, ), both of which can be used to characterize site effects of thin ice or sediment layers (e.g., Yan et al, ). Spectral ratios are constructed by dividing horizontal to vertical amplitude spectra of ambient noise and stacking over multiple record segments.…”

“…However, both passive seismological methods mentioned above require all three component recorders (one vertical and two horizontal) to generate either the receiver function or the spectral ratio. In the autocorrelation approach presented in this study, we use, individually, vertical and horizontal records recorded on a similar set of stations as in Yan et al (), to construct the vertical and horizontal autocorrelation stacks, which in turn feature reflection signals of P and S waves. Consequently, we can estimate the ice thickness using only vertical stacked autocorrelograms and the v P / v S ratio of the ice sheet at those recording sites when horizontal autocorrelograms are incorporated.…”

“…Because of the ever‐growing seismograph networks deployed over ice in Antarctica for cryoseismic studies (Podolskiy & Walter, ), several passive seismological methods widely used to study the crustal structures elsewhere have also been deployed to estimate the ice thickness complementary to the active‐source measurements. Those methods provide local measurements to the recording sites with less logistical support (Yan et al, ). For example, pioneering studies have demonstrated the successful applications of the receiver function as well as the horizontal versus vertical spectral ratio methods.…”

“…The second class of methods use the spectral ratio between vertical and horizontal wave forms to reveal resonance peaks of P or S waves reverberated within a thin layer of snow (e.g., Lévêque et al, ) or ice (e.g., Diez et al, ) or a water layer beneath an ice shelf (Zhan et al, ). Most recently, Yan et al () presented a successful application of the horizontal‐to‐vertical (H/V) spectral ratio method to estimate the ice thickness beneath a large number of seismic stations distributed over Antarctica. Because the method needed a relatively short record of ambient noise of few days, this approach can be potentially used in future temporary deployments.…”

Potentials and pitfalls of permafrost active layer monitoring using the HVSR method: a case study in Svalbard

“…We therefore have more evidence for the cliff at the marine cave being the source of the tremor. A reasonable source mechanism for the tremor signal is therefore slamming of breaking sea waves at the cliff during high tides and significant ocean wave activity (Adams et al, 2002;Young et al, 2016), often accompanied by high wind speeds. At low tides and/or high tides during the neap tide cycle, a narrow beach is exposed and the ocean waves do not reach the cliff, which explains the temporal distribution of tremor occurrences.…”