Seismic Full-wavefield Imaging of the West Antarctica Ice Sheet
Description:
The West Antarctic Ice Sheet (WAIS) contributes considerable yet uncertain projections of sea level rise into the coming centuries. Thwaites Glacier (TG), one of the largest glaciers in West Antarctica, occupies a particularly critical position due to its intrinsic instability. As a complementary geophysical investigation method to airborne sounding surveys, seismic surveys help recover the fine-scale structures and geophysical properties of the ice sheet from shallow firn layers to deep basal conditions. Here, we discuss outcomes of two controlled-source seismic surveys conducted near the Thwaites Glacier, WA, as part of the Thwaites Interdisciplinary Margin Evolution (TIME) project.
Specifically, we observe different types of seismic waves from an active-source acquisition deployed on the WAIS and use seismic full-wavefield imaging methods to uncover the ice sheet's internal structures and physical properties. Surface waves, including leaky and normal modes, are separated from englacial and bed reflections using a cross-component matched filter method. Leaky modes are uniquely strong in the data, possibly due to the firn layer and ice compaction. We use joint inversion of leaky and normal surface waves to estimate P- and S-wave velocities in the near-surface and attribute ultra-low Vp/Vs ratios to pore closure. We observe englacial reflections down to 50 Hz and bed reflections with multiple branches. Such reflection waves are further used to calculate the seismic images of discontinuities in the ice sheet and the bedrock, revealing multiple layers within the ice near the bed and a heterogeneous bedrock with a rugged surface and possibly existing faults. The fine structure of the ice sheet revealed by seismic data helps identify potential drainage points and assess the ice sheet's instability. The study also provides new insights into the glacier's evolution and potentially enhances the accuracy of numerical models predicting future sea level changes.
Session: Cryoseismology: Advances in Technology and Scientific Discovery [Poster]
Type: Poster
Date: 4/15/2026
Presentation Time: 08:00 AM (local time)
Presenting Author: Zhendong Zhang
Student Presenter: No
Invited Presentation:
Poster Number: 4
Authors
Zhendong Zhang Presenting Author Corresponding Author zdzhang@mail.iggcas.ac.cn Chinese Academy of Sciences |
Nori Nakata nnakata@lbl.gov Lawrence Berkeley National Laboratory |
Shengji Wei shjwei@mail.iggcas.ac.cn Chinese Academy of Sciences |
Yike Liu ykliu@mail.iggcas.ac.cn Chinese Academy of Sciences |
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Seismic Full-wavefield Imaging of the West Antarctica Ice Sheet
Category
Cryoseismology: Advances in Technology and Scientific Discovery