Full Waveform Ambient Noise Tomography for East Antarctica
Data DOI:
https://doi.org/10.15784/601763
Cite as
Hansen, S., & Emry, E. (2024) "Full Waveform Ambient Noise Tomography for East Antarctica" U.S. Antarctic Program (USAP) Data Center. doi: https://doi.org/10.15784/601763.
AMD - DIF Record(s)
Abstract
Recent investigations in polar environments have examined solid-Earth-ice-sheet feedbacks and have emphasized that glacial isostatic adjustment, tectonic, and geothermal forcings exert first-order control on the physical conditions at and below the ice-bed interface and must be taken into account when evaluating ice-sheet evolution. However, the solid-Earth structure beneath much of Antarctica is still poorly constrained given the sparse distribution of seismic stations across the continent and the generally low seismicity rate. One region of particular interest is the Wilkes Subglacial Basin (WSB) in East Antarctica. During the mid-Pliocene warm period, the WSB may have contributed 3-4 m to the estimated 20 m rise in sea-level, indicating that this region could also play an important role in future warming scenarios. However, the WSB may have experienced notable bedrock uplift since the Pliocene; therefore, past geologic inferences of instability may not serve as a simple analogue for the future.
Using records of ambient seismic noise recorded by both temporary and long-term seismic networks, along with a full-waveform tomographic inversion technique, we have developed improved images of the lithospheric structure beneath East Antarctica, including the WSB. Empirical Green’s Functions with periods between 40 and 340 s have been extracted using a frequency-time normalization technique, and a finite-difference approach with a spherical grid has been employed to numerically model synthetic seismograms. Associated sensitivity kernels have also been constructed using a scattering integral method. Our results suggest the WSB is underlain by slow seismic velocities, with faster seismic structure beneath the adjacent Transantarctic Mountains and the Belgica Subglacial Highlands. This may indicate that the WSB is associated with a region of thinner lithosphere, possibly associated with prior continental rifting. The seismic heterogeneity highlighted in our model could have significant implications for understanding the geodynamic origin of WSB topography and its influence on ice-sheet behavior.
The model file and associated plotting scripts are provided.
Creator(s):
Date Created:
2024-01-24
Repository:
USAP-DC (current)
Spatial Extent(s)
West: 90, East: 180, South: -90, North: -65
Award(s)
Version:
1
Related Project(s)
References
Keywords
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This dataset has been downloaded 2 times since March 2017 (based on unique date-IP combinations)