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Controlled-Source Seismic Imaging of Mcmurdo Ice Shelf Near Williams Airfield

Description: 

Understanding the structure and thickness of the McMurdo Ice Shelf and the ocean environment below is important from an operational as well as scientific perspective. The McMurdo Ice Shelf is part of the Ross Ice Shelf, and ice shelf mass loss has been observed due to warming ocean conditions in the Ross Sea. During December 2021, the Thwaites Interdisciplinary Margin Evolution (TIME) project team conducted a seismic survey along an 1100-m seismic line near William’s Airfield on McMurdo Ice Shelf. We deployed twenty-four MagseisFairfield, Z-Land Generation 2, 5-Hz, 3-component seismic nodes at 50-m spacing for 30 days. Both passive and active seismic sources were captured, with a day of controlled seismic sources generated by a 12-lb sledgehammer at 23 locations with 50-m spacing, with 3 hammer strikes at each location to stack and enhance the signal. The hammer signal generated 80–100 Hz frequency observed in the spectrograms, which was used to develop four corner filtered shot gathers to observe wave propagations. We process the controlled-source refraction data to define a velocity model of the ice shelf and environment below using Python ObsPy tools. Corrected and filtered data were imported to Shearwater Reveal to visualize the seismic data and make observations about the data quality and wave propagation. The survey was also a methods test for the use of seismic nodes for ice shelf (and glacier) imaging with controlled sources, and we discuss lessons learned for future deployments.

Session: Applications and Discoveries in Cryoseismology Across Spatial and Temporal Scales [Poster Session]

Type: Poster

Date: 5/2/2024

Presentation Time: 08:00 AM (local time)

Presenting Author: Yeshey

Student Presenter: Yes

Invited Presentation: 

Authors