Events

Speaker: Marianne Karplus, Associate Professor, Department of Earth, Environmental, and Resource Sciences, The University of Texas at El Paso

Host: Ginny Catania

Title: Echoes from the edge of Thwaites Glacier, Antarctica: from tectonics to ice flow dynamics

Abstract: The Thwaites Interdisciplinary Margin Evolution (TIME) project illuminates the control that shear margin dynamics have over the future evolution of ice flow in the Thwaites-Amundsen drainage basin. To examine the physical processes and properties at the shear margin, we set up field geophysical observatories between 2019 to 2024 at several locations along the shear margin to study the ice as well as the geology below. I will present results from our seismicity study, describing earthquakes and icequakes recorded by two 7-station passive broadband seismic networks deployed between 2019-2021. Then I will present preliminary images and observations from 2-D and 3-D controlled-source seismic surveys acquired across the Thwaites shear margin in 2023-24, with 1000 3-component seismic nodes deployed in a 27-km line and 3 by 5.5-km seismic grid. We detonated 671 seismic sources, mostly “Poulter” sources with 4-kg explosive boosters suspended on a 6-foot bamboo pole. The seismic signals were recorded across the full extent of the seismic line and grid and penetrated into the bed beneath the ice (~2000-km-thick), allowing for englacial, bed, and geologic imaging and interpretation.