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Speaker: Dallas Sherman, Postdoctoral Research Fellow, Ocean and Earth ElectroMagnetic laboratory (OCEEMlab), University of Texas Institute for Geophysics

Host: Eric Attias

Title: Geophysics in Sustainable Resource Development and Hazard Assessment: A Focus on Marine Electromagnetics

Abstract: Geophysics has an increasingly important role to play in developing resources and assessing hazards for a sustainable future. This talk will present select case studies highlighting the use of geophysics in general, and marine electrogmagnetics in specific, to this end.

As the clean energy transition gains momentum, the demand for rare earth minerals has driven industry to seek deposits with increased logistical difficulties. Geophysics is a key component in not only quantifying the ore body, but also in guiding infrastructure development, as demonstrated by exploration in remote northern British Columbia and Greenland.

Developments in marine electromagnetics has allowed for near-shore surveys in support of discovery and management of offshore fresh ground water reservoirs and assessment of relict permafrost conditions. A surface-towed controlled-source electromagnetic (CSEM) system used offshore Hawaii identified a new mechanism for fresh groundwater discharge, as well as the presence of freshwater plumes and a large offshore fresh groundwater reservoir. The same surface-towed system successfully mapped subsea ice-bearing permafrost on the Beaufort Shelf along 200~km of coastline, an important step in quantifying the climate change hazard posed by relict permafrost and its associated methane hydrate. Maps of depth to permafrost and its thickness were produced from electrical resistivity inversions. This system provides a cost effective method that could be used to further quantify permafrost extent, provide a baseline for measurements of future degradation, and provide observational constraints to aid in permafrost modeling studies.