Master of Science Frances Ann Cooke will Tuesday October 7th, 2025, at 12:15 hold her Thesis Defense for the PhD degree in Science. The title of the thesis is:
« Characterizing gas seepage and small–scale fractures using high–resolution seismic: An Arctic study at the Vestnesa Ridge, eastern Fram Strait »
Understanding the geological controls on subsurface fluid migration and gas leakage is critical for managing environmental risks, ensuring seafloor stability, and developing effective monitoring strategies to support emerging technologies central to the energy transition, such as carbon capture and storage.
This multi-scale seismic study at the Vestnesa Ridge investigated how regional forcing mechanisms, such as glacial dynamics, mid-ocean ridge tectonics, and gravitational processes, have influenced sediment deformation and gas migration in the near-surface (~200 m below the seafloor) over the past 1.2 million years, focusing on seepage periodicity, fracture-controlled gas release, and gas hydrate stability.
The use of seismic discontinuity attributes sensitive to subtle changes in curvature of seismic reflections, enabled more spatially localized analysis than in conventional methods. High-resolution 3D seismic data reveals spatial and temporal variations in leakage behaviour across different areas of the ridge. Highly deformed intervals correspond with global climatic transitions, suggesting that glacially induced fracturing, modulated by shifting gas hydrate stability conditions, has controlled fluid migration and seepage along the ridge.
A semi-automated fault extraction method, using high-resolution seismic data and a pre-trained machine learning model, reveals small-scale faults with throws of only a few metres (>3-4 m), providing new insights into fault evolution and gas migration pathways. Mohr diagrams were employed as a predictive tool to model geological controls on gas leakage, allowing assessment of potential stress conditions and failure mechanisms influencing gas migration pathways, acknowledging uncertainties in subsurface parameters.
This thesis contributes to advancing fluid flow studies by developing adaptable data-driven workflows that integrate subsurface investigation techniques.
1st Opponent: Professor Kim Senger, UNIS, Svalbard
2nd Opponent: Associate Professor Lorna Strachan, Universitet i Aukland, New Zeeland
Internal member and leader of the committee: Associate professor Monica Winsborrow, IG, UiT
The defence and trial lecture will be streamed from these following links at Panopto:
Defence (12:15 - 16:00)
Trial Lecture (10:15 - 11:15)
The thesis is available Here