Illuminating Ice Dynamics with Emerging Seismic Technology

Sea-level rise (SLR) is one of the greatest challenges facing society this century. By 2050, one billion people will be exposed to extreme sea-level rise events. However, how much and how fast sea-levels will rise remains highly uncertain. Much of this uncertainty arises from a lack of observational constraint of ice dynamics models used to estimate future ice loss. Ice dynamics models are sophisticated and satellite-derived surface observations are readily available, but subsurface friction and fracture observational voids remain.I will address this knowledge gap using seismology, one of the few tools that can illuminate the subsurface. I will harness revolutionary emerging technology (fibreoptic sensing and nodes) to interrogate two critical glacier processes (basal slip and hydrofracture) in unprecedented detail. Basal slip dominates accepted uncertainty in SLR projections, while hydrofracture could accelerate SLR far beyond current estimates. Both processes generate seismic energy that can be directly interrogated.I will develop a new seismic source inversion method that harnesses far denser sampling from fibreoptic sensing and nodes to illuminate the physics controlling glacier slip and hydrofracture. This advance will provide new insights, including: (1) direct measurements of ice-bed interface strength, an essential under- constrained model boundary condition; and (2) quantifying ice fracture stress state and extent, essential for assessing whether hydrofracture is as important as hypothesised for accelerating SLR.Excitingly, ice is seismically simpler than rock, so it also provides an ideal testbed for developing new methods. I will capitalise on this to not only realise glaciology impacts, but also simultaneously realise a fundamental step-change in seismology: laying foundations for mechanistic local noise source inversion. This will pave the way both for noise removal (akin to noise-cancelling headphones) and new ways of imaging the subsurface.