Using seismology to track the timing of sea ice ridging events and shorefast ice stabilization in coastal Alaska

Shorefast sea ice is used for hunting and travel by Iñupiat subsistence hunters and has long been monitored for stability by indigenous ice experts. The highly dynamic nature of shorefast sea ice presents a risk to these community users, with local knowledge and experience challenged by global climate change. The grounding of pressure ridges protects the protects the landward extent of the shorefast ice from breaking off from breaking off and makes it safer for travel. Pressure ridges form during convergence events, but it is difficult to determine when a ridge is grounded. Our work utilizes cryoseismic data to identify these grounding events as they happen, in an effort to identify the spectral features that can be used to monitor the stability of the shorefast ice. We pair seismic data from coastal EarthScope Transportable Array stations with radar footage of local ice conditions in Utqiaġvik, Alaska to characterise sea ice deformation events by their seismic signature. Our analysis covers three ice seasons (from 2014 to 2017) using feature tracking,day-by-day radar observations, and community records to provide qualitative and quantitative descriptions of the seasonal evolution of nearshore ice. This presentation will cover event classifications with the UAF Utqiaġvik sea ice radar, the analysis of these events' seismic traces, and the potential applicability of this method as a tool for coastal Arctic communities.