Dense Seismic Array Monitoring of the Glacier Tongue of Isunnguata Sermia, West Greenland

Accelerating mass loss from the Greenland Ice Sheet is affected by meltwater-driven changes in ice dynamics, which remain poorly understood due to limited observations. Here, we present a 2.5 km2 wide dense passive seismic array experiment conducted in the ablation zone of Isunnguata Sermia, West Greenland. We target varying surface melt conditions through one-month long monitoring periods in spring, summer, and fall using 82-117 nodes deployed in 2023 and 2024 complemented by multi-week surface Distributed Acoustic Sensing acquisitions in 2024. We assess data quality using power spectral densities and noise correlation functions. We find that low-frequency seismic power is highly correlated to ice surface velocity, suggesting a strong control of subglacial hydrology on ice dynamics. We retrieve stable and high signal-to-noise ratio noise correlations containing Rayleigh, Love, and P wave arrivals, suggesting these may successfully be used for glacier structure imaging and monitoring. We finally demonstrate we can locate numerous seismic events with resolution down to a few meters using Matched Field Processing and which exhibit characteristic spatial patterns evolving across seasons. These findings establish the potential of such experiment to infer glacier hydrology, dynamics, and structure at high spatial and temporal resolution.