Mapping Glacier Bed Topography in Crevassed Regions: A New Passive Seismic Reflection Method Applied to Isunnguata Sermia, West Greenland

Abstract

Glacier bed topography is crucial for modeling ice mass loss. However, heavily crevassed regions are challenging to survey using conventional methods, leading to data gaps. We establish a passive seismic approach exploiting naturally occurring crevassing events recorded with a dense seismic array to image the ice–bed interface without spatial interpolation. Using P‐wave reflections from shallow events detected by matched field processing, we derive a two‐dimensional ice‐thickness map with ∼15 m vertical resolution in a crevasse field on Isunnguata Sermia, West Greenland. Our measurements are consistent with ground‐penetrating radar ice thickness picks and extend coverage to previously inaccessible areas. The resolved bed shows a ∼100 m deep overdeepening along ice flow, poorly resolved in large‐scale bed elevation products, co‐located with a previously inferred active subglacial lake. This method provides a robust, logistically simpler tool than more conventional radar and active seismic surveys for high‐resolution bed imaging in dynamically active glacier regions.