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.