Fig. 1  : Overview of seafloor fibre sensing at the calving front of EKaS.

a, Map of EKaS and location in Greenland (red rectangle) with colour-coded ice-flow speed and drainage basin outline (white dashed line)⁵¹. b, Magnification into the green rectangle in a. Layout of seafloor fibre-optic cable on satellite imagery (Sentinel 2 from 7 August 2023). The thick yellow–green–purple-shaded line shows the vessel track during cable deployment with bathymetry interpolated from the depth sonar of the vessel and labelled OD along the cable as white circular markers. The specific locations of iceberg calving and both fracturing events presented in Fig. 3 are marked as red symbols. Seismometers QJT01 and QJT03 are located east and west of the calving front. QJT02 is about 0.5 km south of the map extent (Extended Data Fig. 2). c, East–West cross-section with bathymetry along the cable, including along-cable ODs. m.b.s.l., metres below sea level.