Supplemental Material: Seismic evidence of widespread sediments beneath the Greenland Ice Sheet

Additional text, figures, and a data table supporting the main findings. Text S1 describes the seismic data sources, including the broadband networks and DOIs of all Greenland stations used. Text S2 details inversion results from an alternate model configuration that varies ice properties alone, which is shown to be physically inconsistent with observed receiver function delays. Figure S1 shows the ice thickness uncertainty from the BedMachine dataset. Figure S2 illustrates schematic ray paths through ice-over-bedrock and ice-sediment-bedrock systems. Figure S3 presents inversion results assuming ice property variation only. Figure S4 provides a corner plot of posterior probability distributions for sediment properties at one station. Table S1 lists the coordinates, sediment thicknesses, and associated uncertainty bounds for all stations analyzed.