12:15 PM - 12:30 PM
[SCG63-06] Seismic waveform modeling for a structural model with the Greenland ice sheet
Keywords:Greenland ice sheet, Seismic waveform, Guided wave, Finite-difference method (FDM), GLISN project
In this work, we calculate elastic wave propagation up to 2 Hz for four structural models of the Greenland ice sheet radiated from a seismic source with various depths and mechanisms. Our computations for a realistic ice sheet model, the near-surface seismic source produced a very characteristic wave train with the group velocity smaller than the S-wavespeed in the ice, which is considered as an icesheet guided S wave, developed by a superposition of post-critical reflections between the free surface and the ice bed. We named this wave "Le" on the analogy of the Lg wave, a crustally guided S wave ("e" comes from the German word "Eisdecke", meaning the ice sheet). Furthermore, computation for a deeper seismic source resulted in reinforcement of the crustal Sg-coda wave with a group velocity range of ~3.1-2.6 km/s, which well explains the characteristic waveform observed on the Greenland ice sheet.