TY - JOUR
T1 - Numerical modeling of seismic waves for estimating the influence of the Greenland ice sheet on observed seismograms
AU - Toyokuni, Genti
AU - Takenaka, Hiroshi
AU - Kanao, Masaki
AU - Tsuboi, Seiji
AU - Tono, Yoko
N1 - Funding Information:
The authors are grateful to Mr. Dean Childs, Dr. Tetsuto Himeno, and all the other GLISN members for their contribution to the field operations at Greenland. Discussions with Prof. Mare Yamamoto were very helpful in improving the manuscript. The Japanese GLISN team has been supported by JSPS KAKENHI 24403006 . We thank the editor, Prof. Kazuo Shibuya, and the two anonymous referees who provided constructive review comments that have improved this paper. Most figures were generated using the Generic Mapping Tools freeware package ( Wessel and Smith, 1998 ).
PY - 2015/3/1
Y1 - 2015/3/1
N2 - We calculate regional synthetic seismograms for a realistic structure model beneath Greenland, including surface topography and ice sheet thickness, for observations of the multinational GreenLand Ice Sheet monitoring Network (GLISN). The thick and heterogeneous Greenland ice sheet can cause distortion of the seismic waveforms observed at the GLISN stations on ice. We developed a numerical technique that calculates accurate regional seismic wavefields with low computational requirements. Here, we calculate the elastic wave propagation up to 2Hz for four structural models of the Greenland ice sheet from a seismic source at various depths and with different mechanisms. Our computations for a realistic ice sheet model, the near-surface seismic source produced a very characteristic wave train with a group velocity smaller than the S-wavespeed in the ice, considered to be an ice-sheet guided S wave, developed by the superposition of post-critical reflections between the free surface and the ice bed. We named this wave ". Le", analogous to the Lg wave, a crustally guided S wave. Furthermore, computation for a deeper seismic source resulted in reinforcement of the crustal Sg-coda wave with a group velocity range of ~3.1-2.6km/s, which agrees with the characteristic waveform observed on the Greenland ice sheet.
AB - We calculate regional synthetic seismograms for a realistic structure model beneath Greenland, including surface topography and ice sheet thickness, for observations of the multinational GreenLand Ice Sheet monitoring Network (GLISN). The thick and heterogeneous Greenland ice sheet can cause distortion of the seismic waveforms observed at the GLISN stations on ice. We developed a numerical technique that calculates accurate regional seismic wavefields with low computational requirements. Here, we calculate the elastic wave propagation up to 2Hz for four structural models of the Greenland ice sheet from a seismic source at various depths and with different mechanisms. Our computations for a realistic ice sheet model, the near-surface seismic source produced a very characteristic wave train with a group velocity smaller than the S-wavespeed in the ice, considered to be an ice-sheet guided S wave, developed by the superposition of post-critical reflections between the free surface and the ice bed. We named this wave ". Le", analogous to the Lg wave, a crustally guided S wave. Furthermore, computation for a deeper seismic source resulted in reinforcement of the crustal Sg-coda wave with a group velocity range of ~3.1-2.6km/s, which agrees with the characteristic waveform observed on the Greenland ice sheet.
KW - Finite-difference method (FDM)
KW - GLISN project
KW - Greenland ice sheet
KW - Guided wave
KW - Seismic waveform
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U2 - 10.1016/j.polar.2014.12.001
DO - 10.1016/j.polar.2014.12.001
M3 - Article
AN - SCOPUS:84924656552
SN - 1873-9652
VL - 9
SP - 80
EP - 93
JO - Polar Science
JF - Polar Science
IS - 1
ER -