2017 Fiscal Year Final Research Report
Study for estimating the influence of the Greenland ice sheet on observed seismograms
| Project/Area Number |
15K17742
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Solid earth and planetary physics
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Project Period (FY) |
2015-04-01 – 2018-03-31
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| Keywords | グリーンランド氷床 / 地震観測 / 地震波伝播モデリング / 理論地震波形計算 / 地震波干渉法 / 表面波位相速度変化 / 圧力融解 / GLISN |
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| Outline of Final Research Achievements |
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). In 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". Furthermore, we observed seasonal/long-term changes in Rayleigh-wave phase velocities at the bottom of the ice sheet, and found that the patterns of the velocity changes could be opposite due to difference in ice bed conditions (frozen or thawed). These results might be useful to directly obtain meltwater amount at the ice sheet base.
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| Free Research Field |
地震学
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