ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica
Seismic signals are powerful to characterize ice and subsurface structures, and we image shallow ice structure near the West Antarctic Ice Sheet (WAIS) Divide with active and passive seismic data and the Thwaites Glacier eastern shear margin with passive data. The eastern shear margin has a planned...
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ftgfzpotsdam:oai:gfzpublic.gfz-potsdam.de:item_5018348 2023-07-02T03:30:39+02:00 ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica Nakata, N. Zhang, Z. Qin, L. Karplus, M. Kaip, G. Walter, J. Tulaczyk, S. 2023 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018348 eng eng info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2409 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018348 XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) info:eu-repo/semantics/conferenceObject 2023 ftgfzpotsdam https://doi.org/10.57757/IUGG23-2409 2023-06-11T23:39:54Z Seismic signals are powerful to characterize ice and subsurface structures, and we image shallow ice structure near the West Antarctic Ice Sheet (WAIS) Divide with active and passive seismic data and the Thwaites Glacier eastern shear margin with passive data. The eastern shear margin has a planned active-seismic survey in the 23/24 field season. Passively recorded seismic ambient noise can be used to extract wave propagations between receivers and provide complementary information to the active seismic data. High-frequency energy is high in active-seismic data, but surface waves are often more prominent in ambient noise records due to their source mechanisms. We use a surface-wave dispersion analysis, an analysis of horizontal-versus-vertical (H/V) ratio, wave-equation-based seismic imaging, and reflection migration for imaging firn-air, firn and shallow ice layers. We identify the leaky modes following the direct waves by examining their behaviors of energy decay and particle motion. The leaky modes are guided P waves and contain P-wave velocity information and exist possibly due to the sharp velocity contrasts at the firn layer. Together with normal modes, we use a joint inversion of leaky and normal modes for P- and S-wave velocity estimation in the near-surface. Because seismic ambient noise always exists, we also use them for time-lapse analysis of the ice structure for understanding its dynamics. Conference Object Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
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Open Polar |
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GFZpublic (German Research Centre for Geosciences, Helmholtz-Zentrum Potsdam) |
op_collection_id |
ftgfzpotsdam |
language |
English |
description |
Seismic signals are powerful to characterize ice and subsurface structures, and we image shallow ice structure near the West Antarctic Ice Sheet (WAIS) Divide with active and passive seismic data and the Thwaites Glacier eastern shear margin with passive data. The eastern shear margin has a planned active-seismic survey in the 23/24 field season. Passively recorded seismic ambient noise can be used to extract wave propagations between receivers and provide complementary information to the active seismic data. High-frequency energy is high in active-seismic data, but surface waves are often more prominent in ambient noise records due to their source mechanisms. We use a surface-wave dispersion analysis, an analysis of horizontal-versus-vertical (H/V) ratio, wave-equation-based seismic imaging, and reflection migration for imaging firn-air, firn and shallow ice layers. We identify the leaky modes following the direct waves by examining their behaviors of energy decay and particle motion. The leaky modes are guided P waves and contain P-wave velocity information and exist possibly due to the sharp velocity contrasts at the firn layer. Together with normal modes, we use a joint inversion of leaky and normal modes for P- and S-wave velocity estimation in the near-surface. Because seismic ambient noise always exists, we also use them for time-lapse analysis of the ice structure for understanding its dynamics. |
format |
Conference Object |
author |
Nakata, N. Zhang, Z. Qin, L. Karplus, M. Kaip, G. Walter, J. Tulaczyk, S. |
spellingShingle |
Nakata, N. Zhang, Z. Qin, L. Karplus, M. Kaip, G. Walter, J. Tulaczyk, S. ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
author_facet |
Nakata, N. Zhang, Z. Qin, L. Karplus, M. Kaip, G. Walter, J. Tulaczyk, S. |
author_sort |
Nakata, N. |
title |
ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
title_short |
ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
title_full |
ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
title_fullStr |
ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
title_full_unstemmed |
ECS Awardee 2023: Unraveling shallow ice structure with active and passive seismic surveys at west Antarctica |
title_sort |
ecs awardee 2023: unraveling shallow ice structure with active and passive seismic surveys at west antarctica |
publishDate |
2023 |
url |
https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018348 |
long_lat |
ENVELOPE(-106.750,-106.750,-75.500,-75.500) |
geographic |
Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier |
geographic_facet |
Antarctic West Antarctica West Antarctic Ice Sheet Thwaites Glacier |
genre |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Thwaites Glacier West Antarctica |
op_source |
XXVIII General Assembly of the International Union of Geodesy and Geophysics (IUGG) |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.57757/IUGG23-2409 https://gfzpublic.gfz-potsdam.de/pubman/item/item_5018348 |
op_doi |
https://doi.org/10.57757/IUGG23-2409 |
_version_ |
1770274873970524160 |