USAP-DC

Intellectual Merit: The PIs continued and expanded GPS and seismic measurements for ANET-POLENET to advance understanding of geodynamic processes and their influence on the West Antarctic Ice Sheet. ANET-POLENET science themes include: 1) determining ice mass change since the last glacial maximum, including modern ice mass balance; 2) solid earth influence on ice sheet dynamics; and 3) tectonic evolution of West Antarctica and feedbacks with ice sheet evolution. Nine new remote continuous GPS stations augmented ANET-POLENET instrumentation deployed during Phase 1. Siting was designed to better constrain uplift centers predicted by GIA models and indicated by Phase 1 results. A mini-array of temporary seismic sites was deployed to improve resolution of earth structure below West Antarctica. ANET-POLENET Phase 2 achievements included 1) seismic images of crust and mantle structure that resolve the highly heterogeneous thermal and viscosity structure of the Antarctic lithosphere and underlying mantle; 2) improved estimates of intraplate vertical and horizontal bedrock crustal motions; and 3) elucidation of controls on glacial isostatic adjustment-induced crustal motions due to laterally varying earth structure. Broader impacts: Monitoring and understanding mass change and dynamic behavior of the Antarctic ice sheet using in situ GPS and seismological studies has improved understanding of how Antarctic ice sheets respond to a warming world and how this response impacts sea-level and other global changes. Seismic and geodetic data collected by the ANET-POLENET network are openly available to the scientific community. ANET-POLENET has been integral in the development and realization of technological and logistical innovations for year-round operation of instrumentation at remote polar sites, helping to advance scientifically and geographically broad studies of the polar regions. The ANET-POLENET carried out a training initiative to mentor young polar scientists in complex, multidisciplinary and internationally collaborative research, including 2 week-long training schools on "Glacial Isostatic Adjustment" and "Glacial Seismology". ANET-POLENET continued broad public outreach about polar science through the polenet.org website, university lectures, and K-12 school visits. This research involved multiple international partners.

Person	Role
Wilson, Terry	Investigator and contact
Dalziel, Ian W.	Investigator
Bevis, Michael	Co-Investigator
Aster, Richard	Investigator
Huerta, Audrey D.	Investigator
Winberry, Paul	Co-Investigator
Anandakrishnan, Sridhar	Co-Investigator
Nyblade, Andrew	Investigator
Wiens, Douglas	Investigator
Smalley, Robert	Investigator

Antarctic Earth Sciences	Award # 1419268
Antarctic Earth Sciences	Award # 1249631
Antarctic Earth Sciences	Award # 1249513
Antarctic Earth Sciences	Award # 1247518
Antarctic Earth Sciences	Award # 1246776
Antarctic Earth Sciences	Award # 1246712
Antarctic Earth Sciences	Award # 1246666

USAP-1249631_1

Deployment	Type
Richard Aster	field camp

DMP_award_1419268.pdf

Repository	Title (link)	Format(s)	Status
UNAVCO	Network/Campaign: Antarctica POLENET - ANET	None	exists
IRIS	POLENET - Network YT	None	exists

1. Emry, E. L., Nyblade, A. A., Julià, J., Anandakrishnan, S., Aster, R. C., Wiens, D. A., … Wilson, T. J. (2015). The mantle transition zone beneath West Antarctica: Seismic evidence for hydration and thermal upwellings. Geochemistry, Geophysics, Geosystems, 16(1), 40–58. (doi:10.1002/2014gc005588)
2. Anthony, R. E., Aster, R. C., & McGrath, D. (2017). Links between atmosphere, ocean, and cryosphere from two decades of microseism observations on the Antarctic Peninsula. Journal of Geophysical Research: Earth Surface, 122(1), 153–166. (doi:10.1002/2016jf004098)
3. Lucas, E. M., Soto, D., Nyblade, A. A., Lloyd, A. J., Aster, R. C., Wiens, D. A., … Huerta, A. D. (2020). P- and S-wave velocity structure of central West Antarctica: Implications for the tectonic evolution of the West Antarctic Rift System. Earth and Planetary Science Letters, 546, 116437. (doi:10.1016/j.epsl.2020.116437)
4. Winberry, J. P., Huerta, A. D., Anandakrishnan, S., Aster, R. C., Nyblade, A. A., & Wiens, D. A. (2020). Glacial Earthquakes and Precursory Seismicity Associated With Thwaites Glacier Calving. Geophysical Research Letters, 47(3). (doi:10.1029/2019gl086178)
5. Hansen, S. E., Graw, J. H., Kenyon, L. M., Nyblade, A. A., Wiens, D. A., Aster, R. C., … Wilson, T. (2014). Imaging the Antarctic mantle using adaptively parameterized P-wave tomography: Evidence for heterogeneous structure beneath West Antarctica. Earth and Planetary Science Letters, 408, 66–78. (doi:10.1016/j.epsl.2014.09.043)
6. For complete project publication list, see: http://polenet.org/publications
7. Wiens, D. A., Shen, W., & Lloyd, A. (2021). The Seismic Structure of the Antarctic Upper Mantle. Geological Society, London, Memoirs, M56–2020–18. (doi:10.1144/m56-2020-18)
8. Shen, W., Wiens, D. A., Lloyd, A. J., & Nyblade, A. A. (2020). A Geothermal Heat Flux Map of Antarctica Empirically Constrained by Seismic Structure. Geophysical Research Letters, 47(14). (doi:10.1029/2020gl086955)
9. Hay, C. C., Lau, H. C. P., Gomez, N., Austermann, J., Powell, E., Mitrovica, J. X., … Wiens, D. A. (2017). Sea Level Fingerprints in a Region of Complex Earth Structure: The Case of WAIS. Journal of Climate, 30(6), 1881–1892. (doi:10.1175/jcli-d-16-0388.1)
10. Phillips, Erin H. and Sims, Kenneth W.W. and Blichert-Toft, Janne and Aster, Richard C. and Gaetani, Glenn A. and Kyle, Philip R. and Wallace, Paul J. and Rasmussen, Daniel J.. "The nature and evolution of mantle upwelling at Ross Island, Antarctica, with implications for the source of HIMU lavas," Earth and Planetary Science Letters, v.498, 2018. (doi:10.1016/j.epsl.2018.05.049)
11. Shen, W., Wiens, D. A., Anandakrishnan, S., Aster, R. C., Gerstoft, P., Bromirski, P. D., … Winberry, J. P. (2018). The Crust and Upper Mantle Structure of Central and West Antarctica From Bayesian Inversion of Rayleigh Wave and Receiver Functions. Journal of Geophysical Research: Solid Earth, 123(9), 7824–7849. (doi:10.1029/2017jb015346)
12. Alley, R. B., Pollard, D., Parizek, B. R., Anandakrishnan, S., Pourpoint, M., Stevens, N. T., … Holschuh, N. (2019). Possible Role for Tectonics in the Evolving Stability of the Greenland Ice Sheet. Journal of Geophysical Research: Earth Surface, 124(1), 97–115. (doi:10.1029/2018jf004714)
13. Heeszel, D. S., Wiens, D. A., Anandakrishnan, S., Aster, R. C., Dalziel, I. W. D., Huerta, A. D., … Winberry, J. P. (2016). Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities. Journal of Geophysical Research: Solid Earth, 121(3), 1758–1775. (doi:10.1002/2015jb012616)
14. Lloyd, A. J., Wiens, D. A., Zhu, H., Tromp, J., Nyblade, A. A., Aster, R. C., … O’Donnell, J. P. (2020). Seismic Structure of the Antarctic Upper Mantle Imaged with Adjoint Tomography. Journal of Geophysical Research: Solid Earth, 125(3). (doi:10.1029/2019jb017823)
15. Shen, W., Wiens, D. A., Anandakrishnan, S., Aster, R. C., Gerstoft, P., Bromirski, P. D., et al. (2018). The crust and upper mantle structure of central and West Antarctica from Bayesian inversion of Rayleigh wave and receiver functions. Journal of Geophysical Research: Solid Earth, 123, 7824–7849 (doi:10.1029/2017JB015346)
16. Lloyd, A., Wiens, D., Zhu, H., Tromp, J., Nyblade, A., Aster, R.C., Hansen, S.E., Dalziel, I., Wilson, T., Ivins, E., Radially Anisotropic Seismic Structure of the Antarctic Upper Mantle Based on Full-Waveform Adjoint Tomography, J. Geophysics. Res., 10.1029/2019JB017823, 2019. (doi:10.1029/2019JB017823)
17. O'Donnell, J.P., Brisbourne, A.M., Stuart, GW. Dunham, C.K., Yang, Y., Nield, G.A., Whitehouse, P.L., Nyblade, A., Wiens, D., Aster, R.C., Anandakrishnan, S., Huerta, A., Wilson, T., Winberry, J.P., Mapping crustal shear wave velocity structure and radial anisotropy beneath West Antarctica using seismic ambient noise, Geochemistry, Geophysics, Geosystems, 10.1029/2019GC008459, 2019. (doi:10.1029/2019GC008459)
18. O'Donnell, J.P., Stuart, G.W., Brisbourne, A.M., Selway, K., Yang, Y., Nield, G.A., Whitehouse, P.L., Nyblade, A., Wiens, D., Anandakrishnan, S., Aster, R.C., Huerta, A., Wilson, T., Winberry, J.P., The uppermost mantle seismic velocity structure of West Antarctica from Rayleigh wave tomography: Insights into tectonic structure and geothermal heat flow, EPSL, 522, 219-233, 10.1016/j.epsl.2019.06.024, 2019. (doi:10.1016/j.epsl.2019.06.024)
19. White-Gaynor, A., Nyblade, A., Aster, R.C., Wiens, D., Bromirski, P., Gerstoft, P., Stephen, R., Hansen, S., Wilson, T., Dalziel, I. Huerta, A., Winberry, P., Anandakrishnan, S., Heterogeneous upper mantle structure beneath the Ross Sea Embayment and Marie Byrd Land, West Antarctica, revealed by P-wave tomography, EPSL, 513, 40 - 50, 10.1016/j.epsl.2019.02.013, 2019. (doi:10.1016/j.epsl.2019.02.013)
20. Barletta, V., Bevis, M., Smith, B., Wilson, T., Brown, A., Bordoni, A., Willis, M., Khan, S., Rovira-Nararro, M., Smalley, B., Kendrick, E., Konfal, S., Caccamise, D., Aster, R.C., Nyblade, N., Wiens, D., Observed rapid bedrock uplift in Amundsen Sea Embayment promotes ice-sheet stability, Science, 360, no. 6395, p. 1335, 10.1126/science.aao1447, 2018. (doi:10.1126/science.aao1447)
21. Shen, W., Wiens, D., Stern, T., Anandakrishnan, S., Aster, R.C., Dalziel, I., Hansen, S., Heeszel, D., Huerta, A., Nyblade, A., Wilson, T., Winberry, J.P., Seismic evidence for lithospheric foundering beneath the southern Transantarctic Mountains, Geology, 10.1130/G39555.1, 2018. (doi:10.1130/G39555.1)
22. Ramirez, C., Nyblade, A., Emry, E., Julia, J., Sun, X., Anandakrishnan, S., Wiens, D. A., Aster, R. C., Huerta, A. D., Winberry, P., Shore, P., Wilson, T., Crustal structure in the Transantarctic Mountains, Ellsworth Mountains and Marie Byrd Land, Antarctica: New constraints on shear wave velocities, Poisson’s ratios and Moho depths, Geophys. J. Int., 10.1093/gji/ggx333, 2017. (doi:10.1093/gji/ggx333)
23. O'Donnell, J.P., Selway, K., Nyblade, A., Brazier, R., Wiens, D., Anandakrishnan, S., Aster, R.C., Huerta, A., Wilson, T., Winberry, J.P., The uppermost mantle velocity and viscosity structure of central West Antarctica, EPSL, 472, 38-49, 10.1016/j.epsl.2017.05.016, 2017. (doi:10.1016/j.epsl.2017.05.016)
24. Heeszel, D., Wiens, D., Nyblade, A., Aster, R., Huerta, A., Wilson, T., Kanao, M., An, M., Zhao, Y., Upper mantle structure of central and West Antarctica from array analysis of Rayleigh wave phase velocities, J. Geophys. Res., 10.1002/2015JB012616, 2016. (doi:10.1002/2015JB012616)
25. Lough, A. C., Barcheck, C. G., Wiens, D. A., Nyblade, A., & Anandakrishnan, S. (2015). A previously unreported type of seismic source in the firn layer of the East Antarctic Ice Sheet. Journal of Geophysical Research: Earth Surface, 120(11), 2237–2252. (doi:10.1002/2015jf003658)
26. Pourpoint, M., Anandakrishnan, S., & Ammon, C. J. (2018). High-Resolution Rayleigh Wave Group Velocity Variation Beneath Greenland. Journal of Geophysical Research: Solid Earth, 123(2), 1516–1539. (doi:10.1002/2017jb015072)
27. Lucas, E. M., Nyblade, A. A., Accardo, N. J., Lloyd, A. J., Wiens, D. A., Aster, R. C., Wilson, T. J., Dalziel, I. W., Stuart, G. W., O’Donnell, J. P., Winberry, J. P., & Huerta, A. D. (2022). Shear Wave Splitting Across Antarctica: Implications for Upper Mantle Seismic Anisotropy. Journal of Geophysical Research: Solid Earth, 127(4). Portico. (doi:10.1029/2021jb023325)