Velocity and viscosity models for southern Patagonia, from the GUANACO experiment

The gridfiles here contain velocity and viscosity models presented in the following paper:

- Mark, H.F., D.A. Wiens, E.R. Ivins, A. Richter, W. Ben Mansour, M.B. Magnani, E. Marderwald, R. Adaros, & S. Barrientos. Lithospheric erosion in the Patagonian slab window, and implications for glacial isostasy. 2022. Geophysical Research Letters, DOI: 10.1029/2021GL096863.

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Both the paper and the models were updated in June 2022 in response to a bug in the ASWMS software package (Jin and Gaherty, 2015). These updates did not qualitatively change the model or the paper's conclusions. The ASWMS software has been updated on github, and more information about the bug can be found in this pull request.
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The paper contains detailed information on how the velocities and viscosities were calculated. For information on the tomography methods and viscosity calculation used, see the Methods section and references therein, including:

- Barmin, M. P., Ritzwoller, M. H., & Levshin, A. L. (2001). A Fast and Reliable Method for Surface Wave Tomography. Pure Appl. Geophys., 158, 25.
- Bensen, G. D., Ritzwoller, M. H., Barmin, M. P., Levshin, A. L., Lin, F., Moschetti, M. P., et al. (2007). Processing seismic ambient noise data to obtain reliable broad-band surface wave dispersion measurements. Geophysical Journal International, 169(3), 1239–1260. https://doi.org/10.1111/j.1365-246X.2007.03374.x
- Jin, G., & Gaherty, J. B. (2015). Surface wave phase-velocity tomography based on multichannel cross-correlation. Geophysical Journal International, 16.
- Lin, F.-C., & Ritzwoller, M. H. (2011). Helmholtz surface wave tomography for isotropic and azimuthally anisotropic structure. Geophysical Journal International, 186(3), 1104–1120. https://doi.org/10.1111/j.1365-246X.2011.05070.x
- Lin, F.-C., Ritzwoller, M. H., & Snieder, R. (2009). Eikonal tomography: surface wave tomography by phase front tracking across a regional broad-band seismic array. Geophysical Journal International, 177(3), 1091–1110. https://doi.org/10.1111/j.1365-246X.2009.04105.x
- Shen, W., Ritzwoller, M. H., Schulte-Pelkum, V., & Lin, F.-C. (2013). Joint inversion of surface wave dispersion and receiver functions: a Bayesian Monte-Carlo approach. Geophysical Journal International, 192(2), 807–836. https://doi.org/10.1093/gji/ggs050
- Ivins, E. R., Wal, W. van der, Wiens, D. A., Lloyd, A. J., & Caron, L. (2021). Antarctic Upper Mantle Rheology. Geological Society, London, Memoirs, 56. https://doi.org/10.1144/M56-2020-19
- Wu, P., Wang, H., & Steffen, H. (2013). The role of thermal effect on mantle seismic anomalies under Laurentia and Fennoscandia from observations of Glacial Isostatic Adjustment. Geophysical Journal International, 192(1), 7–17. https://doi.org/10.1093/gji/ggs009
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The files contain:
### patagonia_vels.grd:
Vsv at points throughout the study area, spaced 0.3x0.3 degrees laterally and at 500m depth intervals from 500m to 200 km. Points where the velocity is not constrained are filled with -1.
### patagonia_visc.grd:
log10 of viscosity in Pa s at points throughout the study area, spaced 0.3x0.3 degrees laterally and at 500m depth intervals from 100km to 200 km. Points where the viscosity is not constrained are filled with -1.
### patagonia_sed_thickness.grd:
Sediment thickness in km at points throughout the study area, spaced 0.3x0.3 degrees laterally. Points where the sediment thickness is not constrained are filled with -1.
### patagonia_moho_depth.grd:
Moho depth in km at points throughout the study area, spaced 0.3x0.3 degrees laterally. Points where the Moho depth is not constrained are filled with -1.