scholarly journals Uncertainties of Glacial Isostatic Adjustment Model Predictions in North America Associated With 3D Structure

2020 ◽  
Vol 47 (10) ◽  
Author(s):  
Tanghua Li ◽  
Patrick Wu ◽  
Hansheng Wang ◽  
Holger Steffen ◽  
Nicole S. Khan ◽  
...  
Keyword(s):  
North America ◽  
3D Structure ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment ◽  
Adjustment Model ◽  
Model Predictions

Glacial isostatic adjustment of the pacific coast of North America: The Influence of lateral earth structure

2021 ◽  
Author(s):  
Maryam Yousefi ◽  
Glenn A Milne ◽  
Konstantin Latychev
Keyword(s):  
North America ◽  
Data Model ◽  
Pacific Coast ◽  
3D Structure ◽  
Earth Structure ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment ◽  
The Pacific ◽  
Seismic Models ◽  
Lateral Structure

Summary The Pacific Coast of Central North America is a geodynamically complex region which has been subject to various geophysical processes operating on different time scales. Glacial isostatic adjustment (GIA), the ongoing deformational response of the solid Earth to past deglaciation, is an important geodynamic process in this region. In this study we apply Earth models with 3D structure to determine if the inclusion of lateral structure can explain the poor performance of 1D models in this region. Three different approaches are used to construct 3D models of the Earth structure. For the first approach, we adopt an optimal 1D viscosity structure from previous work and add lateral variations based on four global seismic shear wave velocity anomalies and two global lithosphere thickness models. The results based on these models indicate that the addition of lateral structure significantly impacts modelled RSL changes, but the data-model fits are not improved. The global seismic models are limited in spatial resolution and so two other approaches were considered to produce higher resolution models of 3D structure: inserting a regional seismic model into two of the global seismic models and, explicitly incorporating regional structure of the Cascadia subduction zone and vicinity, i.e. the subducting slab, the overlying mantle wedge, and the plate boundary interface. The results associated with these higher resolution models do not reveal any clear improvement in satisfying the RSL observations, suggesting that our estimates of lateral structure are inaccurate and/or the data-model misfits are primarily due to limitations in the adopted ice-loading histories. The different realisations of 3D Earth structure gives useful insight to uncertainty associated with this aspect of the GIA model. Our results indicate that improving constraints on the deglacial history of the southwest sector of the Cordilleran ice sheet is an important step towards developing more accurate of GIA models for this region.

Use of GRACE determined secular gravity rates for glacial isostatic adjustment studies in North-America

2008 ◽  
Vol 46 (3-5) ◽  
pp. 144-154 ◽  
Author(s):  
Wouter van der Wal ◽  
Patrick Wu ◽  
Michael G. Sideris ◽  
C.K. Shum
Keyword(s):  
North America ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment

scholarly journals Absolute gravity calibration of GPS velocities and glacial isostatic adjustment in mid-continent North America

2011 ◽  
Vol 38 (24) ◽  
pp. n/a-n/a ◽  
Author(s):  
S. Mazzotti ◽  
A. Lambert ◽  
J. Henton ◽  
T. S. James ◽  
N. Courtier
Keyword(s):  
North America ◽  
Absolute Gravity ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment ◽  
Gps Velocities

scholarly journals Relative sea-level data from the SEAMIS database compared to ICE-5G model predictions of glacial isostatic adjustment

Data in Brief ◽  
2019 ◽  
Vol 27 ◽  
pp. 104600 ◽  
Author(s):  
Thomas Mann ◽  
Maren Bender ◽  
Thomas Lorscheid ◽  
Paolo Stocchi ◽  
Matteo Vacchi ◽  
...  
Keyword(s):  
Sea Level ◽  
Glacial Isostatic Adjustment ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Level Data ◽  
Model Predictions

Glacial isostatic adjustment along the Pacific coast of central North America

2018 ◽  
Vol 193 ◽  
pp. 288-311 ◽  
Author(s):  
Maryam Yousefi ◽  
Glenn A. Milne ◽  
Ryan Love ◽  
Lev Tarasov
Keyword(s):  
North America ◽  
Pacific Coast ◽  
Glacial Isostatic Adjustment ◽  
Isostatic Adjustment ◽  
The Pacific

Glacial Isostatic Adjustment with 3D Earth models: A comparison of case studies of deglacial relative sea level records of North America and Russian Arctic

2020 ◽  
Author(s):  
Tanghua Li ◽  
Nicole Khan ◽  
Simon Engelhart ◽  
Alisa Baranskaya ◽  
Peltier William ◽  
...  
Keyword(s):  
North America ◽  
Sea Level ◽  
3D Models ◽  
Viscosity Model ◽  
Glacial Isostatic Adjustment ◽  
Russian Arctic ◽  
Scaling Factors ◽  
Relative Sea Level ◽  
Isostatic Adjustment ◽  
Best Fit

<p>The Canadian landmass of North America and the Russian Arctic were covered by large ice sheets during the Last Glacial Maximum, and have been key areas for Glacial Isostatic Adjustment (GIA) studies. Previous GIA studies have applied 1D models of Earth’s interior viscoelastic structure; however, seismic tomography, field geology and recent studies reveal the potential importance of 3D models of this structure. Here, using the latest quality-controlled deglacial sea-level databases from North America and the Russian Arctic, we investigate the effects of 3D structure on GIA predictions. We explore scaling factors in the upper mantle (<em>β<sub>UM</sub></em>) and lower mantle (<em>β<sub>LM</sub></em>) and the 1D background viscosity model (<em>η<sub>o</sub></em>) with predictions of of the ICE-6G_C (VM5a) glaciation/deglaciation model of Peltier et al (2015, JGR) in these two regions, and compare with the best fit 3D viscosity structures.</p><p>We compute gravitationally self-consistent relative sea-level histories with time dependent coastlines and rotational feedback using both the Normal Mode Method and Coupled Laplace-Finite Element Method. A subset of 3D GIA models is found that can fit the deglacial sea-level databases for both regions. These databases cover both the near and intermediate field regions. However, North America and Russian Arctic prefer different 3D structures (i.e., combinations of (<em>η<sub>o</sub>, β<sub>UM</sub>, β<sub>LM</sub></em>)) to provide the best fits. The Russian Arctic database prefers a softer background viscosity model (<em>η<sub>o</sub></em>), but larger scaling factors (<em>β<sub>UM</sub>, β<sub>LM</sub></em>) than those preferred by the North America database.</p><p>Outstanding issues include the uncertainty of the history of local glaciation history. For example, preliminary modifications of the ice model in Russian Arctic reveal that the misfits of 1D models can be significantly reduced, but still fit less well than the best fit 3D GIA model.An additional issue concerns the extent to which the 3D models are able to improve both fits in North America and Russian Arctic when compared with 1D internal structure (ICE-6G_C VM5a & ICE-7G VM7), will be assessed in a preliminary fashion.</p>

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