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You searched for id:"oai:tudelft.nl:uuid:1589eef9-8265-405a-ba3f-242a7d74e3b1". One record found.

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Delft University of Technology

1. Marsman, Celine (author). Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age.

Degree: 2020, Delft University of Technology

In Southeast Alaska extreme uplift rates are primarily caused by Glacial Isostatic Adjustment (GIA), as a result of ice load changes from the Little Ice Age to the present combined with a low viscosity asthenosphere. Current GIA models adopt a one-dimensional (1D) stratified Earth structure. The three-dimensional (3D) structure of the Earth is complex in this region due to the proximity of a subduction zone and the transition from a continental to oceanic plate. A simplified 1D Earth model may not be an accurate representation in this region and therefore affect the GIA predictions. In this study a numerical model for 3D GIA is constructed for Southeast Alaska. We present an assessment on the impact of lateral variations in the upper mantle rheology on the vertical GIA component. We test two different approaches to obtain a 3D viscosity structure in the upper mantle. For the first approach, viscosities are inferred from lateral variations in temperature through flow laws for olivine. The water and grain size are varied to find a viscosity structure that best fits the GPS data. We find a best-fit viscosity structure with wet rheology (400 wt ppm H2O) and grain size 8 mm. However, this model does not perform better (in terms of Χ2) than a radially symmetric model, because predicted uplift rates are much lower than the observed values. For the second approach, we infer a viscosity distribution obtained directly from shear wave anomalies through scaling relationships. Our 3D model reduces the residuals between 1.0-2.7 mm/yr. We find that the effects of lateral variations in viscosity (up to 0.4 log units or, equivalently, a factor of 2.5) are in principle detectable by the GPS network and provide a better overall fit than a radially symmetric 1D viscosity model.

Aerospace Engineering

Advisors/Committee Members: van der Wal, W. (mentor), Riva, R.E.M. (mentor), Delft University of Technology (degree granting institution).

Subjects/Keywords: glacial isostatic adjustment; alaska; little ice age; numerical modeling

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Marsman, C. (. (2020). Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:1589eef9-8265-405a-ba3f-242a7d74e3b1

Chicago Manual of Style (16th Edition):

Marsman, Celine (author). “Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age.” 2020. Masters Thesis, Delft University of Technology. Accessed October 23, 2020. http://resolver.tudelft.nl/uuid:1589eef9-8265-405a-ba3f-242a7d74e3b1.

MLA Handbook (7th Edition):

Marsman, Celine (author). “Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age.” 2020. Web. 23 Oct 2020.

Vancouver:

Marsman C(. Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2020 Oct 23]. Available from: http://resolver.tudelft.nl/uuid:1589eef9-8265-405a-ba3f-242a7d74e3b1.

Council of Science Editors:

Marsman C(. Impact of a 3D compressible Earth structure on glacial isostatic adjustment in Southeast Alaska following the Little Ice Age. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:1589eef9-8265-405a-ba3f-242a7d74e3b1

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