Victoria University

Calculation of the Deviatoric Stress Field in New Zealand

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dc.contributor.advisor Savage, Martha
dc.contributor.advisor Lamb, Simon Hirschberg, Hamish 2018-07-20T01:16:45Z 2018-07-20T01:16:45Z 2017 2017
dc.description.abstract I model the vertically averaged deviatoric stress field for New Zealand using velocity and crustal density data. I use a thin sheet model of a viscously deforming lithosphere, averaging over a depth of 100 km and solve the stress balance equation. Two methods of solving the stress balance equation are compared: one method solves first for deviatoric stresses due to gravitational potential energy per unit volume before accounting for deviatoric stresses due to boundary conditions; the other method assumes an isotropic viscosity to relate deviatoric stress to strain rate, solving for the viscosity field. Under synthetic testing, the two step method is able to cope with high levels of noise but contains edge effects. The method solving for viscosity is accurate at low noise levels, however, it is unreliable at high noise levels. I apply the two step method to New Zealand using a Quaternary and a GPS-derived velocity model. Vertically averaged deviatoric stress magnitudes are found to be 10-30 MPa, similar to magnitudes found for other plate-boundary zones. Gravitational and boundary stresses each account for approximately half of the full deviatoric stress. Effective viscosities are found to be 1-10×10²¹ Pa s in the regions of most active deformation, which can be interpreted in terms of the long term strength of the lithosphere controlled by temperature and/or lithology. en_NZ
dc.language.iso en_NZ
dc.publisher Victoria University of Wellington en_NZ
dc.subject Deviatoric stress en_NZ
dc.subject Effective viscosity en_NZ
dc.subject New Zealand en_NZ
dc.title Calculation of the Deviatoric Stress Field in New Zealand en_NZ
dc.type text en_NZ
vuwschema.contributor.unit School of Geography, Environment and Earth Sciences en_NZ
vuwschema.contributor.unit Institute of Geophysics en_NZ
vuwschema.type.vuw Awarded Research Masters Thesis en_NZ Geophysics en_NZ Victoria University of Wellington en_NZ Masters en_NZ Master of Science en_NZ
dc.rights.license Author Retains Copyright en_NZ 2018-07-09T23:37:12Z
vuwschema.subject.anzsrcfor 040402 Geodynamics en_NZ
vuwschema.subject.anzsrctoa 1 PURE BASIC RESEARCH en_NZ

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