Joint inversion of the kinematics and dynamics of the North American plate
Finite element models are presented in this paper to study the kinematics and dynamics of the North American plate. The plate is represented by a portion of thin spherical shell modeled with Newtonian fluid. The external actions acting at the plate boundary as well as on the plate bottom are express...
| Published in: | Tectonophysics |
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| Main Authors: | , |
| Other Authors: | , |
| Format: | Journal/Newspaper |
| Language: | English |
| Published: |
tectonophysics
1999
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| Subjects: | |
| Online Access: | https://hdl.handle.net/20.500.11897/214604 https://doi.org/10.1016/S0040-1951(98)00290-X |
| Summary: | Finite element models are presented in this paper to study the kinematics and dynamics of the North American plate. The plate is represented by a portion of thin spherical shell modeled with Newtonian fluid. The external actions acting at the plate boundary as well as on the plate bottom are expressed by a set of undetermined parameters in terms of the results of the Nuvel-1 model. The plate viscosity is considered as regionally uniform. Constrained by the observed data of principal stress orientation and VLBI velocity, the tectonic deformations and stresses in the North American plate as well as the driving forces are jointly inverted. By the method of least squares and the principle of linear superposition, the inversion is posed as a standard nonlinear optimization problem, which is solved numerically by the genetic algorithms combined with a kind of quasi-Newtonian method. The computed results show that some of our simple dynamic models can well and consistently fit the observed kinematic and dynamic data, even though the data have very different time scales. The data fitting indicates that continental lithosphere is an order of magnitude more viscous than oceanic lithosphere which, in turn, is an order of magnitude more viscous than lithosphere in plate boundaries, including the diffuse plate boundary in the western United States. In the middle part of the plate, the predicted tectonic stresses are uniform both in orientation and magnitude, with a typical regime of strike-slip type. The modeling results suggest that the plate motion is driven by forces acting along the Atlantic and Arctic ridges, the South American boundary, the Caribbean boundary and the San Andreas fault, while resisted by forces acting along the other boundary segments and by the viscous drag forces at the base of the plate. (C) 1999 Elsevier Science B.V. Al rights reserved. Geochemistry & Geophysics SCI(E) 4 ARTICLE 3-4 173-201 302 |
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