Stress field

About: Stress field is a research topic. Over the lifetime, 11926 publications have been published within this topic receiving 226417 citations.

Eigenstrain analysis of residual strains and stresses

Abstract: Experimental stress evaluation procedures often rely on the measurement of some component(s) of elastic strain followed by point-wise calculation of stress based on continuum elasticity assumptions. Such point-wise assessments are, however, incomplete and not entirely satisfactory, as calculations conducted for different points can easily give rise to values that may not satisfy requirements of global force balance. The real purpose of experimental data interpretation is in fact to obtain a reasonably internally consistent description of the state of stress everywhere in the object to the greatest possible level of detail. What is usually being sought is a residual-stress-admissible (RS-admissible) field, i.e. such that would satisfy boundary conditions imposed both in terms of tractions and displacements, and would correspond to a divergence-free stress field (i.e. such that satisfies stress equilibrium conditions everywhere). Note, however, that elastic strains are no longer required to be compatible. T...

The effect of stress on faulting and minor intrusions in the vicinity of a magma body

Abstract: The stress field in the vicinity of a body of fluid of simple geometry contained within a non-homogeneously stressed solid has been calculated and the result applied to the case of a magma body within a region of the crust subject to triaxial stresses. The types of faulting and minor intrusion which result are described.

Predicting the lithospheric stress field and plate motions by joint modeling of lithosphere and mantle dynamics

Abstract: The way in which basal tractions, associated with mantle convection, couples with the lithosphere is a fundamental problem in geodynamics. A successful lithosphere-mantle coupling model for the Earth will satisfy observations of plate motions, intraplate stresses, and the plate boundary zone deformation. We solve the depth integrated three-dimensional force balance equations in a global finite element model that takes into account effects of both topography and shallow lithosphere structure as well as tractions originating from deeper mantle convection. The contribution from topography and lithosphere structure is estimated by calculating gravitational potential energy differences. The basal tractions are derived from a fully dynamic flow model with both radial and lateral viscosity variations. We simultaneously fit stresses and plate motions in order to delineate a best-fit lithosphere-mantle coupling model. We use both the World Stress Map and the Global Strain Rate Model to constrain the models. We find that a strongly coupled model with a stiff lithosphere and 3-4 orders of lateral viscosity variations in the lithosphere are best able to match the observational constraints. Our predicted deviatoric stresses, which are dominated by contribution from mantle tractions, range between 20-70 MPa. The best-fitting coupled models predict strain rates that are consistent with observations. That is, the intraplate areas are nearly rigid whereas plate boundaries and some other continental deformation zones display high strain rates. Comparison of mantle tractions and surface velocities indicate that in most areas tractions are driving, although in a few regions, including western North America, tractions are resistive. Citation: Ghosh, A., W. E. Holt, and L. M. Wen (2013), Predicting the lithospheric stress field and plate motions by joint modeling of lithosphere and mantle dynamics.

Deformation of the subducted Indian lithospheric slab in the Burmese arc

Abstract: [1] Stress inversion of focal mechanism data in the Burmese arc region indicates distinct stress fields above and below 90 km along the subducted Indian lithospheric slab. In the upper part, the σ1 and σ3 axes trend NNE and ESE respectively, in conjunction with the ambient stress field of the Indian plate. However, in the lower part of the slab there is no preferred orientation of the σ1 or σ2 axes, but a very well defined σ3 axis is observed, that trends steeply in the down-dip direction. It is inferred that while the upper part is governed by the NNE oriented horizontal plate tectonic forces, the lower part is governed entirely by tensile forces due to gravitational loading on the subducted slab. A model of attempted slab detachment at the base of the lithospheric contact zone is suggested, which is supported by results of high-resolution seismic tomographic studies in this region.