The investigators address North America plate dynamics by modeling the forces applied to the plate and comparing the predicted stresses with those inferred from the style of ongoing tectonics and those observed in drill holes. Modeling is done with the finite element method. Input forces applied to modeled North America include boundary and basal forces, and those generated internal to the plate (arising from potential energy variations such as those created by topography). The relative magnitudes of applied forces are estimated to account for stress and deformation information. Furthermore, because the magnitude of many of the forces applied North America are well known a priori (such as ridge push), the magnitude of all the the applied forces will be well constrained. Tectonic stresses deform North America at a rate inversely proportional to its strength. The investigators model strength with a viscous rheology, which they estimate by ratioing the calculated stress with the (reasonably well known) strain rate. The research can be divided into several tasks: estimation of input fields, description of an appropriate finite element representation of North America, evaluation of model predictions against observables, and as modeling progresses toward resolving the input fields and assessment of their uniqueness. --
