North America Dynamics and Western U. S. Deformation

点击翻译按钮获取中文摘要

EAR-0106892Eugene D. HumphreysThe investigators address North America plate dynamics by modeling the forces applied to theplate and comparing the predicted stresses with those inferred from the styleof ongoing tectonics and those observed in drill holes. Modeling is done withthe finite element method. Input forces applied to modeled North Americainclude 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 stressand deformation information. Furthermore, because the magnitude of many of theforces applied North America are well known a priori (such as ridge push), themagnitude of all the the applied forces will be well constrained. Tectonicstresses deform North America at a rate inversely proportional to its strength.The investigators model strength with a viscous rheology, which they estimate by ratioing thecalculated 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 progressestoward resolving the input fields and assessment of their uniqueness.--