The general goals of the project are to continue GPS measurements of deformation in the South American Andes, and to integrate deformation with the earthquake cycle and with coupling on the subduction zone and longer-term tectonic deformation. The importance of the research is that it examines fundamental mechanisms behind how subduction created the modern Andes and deformed this continental margin. Specific research tasks include: obtaining and analyzing GPS data from Chile, Argentina, and Bolivia and coordinating with other GPS efforts in South America; expanding the principal investigator's GPS network; looking at back-arc deformation and at the post-seismic effects of the 1960 earthquake; and improving velocity estimates. The P.I.s will model longer term deformation (tectonic deformation) associated with the stress history of subduction and mantle coupling in the wedge. They will model various tractions arising from the edge of the lithosphere, the base of the plate, larger scale mantle flow, plate motions and basal forces. They will examine the distribution and nature of seismic deformation related to subduction in both the lithosphere and crust, especially the 1960 earthquake, and the deformation associated with oblique convergence.
This combination of the GPS measurements and mantle flow modeling is an attempt to understand the fundamental mantle forces that shape convection at an archetypal convergent continental margin. The multifaceted approach (GPS, seismology, modeling) will integrate the various geodynamic components into a comprehensive model of the mountain building process. ***