Mann, Paul¹ and Calais, Eric²

¹University of Texas at Austin
²Purdue University

Before the advent of GPS-based geodesy, active tectonic processes around the Caribbean plate were dimmly perceived from maps of earthquake epicenters, focal mechanisms of larger, teleseismically, and fault and fold-related deformation of late Neogene sedimentary rocks. These methods provided the basic structure of the Caribbean plate although in some cases subtle late Quaternary faults bounding the plate evaded detection until their catastrophic rupture during great earthquakes. GPS results collected since 1989 have provided insights into tectonic processes that previous geologic studies either were incapable of recognizing or only hinted at. This talk uses a total of about 100 GPS vectors collected by a variety of workers to illustrate three key tectonic processes affecting the active Caribbean plate margins. The GPS vectors are displayed in various of frames of reference to highlight the three processes:

- Indentation and convergent strain partitioning and forearc slivers in the northern Caribbean and the Pacific margin of Central America

- Indentation and tectonic escape in northwestern South America

- Divergent strain partitioning and arc disruption in northern Central America

Understanding these processes leads to more effective strategies for evaluating seismic hazards and producing realistic models for the physical processes controlling the deformation.