GPS estimate of relative motion between the Caribbean and South American plates, and geologic implications for Trinidad and Venezuela

Global Positioning System (GPS) data from eight sites on the Caribbean plat e and five sites on the South American plate were inverted to derive an ang ular velocity vector describing present-day relative plate motion. Both the Caribbean and South American velocity data fit rigid-plate models to withi n +/-1-2 mm/yr, the GPS velocity uncertainty. The Caribbean plate moves app roximately due east relative to South America at a rate of similar to 20 mm /yr along most of the plate boundary, significantly faster than the NUVEL-1 A model prediction, but with similar azimuth, Pure wrenching is concentrate d along the approximately east-striking, seismic, El Pilar fault in Venezue la. In contrast, transpression occurs along the 068 degrees -trending Centr al Range (Warm Springs) fault in Trinidad, which is aseismic, possibly lock ed, and oblique to local plate motion.