The motion of the Northern Lesser Antilles region with respect to the stable Caribbean from GPS geodesy

St. Kitts and Nevis Islands are part of the northern volcanic Caribbees in the Lesser Antilles (LA) region. Little quantitative data exist on arc kinematics and its relationship to the stable interior of the Caribbean plate. Data from GPS geodetic campaign sites from 1998, 2000, and 2001 constrain the motion of the LA at the latitude of St. Kitts and Nevis Island with respect to stable North American (NA) towards N43°E +/− 14.02° with a magnitude of 16.4 +/− 3.11 mm/yr at the 67% confidence level. In a fixed NA reference frame, the velocities derived by the GPS suggest that LA is moving together with the Caribbean plate, but velocities derived in a Caribbean fixed frame show differential motion between the LA islands and the stable Caribbean plate. The cause of residual motion with respect to CA is related to a complex driving mechanism which reflect both tectonic and volcanic deformation. The information obtained in this project reveal that the kinematics and tectonics of this area are not so simple and a more robust data will be necessary to support a better understanding of this part of the Caribbean.