Descr: The proposed seismic reflection profiles (all together three profiles with a total length of 170 km) are complementary to the active seismic measurements of the SE-Caribbean project (NSF-sponsered project coordinated by Alan Levander, Rice University). The profiles consist of segments of 40 km at 70W, 50 km at 67W and 80 km at 64 W. The Texan instruments will be deployed once along each of the profiles (two times in case of the 80 km long profile) with shots of 100 kg of explosives located each 1-2 km along the profiles and recording intervals between 50 and 100 m. The principal structures to be addressed with these profiles will be the Oca-Ancón, La Victoria and El Pilar faults, comprising the main strike-slip fault system separating the Caribbean and South American plates, as well as the complex structure of the coastal belt. The reflection profiles, which will be co-sponsored by a research project of the Venezuelan National Science Foundation FONACIT (Fondo Nacional de Ciencia, Technología e Innovación) (recently approved as a complementary research project to the SE-Caribbean project), and the National Oil Company PDVSA (Petroleos de Venezuela C.A.). PDVSA has been supporting the NSF-project SE-Caribbean from the beginning, during the planning and execution stages. The main scientific objectives of the SE-Caribbean project are: The intention is to evaluate the hypothesis whether an important part of the growth of the continental crust takes place through the accretion of magmatic island arcs and terranes, and crustal fragments. The boundary between the Caribbean and South American plates forms an example of this type of interaction. Since the Mesozoic the Caribbean has moved towards the east with respect to the South American continent and at present the Lesser Antilles arc is in the process of colliding with the continent. Along the plate boundary there is a transpressional zone of approximately 1000 kilometers length, which resulted in a suite of very complex structures both at the crustal level as well as in the upper mantle. The surface expression of this is represented by metamorphic chains, the Lesser Antilles arc, the Caribbean Mountain System and the foreland fold and thrust belt of the Serranía del Interior. The dating of the tectonic and magmatic events allows the identification of the di! fferent orogenic phases within the system. It is assumed that these started during the Eocene in the west and proceeded to migrate towards the east through time. Through the use of multidisciplinary methods an improved understanding of the geological and geophysical structures will be gained. The knowledge of the processes in the upper mantle will help to understand the mechanisms responsible for plate motions. With integrated models the geodynamic hypotheses will be evaluated. The acquired knowledge will make it possible to improve the localization of earthquakes as well as the seismic risk analysis in the northern part of Venezuela.
