SPACE GEODETIC OBSERVATIONS OF NAZCA-SOUTH AMERICA CONVERGENCE ACROSSTHE CENTRAL ANDES

Space geodetic data recorded rates and directions of motion across the convergent boundary zone between the oceanic Nazca and continental So uth American plates in Peru and Bolivia. Roughly half of the overall c onvergence, about 30 to 40 millimeters per year, accumulated on the lo cked plate interface and can be released in future earthquakes. About 10 to 15 millimeters per year of crustal shortening occurred inland at the sub-Andean foreland fold and thrust belt, indicating that the And es are continuing to build. Little (5 to 10 millimeters per year) alon g-trench motion of coastal forearc slivers was observed, despite the o blique convergence.