Large magnitude earthquakes are an intrinsic hazard of active tectonic coastlines. These events result from deformation of the Earth's crust produced by the continual movement of tectonic plates. The particular style of deformation occurring along a plate boundary reflects the geometry and rates of local plate interactions. Uplifted marine terraces along tectonically active coasts represent ancient, abandoned shorelines that record the distribution and rates of coastal deformation (Bull, 1985; Lajoie, 1986). As deformation progresses through time, paleo-shorelines are uplifted, tilted, and warped through successive earthquake cycles. These features therefore, serve as important geomorphic indicators of subduction parameters and of earthquake hazards. The principal goal of the proposed research is to constrain the distribution and rates of coastal deformation along several known seismogenic segments of the Middle America margin in northern Costa Rica. This work will provide important insights into the deformation style and earthquake periodicity of this region.