We estimate several scenarios for source models of megathrust earthquakes likely to occur on the Nazca- South American plates interface in southern Peru. To do so, we use a methodology for estimating the slip distribution of megathrust earthquakes based on an interseismic coupling (ISC) distribution model in subduction margins and on information about historical earthquakes. The slip model obtained from geodetic data represents large-scale features of asperities within the megathrust that are appropriate for simulating long-period waves and tsunami modelling. To simulate broadband frequency strong ground motions, we add small scale heterogeneities to the geodetic slip by using spatially correlated random noise distributions. Using these slip models and assuming several hypocenter locations, we calculate a set of strong ground motions for southern Peru and incorporate site effects obtained from microtremors array surveys in Tacna, the southernmost city in Peru.