The fossil shorelines of the Chilean coast reflect interseismic as well as coseismic movements. The earthquake record is further obscured by the variable pattern of coastal deformation that accompanies large earthquakes, such as the longitudinal warping associated with the 1960 Valdivia (Mw= 9.5) earthquake. The number of events recorded is a minimum, as relaxation can lead to the reoccupation of shorelines, and paleoearthquake magnitude cannot be determined with confidence, as the amount of uplift or subsidence depends on location within the deformed zone and on the timing of the measurements during the deformation cycle. However, provided radiometric dating makes it possible to discriminate between successive earthquakes, variations in the amount of uplift can be used for modeling the deformation numerically to the ultimate benefit of seismic hazard assessment.