A set of observations on site effects and damage patterns from the M w 8.8 Maule, Chile, earthquake is presented, focusing on identification of structural damage variability associated with nonuniform soil conditions and subsurface geology. Observations are reported from: (1) the City of Santiago de Chile (Américo Vespucio Norte Ring Highway, Ciudad Empresarial business park), (2) the Municipality of Viña del Mar, and (3) the City of Concepción, extending over 600 km along the Chilean coast. Reconnaissance information and ground motion recordings from the megathrust event are combined with site investigation data in the regions of interest. Comparisons against macroseismic observations related to uneven damage distribution from the M w 8.0 1985 Valparaíso earthquake are discussed. Complexities associated with identifying the mechanics and underlying physical processes responsible for the manifestation of these effects are elucidated.