RESUMEN:El estudio geologico y estructural detallado de sedimentos recientes en el valle del rio Maipo (Cajon del Maipo), al este de Santiago, muestra la existencia de una deformacion en compresion con fallas inversas y pliegues de arrastre contemporaneos. Estas estructuras son cinematicamente compatibles con una direccion de esfuerzo cercana a N-S (N338°E) que afecta tambien a las unidades de roca mas antiguas (Formacion Abanico), que constituyen el sustrato de las terrazas aluviales cuaternarias. En estas rocas del sustrato, se superponen dos episodios de deformacion, el primero de edad neogena (post 9 Ma), caracterizado por un al de direccion E-O; el segundo cuaternario y con un al cercano a N-S. Este ultimo episodio de deformacion resultaria de la particion regional del vector de convergencia oblicua entre las placas de Nazca y Sudamerica; un 'buttress' a los 33°S produciria el gradiente de velocidad latitudinal necesario en el antearco para conducir a un acortamiento norte-sur. La sismicidad cortical superficial en la parte interna del antearco (Cordillera Principal) es -al menos en parte- compatible con la direccion de compresion obtenida a partir del analisis cinematico de las fallas mesoscopicas.ABSTRACT:A detailed study of recent sediments in the Maipo River Valley (Cajon del Maipo), east of Santiago, shows a compressive deformation documented by coeval reverse faults and drag-folds. These structures are characteristic of a principal stress direction trending roughly N-S (N338°E) that also affects the older sediments of the Abanico Formation constituting the bedrock of the Quaternary alluvial terraces. Two deformation episodes are superposed in the bedrock: a Neogene deformation event (post 9 Ma), having an E-W-trending al, and a late Quaternary event with al roughly trending N-S. The latter would be the result of regional-scale partitioning of the oblique convergence vector between the Nazca and South American Plates; a buttress at 33°S would produce a north-south velocity gradient in the forearc leading to regional, north-south shortening. Shallow crustal seismicity in the inner forearc (Main Cordillera) is -at least in part- compatible with the compression direction as obtained from the kinematic analysis of mesoscopic fault-slip data.A detailed study of recent sediments in the Maipo River Valley (Cajón del Maipo), east of Santiago, shows a compressive deformation documented by coeval reverse faults and drag-folds. These structures are characteristic of a principal stress direction trending roughly N-S (N338°E) that also affects the older sediments of the Abanico Formation constituting the bedrock of the Quaternary alluvial terraces. Two deformation episodes are superposed in the bedrock: a Neogene deformation event (post 9 Ma), having an E-W-trending al, and a late Quaternary event with al roughly trending N-S. The latter would be the result of regional-scale partitioning of the oblique convergence vector between the Nazca and South American Plates; a buttress at 33°S would produce a north-south velocity gradient in the forearc leading to regional, north-south shortening. Shallow crustal seismicity in the inner forearc (Main Cordillera) is -at least in part- compatible with the compression direction as obtained from the kinematic analysis of mesoscopic fault-slip data.