Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Revista Geologica de Chile 233-252 Forearc Neotectonics Strain Stress Quaternaty Central chile Andes 2008 fdi:010042737 SPA Revista Geologica de Chile 0716-0208 ISI:000257954600003 2 10.4067/S0716-02082008000200003 https://www.documentation.ird.fr/hor/fdi:010042737 https://www.documentation.ird.fr/intranet/publi/2008/08/010042737.pdf 35 Horizon (IRD) 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 degrees 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 sigma 1, and a late Quaternary event with sigma 1 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 degrees 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. 064 UR154 Chili