Influence of early strike-slip deformation on subsequent perpendicular shortening: An experimental approach

We used sandbox analogue models to study the influence of previous pure strike-slip and transpressional structures on subsequent perpendicular compression. We performed also a brittle–viscous system in order to analyse the presence of a viscous basal level. Experimental results show that a previous pattern generated under pure strike-slip and transpressive regime causes the reactivation of structures with favourable orientation and the nucleation of oblique thrusts and non-rectilinear deformation fronts under compression perpendicular to the first fault system. The presence of a viscous basal level with the imposed strain rate, which does not favour the coupling between the viscous layer and cover, inhibits the reactivation of previous structures. Comparison with a sector of Northern Chile margin (24–25°S), located in the forearc trench-parallel region supports the experimental results.