2D and 3D analogue modelling of extensional fault structures; templates for seismic interpretation

Abstract

Scaled analogue models of 2D and 3D extensional fault systems provide powerful templates for the seismic interpretation of complex fault structures. 2D sandbox models of extensional faults that link to a lower detachment surface are characterized by roll-over structures together with crestal collapse graben and antithetic fault systems. The geometry of the roll-overs are controlled by the shape of the main detachment surface. 3D extensional fault systems in sandbox models of orthogonal and oblique rift systems are characterized by segmented planar fault systems that grow along strike, link, and overlap forming relay ramp structures and accommodation zones. In orthogonal rifts the border faults and the intra-rift faults are oriented at high angles to the extension direction. In oblique rifts the border faults are parallel to the zone of rifting whereas the intra-rift faults are oriented at a high angle to the extension direction.