During late Cenozoic thrusting, the interior of the peri-Tyrrhenian orogenic belt in the southern Apennines underwent two episodes of nearly orthogonal extension. Early extension was oriented subparallel to the axis of the tectonic belt and formed in response to progressive thrust-belt arcuation. The length of the tectonic belt increased by ∼50%, and the longitudinal strain was accommodated by low-angle normal faults concentrated in tectonic domains recording up to 150%-200% extension. Younger extension, oriented at a high angle to the orogen, was accompanied by Pliocene-Pleistocene uplift and by southeasterly migration of Tyrrhenian Sea rifting.