Abstract On the eastern margin of the Panama Basin, the Nazca oceanic plate converges towards the continental plate of South America at approximately 53 mm a −1 . Subduction processes are accompanied by the presence of anomalous bathymetric elements including the Sandra Ridge. This east–west-orientated ridge is catalogued as an aborted rift derived from a magmatic spreading axis that was active between 12 and 9 Ma. Seismic activity within this structure is considered evidence of fault reactivation and tectonism. Once the structure reached the subduction trench several submarine landslides were triggered. Run-out lengths of these submarine landslides are perpendicular to the convergence of the structure with some units spreading and forming a wide fan that reaches tens of kilometres to the north and south of the trench. The area affected by the three main landslides varies between 130 and 300 km 2 approximately, with relatively superficial earthquakes (<33 km) and with magnitudes that reach up to M w 7.2. The morphology of the landslides suggests a retrogressive nature with younger events proximal to shore. This paper presents estimates of the age of these landslides and discusses sources of uncertainty regarding these times of occurrence.

ABSTRACT The present-day structure of the Neuquén Basin is the result of the deformation of the sedimentary column through a poly-episodic tectonic history. The initial stage was dominated by extension with a general northeast–southwest direction during the Early Jurassic. The resultant structures were a widespread distribution of northwest–southeast striking grabens and half-grabens defined as the Rift stage. Subsequently, different stages of convergent tectonics took place with different directions of convergence vectors, reactivating and inverting the previous extensional structures and creating new ones. The most important stages were the Aluk stage (Early Jurassic-Early Cretaceous), the Farallon stage (Cretaceous), and the Nazca stage (Cenozoic). The tectonic pulses produced distinctive megastructures that affected the early Tithonian to early Valanginian Vaca Muerta Formation, such as the Chihuidos High, the Huincul High, and the Agrio fold-and-thrust belt. Also, multiple fault systems forming kilometer-scale features were created. The main fault systems affecting the Vaca Muerta–Quintuco system are classified according to the Anderson classification: normal, reverse, and strike-slip faults. The following fault families are identified: five normal fault families (northwest–southeast, east-northeast–west-southwest, north-northeast–south-southwest, north-south, and radial), five reverse (high-angle) fault families (east–west, northeast–southwest, north–south, north-northeast–south-southwest, and circular), two thrust (low-angle) fault families (north-northwest–south-southeast and north-northeast–south-southwest), and one strike-slip fault family (east-northeast–west-southwest). The geometrical characteristics, orientations, and distribution of these Vaca Muerta fault families are presented and the interpretation of their genesis is discussed. Second-order structures such as volcanic dikes and sills, soft-sediment deformations and accomodation/transfer zones that participate to the deformation of the Vaca Muerta-Quintuco system are also described because they also affect the unconventional self-sourced play. Finally, some structural aspects of the Chihuidos High, the impact of the inheritance on the Vaca Muerta–Quintuco structures (geometry, orientation, and distribution) and the Structural Risk Analysis are discussed.