Northern Portugal is located in a tectonically complex area affected by major strike‐slip zones, namely the north‐northwest‐trending Porto–Coimbra–Tomar fault zone and the north‐northeast‐trending Verin–Régua–Penacova sinistral strike‐slip fault. Within this region, the sector between Albergaria‐a‐Velha and Águeda is crucial since it is highly affected by large‐scale strike‐slip faults and extensional deformation events. Late Cenozoic tectonics in northern Iberia resulted from the collision of the Africa and Eurasia plates, especially in the eastern segment of the Azores–Gibraltar plate boundary. The continued plate indentation originated the movement of major strike‐slip faults in the Iberian Massif. The movement on these faults, accompanying the regional stress‐field during the early Miocene, initiated the formation of incipient Cenozoic pull‐apart basins.

The Albergaria‐a‐Velha–Águeda fault segment has been studied in an attempt to clarify the dynamic relationship between this active fault zone and the evolving landscape. Three geomorphological sectors were identified in the Albergaria‐a‐Velha region: (i) a littoral platform consisting of a polygenic erosion surface overlain by late Cenozoic alluvial–fluvial sequences; (ii) a tectonically controlled basin (Valongo do Vouga basin) located between hillslopes of two river valleys and normal faults with N–S orientation, where late Cenozoic subsidence is suggested by an influx of alluvial sandy conglomerates; and (iii) a domain of inner elevations of wide metapelitic landforms. Reactivation of the prevailing north‐northwest‐striking Upper Proterozoic/Palaeozoic basement is a regionally important control on the orientation and kinematics of late Cenozoic faults. Thus, the opening and development of these basins was influenced by the intersection of the north‐northwest‐trending dextral faults with north‐northeast‐trending sinistral faults associated with north–south shortening and east–west extension.