1 3 Int J Earth Sci (Geol Rundsch) DOI 10.1007/s00531-015-1143-9 ORIGINAL PAPER 3D geometry of growth strata in a fault-propagation fold: insights into space–time evolution of the Crevillente Fault (Abanilla-Alicante sector), Betic Cordillera, Spain I. Martin-Rojas · P. Alfaro · A. Estévez Received: 31 July 2014 / Accepted: 11 January 2015 © Springer-Verlag Berlin Heidelberg 2015 Keywords Growth strata · 3D geometric model · Fault- propagation fold · Bajo Segura Basin · Crevillente Fault (Abanilla-Alicante sector) Introduction Folds that formed in front of propagating faults can pro- vide evidence to assess the rate of fault slip and associ- ated seismic hazard (Stein and King 1984). Moreover, when syntectonic sedimentation occurs, growth strata provide further constraints to the timing and kinematics of deformation. Much of the literature related to fault-related folds and growth sequences concentrates on two-dimen- sional geometric and kinematic modeling (Suppe 1983; Suppe and Medwedeff 1990; Mitra 2002, among many others). However, in recent years, different works have pointed out the usefulness of the 3D geometric recon- struction of geological structures for both industrial and academic spheres (Mencos et al. 2011; Poblet et al. 1998; Salvini and Storti 2002). Such 3D geometric models help unravel not only the along-section but also the continu- ous along-strike evolution of thrust-related folds, which in turn may impose additional constraints to assess their kinematics. Here, we present a 3D model of growth strata from the Bajo Segura Basin northern limit (Betic Cordillera, Spain), this growth sequence deposited in the syncline of a fault-propagation fold pair related to the Crevil- lente Fault (Abanilla-Alicante section) (CF). This 3D model is based on linear interpolation of serial 2D cross sections from detailed surface geologic mapping, avail- able seismic lines, and well data outside the syncline. The analysis of this 3D model combined with detailed biostratigraphic data enables us to interpret the structure Abstract This work presents a 3D geometric model of growth strata cropping out in a fault-propagation fold asso- ciated with the Crevillente Fault (Abanilla-Alicante sec- tor) from the Bajo Segura Basin (eastern Betic Cordillera, southern Spain). The analysis of this 3D model enables us to unravel the along-strike and along-section variations of the growth strata, providing constraints to assess the fold development, and hence, the fault kinematic evolution in space and time. We postulate that the observed along- strike dip variations are related to lateral variation in fault displacement. Along-section variations of the progressive unconformity opening angles indicate greater fault slip in the upper Tortonian–Messinian time span; from the Messin- ian on, quantitative analysis of the unconformity indicate a constant or lower tectonic activity of the Crevillente Fault (Abanilla-Alicante sector); the minor abundance of stri- ated pebbles in the Pliocene-Quaternary units could be interpreted as a decrease in the stress magnitude and con- sequently in the tectonic activity of the fault. At a regional scale, comparison of the growth successions cropping out in the northern and southern limits of the Bajo Segura Basin points to a southward migration of deformation in the basin. This means that the Bajo Segura Fault became active after the Crevillente Fault (Abanilla-Alicante sec- tor), for which activity on the latter was probably decreas- ing according to our data. Consequently, we propose that the seismic hazard at the northern limit of the Bajo Segura Basin should be lower than at the southern limit. I. Martin-Rojas (*) · P. Alfaro · A. Estévez Dpto. de Ciencias de la Tierra y del Medio Ambiente, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, 03690 San Vicente del Raspeig, Alicante, Spain e-mail: Ivan.Martin@ua.es