Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

334 PATA Days 2024 R E S U LT S / D I S C U S S I O N The SARF consists of a northeast-southwest trending, fault- related fold extending approximately 40 km from the Mers El Hadjadj coastal zone to the El Hamoul locality (Fig. 1b). This structure deforms the Quaternary deposits of the Boufatis plateau (Fig. 1b). Observations suggest that the SARF comprises at least three segments separated by east-west right-lateral slip faults, resulting in a characteristic "S-shaped" fold pattern. The inferred right-lateral strike-slip faults in the study area are concordant with the continuity of the Offshore Yussuf Fault system within the continental part of the Oranie (YF in Fig. 1a). The role of strike- slip faulting at regional scale in north western Algeria has been suggested by many authors (Mustapha Meghraoui & Pondrelli, 2012; Thomas, 1976). The SARF fold exhibits a strong asymmetric aspect with a steeper southwestern limb capped by a surface expression of a northwest-dipping reverse fault (Fig. 6b). This fault flanks an elongated synclinal structure containing a central, enclosed Salt Lake (i.e., Arzew Saline). During the Quaternary period, this depression functioned as a valley with a river system that flowed towards the sea (Gourinard, 1958). However, progressive folding activity during the upper Quaternary subsequently dammed the river (Fig. 1b). The Arzew Saline syncline is followed by a box fold with two steep limbs, with the eastern limb bordering the Habra plain without any apparent faulting. This structural pattern is observed at various scales throughout the study area (Fig. 2). Fig. 1: Tectonic and Seismotectonic Setting of the Oranie region: (a) Regional tectonic context: this map shows the location of the Oranie region (NW Algeria) within the western end of the Alpine orogeny in North Africa. Key zones include: (1) Internal Zones, (2) Tell-Rif-SubBetic Domain, (3) Meseta and Stable Domains, (4) Atlas Domain, (5) Flysch Units, and (6) Basins. Red lines depict active faults in the Alboran Sea and the Algerian Tell, YF=Yussuf Fault. (b) Local Seismotectonic Setting: This map shows the northern Oranie basin and the main neotectonic features identified during this study.