Imaging the Low Dip Onset of the Gibraltar Arc Subduction in the Gulf of Cádiz Using OBS Receiver Functions Parera Portell, Joan Antoni Mancilla Pérez, Flor de Lis Morales Soto, José Stich, Daniel Geissler, W. H. Silveira, G. Tomography Seismometers Oceanic crust We acknowledge funding by the Spanish national projects PID2023‐150188NB‐I00 and PID2019‐109608GB‐I00 (Spanish Research Agency, MCIN/AEI/10.13039/ 501100011033) and the FPI Grant PRE2020‐092556 (Spanish Research Agency and the European Social Fund). We thank the NEAREST project team (http://nearest.bo.ismar.cnr.it/) and the people behind the 3D, ES, GE, IB, LX, MN, PM, WM, XB, ZC and ZI seismic networks, as well as the Editor and the two anonymous reviewers. We acknowledge use of the softwares SAC (Goldstein & Snoke, 2005), ObsPy (Krischer et al., 2015) and GMT (Wessel et al., 2019) Using P and S‐wave receiver function analysis we investigate the lithospheric structure in the Gulf of Cádiz through a combination of ocean‐bottom seismometers and onshore seismic stations located in southwest Iberia and northwest Africa. By applying common conversion point migration with custom earth models accounting for the marine sediment layer, we imaged the Gibraltar–Alboran slab in a low‐dip subduction geometry. Both the oceanic Moho and lithosphere‐asthenosphere boundary were identified, picturing an oceanic lithosphere approximately 125 km thick. The onset of subduction occurs near the Horseshoe fault, at approximately 10 ° W, where the slab begins to descend. At ∼ 4.5 ° W, the slab bends into an almost vertical direction, coincident with the location of intermediate‐depth seismicity. Beneath the western Gibraltar Arc the underthrusted paleomargins of both Iberia and Nubia appear to be fully preserved and still connected to a narrow section ( ∼150 km) of oceanic crust. 2025-11-28T11:54:25Z 2025-11-28T11:54:25Z 2025-12-16 journal article Parera‐Portell, J. A., Mancilla, F., Morales, J., Stich, D., Geissler, W. H., & Silveira, G. (2025). Imaging the low dip onset of the gibraltar arc subduction in the gulf of cádiz using OBS receiver functions. Geophysical Research Letters, 52(23), 10. doi:https://doi.org/10.1029/2025GL117817 https://hdl.handle.net/10481/108452 10.1029/2025GL117817 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional John Wiley & Sons