The Rif Cordillera, located in North Morocco forms, together with the Betic Cordillera, the Gibraltar Arc around the Alboran Sea. This asymmetric curved mountain belt originated during a Miocene continent-continent collision as a result of the westward motion of the Alboran domain between northwest Africa and Iberia. The complexity of the area favored the proposition of diverse tectonic models, poorly constrained by available geophysical data. Previous numerical models that integrate both elevation, geoid and gravity anomalies assuming local isostasy suggest a poorly marked orogenic root beneath the Rif Cordillera, whereas a recent receiver function study from Topo-Iberia project reveals large variations of at least 10 km in crustal thicknesses under northern Morocco, similarly to values obtained in station terms from a Pn tomography. In order to constrain the seismic velocity structure of the Rif Cordillera and to delineate the Moho topography, in October 2011, within the Spanish project RIFSIS complemented by the US-PICASSO one, wide-angle reflection and refraction seismic data were acquired for the first time along two 330 km-length profiles, oriented respectively N-S and E-W. The N-S line was extended northwards by a 70 km long segment in Spain, along the Betics. Southwards, this profile connects with the one recorded in 2010 across the Atlas Mountains (SIMA project), hence delineating a 700 km-long wide-angle seismic transect across the Betic-Rif-Atlas systems. Seismic energy released at 5 shot points was generated by the detonation of 1 TN of explosives and was recorded by ~ 900 Texans stations from the IRIS-PASCAL pool, with an average station spacing of about 750 m. Crustal phases Pg, PcP and PiP and Moho reflected PmP phases are clearly identified in the processed datasets. Preliminary analyses by forward modeling already reveal the existence of major variations in crustal thicknesses, especially along the E-W profile that documents differences of about 20 km in Moho depths. The thickest crust is found beneath the external Rif domain, with a rapid thinning eastwards, in the foreland and Atlasic terranes up to the Algerian border. A complementary operation involving onshore-offshore recordings in Spanish and Moroccan sides of the Western Alboran Basin could be performed in parallel, taking advantage of a marine multichannel seismic experiment ongoing in the Alboran Sea during the same period.

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