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In typical subduction systems, plate convergence is subperpendicular to the trench. The Gibraltar Arc System is exceptional, with its narrow subduction arc oriented N‐S and laterally "squeezed" by the NNW‐SSE tectonic convergence between Nubia and Iberia. The extent to which the slab is still coupled to the surface and how it interacts actively with the surrounding mantle is a matter of ongoing debate. Here, we analyze new densely spaced GPS data, together with crustal and mantle observations, to better understand the slab kinematics, plate dynamics, and mantle flow. In light of previous and current research, we find that subduction below the Gibraltar Arc is currently in the middle of a disruption process, with parts of it already detached and others yet coupled to the surface. In particular, the slab seems to be detached to the north of the Gibraltar Strait, with a small portion still attached to the surface or in the process of detaching below the western Betics. South of Gibraltar, the slab is still coupled to the overriding plate, although the subduction seems to be very slow or stopped. Flow of mantle material around the detached portions of the slab causes most of the surface uplift and a positive residual topography anomaly. Our findings show that the interplay between slab dynamics, mantle flow, and plate convergence explains much of the observed residual topography, surface motion, seismicity, and mantle structure. Key Points: The Gibraltar subduction is undergoing a phase of progressive lateral disruption, with some segments still attached to the surface in the Rif and western BeticsThe slab appears segmented into two domains, one north and the other south of the Gibraltar strait; the segmentation is likely driven by Eurasia‐Nubia convergenceMantle flow around the slab seems still active and causing most of the surface uplift, although the slab is not retreating anymore [ABSTRACT FROM AUTHOR]

We discuss crustal surface velocities in the Gibraltar Arc System derived from around 150 GPS sites in Iberia and Morocco operating between 1995 and 2018. The estimated velocity field shows patterns that are strongly correlated with other geophysical constraints (tomographically imaged velocity anomalies, SKS-splitting, etc.) including seismicity patterns. Broad-scale surface uplift characterizes the Rif-Betics belts, which appear underlain by seismically slow, presumably relatively hot, mantle. Significant rates of subsidence are observed around Cartagena and east of El Hoceima where high-velocity seismic anomalies are imaged in the mantle. This abrupt change of the sign of vertical crustal motions coincides with the location of the Trans-Alboran Shear Zone (TASZ), which is marked by lineaments of mostly strike-slip and trans-tensional shallow earthquakes. We interpret the surface uplift as result of the quasi-toroidal mantle flow induced by the interaction of the retreating Gibraltar slab and the resulting sub-slab upwelling. The part of the Gibraltar slab that is still attached to the crust imaged east of the TASZ may contribute to the observed subsidence rates. The trend of the residual topography also suggests that topography may be controlled in part by mantle-driven processes. Around the Gibraltar slab the contrasting signal between the negative residual topography and positive vertical GNSS data is likely due to the fact that the surface, which was previously depressed by the load of the subduction, is now isostatically recovering. Our results on the Gibraltar Arc System suggest that both surface deformation along the arc and shallow earthquake activity are strongly controlled by coupling between the lithosphere and underlying mantle dynamics. [ABSTRACT FROM AUTHOR]