Topo-Iberia CGPS network: A new 3D crustal velocity field in the Iberian Peninsula and Morocco based on eleven years (2008–2019)

Résumé

Topo-Iberia network covering the Spanish part of the Iberian Peninsula and Morocco was established in 2008. After the first publication in 2015 of the horizontal velocity field based on the analysis of the first four activity years (2008–2012), a new 3D velocity field based on eleven years (2008–2019) is presented in this paper. Double-differencing technique with GAMIT software and precise point positioning (PPP) technique with GipsyX software are used for GPS processing obtaining loosely constrained solutions, and the methodology merging both solutions within a Kalman filter (GLOBK) is exposed. Position time series analysis carried out is described and results obtained by each processing strategy are compared. The combined velocity solution is presented in this paper as the new horizontal velocity field and the first vertical velocity field of Topo-Iberia CGPS network. A global view of Topo-Iberia stations quality for the processed period is also presented for the first time. The results are in good accordance with previous publications except in Betic Cordillera. Smallest and highest residual displacements with respect to Eurasia occur in northern Iberia and Morocco respectively. The results could confirm that a clockwise block rotation would have been occurring at present in the northern branch of the Gibraltar Arc, which present-day undergoing a northwest-southeast convergence rate of 3.6 mm/yr. A general low subsidence is observed in the Iberian Peninsula except for some isolated stations presenting uplift.