Bibliographical noteFunding Information:
We thank Claudio Faccenna and Wim Spakman for thoughtful and insightful reviews that helped improve the manuscript. Our understanding of the westernmost Mediterranean has greatly benefited from many conversations with John Platt. This work is funded by the PICASSO project (NSF grant EAR-0808939 ), The deployment and data processing for Spanish stations was funded by Consolider-Ingenio 2010 project TOPO-IBERIA ( CSD2006-00041 ) as well as ALERT-ES ( CGL2010-19803-C03-02 ). We thank Ingo Grevemeyer for access to data from the TOPO-MED OBS deployment as wells as Christine Thomas and James Wookey for access to data from Münster and Bristol stations in western Morocco.