Well, that is the headline at http://phys.org/print290673740.html …. but it emerges that what has been found is an active tectonic zone to the west of Portugal – or rather, a reaffirmation that a fault line exists out in the sea which was responsible for the 1755AD Lisbon earthquake and tsunami.
The idea of an embryo subduction zone comes from some hopeful geologists in an article in Geology where speculation is heaped on the discovery of a fracture zone on the sea floor. Conveniently, for the authors, if it is a subduction zone in the making they can't be disproved, not in their lifetime, or many millions of years (in a uniformitarian model). It is assumed to be an exceedingly slow process.
On the Plate Tectonics model this is exciting as computer simulations will quickly be dreamed up that shift this block of land, including Iberia itself, around, shrinking the Atlantic basin, and doing all sorts of whizzy things – on the screen.