Active Fragmentation of Adria, the North African Promontory Central Mediterranean Orogen.

Global Positioning System (GPS) velocities indicate that the circumthyrrenian region (part of Mesozoic Adria) is divided into northwestern and southeastern velocity domains. Differential motions are recognized in a velocity field determined from Peri-tyrrhenian Geodetic Array (PTGA) and International GPS Service (IGS) sites in the circum-tyrrhenian region. In a fixed Eurasian reference frame, PTGA and IGS site velocities in Sicily and Southern Italy are as much as 10 mm/y in a northward direction. In contrast, velocities in Northen Italy are small and similar to velocities in Sardinia and Corsica. The tectonic boundary dividing Adria is seismically active and passes around the southern and eastern margins of the Tyrrhenian Basin, crosses Central Italy and extends into the Adriatic Sea. Southeastern Adria has a velocity related to northward motion of Africa, whereas northwestern Adria now is part of the Alpine collage of Southern Europe.