Rheological control of subcrustal seismicity in the Apennines subduction (Italy)

Abstract

Different rheological behavior of continental vs oceanic lithosphere can account for the shallower and lower subcrustal seismicity below the northern Apennines with respect to the deeper and more intense seismicity below the Calabrian arc in the south along the same subduction zone. We show that, for equal temperature distribution, oceanic slabs are predicted to display brittle behavior down to depths higher than those predicted for a continental slab. This opposite rheology is likely amplified by the higher strain rates and cooler slab temperatures in the south due to the faster subduction rollback and the oceanic composition of the downgoing lithosphere. Therefore the paucity of seismicity in the central‐northern Apennines might not be related to the absence of the slab, but rather to its continental nature and to lower strain rates.