From underplating to delamination-retreat in the northern Apennines

摘要: Abstract Recordings of teleseismic earthquakes from a dense set temporary and permanent broadband seismic stations reveal the lithospheric structure northern Apennines support scenario retreating detachment within mid-crust. Lithospheric delamination appears crucial to formation evolution orogen. Receiver-function (RF) stacks outline continuous west-dipping Ps converted phase positive velocity jump that we interpret as top lower crust mantle Adria continental lithosphere, which is descending into shallow mantle. The correlation seismicity with two RF profiles across suggests distinct stages delamination. Active penetration lithosphere seems evident in south/east, induced shallow-mantle flow facilitated by slab dehydration. Penetration north/west have arrested, possibly marked crustal underplating. This layer atop visible only down 80 km depth suspends above an oppositely-dipping paired positive/negative stacked receiver functions. break conflicts westward-subduction Oligocene. Lateral changes deep along suggest underplating material delamination-retreat are mechanisms active today western eastern sectors, respectively, Apennines. Negative Ps-pulses at 100–120 help define lithosphere–asthenosphere boundary (LAB), but cross-cut volume high-velocity rock, inferred tomographic models. We hypothesize this LAB rheological discontinuity affects frequency band body waves, not long-term viscous response governs eventual slab.