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In W-dipping subduction zones there is a general eastward progression of the back-arc basin-accretionary wedge-foredeep complex. With the forward progression, early stages of the complex are revealed by slices of upper crust and sedimentary cover abandoned to the west left floating above a new section of mantle. A major shear zone should form at the new Moho separating upper crust slices of earlier accretionary stages and the eastward flowing mantle. The mantle wedgingat the top of the subduction plane could be responsible for the uplift of the central parts of the belt. The retreating of the subduction hinge is interpreted as due to the push generated by the 'eastward mantle flow detected in the hot spot reference frame. The foredeep depth is mainly a function of the radius of curvature of the subduction hinge. The frontal wedge is constructed from the stacking of the upper layers of the subducting plate and the syntectonic clastics that fill the foredeep which are progressively involved in thrusting and later by extension. In order to preserve volume balance, the lithosphere of the eastern plate before subduction has to be the same size as that which has been subducted: due to the longer length of the arc with respect to the original length of the linear margin between the two converging plates, laterally stretched subducted lithosphere is predicted at depth. W-dipping subductions usually have a short life probably due to their inherent capability to produce new lateral heterogeneities of the lithosphere (the thin back-arc) which are a key factor in controlling and generating new subductions (both Eand W-dipping). This model is applied to the Apennines-Tyrrhenian Sea system. Terra Nova, 3,423-434 della tettonica globale, Le Scienze, 270, 32-42. Doglioni., Moretti I. and R o w F. (1991) Basal lithospheric detachment, eastward mantle flow and Mediterranean Geodynamics: a discussion, 1. Geodyn., 13,l. Elter P., Giglia G., Tongiorgi M. and Trevisan L. (1975) Tensional and compressional areas in the recent (Tortonian to present) evolution of the Northern Apennines, Boll. Geofis. Teor. A w l . , 17, 3-18. NOW, 2,577-584. ~ ~ ~ ~~ ~ ~ ~

We investigate a large geodetic data set of interferometric synthetic aperture radar (InSAR) and GPS measurements to determine the source parameters for the three main shocks of the 2016 Central Italy earthquake sequence on 24 August and 26 and 30 October (Mw 6.1, 5.9, and 6.5, respectively). Our preferred model is consistent with the activation of four main coseismic asperities belonging to the SW dipping normal fault system associated with the Mount Gorzano‐Mount Vettore‐Mount Bove alignment. Additional slip, equivalent to a Mw ~ 6.1–6.2 earthquake, on a secondary (1) NE dipping antithetic fault and/or (2) on a WNW dipping low‐angle fault in the hanging wall of the main system is required to better reproduce the complex deformation pattern associated with the greatest seismic event (the Mw 6.5 earthquake). The recognition of ancillary faults involved in the sequence suggests a complex interaction in the activated crustal volume between the main normal faults and the secondary structures and a partitioning of strain release.

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The Apenninic foreland shows two distinct structural signatures comparing the central Adriatic Sea and the Puglia region. During the Pliocene‐Pleistocene the central Adriatic underwent high subsidence rates due to the eastward rollback of the hinge of the west dipping Apenninic subduction. The Puglia region and the Bradanic foredeep are located southward along strike in the same foreland, but, in contrast with the central Adriatic, after Pliocene‐early Pleistocene subsidence they underwent uplift since the middle Pleistocene. The geometry and the kinematics of the frontal accretionary wedge and related foreland changed from that moment on between the two areas. At the front of the central northern Apennines, off scraping and subsidence continued, whereas the foredeep and foreland of the southern Apennines were buckled. Those differences are interpreted as being due to the larger subduction hinge rollback rate since middle Pleistocene of the central Adriatic lithosphere (70 km thick) with respect to the thicker Puglia (110 km). The different thicknesses of the continental crust and lithosphere were inherited from the Mesozoic rifting that disrupted the Adriatic plate. The different thicknesses appear to have controlled the variable degree of flexure of the lithosphere and its asthenospheric penetration rate. The Tremiti E–W alignment is the right‐lateral lithospheric transfer zone of those different tectonic regimes. The consequent different dip of the subduction in the two sections (steeper west of Puglia) could also explain the lower elevation of the southern Apennines, compared to their central‐northern sector.

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SUMMARY New seismic reflection profiles of the Italian deep crust project CROP provide new insights on the structure of the Ionian sea. In spite of the Apennines and Hellenides Neogene subduction zones, two conjugate passive continental margins are preserved at the margins of the Ionian sea, along the Malta escarpment to the southwest and the Apulian escarpment to the northeast. The Ionian sea is likely to be a remnant of the Mesozoic Tethys Ocean, confined by these two conjugate passive continental margins. The transition from continental to oceanic crust appears sharper to the northeast than to the southwest. The basin between southeast Sicily and southwest Puglia was about 330 km wide and suggests a low spreading rate. The inferred oceanic ridge should have been flattened by thermal cooling and buried by later sediments. Based on stratigraphic and structural constraints to the north in the Apennines belt, the ocean continued to the northwest. This palaeogeography is supported by the seismicity of the Apennines slab underneath the southern Tyrrhenian sea, which implies downgoing oceanic lithosphere. The adjacent absence or paucity of deep seismicity does not imply absence of subduction, but rather it can be interpreted as due to the more ductile behaviour of the subducted continental lithosphere. Surprisingly, we note that where the oceanic inherited basin is subducting underneath the Apennines, in the hangingwall of the subduction hinge there are outcropping slices of continental crystalline basement previously deformed by the Alpine orogen.