A B S T R A C TIn order to characterize and quantify the Middle-Late Quaternary and ongoing deformation within the Southern Aegean forearc, we analyse the major tectonic structures affecting the island of Crete and its offshore. The normal faults typically consist of 4-30-km-long dipslip segments locally organised in more complex fault zones. They separate carbonate and/or metamorphic massifs, in the footwall block, from loose to poorly consolidated alluvial and colluvial materials within the hangingwall. All these faults show clear evidences of recent re-activations and trend parallel to two principal directions: WNW-ESE and NNE-SSW. Based on all available data for both onland and offshore structures (morphological and structural mapping, satellite imagery and airphotographs remote sensing as well as the analysis of seismic profiles and the investigation of marine terraces and Holocene raised notches along the island coasts), for each fault we estimate and constrain some of the principal seismotectonic parameters and particularly the fault kinematics, the cumulative amount of slip and the slip-rate. Following simple assumptions and empirical relationships, maximum expected magnitudes and mean recurrence periods are also suggested. Summing up the contribution to crustal extension provided by the two major fault sets we calculate both arc-normal and arcparallel long-term strain rates. The occurrence of slightly deeper and more external low-angle thrust planes associated with the incipient continental collision occurring in western Crete is also analysed. Although these contractional structures can generate stronger seismic events (M ≈ 7.5.) they are probably much rarer and thus providing a minor contribution to the overall morphotectonic evolution of the island and the forearc. A comparison of our geologicallybased results with those obtained from GPS measurements show a good agreement, therefore suggesting that the present-day crustal deformation is probably active since Middle Quaternary and mainly related to the seismic activity of upper crustal normal faults characterized by frequent shallow (<20 km) moderate-to-strong seismic events seldom alternating with stronger earthquakes occurring along blind low-angle thrust planes probably ramping from a deeper aseismic detachment (ca. 25 km). This apparently contradicting co-existence of juxtaposed upper tensional and lower compressional tectonic regimes is in agreement with the geodynamics of the region characterised by continental collision with Nubia and the Aegean mantle wedging.

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[1] In this paper we present a study of a segment of the southern Apennine mountain belt which extends from the Pollino mountain range to the south and the Sele valley to the north. Combining regional data and structural information with the results based on the interpretation of several seismic reflection lines and many deep well logs, three regional cross sections have been constructed. The cross sections highlight the overall architecture of the orogenic belt which is constituted by a thin tectonic layer of allochthonous nappes represented by remnants of the Neotethyan accretionary wedge (e.g., Liguride and Sicilide units) resting above a thick imbricated thrust belt. This latter comprises distinct units represented by platform carbonates (western platform, Monte Alpi, Costamolina and Tempa Rossa units) and pelagic basin domains (Lagonegro, Campomaggiore and Faeto units) deriving from the Late TortonianQuaternary deformation of the Adria paleomargin. The restoration of the three cross sections furnished information on the primary geometry of the Adria paleomargin which was characterized by the occurrence of a large platform domain dissected by distinct pelagic basins with complex and irregular margins represented by pelagic embayments and platform promontories developed during the Mesozoic and the Late Cretaceous-Tertiary times. The reconstructed geometry of the paleomargin provided, moreover, useful insights to evaluate the mode of deformation and the rates of shortening of the thrust belt and to explain the Neogene stratigraphy of the distinct platform domains. The mode of deformation of this portion of the southern Apennines was dominated by the occurrence of crustal thrusts located along previous weakness zones represented by the boundaries between platform and pelagic domains. These crustal thrusts caused the complete closure of the basin areas and the direct overthrusting of the different buoyant platform domains, with contractional rates characterized by values ranging from 3.1 to 4.3 cm/yr. Finally, a geodynamic model in which the southern Apennine mountain belt is considered the result of lateral extrusion produced by the indentation of the Pelagian block and by the consequent opening of the Tyrrhenian Sea is also proposed.

Structural studies carded out in the Lucanian Apennines (Southern Italy) show that strike-slip faulting was the principal mode of deformation of this area during middle-upper Pleistocene time. W-NW to E-SE trending left strike-slip fault systems dissect the entire Apennine mountain belt and affect the preexisting thrust geometry. Strike-slip faults, activated by a roughly E-W shortening, are characterized by different geometries representing the surface response to lateral motion occurring along deep-seated structures. The occurrence of different structuralpatterns which characterize different segments of strike-slip system is related to (1) the depth of a major decoupling surface which separates the upper tectonic multilayered horizon (Apennines thrust belt system) from the lower rigid horizon (Apulian belt) in which strike-slip structures have originated and (2) the geometric relationships between the strikeslip faults and the thrust belt pattern which characterize the upper horizon. The different segments of the strike-slip system are interpreted as internal deformation developed within a crustal shear zone. This zone, which corresponds to the boundary between the Apulian block and the Apennine chain, is characterized by sinistral movement as a response to the northwesterly convergent motion of the African plate with respect to Europe.