The Main Ethiopian Rift (MER) has a complex structural pattern composed of southern, central, and northern segments. Ages of onset of faulting and volcanism apparently indicate a heterogeneous time‐space evolution of the segments, generally referred to as a northward progression of the rifting process. New structural, petrological, and geochronological data have been used to attempt reconciling the evolution of the distinct MER segments into a volcanotectonic scenario accounting for the propagation of the Afar and the Kenya Rifts. In this evolutionary model, extension affected the Southern MER in the early Miocene (20–21 Ma) due to the northward propagation of the Kenya Rift‐related deformation. This event lasted until 11 Ma, then deformation decreased radically and was resumed in Quaternary times. In the late Miocene (11 Ma), deformation focused in the Northern MER forming a proto‐rift that we consider as the southernmost propagation of Afar. No major extensional deformation affected the Central MER in this period, as testified by the emplacement at 12–8 Ma of extensive plateau basalts currently outcropping on both rift margins. Significant rift opening occurred in the Central MER during the Pliocene (∼5–3 Ma) with the eruption of voluminous ignimbritic covers (Nazret sequence) exposed both on the rift shoulders and on the rift floor. The apparent discrepancy between the heterogeneous propagation of the three MER segments could be reconciled by considering the opening of Central MER and the later reactivation of the Southern MER as due to a southward propagation of rifting triggered by counterclockwise rotation of the Somalian plate starting around 10 Ma.

Continental rifting is a geodynamic process that involves the breakup of the crust and may eventually evolve to seafloor spreading. Although it is often assumed to be a product of orthogonal divergence, continental rifting may result from oblique extension, and in several cases, it is related to the rotation of plates or crustal blocks about a vertical axis. This implies the occurrence of rifts with straight but not parallel margins and rift axis‐parallel gradients in extension velocity and amount of strain. The effects of rift propagation through the continental crust has only recently started to be addressed, and even less investigated is the interaction between rift propagation and inherited crustal fabrics. We have studied this issue by carrying out a series of analog laboratory experiments. Modeling results suggest that inherited linear discontinuities in the model brittle upper crust that are oriented above a threshold angle (≥45°) from the orthogonal to the rift axis have the ability to interact with rift‐related structures. Depending on their orientation, such inherited discontinuities are reactivated as either transfer zones or rift‐bounding faults. We compare our models with four natural prototypes in which rift propagation is likely to have occurred (the Trans Mexican Volcanic belt, the Gofa Province, the Gulf of Suez, and the Kenya Rift). For each case study, we show how the kinematics of propagating rifts is comparable to our model results, and we provide insights into how rift‐related deformation may interact with inherited crustal fabrics.

The behaviour of a granular material is mainly dependent on its frictional properties, angle of internal friction, and cohesion, which, together with material density, are the key factors to be considered during the scaling procedure of analogue models. The frictional properties of a granular material are usually investigated by means of technical instruments such as a Hubbert-type apparatus and ring shear testers, which allow for investigating the response of the tested material to a wide range of applied stresses. Here we explore the possibility to determine material properties by means of different empirical methods applied to mixtures of quartz and K-feldspar sand. Empirical methods exhibit the great advantage of measuring the properties of a certain analogue material under the experimental conditions, which are strongly sensitive to the handling techniques. Finally, the results obtained from the empirical methods have been compared with ring shear tests carried out on the same materials, which show a satisfactory agreement with those determined empirically.

The Chianti Mountains is an important sector of an E-verging regional thrust-related fold (the so-called Tuscan Nappe) extending along the whole length of the Northern Apennines. This thrust system involves the Tuscan Sequence superposing the Macigno sandstones onto Cervarola-Falterona sandstones, both of which are sedimented in adjacent foredeep basins. Detailed field mapping and analysis of superposition relations among tectonic structures, as well as correlation between structures and syntectonic deposition, has allowed Chianti Mountain evolution to be interpreted in terms of three main stages of deformation.The D₁ stage resulted in the NE-directed synsedimentary thrusting of the Macigno onto the Cervarola-Falterona sandstones, while large NE to ENE-vergent thrust-related folds developed during the two successive deformation stages (D₂ and D₃). Fault-propagation folds developed during the D₂ stage, and were affected by the Main Chianti Mountains Thrust (MCMT) during the successive D₃ stage. In particular, the D₃ stage has been correlated to the development, during the Pliocene period, of the hinterland Upper Valdarno Basin, which was previously considered to be an extensional basin. In fact, this continental basin formed along the eastern margin of the Chianti Mountains, ahead of the MCMT that also produced a shortening of the basin fill. With the beginning of the Quaternary period, the tectonic regime switched to extensional, as manifested by the development of a normal fault system on the opposite basin margin.The data presented here allow us to infer that the Chianti Mountains thrust system (D₂ and D₃) developed during a time interval spanning from the Late Miocene (∼12 Ma) until the Late Pliocene (∼2 Ma) periods. In the Northern Apennines, polyphase thrusting recorded by cover rocks has been related to the activity of basement thrusts, which have been recently evidenced by geophysical data. In this context, the two latest stages of deformation recognised in the Chianti Mountains have been attributed to the activity of the Abetone–Cetona crustal thrust, the deformational effects of which propagated forward in the sedimentary cover.