3D-thrust fault pattern control on negative inversion: An analogue modelling perspective on central Italy. (February 2021)

• Record Type: Journal Article
• Authors: Del Ventisette, Chiara; Bonini, Marco; Maestrelli, Daniele; Sani, Federico; Iavarone, Emanuele; Montanari, Domenico
• Is Part Of: Journal of structural geology. Volume 143(2021)
• Publication Date: 2021-02
• Subjects: Structural deformation -- Analogue models -- Negative fault reactivation -- Central apennines -- Active extension -- Deformation style -- Extended fold-and-thrust belts; Geology, Structural -- Periodicals; Géomorphologie structurale -- Périodiques; Geology, Structural; Periodicals; 551.805
• DOI: 10.1016/j.jsg.2020.104254
• Languages: English
• ISSNs: 0191-8141

Abstract

Abstract: During the last decades, central Italy has been struck by severe seismic sequences. Some authors have suggested that inherited thrust faults may have played an important role in controlling the recent-to active extensional deformation in the area, particularly during the 2016 Central Italy seismic sequence. To explore this hypothesis, we performed an analogue modelling study that addressed the structural evolution of a composite, heterogeneous multilayer affected by polyphase deformation. The overall three-dimensional geometry resulting from the modelling consists of a flat-ramp extensional fault system, with flats being localised along the weaker stratigraphic units, and ramps locally reactivating the pre-existing thrust ramps at depth. At shallower levels, deformation can localize at newly-formed short-cut faults depending on the geometry of deeper structures. The experimental results provide further support to the hypothesis of a link between Quaternary normal faults and inherited thrust faults during the 2016 seismic sequences. Specifically, analogue modelling results suggest that the Quaternary fault pattern may be controlled by the interaction between the active stress field and the pre-existing compressional structures. This scenario bears significant implications regarding the empirical relationship between the geometry of surface faulting and the magnitude of earthquakes, with considerable repercussions on seismic risk assessment. Highlights: Analogue models are applied to the 2016 seismic sequences in central Italy. Connection between Quaternary normal faults and thrust faults is proposed. Active extensional system show a flat-ramp geometry.