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.

中文翻译：

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负反演的 3D 逆冲断层模式控制：意大利中部的模拟建模视角

摘要 在过去的几十年里，意大利中部遭受了严重的地震序列袭击。一些作者认为，继承的逆冲断层可能在控制该地区最近到活动的伸展变形方面发挥了重要作用，特别是在 2016 年意大利中部地震序列期间。为了探索这一假设，我们进行了模拟建模研究，该研究解决了受多相变形影响的复合异质多层的结构演变。建模产生的整体三维几何结构由平坦斜坡伸展断层系统组成，平坦斜坡沿较弱的地层单元定位，斜坡局部重新激活深处预先存在的逆冲斜坡。在较浅的层次上，根据更深结构的几何形状，变形可以定位在新形成的短切断层处。实验结果进一步支持了 2016 年地震序列期间第四纪正断层与继承逆冲断层之间存在联系的假设。具体而言，模拟建模结果表明，第四纪断层模式可能受活动应力场和预先存在的压缩结构之间的相互作用控制。这种情况对地表断层几何形状与地震震级之间的经验关系具有重要意义，对地震风险评估产生了相当大的影响。实验结果进一步支持了 2016 年地震序列期间第四纪正断层与继承逆冲断层之间存在联系的假设。具体而言，模拟建模结果表明，第四纪断层模式可能受活动应力场和预先存在的压缩结构之间的相互作用控制。这种情况对地表断层几何形状与地震震级之间的经验关系具有重要意义，对地震风险评估产生了相当大的影响。实验结果进一步支持了 2016 年地震序列期间第四纪正断层与继承逆冲断层之间存在联系的假设。具体而言，模拟建模结果表明，第四纪断层模式可能受活动应力场和预先存在的压缩结构之间的相互作用控制。这种情况对地表断层几何形状与地震震级之间的经验关系具有重要意义，对地震风险评估产生了相当大的影响。