Regional deformation and offshore crustal local faulting as combined processes to explain uplift through time constrained by investigating differentially-uplifted Late Quaternary palaeoshorelines: the foreland Hyblean Plateau, SE Sicily.

Quaternary uplift is well documented in SE Sicily, a region prone to damaging seismic events, such as the 1693 “Val di Noto” Earthquake (Mw 7.4), the largest seismic event reported within the Italian Earthquake Catalogue, whose seismogenic source is still debated and, consequently, the long-term seismic hazard is poorly-understood. However, the spatial variation in the timing and rates of uplift are still debated, so it is difficult to link the dominant tectonic process(es) responsible for the uplift and the location of seismogenic sources. To better constrain the uplift rate, we have refined the dating of Late Quaternary marine terraces, using a synchronous correlation approach, driven by both published and newly obtained numerical age controls (234U/230Th dating on corals). This has allowed re-calculation of uplift rates along a N-S oriented transect within the Hyblean Plateau (HP) foreland region. Consequently, we have mapped the geometry of palaeoshorelines along a coastline-parallel transect, and hence the rates of uplift. The results suggest increasing uplift rate from south to north across the HP, and that uplift rates have remained constant through the late Quaternary. This spatially-changing but temporally constant uplift places constraints on the proportion of uplift produced by regional geodynamic processes versus produced by local faults, such as an offshore E-dipping active normal fault. We discuss these new findings in terms of the long-term seismic hazard for one of the most seismically-active regions in the Mediterranean Basin.

西西里东南部地区的第四纪（Quaternary）抬升已有充分研究记录，该区域易发生破坏性地震事件，例如1693年的"瓦莱迪诺托"地震（Mw 7.4）——这是意大利地震目录中记载的最大地震事件，其发震源至今仍存在争议，因此长期地震危险性尚未得到充分认知。然而，抬升的时间与速率的空间差异仍存在学术争议，故难以将控制抬升的主要构造过程与发震源的位置建立关联。为更精准地限定抬升速率，本研究采用同步对比法，结合已发表及新获取的数值年代约束（对珊瑚样品的234U/230Th测年（234U/230Th dating）），对晚第四纪海成阶地的年代学进行了厘定。据此，我们重新计算了伊布莱安高原（Hyblean Plateau, HP）前陆区域内沿南北向剖面的抬升速率。进而，我们沿与海岸线平行的剖面绘制了古滨线的几何形态，并由此推算出抬升速率。研究结果显示，伊布莱安高原的抬升速率自南向北逐渐升高，且晚第四纪以来抬升速率始终保持恒定。这种空间分布存在差异但时间尺度上保持恒定的抬升模式，为区分区域地球动力学过程与局部断层（如近海东倾活动正断层）所贡献的抬升占比提供了约束条件。最后，我们针对地中海盆地地震活动性最强的区域之一的长期地震危险性，对本次研究的新发现展开了讨论。