Evidence for Surface Faulting Earthquakes on the Montereale Fault System (Abruzzi Apennines, Central Italy)
Evidence for Surface Faulting Earthquakes on the Montereale Fault System (Abruzzi Apennines, Central Italy)
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DOI：
10.1029/2017tc004780
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发表时间：
2018-09-01
期刊：
影响因子：
4.2
通讯作者：
Brunori, C. A.
中科院分区：
文献类型：
--
作者：
Cinti, F. R.;Civico, R.;Brunori, C. A.
我们进行了古地震研究沿着的蒙特雷亚莱断层系统（MFS;意大利中部）。MFS显示了晚第四纪活动的地貌证据，福尔斯位于亚平宁山脉中部最高地震危险区，位于最近两次地震序列的震中区域之间：2009年拉奎拉和2016-2017年意大利中部。我们沿该系统的圣乔瓦尼断层展布沿着开挖了两条沟道，一条沟道与N140度走向基岩主断层面相交，另一条沟道在断层上盘的崩积/冲积层上切割出两个近平行的断层陡坎。研究表明，在史前和历史时期，断层反复复活，并伴有地表断层。我们在过去的26 kyr中识别并确定了七个事件的日期。最近的一次地面破裂事件（evb 1）可能发生在公元650- 1820年，与公元1,703年袭击该地区的三次主要地震之一一致。之前的事件（evb 2）发生在公元前5,330年至公元前730年之间，而更早的事件发生在公元前6590年至公元前5440年（evb 3），公元前9770年至公元前6630年（evb 4）和公元前16860年至公元前13480年（evb 5）。我们记录了两个更早的迁移事件（evb 7和evb 6），发生在公元前23,780年到公元前16,850年之间。在过去的28- 24 kyr中，沟址处的最小垂直滑动速率为0.3-0.4mm/年。推断的平均复发间隔地表断层事件沿着MFS是不长于类似4kyr。根据地表断层长度在12 - 20 km之间，MFS可能发生6.0级地震。MFS是一个独立的震源，它的古地震数据与亚平宁山脉中部已知的断层完全可比。
We conducted paleoseismic studies along the Montereale fault system (MFS; central Italy). The MFS shows geomorphological evidence of Late Quaternary activity and falls within the highest seismic hazard zone of central Apennines, between the epicentral areas of two recent earthquake sequences: 2009 L'Aquila and 2016-2017 central Italy. We excavated two trenches along the San Giovanni fault splay of the system, one intercepting the N140 degrees striking bedrock main fault plane and the other cutting two subparallel fault scarps on the colluvial/alluvial deposits on the fault hanging wall. Excavations revealed repeated fault reactivation with surface faulting in prehistorical and historical times. We recognized and dated seven events in the last 26kyr. The most recent ground-rupturing event (evb1) possibly occurred 650-1,820AD, consistent with one of the three main shocks that struck the area in 1,703AD. A previous event (evb2) occurred between 5,330bc and 730bc, while older events occurred at 6,590-5,440bc (evb3), 9,770-6,630bc (evb4), and 16,860-13,480bc (evb5). We documented two older displacement events (evb7 and evb6) between 23,780bc and 16,850bc. The minimum vertical slip rate at the trench site in the last 28-24kyr is 0.3-0.4mm/year. The inferred average recurrence interval for surface-faulting events along the MFS is no longer than similar to 4kyr. Based on the surface fault length ranging between 12 and 20km, earthquakes with M 6.0 are possible for the MFS. The MFS is an independent earthquake source, and its paleoseismic data are fully comparable with those known for faults in central Apennines.