Faults Geometry and the Role of Fluids in the 2016-2017 Central Italy Seismic Sequence
Faults Geometry and the Role of Fluids in the 2016-2017 Central Italy Seismic Sequence
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DOI：
10.1029/2018gl077485
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发表时间：
2018-07-28
影响因子：
5.2
通讯作者：
Segou, M.
中科院分区：
文献类型：
--
作者：
Chiarabba, C.;De Gori, P.;Segou, M.
2016-2017年意大利中部的地震序列破坏了亚平宁山脉的重叠正断层，在几个月内发生了9次Mw > 5级的地震。在这里，我们调查的断层系统的结构，使用一个广泛的余震数据集，从联合永久和临时地震网络，和3-D Vp和Vp/Vs速度模型。我们发现，主震成核轻轻西倾的飞机，我们解释为倒置的陡峭斜坡继承上新世晚期的压缩。8月24日（Mw = 6.0阿马特里斯）和10月30日（Mw = 6.5 Norcia）这两次大地震发生在下盘高孔隙压力重新激活的明显断层上，如Vp/Vs正异常所示。超压体积的横向范围包括诺尔恰地震的断层补丁。不规则的几何形状的正断层，再加上活动的坡道，导致在同震破裂和余震的空间分布观察到的运动学的复杂性。
The 2016-2017 Central Italy seismic sequence ruptured overlapping normal faults of the Apennines mountain chain, in nine earthquakes with magnitude Mw > 5 within a few months. Here we investigate the structure of the fault system using an extensive aftershock data set, from joint permanent and temporary seismic networks, and 3-D Vp and Vp/Vs velocity models. We show that mainshocks nucleated on gently west dipping planes that we interpret as inverted steep ramps inherited from the late Pliocene compression. The two large shocks, the 24 August, Mw = 6.0 Amatrice and the 30 October, Mw = 6.5 Norcia occurred on distinct faults reactivated by high pore pressure at the footwall, as indicated by positive Vp/Vs anomalies. The lateral extent of the overpressurized volume includes the fault patch of the Norcia earthquake. The irregular geometry of normal faults together with the reactivated ramps leads to the kinematic complexity observed during the coseismic ruptures and the spatial distribution of aftershocks.