Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Via Diocleziano, 328, 80134, Naples, Italy.
Ecole Normale Supérieure, Laboratoire de Géologie, 24 rue Lhomond, 75231, Paris cedex 05, France.
Sci Rep. 2019 Mar 21;9(1):5005. doi: 10.1038/s41598-019-41453-1.
Faults communicate with each other. Strong earthquakes perturb stress over large volumes modifying the load on nearby faults and their resistance to slip. The causative fault induces permanent or transient perturbations that can change the time to the next seismic rupture with respect to that expected for a steadily accumulating stress. For a given fault, an increase of stress or a strength decrease would drive it closer to - or maybe even trigger - an earthquake. This is usually perceived as an undesired circumstance. However, with respect to the potential damage, a time advance might not necessarily be a bad thing. Here we show that the central Italy seismic sequence starting with the Amatrice earthquake on 24 August 2016 advanced the 30 October Norcia earthquake (M = 6.5), but limited its magnitude by inhibiting the rupture on large portions of the fault plane. The preceding events hastened the mainshock and determined its features by shaping a patch of concentrated stress. During the Norcia earthquake, the coseismic slip remained substantially confined to this patch. Our results demonstrate that monitoring the seismicity with very dense networks and timely analyses can make it feasible to map rupture prone areas.
断层之间相互连通。强震会在较大范围内改变应力，从而改变附近断层的受力情况及其抗滑能力。诱发断层的永久性或瞬时性扰动可能会改变下一次地震破裂的时间，使其与预期的稳定积累的应力破裂时间不同。对于给定的断层，应力增加或强度降低会使其更接近地震，甚至可能引发地震。这通常被视为一种不良情况。然而，就潜在的破坏而言，提前发生地震不一定是坏事。在这里，我们表明，2016 年 8 月 24 日阿马特里切地震引发的意大利中部地震序列提前了 10 月 30 日的诺尔恰地震（M = 6.5），但通过抑制断层面上大部分地区的破裂，限制了其震级。前震加速了主震，并通过形成一个集中应力的区域来确定其特征。在诺尔恰地震期间，同震滑动基本上局限在这个区域内。我们的研究结果表明，通过使用非常密集的网络进行监测和及时分析，可以实现对易发生破裂区域的绘制。
