Imaging the tectonic framework of the 24 August 2016, Amatrice (central Italy) earthquake sequence: new roles for old players?

We reconstruct the tectonic framework of the 24 August 2016, Amatrice earthquake. At least three main
faults, including an older thrust fault (Sibillini Thrust), played an active role in the sequence. The
mainshock nucleated and propagated along an extensional fault located in the footwall of the Sibillini Thrust,
but due to the preliminary nature of the data the role of this thrust is still unclear. We illustrate two competing
solutions: 1) the coseismic rupture started along an extensional fault and then partially used the
thrust plane in extensional motion; 2) the thrust fault acted as an upper barrier to the propagation of the
mainshock rupture, but was partially reactivated during the aftershock sequence. In both cases our tectonic
reconstruction suggests an active role of the thrust fault, providing yet another example of how structures
inherited from older tectonic phases may control the mainshock ruptures and the long-term evolution of
younger seismogenic faults.