Coseismic ruptures of the 24 August 2016, Mw 6.0 Amatrice earthquake (central Italy)

On 24 August 2016, a M-w 6.0 normal-faulting earthquake struck central Italy, causing about 300 fatalities and heavy damage. A geological survey collected the coseismic effects observed at the surface in order to evaluate two competing hypotheses about their nature: surface faulting versus gravitational deformation. We find that the most significant geological effect is a 5.2km long alignment of ground ruptures along the Mount Vettore Fault System. These ruptures are independent from lithology, topography, morphology, and change in slope and exhibit an average dip-slip displacement of similar to 13cm. Geometry, kinematics, and dimensional properties of this zone of deformation strongly lead us to favor the primary surface faulting hypothesis that fits well the predicted estimates from experimental scaling law relationships. Our study provides relevant hints for surface faulting in extensional domains, contributing to implement the worldwide database of the moderate earthquakes.