Effects of coseismic ground vertical motion on masonry constructions damage during the 2016 Amatrice-Norcia (Central Italy) earthquakes

Horizontal acceleration and velocity are considered the most important parameters in determining damage potential to buildings during the paroxysmal energy dissipation of an earthquake. However, taking as example the two mainshocks of the 2016 Central Italy seismic sequence and comparing Interferometric Synthetic-Aperture Radar (InSAR) and macroseismic data, it is shown that maximum damage was concentrated where the ground subsided coseismically. A number of empirical relationships are determined between InSAR vertical displacement on the one hand, and macroseismic intensity or ground motion intensity measures on the other. Finally, resorting to a finite-discrete element model, the effect of the vertical component of ground motion is investigated on a test masonry structure under recorded accelerograms.