Instantaneous limit equilibrium back analyses of major rockslides triggered during the 2016–2017 central Italy seismic sequence

• Published in: Natural hazards and earth system sciences Vol. 23; no. 3; pp. 1177 - 1190
• Main Authors: Verrucci, Luca, Forte, Giovanni, De Falco, Melania, Tommasi, Paolo, Lanzo, Giuseppe, Franke, Kevin W, Santo, Antonio
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 22-03-2023; Copernicus Publications
• Subjects: Analysis; Cliffs; Earthquakes; Equilibrium; Geomechanics; Hazard assessment; Investigations; Landslides; Lithology; Mathematical models; Numerical models; Rockslides; Seismic stability; Sequencing; Stability analysis; Topographic effects; Topography; Unmanned aerial vehicles; Italy
• ISSN: 1684-9981; 1561-8633; 1684-9981
• DOI: 10.5194/nhess-23-1177-2023

Among the almost 1400 landslides triggered by the shocks
of the 2016–2017 central Italy seismic sequence, only a limited number, all
classifiable as rockslides, involved volumes larger than 1000 m3. Four
of these failures, including the three largest among the documented
landslides, were described in terms of structural and geomechanical
investigations in a previous paper. In this study, the estimated
acceleration time histories at the rockslide sites were evaluated through a
2D simplified numerical model accounting for the attenuation phenomena and
for the topographic effect of the rock cliffs from which the slide detached.
Instantaneous stability analyses were carried out to obtain insights into
the variability of the instantaneous margin of safety along the motion, over
the entire spectrum of mechanisms that could be activated. Finally, some
general suggestions on the pseudo-static verification method for
3D cases are proposed, which represent useful indications to
hazard evaluation at local and regional scales.