Assessing active and capable faulting as best practice for post-earthquake reconstruction activities: the Sant’Eutizio Abbey case study, in the epicentral area of the 2016 central Italy seismic sequence

Abstract

Surface faulting is, together with strong ground shaking, a hazard associated with major earthquake

faults. Assessing surface faulting potential of a given active tectonic structure is a fundamental

prerequisite to adequately plan the use of territories and to perform new constructions, in order

to act practices aimed to mitigate the associated risk. Assessing the surface faulting potential

represents also ground for correctly performing re-construction and retrofitting of buildings and

infrastructures during post-earthquake activities. We investigated a branch of a major seismogenic

normal fault in the central Apennines of Italy, the Campi-Preci fault, along which the monumental

Sant’Eutizio Abbey is located. The medieval Abbey is one of the most important cultural/religious

edifices of the central Apennines, heavily damaged by the MW 6.5 October 30, 2016, earthquake,

focused a few km to the south. Our study, based on field geological, geomorphological and structural

survey and trenching investigations revealed that I) the trace of the Campi-Preci active fault

branch is not actually located where presently reported in the available literature, II) the supposed

morpho-tectonic features (basically, some km-long scarp carved on the Meso-Cenozoic carbonate

bedrock), that suggested the presence of the fault segment in the area of the Sant’Eutizio Abbey,

are not related to the active fault but are probably associated to a presently inactive reverse fault

and III) the Sant’Eutizio Abbey is likely not potentially affected by primary surface faulting. Our

work highlights that only a comprehensive multidisciplinary approach allows to correctly assess

surface faulting potential in both seismotectonic and engineering perspectives.