Site effects and widespread susceptibility to permanent coseismic deformation in the Avezzano town (Fucino basin, Central Italy): Constraints from detailed geological study

The Quaternary Fucino basin in the central Apennines of Italy was struck by one of the strongest Italian
earthquakes of the last millennium (1915, Mw 7.0). The Avezzano town, ~ 9.0 km away from the epicentre, was
completely destroyed. In the surrounding area sizable coseismic surface deformation were catalogued, attesting
the severity of earthquake, the proximity to the causative fault and the geological and geomorphological
complexity of a basin filled by thick lacustrine sediments.
The Avezzano area provides a case study to understand how shallow subsurface geology influences site effects
in a deep Quaternary continental basin environment, thus being of potential interest for similar geologic contexts
worldwide. Within the investigated area, different possible earthquake-induced effects can occur, such as a)
stratigraphic amplifications in a wide range of resonance frequencies (from 0.4 to 15–20 Hz); b) liquefaction; c)
coseismic surface faulting; d) basin-edge effects; and e) slope instability.
We present and discuss results of basic seismic microzonation study (SM) of the Avezzano area, focusing on
geologic constraints aimed at the reconstruction of the shallow subsurface geology, and associated potential for
local seismic hazard.
We adopted an interdisciplinary approach based on detailed geological-structural, geophysical and seismic
analyses to investigate the seismic response of high-seismic risk area, such as the Avezzano town, given the
urban and industrial expansion since the last century. We discuss methodological approaches and their uncertainties.