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University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy
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- PublicationRestrictedSite effects and widespread susceptibility to permanent coseismic deformation in the Avezzano town (Fucino basin, Central Italy): Constraints from detailed geological study(2020)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; 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.273 4 - PublicationRestrictedSeismic response of a deep continental basin including velocity inversion: the Sulmona intramontane basin (Central Apennines, Italy)(2016-01-01)
; ; ; ; ; ; ; ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;de Nardis, R.; University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy ;Boncio, P.; University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rosatelli, G.; University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy ;Stoppa, F.; University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy ;Laecchia, G.; University of Chieti-Pescara “G. d'Annunzio”, DiSPUTer, Via dei Vestini 30, I-66100, Chieti Scalo (CH), Italy; ; ; ; ; ; The Sulmona plain (central Italy) is an intramontane basin of the Abruzzi Apennines that is known in the literature for its high seismic hazard. We use extensive measurements of ambient noise to map the fundamental frequency and to detect the presence of geological heterogeneities in the basin. We perform noise measurements along two basin-scale orthogonal transects, in conjunction with 2-D array experiments in specific key areas. The key areas are located in different positions with respect to the basin margins: one at the eastern boundary (fault-controlled basin margin) and one in the deepest part of the basin. We also collect independent data by using active seismic experiments (MASW), down-hole and geological surveys to characterize the near-surface geology of the investigated sites. In detail, the H/V noise spectral ratios and 2-D array techniques indicate a fundamental resonance (f0) in the low-frequency range (0.35–0.4 Hz) in the Sulmona Basin. Additionally, our results highlight the important role that is played by the alluvial fans near the edge-sectors of the basin, which are responsible for a velocity inversion in the uppermost layering of the soil profile. The H/V ratios and the dispersion curves of adjacent measurements strongly vary over a few dozens of meters in the alluvial fan area. Furthermore, we perform 1-D numerical simulations that are based on a linear-equivalent approach to estimate the site response in the key areas, using realistic seismic inputs. Finally, we perform a 2-D simulation that is based on the spectral element method to propagate surface waves in a simple model with an uppermost stiff layer, which is responsible for the velocity inversion. The results from the 2-D modelling agree with the experimental curves, showing deamplified H/V curves and typical shapes of dispersion curves of a not normally dispersive site.294 80