Beschreibung: The August 24, 2016 Amatrice earthquake (Ml 6.0) struck a region of the central Apennines (Italy) where several active faults were known since decades, most of which are considered the surface expression of seismogenic sources potentially able to rupture during earthquakes with M of up to 6.5-7. The current de-bate on which structure/s activated during the mainshock and the possibility that conterminous faults may activate in a near future urged us gathering all the data on surface geological evidence of fault activi-ty we collected over the past 15-20 years in the area. We then map the main tectonic structures of the 2016 earthquake epicentral and mesoseismal region. Our aim is to provide hints on their seismogenic potential, as possible contribution to the national Database of Individual Seismogenic Source (DISS) and to the Da-tabase of the active and capable fault ITaly HAzard from CApable faults (ITHACA).

Beschreibung: Published

Beschreibung: 1T. Deformazione crostale attiva

Beschreibung: JCR Journal

Beschreibung: The study deals with the morphogenetic meaning of several linear scarps that carved the paleo-landsurface of Valle Daria, an extended geomorphological feature located between Barisciano (AQ) and Prata D'Ansidonia (AQ). These villages are situated in the southern termination of the L'Aquila intermontane basin (one of the largest basin of the central Apennines), nearby the epicentral area of the 6th April 2009 earthquake (Mw 6.1). These scarps, up to 3 meters high and up to 1.5 km long, define narrow/elongated flat-bottom depressions, filled by colluvial deposits. These depressions are carved into fluvial-deltaical conglomerates, dated back to the lower Pleistocene. Even if different authors have interpreted these shapes as a paleodrainage or secondary faults, a morphometrical study of the Valle Daria paleo-landsurface provided several information which cast doubt on these two interpretations. In order to better understand the nature and the state of activity of these lineaments, geological, geomorphological and geophysical surveys were carried out. A paleoseismological trench pointed out two events of deformation. The curvilinear shape of the shear plane seems to be related to a slow deformation, attributable to collapse-phenomena. Three GPR profiles, two ERT profiles and two microgravimetrical profiles seem to corroborate this interpretation. Therefore, this study permits to attribute the genesis of these scarps to tectono-karstic phenomena, excluding the presence of an active and capable fault.

Beschreibung: Published

Beschreibung: 346-349

Beschreibung: 4T. Sismologia, geofisica e geologia per l'ingegneria sismica

Beschreibung: N/A or not JCR

Beschreibung: The preparation, initiation, and occurrence dynamics of earthquakes in Italy are governed by several frequently unknown physical mechanisms and parameters. Understanding these mechanisms is crucial for developing new techniques and approaches for earthquake monitoring and hazard assessments. Here, we develop a first-order numerical model simulating quasi-static crustal interseismic loading, coseismic brittle episodic dislocations, and postseismic relaxation for extensional and compressional earthquakes in Italy based on a common framework of lithostatic and tectonic forces. Our model includes an upper crust, where the fault is locked, and a deep crust, where the fault experiences steady shear.

Beschreibung: Published

Beschreibung: 627–645

Beschreibung: 2T. Deformazione crostale attiva

Beschreibung: JCR Journal

Beschreibung: Negli ultimi 20 anni l’Italia centrale è stata colpita da tre sequenze sismiche che hanno causato centinaia di vittime e ingentissimi danni all’edificato, a partire da quella umbro-marchigiana del 1997. La sequenza sismica di Colfiorito-Sellano del 1997 fu la prima in Italia ad essere studiata in modo approfondito attraverso diverse metodologie di analisi, geologiche, sismologiche e geodetiche. Successivamente, il crescente avanzamento tecnologico e l’integrazione di diverse discipline e tecniche di indagine ha poi reso quello del 2009 dell’Aquila il terremoto per faglia normale meglio studiato al mondo, fino alla sequenza sismica del 2016-2017. Quest’ultima ha determinato l’impegno di decine di gruppi di ricerca italiani ed esteri nella comprensione del processo sismogenetico che ha dato luogo alla più importante sequenza sismica, in termini energetici e di vastità di area coinvolta, degli ultimi cento anni di questo settore del territorio nazionale. L’analisi della letteratura scientifica prodotta a seguito di queste sequenze sismiche evidenzia tuttavia che ad oggi rimango alcuni nodi non sciolti, alcune incertezze e diversità di interpretazione sui processi sismogenetici che le hanno causate e, più ingenerale, sul quadro sismotettonico dell’Appennino centrale. Il presente contributo ha lo scopo di mostrare il quadro delle conoscenze relative alle tre sequenze sismiche in esame; attraverso l’interpretazione delle informazioni disponibili, acquisite sia prima che dopo gli eventi sismici, e a nuove analisi sui dati raccolti durante le tre sequenze, aiuta a fornire una chiave di lettura “neotettonica” della sismicità maggiore dell’Italia centrale, nonché nuove prospettive in termini di definizione del potenziale sismico associabile alle principali sorgenti sismogenetiche.

Beschreibung: Unpublished

Beschreibung: Roma

Beschreibung: 4T. Sismicità dell'Italia

Beschreibung: A multidisciplinary study based mainly on aerophotogeological interpretation and geochemical prospectings were performed in the Comino valley area which extends between Vicalvi and San Donato Val di Comino villages. The studied area covers 70 km2 of a considered key-area in the geological-seismic framework of the Central Apennines. The Comino valley is located in the SW sector of the Central Apennine (Southern Latium) where the “Val Roveto-Atina-Caserta” regional fault has been studied since many years. Indeed, according with some authors, this fault can be interpreted as a crustal discontinuity probably corresponding to a deep step of the Moho. The studied area is also characterized by the presence of secondary tectonic lineaments (e.g. San Donato-Val Comino fault) having a typical Apenninic orientation (NW-SE). The Comino valley is affected by high seismic activity: last destructive earthquake was in May 7, 1984 (ML 5.9) while during 2009 many seismic events (ML 〈 4) have occurred for several months suggesting a new micro-seismic activity. The spatial soil-gas distributions have been compared with the location and orientation of brittle deformations described in the literature and/or recognized by new field surveys, as well as with morphotectonic features obtained by photogeological analysis. Soil gas results show a pervasive character of the radon, helium and methane values. Soil gas prospecting together with geological survey has provided an inedited and detailed mapping of the structural setting of the studied area and in particular new data about the Comino valley have been acquired. The identified structural lineaments by geological survey as well as the He, CH4 and Rn anomalies in soil gas in correspondence of lineament crossing, suggest that such faults may be considered as the surface expression of a deep structure network (probably down to the Moho) playing a role of important avenue for a vertical and rapid migration of endogenetic gases. In particular, the high Rn median value (51.80 Bq/L) in an area without shallow possible radon sources, suggests a deep origin for this gas and therefore a vertical migration through fractured media, i.e. faults and fractures. The elongated gas anomalies show that the area is characterized by tectonic discontinuities oriented mainly NNW-SSE in accordance with and linked to the regional Val Roveto-Atina-Caserta fault and WSW-ENE that suggest transversal fractured zones. The investigated area is also interested by mineralized springs with a high gaseous component: CO2 is the dominant gas (concentrations 〉 95 %, v/v) but also discrete amounts of CH4 have been measured (max value: 4200 ppm). The spatial distribution of thermal springs, cold CO2-rich springs and localized gas emissions suggests that the structural framework of the studied area, i.e. the bordering faults of buried structural highs of the carbonate basement, exerts a strong control on the uprising patterns of fluids.

Beschreibung: Unpublished

Beschreibung: Torino (Italy)

Beschreibung: 3.2. Tettonica attiva

Beschreibung: open

Beschreibung: Thanks to its favourable hydrogeological conditions, Cassino is one of the most studied sites of Central Italy. More than two hundred soil borings, some of them reaching depths as high as 100 m, have revealed a subsoil characterized by a calcareous platform and post-orogenetic series forming a tectonic basin filled by lacustrine and volcanic deposits. Together with the already available data, a number of geological, geotechnical and geophysical data have collected to study at a very detailed scale the seismic response of the site. Among them, a series of HVSR (horizontal to vertical spectral ratio) measurements have been performed to estimate the natural frequency of oscillation of the more deformable deposits. The combination of these data with the information given by the deep boreholes, permitted to rebuild the geological complexities of the tectonically driven seismic bedrock, outcropping continuously at east and west of the basin. This study forms the basis for mono, bi and three-dimensional numerical analyses aimed at predicting local amplification effects.

Beschreibung: Published

Beschreibung: 1115-1118

Beschreibung: 4T. Sismologia, geofisica e geologia per l'ingegneria sismica

Beschreibung: In this paper, we have investigated the capability of Differential Interferometry Synthetic Aperture Radar (DInSAR) technique to detect the ground effects induced by liquefaction phenomena occurred during the May 20, 2012 Emilia earthquake. To this aim, a set of COSMO-SkyMed (CSK) SAR images covering the coseismic phase has been used. The detected surface effects have been related to liquefaction of deep sandy layers. Thanks to the geological/geotechnical data in the area and a liquefaction susceptibility analysis of the subsoil, it has been identified a sandy layer between 9 and 13 m in deep, which probably liquefied during the earthquake. The estimated vertical displacements due to liquefaction are comparable with the values measured by DInSAR.

Beschreibung: Published

Beschreibung: 5-9

Beschreibung: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Beschreibung: N/A or not JCR

Beschreibung: We investigated the contribution of earthquake-induced surface movements to the ground displacements detected through Interferometric Synthetic Aperture Radar (InSAR) data, after the Mw 3.9 Ischia earthquake on 21 August 2017. A permanent displacement approach, based on the limit equilibrium method, allowed estimation of the spatial extent of the earthquake-induced landslides and the associated probability of failure. The proposed procedure identified critical areas potentially affected by slope movements partially overlapping the coseismic ground displacement retrieved by InSAR data. Therefore, the observed ground displacement field is the combination of both fault slip and surficial sliding caused by the seismic shaking. These findings highlight the need to perform preliminary calculations to account for the non-tectonic contributions to ground displacements before any estimation of the earthquake source geometry and kinematics. Such information is fundamental to avoid both the incorrect definition of the source geometry and the possible overestimation of the coseismic slip over the causative fault. Moreover, knowledge of the areas potentially affected by slope movements could contribute to better management of a seismic emergency, especially in areas exposed to high seismic and hydrogeological risks.

Beschreibung: Published

Beschreibung: 0303

Beschreibung: 2T. Deformazione crostale attiva

Beschreibung: JCR Journal

Beschreibung: We developed a numerical model by using only early and unreviewed data and information related to the 2016 Mw 6 earthquake in central Italy to quickly evaluate the pore pressure contribution to the aftershock release after a severe mainshock. Moreover, a computational procedure is proposed for discussing if and how such an approach could be useful in the management of a seismic crisis. The two‐dimensional finite element model in this study is based on poroelastic theory and includes a planar seismogenic fault. The model geometry and parameters are based on data collected from the literature before the mainshock. The dip and depth of the seismogenic fault are based on preliminary information from focal mechanisms and related fault inversions. The fault slip is calibrated with synthetic aperture radar interferometric data, and the hydraulic properties of the medium are progressively calibrated based on routine aftershock data collected during the sequence. The procedure proposed here can be efficiently applied in a diverse range of cases depending on data availability. Typically, the available “ingredients” allow for a quick, simplified analysis to be conducted rapidly. The simulation results show that early information and routine data are useful in developing and calibrating a model that can rapidly describe the approximate temporal evolution of overpressured conditions, which represent a crucial driving mechanism in the occurrence of aftershocks. These findings highlight the need to adequately consider time‐dependent poroelastic effects when modeling postseismic scenarios and predicting the spatiotemporal evolution of the stresses following a large earthquake.

Beschreibung: Published

Beschreibung: 995-1015

Beschreibung: 1T. Deformazione crostale attiva

Beschreibung: 2T. Sorgente Sismica

Beschreibung: JCR Journal

Beschreibung: The Sorrentina Peninsula is a densely populatedarea with high touristic impact. It is located in a morphologically complex zone of Southern Italy frequently affected by dangerous and calamitous landslides. This work contributes tothe prevention of such natural disasters by applying a GIS-based interdisciplinary approach aimed to map the areas more potentially prone to trigger slope instability phenomena. We have developed the Landslide Susceptibility Index (LSI) combining five weighted and ranked susceptibility parameters on a GIS platform. These parameters are recognized in the literature as the main predisposing factors for triggering landslides. This work combines analyses conducted on Remote Sensing, Geo-Lithology and Morphometry data and it is organized in the following logical steps: i) Multi-temporal InSAR technique was applied to Envisat-ASAR (2003–2010) and COSMO-SkyMed (2013–2015) datasets to obtain the ground displacement time series and the relative mean ground velocity maps. InSAR allowed the detection of the areas that are subjected to ground deformation and the main affected municipalities;ii) Such deformation areas were investigated through airborne photointerpretation to identify the presence of geomorphological peculiarities connected to potential slope instability. Subsequently, some of these peculiarities were checked on the field; iii) In these deformation areas the susceptibility parameters were mapped in the entire territory of Amalfi and Conca dei Marini and then investigated with a multivariate analysisto derive the classes and the respective weights used in the LSI calculation. The resultingLSI map classifies the two municipalities with high spatial resolution (2m) according to five classes of instability. The map highlights that the high/very high susceptibility zones cover6% of the investigated territory and correspond to potential landslide source areas characterized by 25°-70° slope angles. A spatial analysis between the map of the historical landslides and the areas classifiedaccording to susceptibility allowed testing of the reliability of the LSI Index, resulting in 85% prediction accuracy.

Beschreibung: Published

Beschreibung: 940-965

Beschreibung: 7SR AMBIENTE – Servizi e ricerca per la società

Beschreibung: JCR Journal