ALBERT

Description: We present the results of a multidisciplinary and multiscale study at Mt. Massico, Southern Italy. Mt. Massico is a carbonate horst located along the Campanian-Latial margin of the Tyrrhenian basin, bordered by two main NE–SW systems of faults, and by NW–SE and N–S trending faults. Our analysis deals with the modelling of the main NE– SW faults. These faults were capable during Plio-Pleistocene and are still active today, even though with scarce and low-energy seismicity (Mw maximum = 4.8).We inferred the pattern of the fault planes through a combined interpretation of 2-D hypocentral sections, a multiscale analysis of gravity field and geochemical data. This allowed us to characterize the geometry of these faults and infer their large depth extent. This region shows very striking gravimetric signatures, well-known Quaternary faults, moderate seismicity and a localized geothermal fluid rise. Thus, this analysis represents a valid case study for testing the effectiveness of a multidisciplinary approach, and employing it in areas with buried and/or silent faults of potential high hazard, such as in the Apennine chain.

Description: Published

Description: 1673–1681

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: We report the results of a multidisciplinary investigation performed across the normal Quaternary faults that ruptured the surface during the August 24 (Mw 6.0) and October 30 (Mw 6.5), 2016 strong earthquakes in the Mt. Vettore-Mt. Bove areas, central Italy. Our aim is to test the effectiveness of the contribution of a multi-scale gravimetric analysis in characterizing seismogenic faults’ geometry at hypocentral depths on well-known outcropping faulty systems with known earthquake distribution. We adopted a multi-scale geophysical/geological approach consisting in the comparison of gravity lineaments inferred by Multiscale Derivative Analysis with the Quaternary structural setting mapped in the study area, the primary coseismic surface ruptures of the 2016-2017 sequence and the earthquakes’ epicentral distribution. Moreover, we performed a combined interpretation of 2D hypocentral sections of the 2016-2017 seismic sequences with images resulting from the Depth from Extreme Points method, to infer the faults’ geometry at depth. Based on our results, the investigated NW-SE Mt. Vettore-Mt. Bove fault system is dipping 60°-70° westward. We also detected the splays of this primary fault and its blind antithetic NW-SE structure, dipping northeastward. In the Norcia basin we highlight two main faults bordering the basin with a dip of about 45°. The one edging the eastern side dips westward, whereas the fault edging the western side dips eastward. Thanks to our analysis we could identify and characterize the geometry of the Norcia and Vettore master faults, as well as other blind/buried and/or silent faults that are related to the 2016 seismogenic structure. Our results show the effectiveness of this approach in potentially high-hazard areas that are structurally poorly known.

Description: Published

Description: DA558

Description: 2T. Deformazione crostale attiva

Description: JCR Journal

Description: The area of San Giuliano di Puglia (Southern Italy) was struck by a moderate earthquake of Mw=5.7 on October 31st, 2002. The aim of this study is to identify and better constrain the geometry of the seismogenic structures (active, outcropping and buried faults) in the area. We used an integrated analysis of geo-structural, seismic and gravimetric data. We built three thematic databases: “faults”, “earthquakes” and “gravimetric" data: 1. The fault database consists of data extracted from the available structural and geological maps: ITHACA (ITaly HAzard from CApable faults) catalogue; DISS (Database of Individual Seismogenetic Sources) database; the "Neotectonic Map of Italy" 1:500.000; the Geological Map 1:100.000, Sheets 154, 155, 162, 163; several geological studies. 2. The earthquakes database was created by merging the data from historical and instrumental Catalogues (CPTI11; ISIDE-INGV). 3. The gravimetric database was created through the Multiscale Derivative Analysis (MDA) of the Bouguer anomaly map of the area, whose maxima show the presence of density lineaments. The integration of these datasets in GIS environment, identified three possible cases of correlation between faults, earthquakes and MDA maxima: ⦁ A clear correlation between epicentral location, fault positions and MDA maxima shows the existence of active faults; ⦁ A good correlation between MDA maxima and epicentral positions, without correspondence with faults known from geological data, can suggest the presence of buried active faults; ⦁ A good correlation between faults from geological datasets and literature and MDA maxima, without correlation with earthquakes, can indicate the existence of inactive or silent faults. Previous studies show that the main shock in the area of San Giuliano di Puglia was generated by a deep and subvertical strike-slip structure E-W trending, with a right lateral focal mechanism (Galli & Molin, 2004). Nevertheless, Vezzani et al. (2009) proposed a reverse fault mechanism. Valensise et al. (2004) suggested that the 2002 events could be related to the Mattinata fault, a major active right lateral strike-slip fault cutting across the Gargano promontory, In order to better constrain the structural framework of this area, we combined faults seismic data and a multiscale approach of gravity data in GIS environment.

Description: Published

Description: Napoli

Description: 1T. Deformazione crostale attiva