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Progetto CARG - ISPRA, Note illustrative del Foglio 590 - Taurianova

Sea floors surrounding Procida Island in the Bay of Naples have been studied from a morpho-structural point of view. Such a study has been based on both direct survey of the submarine environment (up to the depth of 30 m) and seismic lines and echographic data interpretation, and allowed us to realize an accurate geomorphological map of the pericoastal areas. Marine recent deposits, tectonic morpho-lineaments, submarine erosional terraces, submerged notches and other submerged sea level markers have been mapped, so contributing to define the Holocene morpho-evolutionary picture of the Phlegraean offshore. The good fit between the submarine fracture system and the inland fault and fracture pattern suggests that the investigated coastal marine areas underwent the same late- Quaternary structural history of the nearby continental region. In addition, the recognition of several base-palaeolevels of the erosion allows to better define the interplay among sea-level changes, tectonics, and volcanogenic vertical movements. Archaeological data, ages of the volcanic products, their morpho-stratigraphic relationships with the submarine erosional terraces and other geomorphological constraints permit now a suitable chronological attribution to the different orders of land surfaces, making more reliable the calculation of the subsidence rates and helping the comprehension of the morpho-evolutionary trend of the study area. The planimetric geometry of the strain field has been achieved by both submarine survey and morphostructural analysis: It clearly shows en echelon style, consisting of three dimensionally similar fault-bounded sectors (Canale di Procida, Isola di Procida p.p. and Promontorio di Solchiaro - Isola di Vivara - Canale di Ischia). From a physiographic viewpoint, such sectors result separated by E-O to N120°-striking faults producing an apparent dextral offset. It is likely that they may represent transfer structures due to extensional deformation by NNE-SSO-striking master faults and, therefore, featured by a "passive" left-lateral slip. The fault set displacing the Neapolitan Yellow Tuff in the Capo Posillipo area and absent in the Procida Island area is N50-60° oriented. Such a trend also characterizes joint sets affecting submarine outcrops associated to hydrothermal phenomena. Then, one can conclude that this trend represent very recent structures, cut only by erosional surfaces located at a depth of 14/-15 m and attributed to the Middle Bronze Age. The subsidence rate calculated for five different orders of submarine erosional surfaces is apparently constant, showing always values around 4-5 mm/y and so suggesting a regular evolution trough the time of the studied pericoastal system, characterized by the submersion of portions of coastal sectors by continuous and invariable volcano-tectonic subsidence. Yet, using the Post-Holocene sealevel rising curve to set the eustatic correction, it is possible to obtain a more articulated picture of the morpho-evolutive sequence, characterized by alternating periods of different subsidence rates. This scenario seems to be more realistic in an area of complex interplay between tectonics and sea-level changes such as the Phlegraean Fields.

New stratigraphic constraints have been detailed for the Amatrice Basin, an intermountain morpho-structural depression of the central Apennines (Italy) hosting up to 60-m-thick Quaternary continental deposits. Through the results coming from a 1:5,000 scale field survey and from facies analyses, we documented the geometry, thickness, and extent of the post-orogenic continental deposits filling this basin. The Quaternary deposits form a complex architecture of purely aggradational and aggradational/degradational terraces with a dominant component of conglomerates and gravels, at the bottom, and subordinate sands, at the top. The Quaternary deposits overlie an up to 1-km-thick succession of flysch sediments that accumulated in the western Laga Basin during the Miocene syn-orogenic phases in central Apennines. The collected data are used to constrain the style and mechanisms of both syn-orogenic (i.e., subsidence and terrigenous sedimentation in foredeep environment) and post-orogenic (i.e., uplift, erosion, and continental sedimentation) phases documented for the central Apennines. In particular, the post-orogenic history of the Amatrice Basin, if compared with those of surrounding intermountain basins of the central Apennines, includes limited basin subsidence, reduced thickness of the post-orogenic covers and progressive deepening of the drainage network during the Quaternary. The results shed light on the source-to-sink history of the Amatrice Basin, which results from a long-lived interaction between regional-scale factors (climate changes, chain uplift, and extensional tectonic regime) that influenced the activity of the hydrodynamic pattern and the amount of intrabasinal sedimentation during the Quaternary.

A 1:5,000 scale geological map and 31 geological cross-sections are presented for the surroundings of Amatrice village (central Apennines, Italy), epicentral area of the first damaging earthquake of the 2016–2017 seismic sequence. This detailed geological dataset focuses on: (i) the extent, the thickness, and the internal stratigraphic architecture of the Quaternary continental deposits; (ii) the bedding and the thickness of the Miocene substratum; and (iii) the spatial distribution of the main fault systems. The provided dataset would update the available regional geological maps in deciphering the syn-to-post-orogenic history of the Amatrice Basin. Eventually, the accuracy of the geological mapping would represent a basic tool for interpreting and integrating the multidisciplinary dataset deriving from post-seismic activities.

This work presents the results from numerical analyses in the damaged area of Saletta hamlet (Amatrice municipality), aiming at discussing factors leading to the observed damages after the 24th August 2016 Mw 6.0 earthquake and the following aftershocks. The area of Saletta was in fact highly ravaged by the first earthquake and during the whole seismic sequence. Geological-technical detailed field investigations were combined with an Electrical Resistivity Tomography and several noise measurements for better evaluating the main geological-morphological variability over the study area. Following insights from the reconstructed geological setting, a continuous coring borehole was drilled and a down-hole test performed together with a passive 2D small array and an active 1D MASW measurement. All these data were used to obtain the subsoil model for the numerical analyses that were carried out using both 1D and 2D approaches, including linear and equivalent linear ones, aiming at evaluating site effects.