Cartografia prototipale di faglie attive e capaci in relazione alla distribuzione di sorgenti sismogenetiche

An "active and capable fault" (ACF) defines an active fault able to permanently dislocate the ground surface, while a "seismogenic source" (SS) is a fault capable of generating earthquakes. When the deep coseismic rupture along a SS propagates towards the surface, the latter can be permanently dislocated. Consequently, the geological features of an ACF could be considered the surface expression of the deep activity of a SS. For example, the geological studies, carried out before the seismic sequences of central Italy along the faults responsible for the main earthquakes of 2009 and 2016-2017, are been partly confirmed by the coseismic ruptures produced during these seismic sequences. This highlighted the importance of defining in a "preventive" way what are the ACFs and SSs and where they are located in a given area. The dichotomy between ACF and SS in Italy is, however, still marked in the literature, resulting in the presence of two national databases: the "Catalog of capable faults" (ITHACA) and the "Database of Individual Seismogenic Sources" (DISS) which deal with ACF and SS, respectively. Nonetheless, the analysis of the two databases highlights the presence of some conceptual and critical differences that can not permit conceptual and factual interoperability between them. These difficulties highlight the lack of criteria used for the assessment of the ACF and SS and, therefore, the need to define a clear and well-defined methodological approach, allowing to map an ACF in relation to a SS. The following Ph.D. research, therefore, proposes a conceptual model able to combine the concept of ACF with that of an SS. The result of this model is represented by a prototype thematic map (Attached I) of ACFs that represent the superficial expression of SSs, in the central-southern Apennines. The realization of the conceptual model and the identification of the geological and segmentation criteria, useful for establishing the relationship between ACF and SS (the object of Map C), were made possible by the use of a multidisciplinary methodological approach: the acquisition and analysis of literature, photogeological analysis and, especially, the acquisition of geological, geomorphological, structural and paleoseismological data in 5 test areas of the central-southern Apennines. These geological studies have allowed clarifying that many of the criteria, used individually to assess an ACF as an expression of a SS, may not always be sufficient to define the presence of ACF in a given area if they are not framed within a comprehensive geological study. The use of this approach and the resulting map (Attached I) provides the knowledge to conceptually relate the main ACFs of the central-southern Apennines with the respective SSs, superimposing seismogenic parameters to information concerning the distribution and entity of permanent dislocations of the ground surface. These elements represent the input data for an evaluation of the seismic hazard of a given area, in terms both of maximum magnitude expectations, useful for the definition of shaking scenarios in the context of the design of infrastructures and major buildings, and surface faulting hazard for land planning studies.