GNGTS 2023 - Atti del 41° Convegno Nazionale

Session 1.1 GNGTS 2023 The November 2022 Pesaro offshore seismic sequence (Adriatic sea, Italy): reinterpretating public seismic reflection profiles images the earthquake causative fault system into a new 3D geological model F.E. Maesano 1 , M. Buttinelli 1 , R. Maffucci 1 , G. Toscani 2,3 , R. Basili 1 , L. Bonini 4,1 , P. Burrato 1 , J. Fedorik 5 , U. Fracassi 1 , Y. Panara 5 , G. Tarabusi 1 , M. M. Tiberti 1 , G. Valensise 1 , R. Vallone 1 , P. Vannoli 1 1 Istituto Nazionale di Geofisica e Vulcanologia, Rome, ITALY 2 Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, Pavia, Italy 3 Centro InteRUniversitario per l’Analisi SismoTettonica Tridimensionale con applicazioni territoriali, Chieti, Italy 4 Dipartimento di Matematica e Geoscienze, Università di Trieste, ITALY 5 King Abdullah University of Science and Technology, Thuwal, Saudi Arabia The Northern Apennines chain is characterized by thrust faults running from the Po Plain to the Adriatic Sea on the northeastern side of peninsular Italy. These thrusts are deeply buried below a thick cover of Plio-Pleistocene deposits. Diverging interpretations and views arose concerning the activity and earthquake potential of these thrust faults, based on their hidden geological signature and the scarce seismicity associated with them. The prompt identification of faults responsible for moderate-to-large earthquakes is of critical relevance, especially when the seismic source is a buried fault located in offshore areas, where neither surface co-seismic ruptures nor GPS/InSAR deformation data are available in the aftermath of a damaging shock. In these cases, multichannel seismic reflection profiles rather represent the sole means to appraise the subsurface structural setting. In this work, we reinterpreted publicly available seismic reflection profiles and well logs to analyze the crustal volume affected by the seismic sequence started on 9 November 2022 with an Mw 5.5 in the Pesaro Offshore. This earthquake ruptured a portion of the buried Northern Apennines outermost thrust front that was already mapped as a potential seismogenic source in the DISS database, albeit at a much lower resolution ( https://diss.ingv.it/diss330/sources.php?ITCS106 ). The 3D geometry of the thrust activated during the seismic sequence suggests that it can also host larger earthquakes. These results are a significant input for earthquake hazard models as well as