GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 The ‘Many’ Seismogenic Sources of the 1706, Mw=6.8, Maiella Earthquake: New Insights from Source Modelling T. Volatli 1 , V. Gironelli 1, 5 , L. Luzi 2 , P. Galli 3 , M. M. C. Carafa 4 , E. Tondi 1, 5 1 Scuola di Scienze e Tecnologie – Sezione di Geologia, Università di Camerino, Italy 2 Isttuto Nazionale di Geofsica e Vulcanologia, Milano, Italy 3 Presidenza del Consiglio dei Ministri, Dipartmento della Protezione Civile, Servizio Rischio Sismico - Roma, Italy 4 Isttuto Nazionale di Geofsica e Vulcanologia, Sezione di Sismologia e Tetonofsica, L’Aquila, Italy 5 Isttuto Nazionale di Geofsica e Vulcanologia, Sezione di Sismologia e Tetonofsica, Camerino, Italy Introducton Inner Abruzzi (central Italian Apennines), rank among the highest seismic hazard regions of Italy (Akinci et al., 2009; Petricca et al., 2015). All along the Apennines divide, a well-studied system of SW-dipping normal faults has been actve both historically and in recent tmes, as evidenced by moderate-to-large earthquakes (Mw ≥ 5.5. Galadini and Galli, 2000). The most recent destructve seismic sequence occurred on April 6, 2009, (Mw = 6.3), known as the L’Aquila earthquake. Following the events of 2009, there has been a growing interest in assessing the seismogenic potental of actve faults in this region. Numerous studies have been conducted to identfy actve and potentally seismogenic structures. However, there are areas like the Maiella Massif, where both historical and instrumental seismicity are elusive, notwithstanding the occurrence of two strong events on November 3, 1706, and September 26, 1933, with Mw ~6.8 and 5.9, respectvely (Rovida et al., 2022). According to Galli and Pallone (2019) and the Italian Macroseismic Database (DBMI15; Locat et al., 2022), these earthquakes caused severe damage over a wide area, with maximum epicentral intensites on the Mercalli-Cancani-Sieberg (MCS) scale reaching X-XI and IX, respectvely. Despite being labelled as the Maiella earthquakes, the seismogenic structure responsible for these events remains controversial. Various hypotheses have recently been proposed in the literature regarding the source of the 1706 earthquake. Before mentoning these hypotheses, it is worth notng that Pomposo and Pizzi (2009) have hypothesized that the area east of the Morrone-Porrara fault alignment is undergoing actve compression, based on morphotectonic evidence of actve antcline growth in the Orsogna area, suggestng a relatonship with another strong event of the area (1881, Mw 5.4). Galli and Pallone (2019), who re-evaluated the macroseismic intensity distributon on the basis of previously unknown historical sources, have suggested the actvaton of a blind backthrust that developed during Early-Middle Pleistocene in the footwall of the Maiella antcline as the potental