GNGTS 2016 - Atti del 35° Convegno Nazionale

110 GNGTS 2016 S essione 1.1 • the May 31, 1646 (Gargano, I 0 = X MCS, Mw=6.7 ); • the January 29, 1657 (Capitanata, I 0 =VIII-IX MCS, Mw=6.0 ); • the March 20, 1731 (Tavoliere delle Puglie, I 0 =IX MCS, Mw=6.3 ); • the February 7, 1844 (Adriatic sea, I 0 =VIII MCS, Mw=5.6 ); • the December 6, 1875 (Gargano, I 0 =VIII MCS, Mw=5.9 ); • the August 10, 1893 (Gargano, I 0 =VIII MCS, Mw=5.4) The strongest historical seismic events of the SouthernApennines, powerfully felt in Salento with intensity I ≥ VI MCS are: • the December 5, 1456 Molise earthquake (Imax = XI MCS) felt in Lecce and Brindisi with I=VI MCS (Figliuolo, 1988); • the June 5, 1688 Sannio earthquake (Imax= XI) with collapse of the tower in Galatina (I=VII MCS, Serva, 1985); • the September 8, 1694 Irpinia-Basilicata earthquake, (Imax=X-XI MCS) felt in Canosa with IX MCS, Brindisi, Lecce and Mesagne with I= V MCS. In Brindisi were observed tsunami environmental effects; • the Febrary 5, 1783 ad following shocks (Imax= XI, MCS, Margottini, 1992) with felts in Salento peninsula (Margottini, 1992); • the December 16, 1857 Basilicata earthquake, (Imax = XI MCS) felt in Canosa di Puglia with I=VIII MCS, in Altamura with I=VI-VII MCS, in Taranto with I=VI MCS and in Bari and Lecce with I=V MCS (Branno et al. , 1985). More recently, the July 23, 1930 (Imax =X MCS) and the November 23, 1980 (Imax =X MCS) Irpinia earthquakes gave rise to several ground effects, mostly hydrological variations, in the Apulian region (Porfido et al. , 2007). The Salento peninsula is less than 100 km far from Albanian and Greek coasts where many energetic earthquakes occur and are strongly felt in Salento. Well documented examples of earthquakes from central-eastern Mediterranean area, felt in Salento, are the following: • theAugust 27, 1886 earthquake (Peloponnesus, Greece) felt in Salento with high intensity, I=VII MCS (Margottini, 1982; Papazachos et al. , 2003; Serva et al. , 2010; Grünthal et al. , 2013); • the May 28, 1897 earthquake (epicenter in Tripole, Greece) with intensity I=VI MCS in Salento (Papazachos et al. , 2003; Serva et al. , 2010, Grünthal et al. , 2013); • the August 11, 1903 earthquake (epicenter in Peloponnesus area) with I=IV-V MCS in Salento (Margottini 1982; Serva et al. , 2010); • the June 26, 1926 earthquake (epicenter close to Rhodes Imax=IX MSK, Ambraseys et al., 1998) felt throughout Southern Italy. The intensity in the town of Taranto (western Salento) was IV-V MCS (Castenetto et al., 1986); • the August 28, 1962 earthquake (epicenter in Peloponnesus area) with I=VI MCS in Salento (Margottini 1982; Serva et al. , 2010). Conclusions. The current classification of the Salento seismic hazard is underestimated in our opinion and is prevalently attributed to the lack of high energy seismicity inside the area. Tab. 1 shows that the Salento is seismically active and characterized by historical and instrumental seismicity of low and moderate energy (3<M<5); this level of activity cannot be neglected. This study has allowed us to point out a quite different scenario for the seismic hazard assessment of the Salento peninsula, currently classified in IV category (Seismic Classification Map of the Italian territory, MPSO4-Order PCM 3519/2006), taking into account also the effects due to the faraway and strong earthquakes located in the central Mediterranean, and the relative damages on urbanized and natural environment. Moreover, it is also important to remind, as regards the local risk level, that the Salento peninsula represents one of the most crowded touristic destination of the Southern Italy, all over the summer season.