GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 The study allowed to reconstruct in detail the March 1952 seismic sequence and to obtain the intensity data points (IDPs) for the mainshock as well as for two strong foreshocks. The frst event occurred on 1 March (12.35 GTM) and had epicenter near Zaferana, where produced difuse but minor damage (I 0 = VI-VII EMS); it was followed the day afer (14.14 GTM) by a stronger shock increasing damage in the same area (I 0 = VII EMS). In the following days there were several other minor shocks of low intensity, locally felt by people; the seismic sequence culminates with the mainshock on 19 March (08.13 GMT, I 0 = VIII-IX EMS), which produced very heavy damage in Linera and other localites nearby, causing two victms and around sixty injured. Afershocks (not damaging) followed for some days. Fig. 3 shows the IDPs determined for the mainshock of 19 March: Linera sufered the partal destructon (I = VIII-IX EMS) whereas Bongiardo and Rocca d'Api (I = VIII) had a number of partal/ total collapses especially for the most vulnerable buildings. As usual for the shallow volcano- tectonic earthquakes at Etna (Azzaro et al., 2006), the intensity atenuaton is very strong so damage efects disappear quickly at a few kilometers of distance from the causatve fault (in Catania the event was only felt). Impressive coseismic faultng phenomena accompanied this earthquake as well as the two strong foreshocks of 1 and 2 March. This macroseismic feld is basically diferent compared to the one by Patanè and Imposa (1995), both in terms of maximum intensity – I max = VIII-IX vs VII-VIII EMS, respectvely – and for the number of IDPs.