GNGTS 2016 - Atti del 35° Convegno Nazionale

164 GNGTS 2016 S essione 1.1 here we calculated a kind of linear regression between our site intensities (Is) and those of Cavasino in order to calibrate his values and fill our lacking datapoints, mainly the lowermost Is. The new areal distribution of the highest intensity datapoints (Fig. 3) provides a slightly different image of the mesoseismic area which remains strongly focused on the Maiella massif, with a macroseismic epicenter falling close to Lama dei Peligni (black rhomb in Fig. 3). The epicentral intensity can be evaluated around Io IX MCS. In turn, the equivalent magnitude that we have calculated by applying BOXER4 algorithm (Gasperini et al. , 1999) is Mw 6.01±0.07, with a source length of 13 km striking N30°±13°, that is perpendicular to all the main extensional, NW-SE fault of the Apennine. As a concluding remark, it is worth noting that this possible fault bearing fits with most of the focal mechanism calculated by Palombo (2010) on the basis of the analysis of historical seismograms, suggesting the possibility that the 1933 earthquake was generated by a roughly right strike-slip fault. References Cavasino A.;1935a. I terremoti d’Italia nel trentacinquennio 1899-1933 , in “Memorie del Regio Ufficio Centrale di Meteorologia e Geofisica”, s. III, appendice al vol.4. Roma 1935. Cavasino A.; 1935b. Bollettino sismico anno 1933 , fasc.2 (Macrosismi), Regio Ufficio Centrale di Meteorologia e Geofisica. Roma 1935. Corriere della Sera, 27-28-29-30/09/1933, Milano 1933. Gasperini P., Bernardini F., Valensise G., Boschi E.; 1999: Defining seismogenic sources from historical felt reports, Bull. Seism Soc. Am ., 89 , 94-110. Guidoboni E., Ferrari G., Mariotti D., Comastri A., Tarabusi G. and Valensise G.; 2007. CFTI4Med, Catalogue of Strong Earthquakes in Italy (461 B.C.-1997) and Mediterranean Area (760 B.C.-1500) . INGV-SGA. http:// storing.ingv.it/cfti4med/ Il Giornale d’Italia, 27-28/09/1933; 5-6/10/1933, Roma 1933. Il Lavoro Fascista, 27- 29/09/1933; 1/10/1933, Milano 1933. Il Mattino, 27-29/09/1933; 5/10/1933, Napoli 1933. Il Messaggero, 27-28-29/09/1933, Roma 1933. Il Popolo d’Italia, 27-28/09/1933; 1-4/10/1933, Milano 1933. Il Popolo di Roma, 27-29/09/1933, Roma 1933. Il Regime Fascista, 27-28/09/1933; 4/11/1933, Cremona 1933. Il Tevere, 27-29-30/09/1933; 4-5-26/10/1933; 6-24/11/1933, Roma 1933. L’Avvenire d’Italia , 27/09/1933; 1/10/1933; 24/11/1933, Bologna 1933. L’Osservatore Romano, 27-28-29/09/1933; 24/11/1933, Città del Vaticano 1933. La Gazzetta del Popolo, 27-28-29-30/09/1933, Torino 1933 La Nazione, 27-29/09/1933, Firenze 1933. La Tribuna, 27-28-29-30/09/1933; 24/11/1933, Roma 1933. Fig. 3 – Distribution of the highest intensities distribution re-evaluated for the 1933 earthquake (yellow circles proportional to Is V-IX MCS). Dashed lines are the isoseismal lines from VII to IX MCS. Image colors indicate the areal distribution of the intensities; black rhomb is the macroseismic epicenter.