GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 The analysis involves the creaton of 3D seismogenic source models, considering the available geological and geophysical informaton. By varying individual source parameters such as dip angle and hypocentral depth, we estmate seismic scenarios in terms of macroseismic intensity. This is achieved by calculatng synthetc peak ground moton values, including peak ground acceleraton (PGA) and peak ground velocity (PGV), for each point within the 1706 macroseismic feld (i.e., site). These peak values are subsequently converted into intensites using empirical relatonships. This procedure incorporates site amplifcaton efects into the synthetc ground moton calculatons at each site within the macroseismic feld. For this purpose, Vs,30 data representatve of site efects are obtained from the more recent Vs,30 map proposed as a reference for Italy by Mori et al. (2020). The determinaton of the best source model involves assessing the misft (residuals) between the simulated macroseismic intensites and the observed ones. The accuracy of the simulated macroseismic feld in reproducing the real feld is evaluated by calculatng the residual mean and the root-mean-square error (RMSE). The residual mean is deemed reliable if it is less than 0.1. Our analysis shows a general fair matching between the synthetc and observed macroseismic feld, especially using BORDONI23 and TONDI24 source models. However, the last surface rupture documented by paleoseismological survey in the northwestern sector of the Mt. Morrone fault dates back to the 2nd cent. CE (Galli et al., 2015), with no evidence at all of further actvity (i.e., 1706 and 1933 events). Furthermore, the distributon of the macroseismic feld, with the highest intensites surrounding the Maiella relief does not support the rupture of a normal fault dipping SW. On the other hand, the distributon of the macroseismic feld may be biased by the setlement distributon itself, its characteristcs, and relatve site efects. In conclusion, it is evident that despite the possibility that this study might shed light on this open issue within the Apennine seismicity, there is stll room for discussion and hopefully improvements to beter constrain the seismic hazard of this region.