## 4 Results  
### Update of the 1980 Iripinia-Basilicata Dataset  
To reach the first aim of this work, we created a new dataset [38], where we updated the number of IDPs for the 1980 Iripinia-Basilicata earthquake, moving from 66 [37] to 563 IDPs. Figure 3 shows the spatial distribution of the IDPs, color-coded according to the type of effect, and the ESI-07 isoseisimals. Most of the effects are located in the epicentral area: 56.9% are within 20 km of the macroseismic epicenter (40.842 N, 15.283 E; [36]) and 84.4% are within 40 km; however, some effects were located nearly 200 km from the epicenter. The area with severe effects (I = X ESI-07) covers about 200 km\({}^{2}\); if we consider the area included in isoseisimal VIII ESI-07, it covers about 2000 km\({}^{2}\).  
Figure 3: Location of IDPs contained in the new dataset, and ESI-07 isoseisimals, referring to the 1980 Iripinia–Basilicata, Southern Italy earthquake.  
We explored the intensity attenuation using different data inputs, namely, (i) the dataset introduced by [PERSON] et al. (2007) [37], (ii) the \"new\" database [38], and (iii) the ESI-07 isoseismals originally drawn in the current research. The first two datasets were analyzed using the IDP method, while the third dataset was analyzed using the grid method.  
As shown in Table 2, the dataset realized by [PERSON] et al. (2007) [37] includes 66 IDPs, the \"new\" dataset contains 563 IDPs, and the grid-based dataset derived from the isoseismals includes 12,634 data points.  
Figure 4a shows the new IDPs (orange dots) and the median epicentral distance calculated for each intensity class. The new dataset shows a considerable increase in the number of IDPs over the entire intensity range (Table 2), with particular reference to the points documented within 40 km from the epicenter. In Figure 4b, we provide the median distances for each ESI-07 degree obtained from the three Irpinia-Basilicata datasets (open symbols);, the black line is the reference IPE for the Apennines derived after [PERSON] et al. (2020) [10] considering an epicentral intensity of ESI-07 X.  
Figure 4b shows that the quality of the input data significantly affects the final output. We recall that the purpose here is to explore the methodological issues and not to derive an IPE specific for the 1980 Irpinia-Basilicata earthquake. When examining the database created by [PERSON] et al. (2007) [37], the median values for each intensity level were higher than those calculated using the new dataset and through isoseismal ma  
Figure 4: (a) IDPs and their relative medians from the “new” 1980 Irpinia–Basilicata dataset; (b) ESI-07 attenuation of each analyzed dataset compared to the reference IPE for the Apennines, Italy, calculated by [PERSON] et al. (2020) [10] and [37;38].  
be attributed to the total number of intensity data points (IDPs) analyzed and their spatial distribution. The new database [38] has lower values compared to the previous [37] and the isoseisomal-derived databases. Specifically, the new database has a higher percentage of points in the near field (within 15 km), 40% compared to 5% for \"Isoseismal Irpinia\", and none for [PERSON] et al. (2007) [37].