GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.1 GNGTS 2024 the coseismic efects in the territory as it appeared at the tme, including cracks, landslides, efects on surface waters, liquefactons, appearance of ponds, etc. The detailed visual representaton of the efects allowed for a beter atributon to the correct efect category, compared to only consultng historical sources. Moreover, since in many cases it was possible to georeference the drawings accurately, we were able to improve the locaton of the efects. As an in-depth part of this work, we also conducted a specifc analysis of the Historical Earthquake- Induced Landslides (HEILs), in order to include new data in the CFTI Landslide (Zei et al., 2023). Our goal was to achieve a more accurate locaton and defniton of the slope movement types of the HEILs, whenever the descriptons of the historical sources or drawings allowed it, through a geographical comparison with data of diferent origins. When possible, these efects were associated with the individual landslides reported in the IFFI database ( htps:// www.progetoif.isprambiente.it/) . Our review led to a 120% increase in the pre-review number of efects, totalling 494 elements. Over 67% of the efects are now connected to a specifc earthquake in the sequence, compared to the previous 2%. The most numerous efects are those afectng the ground (69% of the total); within this class, the more common are landslides (59% of ground efects). Furthermore, the review returned efects related to seven EE categories for which there were no data (fgure 1). Fig.1 Pre- and post-review efects on the natural environment collected for the 1783 Calabria earthquake sequence. Regarding HEILs, 36% of them have excellent/good locaton accuracy. All earthquake-induced landslides, along with their improvements in number, movement type and locaton, are now collected into the CFTILandslides database (Zei et al., 2023).