Ground effects triggered by the 24th August 2016, Mw 6.0 Amatrice (Italy) earthquake: surveys and inventorying to update the CEDIT catalogue

Abstract

The CEDIT catalogue, Italian acronym of Catalogue of Earthquake- Induced Ground Effects, is available since 2011. After the Mw 6.0 Amatrice (Italy) earthquake (occurred at 01:36:32 UTC on 24th August, 2016) this catalogue was updated with 147 new inventoried ground effects. Since the first hours after the mainshock, field works and targeted remote sensing analyses were performed for recognizing and inventorying earthquake-induced ground effects. To avoid an inextricable overlap of ground effects due to either earthquake or rainfall events, intensive field activities were carried out and completed within a week, hence before the first intense rainfalls occurred on 30th of August. Ground effects mainly consist of landslides, in particular rock-falls and rock- and debris- slides, whereas less than 2% of the effects consist of ground cracks not directly related to landslides. The maximum distance from the epicenter of the surveyed ground effects is about 36 km, though more than 50% of the effects occurred within 20 km. The plano-altimetric distribution of ground effects is rather conditioned by the presence of road cuts, as well as by local natural hillslope topographic and morphological setting. The 73% of the triggered landslides intercepted road-cuts and accounted for significant interference with local traffic and emergency activities. The altimetric distribution of the ground effects covers a range of about 1000 m (from 600 up to 1600 m a.s.l.), emphasising that the ground effects involved the outcropping rock masses in different topographic conditions. Moreover, the homogeneous distribution of the ground effects into the different outcropping lithological units suggests that lithology did not play a principal role as predisposing factor for the earthquake-induced slopes failures occurred in the area. This work presents the methodological approach used for efficiently recognizing and inventorying ground effects triggered by the 24th August 2016 (Mw 6.0) Amatrice earthquake, as well as for managing and sharing results online on a global, pre-existing and public geo-database.