Guest editorial: seismic microzonation of Central Italy following the 2016-2017 seismic sequence

The August 24th 2016 Mw 6.0 Amatrice earthquake struck Central Italy (http://cnt. rm.ingv.it/event/7073641; Chiaraluce et al. 2017), causing 298 casualties, hundreds of injured and almost complete destruction of the historical villages of Amatrice, Accumoli, Arquata del Tronto and Montegallo (Graziani et al. 2019; Sorrentino et al. 2018). Unfortunately, the Amatrice earthquake was the beginning of a long-lasting seismic sequence of more than 50,000 events that culminated in the October 30th Mw 6.5 2016 Norcia earthquake, located about 20 km NW of the Amatrice epicentre (http://cnt.rm.ingv. it/event/8863681). Moreover, the sequence included two Mw 5.4 and 5.9 earthquakes occurred on October 26th 2016 close to the Norcia epicentre (Valensise et al. 2017) and four earthquakes of Mw in the range 5.0–5.5 on January 18th 2017, about 20 km SE of the Amatrice earthquake epicentre. This sequence left behind a widespread damage across the territory of 138 municipalities hosting about 582,000 inhabitants distributed over 10 Prov inces in 4 Regions in Central Italy (https://sisma2016data.it/report-page/). Soon after the emergency period, the Italian Government sponsored and funded struc tural and non-structural actions for the reconstruction of the territory struck by the seis mic sequence (Dolce and Di Bucci 2018; Law of the 15th December 2016, n. 229 and Law of the 7th April 2017, n. 45). In particular, the Italian Government Commissioner for the reconstruction allocated about 5,6 million euros to an ambitious project for the Seismic Microzonation of the 138 municipalities (hereinafter, SM project). In such a difficult circumstance, Seismic Microzonation was considered as an important tool for the reconstruction as it allows for the calculation of detailed seismic hazard esti mates accounting for modifications of the expected ground shaking due to local geological conditions.