Introduction to the special volume “THE AMATRICE SEISMIC SEQUENCE: PRELIMINARY DATA AND RESULTS”

The M=6.0 earthquake that struck central Italy at 01:36 UTC (Universal Time Co- ordinated) on August 24, 2016, marked the beginning of a long, still-ongoing seismic sequence, which culminated in the Mw 6.5 event at 06:40 UTC on October 30, 2016, while this volume was already in preparation, and reactivated again when this preface was almost complete. This dramatic seismic sequence, which on January 18, 2017, released four additional events of M between 5.0 and 5.5 in a few hours, caused 298 casualties, hundreds of injuries, and the practically total destruction of several villages across a wide area of the central Apennines, cov- ering the Italian Regions of Lazio, Umbria, Marche and Abruzzo. In particular, the historical village of Amatrice was completely destroyed. This seismic sequence represents an important new case study for Earth scientists only 5 years after the Ml 5.9 destructive event in the Emilia- Romagna region in 2012 [Scognamiglio et al., 2012] and 7 years after the Mw 6.3 L’Aquila earthquake of April 6, 2009 [Chiarabba et al., 2009]. During these few years, the skill of the scientific community and its reaction to the emergencies of large destructive earthquakes have improved: the earthquake epicenter and source parameters were precisely located within a few minutes of the mainshock, while the acquisi- tion of on-site multiparametric data started just a few hours after the onset of the seismic sequence. Seismological, geodetic, geological and geochemical data were rapidly collected and analyzed to identify the features of the seis- mogenic source and the geological structures re- sponsible for these earthquakes. The level of damage, the effects on the environment and the extension of ground deformations were rapidly assessed with the ultimate goal of better under- standing earthquake characteristics in order to respond to civil protection requirements. Pre- liminary data were shared worldwide through the internet via the www.ingv.it webpages, while scientific information to the media was rapid and exhaustive, also through dedicated pages (https://ingvterremoti.wordpress.com/). Less than three months after the mainshock, the Istituto Nazionale di Geofisica e Vulca- nologia (INGV) is now publishing a collection of the first scientific results in this special issue of Fast Track papers of Annals of Geophysics, vol. 59, n. 5, 2016, entirely dedicated to The Amatrice seismic sequence: preliminary data and results, as in the case of the 2012 Emilia earth- quake [Anzidei et al., 2012]. Papers are freely available online at the web site of Annals of Geophysics (http://www.annalsof geophysics.eu/), for the rapid distribution of these scientific results. This special issue repre- sents an important goal for the INGV and the whole scientific community which was involved in the study of this seismic sequence.Published1-102T. Sorgente SismicaJCR Journa