Engineering Reconnaissance of the 24 August 2016 Central Italy Earthquake. Geotechnical Earthquake Engineering Reconnaissance GEER Association, Report No. GEER-050,

The central Italy earthquake occurred on 24 August 2016 at 03:36 AM local time. The magnitude is listed as M6.0 by INGV and M6.2 by USGS. Although initially reported as occurring at relatively shallow depths, the current source model from INGV places the hypocentral depth at 8 km, which is not especially shallow for shallow crustal earthquakes. The earthquake was located in a gap between two earlier damaging events, the 1997 M6.1 Umbria-Marche earthquake to the north-west and the 2009 M6.1 L’Aquila earthquake to the south-east. This gap had been recognized prior to the event as a zone of elevated risk (GdL Istituto Nazionale di Geofisica e Vulcanologia, hereafter INGV, 2016). The present event and those that preceded it occurred along the spine of the Apennine Mountain range on normal faults and had rake angles ranging from -80 to -100. Each of these events produced substantial damage to local towns and villages; the present event most strongly affected Arquata del Tronto, Accumoli, Amatrice, and Pescara del Tronto, with a loss of life as of this writing of 294, generally from collapses of unreinforced masonry dwellings. The NSF-funded Geotechnical Extreme Events Reconnaissance (GEER) association, with co-funding from the B. John Garrick Institute for the Risk Sciences at UCLA and the NSF I/UCRC Center for Unmanned Aircraft Systems (C-UAS) at BYU, mobilized a US-based team to the area from 5-9 September 2016. The US team worked in close collaboration with Italian researchers organized under the auspices of the Italian Geotechnical Society, the Italian Center for Seismic Microzonation and its Applications, the Consortium ReLUIS, Centre of Competence of Department of Civil Protection and the DIsaster RECovery Team of Politecnico di Torino. The objective of the Italy-US GEER team was to collect and document perishable data that is essential to advance knowledge of earthquake effects, which ultimately leads to improved procedures for characterization and mitigation of seismic risk. The Italy-US GEER team was multi-disciplinary, with expertise in geology, seismology, geomatics, geotechnical engineering, and structural engineering. Our approach was to combine traditional reconnaissance activities of on-ground recording and mapping of field conditions, with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. This combination of reconnaissance techniques provides opportunities for innovative future study. The objective of this brief report is to provide to the technical community, emergency responders, and public an account of our activities and preliminary findings in a timely way. A more complete presentation of significant aspects of this event and our detailed findings will be presented in a subsequent Version 2 report.