Engineering reconnaissance following the August 24, 2016 M6.0 Central Italy earthquake (original) (raw)
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Reconnaissance of geotechnical aspects of the 2016 Central Italy earthquakes
Bulletin of Earthquake Engineering, 2018
Between August and November 2016, three major earthquake events occurred in Central Italy. The first event, with M6.1, took place on 24 August 2016, the second (M5.9) on 26 October, and the third (M6.5) on 30 October 2016. Each event was followed by numerous aftershocks. The 24 August event caused massive damages especially to the villages of Arquata del Tronto, Accumoli, Amatrice, and Pescara del Tronto. In total, there were 299 fatalities, generally from collapses of unreinforced masonry dwellings. The October events caused significant new damage in the villages of Visso, Ussita, and Norcia, although not producing fatalities, since the area had largely been evacuated. The Italy-US Geotechnical Extreme Events Reconnaissance team investigated earthquake effects on slopes, villages, and major infrastructures. The approach adopted to carry out post-earthquake reconnaissance surveys was to combine traditional reconnaissance activities of onground evidences and mapping of field conditions with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. Presented herein are & G. Vessia
Chapter 2 describes active faults in the region that produced the 24 August 2016 earthquake. Each sub-section describes geological data (mainly based on criteria from Falcucci et al., 2016) and reviews historical seismicity, which collectively provide the basis for inferences of current activity. Data on the past earthquakes and the damage distribution have been derived from Rovida et al. (2016). Two faults among those presented below (namely the Montagna dei Fiori-Monti Gemelli and Leonessa faults) are considered inactive in the sense than they are likely unable to generate earthquakes of sufficient size to produce primary surface rupture (i.e., M>6.0±0.2; Falcucci et al., 2016). The discussion about inactivity is relevant for three reasons: i) They are normal faults with a trend consistent with the current tectonic regime; ii) They are characterized by geomorphologic features that could be incorrectly associated with current activity; and iii) Activity has been hypothesised for one of them (Leonessa) in the available literature. Finally, we discuss an unsolved seismogenic issue, related to the earthquake that struck in 1950 along the Gran Sasso chain (M 5.7).
Engineering Reconnaissance following the 2016 M 6.0 Central Italy Earthquake: Ver 1
2016
The earthquake was located in a gap between two earlier damaging events, the 1997 M6.1 Umbria-Marche earthquake to the northwest and the 2009 M6.1 L'Aquila earthquake to the southeast. 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 cofunding 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.
2017
The GEER Association is supported by the National Science Foundation (NSF) through the Geotechnical Engineering Program under Grant No. CMMI-1266418. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the NSF. The GEER Association is made possible by the vision and support of the NSF Geotechnical Engineering Program Directors: Dr. Richard Fragaszy and the late Dr. Cliff Astill. GEER members also donate their time, talent, and resources to collect time-sensitive field observations of the effects of extreme events. Sponsorship of GEER activities was also provided by 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 under Project BYU13-03. We thank Prof. Mauro Dolce and Engs. Paola Pagliara and Paola Bertuccioli from the Department of Civil Protection for their support and assistance. Matteo Francesco Stancato, master's student at Università della Calabria, contributed to data collection for building structures. We thank Giuseppe Riccioni (Ussita Municipality), Roberto Cantoni, and Raffaele Sorriento (Corpo Nazionale dei Vigili del Fuoco) for allowing surveys at Monte Bove northern flank and Valle di Panico. Eng. Monica Di Mattia (Teramo Province) supported survey activities in Crognaleto. Organizations within Italy that supported the activities reported herein include the Italian Geotechnical Society; the Consortium ReLUIS (Network of Italian Laboratories of Earthquake Engineering), headquartered in the
2010
The earthquake (M w =6.3) was located in the central Italy region of Abruzzo. Much of the damage occurred in the capital city of L'Aquila, a city of approximate population 73000, although many small villages in the surrounding region of the middle Aterno river valley were also significantly damaged. In the weeks following the earthquake, the Geo-Engineering Extreme Events Reconnaissance (GEER) international team, comprised of members from different European countries and the U.S., was assembled to provide post-earthquake field reconnaissance. The GEER team focused on the geological, seismological, and geotechnical engineering aspects of the event. We describe the principal seismological findings related to this earthquake including moment tensors of the main shock and two triggered events, the aftershock pattern and its variation with time, tectonic deformations associated with the main shock, surface fault rupture, and the inferred fault rupture plane. We describe damage patterns on a village-to-village scale and on a more local scale within the city of L'Aquila. In many cases the damage patterns imply site effects, as neighbouring villages on rock and soil had significantly different damage intensities (damage more pronounced on softer sediments). The April 6 mainshock was the best-recorded event to date in Italy. We present metadata related to the recording sites and then present preliminary comparisons of the data to GMPEs. Those comparisons support the notion of faster distance attenuation in Italy relative to the average for active regions as reflected in NGA GMPEs. Several incidents of ground failure are then discussed, including a number of rockfalls and minor landslides. Perhaps the most significant incidents of ground failure occurred at Lake Sinizzo, for which we describe a number of slumps and spreads around the lake perimeter. This is documented using field observations as well as LIDAR and bathymetric data.