Local site effects and incremental damage of buildings during the 2016 Central Italy earthquake sequence

The Central Italy earthquake sequence initiated on 24 August 2016 with a moment magnitude M6.1 event followed by a M5.9 and a M6.5 earthquake, that caused significant damage and loss of life in the town of Amatrice and other nearby villages and hamlets. The significance of this sequence led to a major international reconnaissance effort to thoroughly examine the effects of this disaster. Specifically, this paper presents evidences of strong local site effects (i.e., amplification of seismic waves due to stratigraphic and topographic effects that leads to damage concentration in certain areas). It also examines the damage patterns observed along the entire sequence of events in association with the spatial distribution of ground motion intensity with emphasis on the clearly distinct performance of reinforced concrete and masonry structures under multiple excitations. The paper concludes with a critical assessment of past retrofit measures efficiency and a series of lessons learned as per the behavior of structures to a sequence of strong earthquake events

Engineering Reconnaissance Following the October 2016 Central Italy Earthquakes - Version 2

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. As shown in Figure 1.1, this earthquake sequence occurred 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 previously recognized as a zone of elevated risk (GdL INGV sul terremoto di Amatrice, 2016). These events occurred along the spine of the Apennine Mountain range on normal faults and had rake angles ranging from -80 to -100 deg, which corresponds to normal faulting. Each of these events produced substantial damage to local towns and villages. The 24 August event caused massive damages to the following villages: Arquata del Tronto, Accumoli, Amatrice, and Pescara del Tronto. In total, there were 299 fatalities (www.ilgiornale.it), generally from collapses of unreinforced masonry dwellings. The October events caused significant new damage in the villages of Visso, Ussita, and Norcia, although they did not produce fatalities, since the area had largely been evacuated. 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 in two main phases: (1) following the 24 August event, from early September to early October 2016, and (2) following the October events, between the end of November and the beginning of December 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. The composition of the team was largely the same for the two mobilizations, particularly on the Italian side. 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. GEER coordinated its reconnaissance activities with those of the Earthquake Engineering Research Institute (EERI), although the EERI mobilization to the October events was delayed and remains pending as of this writing (April 2017). For the August event reconnaissance, EERI focused on emergency response and recovery, in combination with documenting the effectiveness of public policies related to seismic retrofit. As such, GEER had responsibility for documenting structural damage patterns in addition to geotechnical effects. This report is focused on the reconnaissance activities performed following the October 2016 events. More information about the GEER reconnaissance activities and main findings following the 24 August 2016 event, can be found in GEER (2016). The objective of this document is to provide a summary of our findings, with an emphasis of documentation of data. In general, we do not seek to interpret data, but rather to present it as thoroughly as practical. Moreover, we minimize the presentation of background information already given in GEER (2016), so that the focus is on the effects of the October events. As such, this report and GEER (2016) are inseparable companion documents. Similar to reconnaissance activities following the 24 August 2016 event, the GEER team investigated earthquake effects on slopes, villages, and major infrastructure. Figure 1.2 shows the most strongly affected region and locations described subsequently pertaining to: 1. Surface fault rupture; 2. Recorded ground motions; 3. Landslides and rockfalls; 4. Mud volcanoes; 5. Investigated bridge structures; 6. Villages and hamlets for which mapping of building performance was performed

Reconnaissance of 2016 Central Italy Earthquake Sequence

The Central Italy earthquake sequence nominally began on 24 August 2016 with a M6.1 event on a normal fault that produced devastating effects in the town of Amatrice and several nearby villages and hamlets. A major international response was undertaken to record the effects of this disaster, including surface faulting, ground motions, landslides, and damage patterns to structures. This work targeted the development of high-value case histories useful to future research. Subsequent events in October 2016 exacerbated the damage in previously affected areas and caused damage to new areas in the north, particularly the relatively large town of Norcia. Additional reconnaissance after a M6.5 event on 30 October 2016 documented and mapped several large landslide features and increased damage states for structures in villages and hamlets throughout the region. This paper provides an overview of the reconnaissance activities undertaken to document and map these and other effects, and highlights valuable lessons learned regarding faulting and ground motions, engineering effects, and emergency response to this disaster

Is oral contraceptive-induced headache dependent on patent foramen ovale? Clinical dynamics, evidence-based hypothesis and possible patient-oriented management

Secondary headache is one of the most common side effect during oral contraceptive (OC) treatment and it leads many patients to stop the therapy. Patent foramen ovale (PFO) is an interatrial communication that spontaneously closes at birth in about 75% of the population. However, in the rest of adults PFO maintains a direct communication between the right and left side of circulation. In these patients PFO is a tunnel-like structure that could allow a blood clot to pass from the right to the left side of circulation, thus can cause paradoxical embolization. Although an increased frequency of PFO in patients with migraine was already reported, the relationship between PFO and migraine remains uncertain. In patients with migraine, the prevalence of moderate or large PFO is 35% and seems not associated with the presence of aura or the frequency of headache. Basing on these assumptions, we hypothesize that asymptomatic PFO could play a role in secondary headache due to OC. The procoagulant effect of OC improves the production of microemboli that through the POF could pass from the right to the left atrium and than to the brain, where they could be responsible of secondary headache. If our hypothesis would be confirmed in future studies, it would be possible to identify high-risk patients for developing OC-induced headache and other cerebrovascular major diseases through transcranial Doppler and transesophageal echocardiography. This scenario may radically change the management of reproductive-age woman who have to undergo OC therapy for contraception or other medical conditions

Dynamic characterization of fine-grained soils for the seismic microzonation of Central Italy

An accurate measurement of dynamic soil properties is essential to predict the nonlinear soil behavior under seismic loading conditions. This paper presents a database of cyclic and dynamic laboratory tests carried out after the 2016-2017 Central Italy Earthquake sequence, as part of the seismic microzonation studies in the area. The database consists of experimental results obtained on 79 samples investigated by means of dynamic resonant column tests, cyclic torsional shear tests or cyclic double specimen direct simple shear tests. The dynamic soil behavior is analyzed with reference to the small-strain wave velocity and damping ratio and to the modulus reduction and damping ratio curves. Experimental data are compared with the most widely used predictive models to underline the peculiarities of the investigated soils. Finally, a predictive model is calibrated to capture the nonlinear behavior of typical fine-grained soils from Central Italy