Site response analyses for complex geological and morphological conditions: relevant case-histories from 3rd level seismic microzonation in Central Italy

The paper presents the results of 5 case studies on complex site e ects selected within the project for the level 3 seismic microzonation of several municipalities of Central Italy dam- aged by the 2016 seismic sequence. The case studies are characterized by di erent geo- logical and morphological con gurations: Monte San Martino is located along a hill slope, Montedinove and Arquata del Tronto villages are located at ridge top whereas Capitignano and Norcia lie in correspondence of sediment- lled valleys. Peculiarities of the sites are constituted by the presence of weathered/jointed rock mass, fault zone, shear wave veloc- ity inversion, complex surface and buried morphologies. These factors make the de ni- tion of the subsoil model and the evaluation of the local response particularly complex and di cult to ascertain. For each site, after the discussion of the subsoil model, the results of site response numerical analyses are presented in terms of ampli cation factors and acceleration response spectra in selected points. The physical phenomena governing the site response have also been investigated at each site by comparing 1D and 2D numerical analyses. Implications are deduced for seismic microzonation studies in similar geological and morphological conditions.Published5741–57775T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa

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

Impianto cocleare in bambini con disturbi dello spettro autistico (DSA): risultati e caratteristiche di fitting.

Scopo dello studio è stato la valutazione a lungo termine delle abilità percettive ed espressive del linguaggio e le caratteristiche del fitting di un gruppo di bambini con ipoacusia grave/profonda, diagnosticati con disturbi dello spettro autistico (DSA), portatori di impianto cocleare (IC). Materiali e metodi: Lo studio osservazionale multicentrico ha incluso 22 bambini con DSA e sordità neurosensoriale profonda. Sono stati raccolti i dati riguardanti la diagnosi di sordità , la diagnosi di DSA, il timing e la compliance all’IC. La percezione uditiva e le abilità linguistiche a 2 anni, 5 anni e 10 anni di follow up sono state riportate utilizzando le Categories of Auditory Performance (CAP) e le Categories of Language (CL). Sono stati inoltre raccolti i parametri elettroacustici dell’IC. Risultati: Il controllo delle abilità percettive ed espressive a lungo termine ha evidenziato un punteggio CAP estremamente variabile. Solo il 22% dei bambini aveva raggiunto un livello equivalente alla comprensione di frasi comuni (CAP 5), o era in grado di sostenere una conversazione (CAP 6) senza la lettura labiale. Nella maggior parte dei bambini (72,7%) il punteggio CL equivaleva all’uso di una vocalizzazione indifferenziata (CL 1) o all’uso di poche parole isolate (CL 2), mentre solo il 18,2% aveva raggiunto il livello più alto di abilità linguistiche. I punteggi di CAP e CL erano significativamente correlati con la gravità dei sintomi di DSA. Le caratteristiche elettroacustiche dell’IC non erano correlate alla soglia uditiva o all’ età all'impianto, mentre erano correlate alla gravità dei DSA. Il 13,6% (3) dei bambini con una forma grave di DSA avevano un utilizzo parziale ed incostante dell’IC. Conclusioni: Il presente studio vuole essere un contributo mirato a fornire una maggiore comprensione dei parametri e delle caratteristiche di fitting che si correlano con la gravità dei disturbi di DSA, tale da supportare le procedure cliniche di regolazione dell'impianto cocleare

Cochlear implantation in children with Autism Spectrum Disorder (ASD): outcomes and implant fitting characteristics

Background: Little is known regarding fitting parameters and receptive and expressive language development in cochlear-implanted children (CCI) with profound sensorineural hearing loss (SHL) who are diagnosed with Autism Spectrum Disorder (ASD). The aim of the study was to evaluate a group of ASD CCI users in order to describe their ASD clinical features and CCI outcomes; report on the average electrical charge requirements; and evaluate the possible correlations between electrical and psychophysical outcomes with ASD characteristics. Materials and Methods: A multicentre observational study of 22 ASD children implanted in four cochlear implant (CI) centres. Data concerning profound SHL diagnosis, ASD diagnosis, CI timing and CI compliance were collected. Sound Field (SF) was assessed through repeated behavioural measurements. Categories of Auditory Perception (CAP) and Categories of Language (CL) were used to evaluate speech perception and language skills at short (≤2 yrs), medium (5 yrs) and long term (>10 yrs) follow-up. Fitting parameters such as comfortable thresholds, pulse-width (pw, µsec) and clinical units converted into units of charge/phase were collected. The diagnosis of ASD was acquired by the referral neuropsychiatric department and severity was assessed through the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) and the Childhood Autism Rating Scale (CARS). Results: At the final follow-up session the median SF threshold for CI outcomes was 30 dB HL (min 15 – max 60). CAP score was extremely variable: 45.5 % showed no improvement over time and only 22% of children reached CAP scores of 5-7. CL 45.5% showed no improvement over time and score was 1-2 in the majority of ASD children (72.7%), while only 18.2% reached the highest level of language skills. There were no statistically significant differences at each follow-up between subjects with or without comorbidities. CAP and CL were inversely correlated with DSM-V A and B domains, corresponding to lower speech and language scores in children with more severe ASD symptoms, and maintained their correlation at mid and long follow-ups whilst controlling for age at CI. Electrical charge requirements did not correlate with SF or age at implant but did inversely correlate with ASD severity. With regards to CI compliance: only 13.6% children (3) with severe DSM-V A/B levels and CARS score were partial/intermittent users. Conclusion: The present study is a targeted contribution to the current literature to support clinical procedures for CI fitting and audiological follow-up in children with ASD. The findings indicate that the outcomes of CI use and the fitting procedures are both influenced by the severity of the ASD symptoms rather than the demographic variables or associated disorders

Local seismic hazard assessment in explosive volcanic settings by 1d and 2d numerical analyses

In this study, we face the problem of local seismic response in explosive volcanic setting by using an integrated geological-geophysical-geotechnical approach in the test area of Stracciacappa maar (Sabatini Volcanic District, central Italy). Our aim is to understand if the horizontal and vertical chaotic heterogeneity typical of the volcanic deposits influence site response. The Stracciacappa maar is an active eruptive centre characterised by a crater of about 1 km in diameter and a crater floor of about 30-40 m below the rim (De Rita et al. 1983; Sottili et al. 2012). The ring is mainly composed by the pyroclastic succession belonging to the last phreatomagmatic activity. This pyroclastic succession generally bends outward the rim with low angle dip (10-20°). It consists of at least 25 metres thick alternation of decimetre- to centimetre-thick layers of fine-medium ash and small lapilli. The crater depression is filled by epiclastic debris deposits and by recent and present-day lacustrine muds. The epiclastic debris deposits, of alluvial and delta origin, consist of alternation of cm-thick reworked fine-grained and coarse-grained volcaniclastic material, dipping with low-angle (1s) motions, compared to tectonic events of equivalent magnitude (Jousset and Douglas 2007); the unscaled recording at Bronte Station (BNT in ITACA database, http://itaca.mi.ingv.it) of the ML=4.4 October 27, 2002 event was employed; 2) a high magnitude far-field “tectonic” event (tectonic scenario), whose reference spectrum was built with Ground Motion Prediction Equations (Ambraseys et al., 2005) assuming M=6.5 and distance of 70 km. These conditions are compatible with seismogenic sources located in central Apennines of Italy. Three unscaled recordings of events characterised by magnitude and distance in the range of 6-7 and 60-90 km, respectively, were extracted from ITACA database (http://itaca.mi.ingv.it), matching on average the reference spectrum Two subsoil models have been considered: a detailed model (based on distribution of the lithotypes unravelled by the geological survey) and a simplified one (obtained by grouping interfingering lithotypes resting below the lacustrine silty clays). The result show that the two models have similar response in all range of the interesting period (0.1-1.0s); the damping properties of soft clays and sands deposits in the upper meters reduce the difference in the seismic response at the surface of both models. The results suggest the possibility to simplify the heterogeneous distribution of deposits in this volcanic context for assessment of seismic response purposes. Finally, we carried out both linear and equivalent linear analyses in one-dimensional and bi-dimensional conditions, in order to investigate the bidimensional effects and the role of nonlinearity on the seismic response,. In linear case the behaviour of soils was assumed linear visco-elastic with small strain damping ratio values D0; amplification factors higher than 10 were reached at 2 Hz at soft clays surface in correspondence of the centre and western edge of the maar in bi-dimensional analysis, whereas the 2D/1D ratios were in the order of 2-3 around 2 Hz with maximum values at the maar edges. In the nonlinear analyses, the maximum amplifications dropped below 10 and the 2D effects (i.e., 2D/1D ratios) were generally lower than 2 in the whole range of frequency

LOCAL SEISMIC HAZARD ASSESSMENT IN EXPLOSIVE VOLCANIC SETTINGS BY 1D AND 2D NUMERICAL ANALYSES

In this study, we face the problem of local seismic response in explosive volcanic setting by using an integrated geological-geophysical-geotechnical approach in the test area of Stracciacappa maar (Sabatini Volcanic District, central Italy). Our aim is to understand if the horizontal and vertical chaotic heterogeneity typical of the volcanic deposits influence site response. The Stracciacappa maar is an active eruptive centre characterised by a crater of about 1 km in diameter and a crater floor of about 30-40 m below the rim (De Rita et al. 1983; Sottili et al. 2012). The ring is mainly composed by the pyroclastic succession belonging to the last phreatomagmatic activity. This pyroclastic succession generally bends outward the rim with low angle dip (10-20°). It consists of at least 25 metres thick alternation of decimetre- to centimetre-thick layers of fine-medium ash and small lapilli. The crater depression is filled by epiclastic debris deposits and by recent and present-day lacustrine muds. The epiclastic debris deposits, of alluvial and delta origin, consist of alternation of cm-thick reworked fine-grained and coarse-grained volcaniclastic material, dipping with low-angle (1s) motions, compared to tectonic events of equivalent magnitude (Jousset and Douglas 2007); the unscaled recording at Bronte Station (BNT in ITACA database, http://itaca.mi.ingv.it) of the ML=4.4 October 27, 2002 event was employed; 2) a high magnitude far-field “tectonic” event (tectonic scenario), whose reference spectrum was built with Ground Motion Prediction Equations (Ambraseys et al., 2005) assuming M=6.5 and distance of 70 km. These conditions are compatible with seismogenic sources located in central Apennines of Italy. Three unscaled recordings of events characterised by magnitude and distance in the range of 6-7 and 60-90 km, respectively, were extracted from ITACA database (http://itaca.mi.ingv.it), matching on average the reference spectrum Two subsoil models have been considered: a detailed model (based on distribution of the lithotypes unravelled by the geological survey) and a simplified one (obtained by grouping interfingering lithotypes resting below the lacustrine silty clays). The result show that the two models have similar response in all range of the interesting period (0.1-1.0s); the damping properties of soft clays and sands deposits in the upper meters reduce the difference in the seismic response at the surface of both models. The results suggest the possibility to simplify the heterogeneous distribution of deposits in this volcanic context for assessment of seismic response purposes. Finally, we carried out both linear and equivalent linear analyses in one-dimensional and bi-dimensional conditions, in order to investigate the bidimensional effects and the role of nonlinearity on the seismic response,. In linear case the behaviour of soils was assumed linear visco-elastic with small strain damping ratio values D0; amplification factors higher than 10 were reached at 2 Hz at soft clays surface in correspondence of the centre and western edge of the maar in bi-dimensional analysis, whereas the 2D/1D ratios were in the order of 2-3 around 2 Hz with maximum values at the maar edges. In the nonlinear analyses, the maximum amplifications dropped below 10 and the 2D effects (i.e., 2D/1D ratios) were generally lower than 2 in the whole range of frequency