Seismic Ground Motion Amplifications Estimated by Means of Spectral Ratio Techniques: Examples for Different Geological and Morphological Settings

One of the most important issue in seismic hazard and microzonation studies is the evaluation of local site response (i.e. the tendency of a site to experience during an earthquake greater or lower levels of ground shacking with respect to another). In general site effects reflect all modifications (in amplitude, frequency content and duration) of a wave-field produced by a seismic source during the propagation near the surface, due to particular geologic (stratigraphy and morphology), geotechnical (mechanical properties of deposits) and physical (e.g. coupling of incident, diffracted and reflected seismic waves) conditions of a particular site. Actually local seismic amplification represents one of the main factors responsible for building damage during earthquakes: this statement is supported by well documented evidences of structural damages during past moderate to high energy events occurred both in Italy (e.g. 23th November 1980, Mw 6.9, Irpinia earthquake, Faccioli, 1986; 26th September 1997, Mw 6.0, Umbria-Marche earthquake, Caserta et al., 2000; the 31th October 2002, Mw 5.7, Molise earthquake, Strollo et al., 2007; 6th April 2009, Mw 6.3, L’Aquila earthquake, Cultrera et al., 2009) and in other worldwide countries (e.g. 3rd March 1985, Mw 7.8, Chile earthquake, Celebi, 1987; 17th August 1999, Mw 7.6, Izmit earthquake, Sadik Bakir et al., 2002). For this reason the site effects evaluation, performed by experimental methods but also through numerical simulations, has attracted the attention of engineering seismology and earthquake engineering communities. Of consequence, in the last decade many experiments were performed in correspondence of different setting such as alluvial basins (Parolai et al., 2001 and 2004; Ferretti et al., 2007; Massa et al., 2009; Bindi et al., 2009) or topographies (e.g. Pischiutta et al., 2010; Massa et al., 2010; Buech et al., 2010; Marzorati et al., 2011; Lovati et al., 2011). The present work has the aim to evaluate the capabilities of the most common passive methods at present used in seismology to evaluate the site response: HVSR (Horizontal to Vertical Spectral Ratio technique on seismic noise, Nakamura, 1989, or earthquakes, Lermo & Chavez Garcia, 1993) and SSR (Standard Spectral Ratio, Borcherdt, 1970).Published195-2184.1. Metodologie sismologiche per l'ingegneria sismicaope

Evaluating a BiPV sun shading system with various software and methods

This paper aims to explore the attractiveness of a BiPV (building integrated photovoltaic) fixed façade shading systems in view of a deep retrofit of the residential building envelope. While doing so is necessary to access the confidence and differences among optimization and simulation tools. A facade equipped with a fixed BiPV shading system is simulated with different methods, software and modelling assumptions. The output of the simulations is compared and discussed, underlining the strong and weak points of each considered method. The performance of the BiPV façade is accessed by comparison with a more traditional one without BiPV. The traditional façade is characterized by a lower WWR (window to wall ratio) compared to the BiPV one because they have the same DF (daylight factor) by design. The BiPV façade is characterized by a better behavior toward annual radiative solar gain, while the traditional façade relies on lower thermal conductivity. Both the façade solutions are the result of a performance optimization method developed at EURAC and described in the paper. The method is based on the use of genetic optimization algorithms to find the parameters, WWR tilt angle and distance from the window, that maximize target performance indicators. Aims of the study are to evaluate the BiPV impact on the façade (i.e. whether it ensures an improved annual thermal performance or only better energy balance thanks to energy production) and to compare the results obtained with different simulation methods (i.e. by evaluating the results coherency and discrepancy). The comparison between these two facades performance and the consequent BiPV impact assessment, is carried out with different methods by coupling different software tools (e.g. PVGIS + COMFEN, Archsym + postprocessing). The software tools capabilities, the relative errors and the simplifying assumptions that can be considered safe in a performance-driven design perspective are discussed in the paper

Livelli di detezione da stazioni sismiche in pozzo

Nell’ambito di un progetto pilota per l’iniezione e lo stoccaggio di CO2 da effettuarsi nell’area di Cortemaggiore (PC), la Sezione di Milano-Pavia dell’INGV è stata incaricata dell’attività di monitoraggio sismico di superficie. A tale scopo è stata realizzata una rete costituita da 7 stazioni. I sensori sono posizionati in un’area di dimensioni di circa 6x2 km. Tutte le stazioni sono dotate di acquisitore digitale a 24 bit tipo Lennartz M24/NET con ricevitore del segnale di tempo GPS. L’area è caratterizzata da un forte disturbo antropico ed industriale. Per migliorare la qualità del segnale, 4 sensori sono installati in pozzo alla profondità di 100 metri. Per le stazioni in pozzo il sensore usato è il Lennartz LE-3D/BH mentre in superficie viene utilizzato LE-3Dlite MKII. I 2 sensori presentano caratteristiche tecniche simili, con frequenza propria pari ad 1 Hz, limite superiore in frequenza di 80 Hz e range dinamico di 136 dB. In questo lavoro sono stimati i livelli di microtremore sismico e viene valutata la soglia di detezione, ovvero il valore minimo di magnitudo registrabile in funzione della distanza dalla sorgente sismica

A microtremor survey in the area shocked by the ml 5.2 Salò earthquake (north Italy): an empirical approach to determine the effects of ground motions

In this work the results of a quick microtremor survey performed in the municipalities situated in the epicentre area of the Ml 5.2 2004 Salò earthquake (North Italy) are presented. The aim of this study is to understand if the large amount of damage caused by the event (about 215 millions of euros only in the areas near to the epicenter) is correlated more to the local surface geology conditions or to the vulnerability of ancient Italian historical centers. A preliminary seismic zonation was carried out in 5 villages including about 30 measurements of microtremors analysed by the Nakamura technique (hereinafter HVNR). The points of measurement were carefully selected considering sites located both near damaged buildings and over different local geology conditions (alluvium deposits, fluvial-glacial deposits, debris fans and rock). In order to strengthen the HVNR results and to evaluate the reliability of the Nakamura analysis, a comparison with spectral ratios calculated on earthquakes (hereinafter HVSR) recorded at the strong motion station of Vobarno was made. In general, the outcomes of the survey highlight a possible correlation between local geology conditions and ground motion amplification for different frequency bands. In order to check if this evidence is linked with the damage, a series of macroseismic intensities values were collected for different zones of the investigated area, and a non parametric correlation approach was used to establish a possible correlation between damage and ground motion amplification for selected frequency bands. The results show, from a statistical point of view, that in the area surrounding the epicenter of the 24 November 2004 mainshock, the damage pattern is not strongly dependent upon the local surface geology but more correlated to the low quality of the civil structures present in the area, including old buildings of the last century

Analysis of BRCA1 and RAD51C promoter methylation in italian families at high-risk of breast and ovarian cancer

Previous studies on breast and ovarian carcinoma (BC and OC) revealed constitutional BRCA1 and RAD51C promoter hypermethylation as epigenetic alterations leading to tumor predisposition. Nevertheless, the impact of epimutations at these genes is still debated. One hundred and eight women affected by BC, OC, or both and considered at very high risk of carrying BRCA1 germline mutations were studied. All samples were negative for pathogenic variants or variants of uncertain significance at BRCA testing. Quantitative BRCA1 and RAD51C promoter methylation analyses were performed by Epityper mass spectrometry on peripheral blood samples and results were compared with those in controls. All the 108 analyzed cases showed methylation levels at the BRCA1/RAD51C promoter comparable with controls. Mean methylation levels (\ub1 stdev) at the BRCA1 promoter were 4.3% (\ub1 1.4%) and 4.4% (\ub1 1.4%) in controls and patients, respectively (p > 0.05; t-test); mean methylation levels (\ub1 stdev) at the RAD51C promoter were 4.3% (\ub1 0.9%) and 3.7% (\ub1 0.9%) in controls and patients, respectively (p > 0.05; t-test). Based on these observations; the analysis of constitutional methylation at promoters of these genes does not seem to substantially improve the definition of cancer risks in patients. These data support the idea that epimutations represent a very rare event in high-risk BC/OC populations

What can we learn from the January 2012 Northern Italy earthquakes?

This note focuses on the ground motion recorded during the recent moderate earthquakes occurred in the central part of Northern Italy (panel 1), a region characterized by low seismicity. For this area the Italian seismic hazard map (Stucchi et al., 2011) assigns a maximum horizontal acceleration (rock site) up to 0.2 g (10% probability of exceedance in 50 yrs). In the last 4 years, the region was struck by 9 earthquakes in the magnitude range 4≤Mw≤5.0, with the three largest located in the Northern Apennines (Mw 4.9 and 5.0 Parma events, December 2008 and January 2012) and in the Po plain (Mw 4.9 Reggio Emila event of January 2012). We analyze the strongmotion data (distance < 300 km) from these events recorded by stations belonging to the INGV (RAIS, http://rais.mi.ingv.it; RSNC http://iside.rm.ingv.it) and DPC (RAN, www.protezionecivile.it; http://itaca.mi.ingv.it). The 2008 and 2012 Parma events, both characterized by reverse focal mechanisms (http://cnt.rm.ingv.it/), have depths of 27 and 60 km respectively. The deep event produced a maximum peak ground acceleration (PGA) of 97 cm/s2 at Novellara (NVL, EC8 C class) station (70 km from the epicenter). The 25th January 2012 event (depth of 34 km) produced a maximum PGA of 114 cm/s2 at Sorbolo (SRP) station (7 km from the epicenter). Preliminary analyses show: 1) a peculiar ground-motion attenuation of the deep Parma event with respect to the shallow one. In panel 2, the PGAs for the two Parma events are plotted as a function of hypocentral distance and compared to the global ground motion prediction equation (GMPE) calibrated by Cauzzi and Faccioli (2008) using events with depth < 30 km. The different distance-decay of PGA for the deep event (blue for A class of EC8 and red for B and C classes, CEN 2003) is evident, in particular for distance up to 100 km. On the other hand, the PGAs of the 2008 Parma crustal event (grey) are well explained by this GMPE. In panel 3, the PGAs for the deep 2012 event, grouped for EC8 classes, are compared to the national GMPE calibrated by Bindi et al. (2011) using crustal events and epicentral distance. Also in this case, the GMPE underestimates the PGAs up to 200 km. Although most of the class C sites (red) show the largest PGAs, the underestimation cannot be completely ascribed to site effects. The large PGAs from the Parma deep event, with respect to the shallow one, could be explained in terms of source effects (e.g. large stress drop values enhancing the high-frequency radiation). In addition, as explained by Castro et al. (2008), the different attenuation in the lower and upper crust could explain the large PGAs recorded for the 2012 deep event. 2) seismic amplification at Po Plain sites: In panel 4, the PGAs of the January 25th, Mw 4.9, Reggio Emilia event are plotted as a function of the epicentral distance, together with the Bindi et al. (2011) GMPE. In general, the largest amplitudes occur at the Po plain sites (red), suggesting possible peculiar site response. An overall increase of the PGAs is observed around 100km, in agreement with the results of Bragato et al. (2011) that studied the regional influence of Moho S-wave reflections in the area. An example of site response is shown in panel 5, considering TREG (class C) and ZEN8 (class A) stations (panel 5a), located at 88 km from the Reggio Emila epicentre. The rotational standard spectral ratio (panel 5b) for 10 s of S wave shows polarized amplifications around 2 Hz, detected also at others Po plain sites (not reported), as well as amplification on the vertical component. The points discussed above should to be interpreted as a warning for future applications dealing with ground motion estimation in the aftermath of an earthquake in this area (e.g. ShakeMap calculation): currently used GMPEs, based on different events and sites characteristics could lead to significant bias in the final results

OMBRA: OBSERVING MONTELLO BROAD ACTIVITY DEPLOYMENT OF A TEMPORARY SEISMIC NETWORK TO STUDY THE DEFORMATION PROCESS ACROSS MONTELLO FAULT (EASTERN ALPS)

Istituto Nazionale di GeofisicaPublishedope

Qui INGV

L’INGV, a partire dal 2006, ha iniziato una fase di potenziamento del monitoraggio accelerometrico, installando nelle aree centrali della pianura padana 22 sensori strong-motion (Rete Accelerometrica Italia Settentrionale, RAIS, http://rais.mi.ingv.it/). Dal 2008, sensori accelerometrici sono stati via via installati in 105 siti a Rete Sismica Nazionale (RSN), gestita dal Centro Nazionale Terremoti (CNT). Nel complesso le 127 stazioni accelerometriche presenti sul territorio nazionale costituiscono a tutti gli effetti la rete accelerometrica nazionale INGV. I dati acquisiti da tutte le stazioni accelerometriche sono attualmente distribuiti in tempo reale tramite il portale EIDA (European Integrated Data Archive; http://eida.rm.ingv.it/) e sono principalmente utilizzati per il calcolo delle Shakemaps a scala nazionale. Attualmente, l’INGV sta realizzando un portale web per la distribuzione dei dati accelerometrici registrati dalle stazioni INGV, composto da 2 moduli distinti: il primo, denominato ISMD, ha lo scopo di archiviaziare e distribuire in tempo quasi reale (poche ore dopo l’evento) le forme d’onda accelerometriche in formato non corretto ed i relativi metadati ottenuti a seguito di una procedura di processamento automatico; il secondo, denominato DYNA, è una banca dati relazionale, contenente le forme d’onda di accelerazione, velocità e spostamento e gli spettri di risposta di accelerazione, ottenuti attraverso il processamento manuale dei segnali non corretti, oltre ai relativi metadati associati agli eventi sismici ed alle stazioni di registrazione Il prototipo del portale dei dati accelerometrici INGV (Figura 1) è stato pubblicato lo scorso maggio, a seguito della sequenza sismica Emiliana