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Cercato, Michele
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Cercato, Michele
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- PublicationOpen AccessThe use of a very dense seismic array to characterize the Cavola, Northern Italy,(2006-08-30)
; ; ; ; ; ; ; ; ;Bordoni, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cercato, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Haines, A. J.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Ruso, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ;; ; The analysis of data coming from a dense 95-station array installed on the Cavola landslide (northern Apennines) is presented. The array extended along a 112X80 m2 area covered by clay deposits related to a recent and still active landslide. It operated along a four month time period in a continuous mode recording. Both earthquake and noise data are used to assess the amplification effects and relate them to thickness and geophysical properties of outcropping terrain. Compared to a reference site, earthquake data recorded on the landslide show a ground motion amplification up to a factor of 4 in the 2.5 to 5 Hz frequency band. Moreover, the study of the predominant frequency distribution derived from spectral analysis of ambient noise allows to infer thickness variations along the array. We then identify zones with small lateral variations to select sub-arrays with homogenous geometrical subsoil conditions where passive and active 1D and 2D array data analysis techniques are applied to evaluate shear waves velocity in the landslide body. Available drilling and down-hole data are used to calibrate the velocity model inferred from seismic surface data. This analysis permits to reconstruct an approximate 2D geometry used as a base for modelling waveform changes along the array.137 207 - PublicationRestrictedExtensive surface geophysical prospecting for seismic microzonation(2020-05-27)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ; ; ; ;This paper presents an overview of the geophysical activities for the seismic microzonation of 138 municipalities belonging to four Italian regions (Abruzzo, Lazio, Marche and Umbria) that were severely damaged by the seismic sequence of Central Italy (August 2016–January 2017). This study is the result of a collaborative effort between research Institutions and professional geologists with the support of local Administrations and the Italian Civil Protection Department and sets an unprecedented large-scale example of geophysical investigations supporting detailed seismic microzonation studies. This manuscript presents the methodological approach adopted for the geophysical activities, including the technical protocols and procedures, the best practices, the final products and the results supporting a detailed microzonation study of III level. The first step of the study was the collection and critical review of all available geophysical and geological information for planning the new geophysical surveys (specifically their type and location), in order to assess the subsoil geometry and the seismic characterization of the areas under investigation. Integration with the newly acquired geophysical data allowed the identification of zones with homogeneous local seismic hazard as well as the reference seismo-stratigraphy for each area, defining for each geological unit the ranges of the relevant properties in seismic amplification studies: layering and thicknesses, density, P-wave and S-wave seismic velocity. We also present a few representative case studies illustrating the geophysical investigation for different geomorphological situations. These examples, together with the findings of the entire project, are discussed to point out the strength points and the criticalities, as well as the necessary requirements in the application of geophysical methods to detailed microzonation studies.180 4 - PublicationOpen AccessCavola experiment site: geophysical investigations and deployment of a dense seismic array on a landslide(2007-10)
; ; ; ; ; ; ; ; ;Cavola Experiment Team ;Bordoni, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Haines, J.; Bullard Laboratories, Department of Earth Sciences, University of Cambridge, U.K. ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Augliera, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Cercato, M.; Dipartimento di Idraulica Trasporti e Strade (DITS), Facoltà di Ingegneria, Università degli Studi di Roma «La Sapienza», Roma, Italy ;Martelli, L.; Regione Emilia Romagna, Servizio Geologico Sismico e dei Suoli, Bologna, Italy ;Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cavola Experiment Team; 0; ; ; ; ; ; ; ; Geophysical site investigations have been performed in association with deployment of a dense array of 95 3-component seismometers on the Cavola landslide in the Northern Apennines. The aim of the array is to study propagation of seismic waves in the heterogeneous medium through comparison of observation and modelling. The small-aperture array (130 m×56 m) operated continuously for three months in 2004. Cavola landslide consists of a clay body sliding over mudstone-shale basement, and has a record of historical activity, including destruction of a small village in 1960. The site investigations include down-hole logging of P- and S-wave travel times at a new borehole drilled within the array, two seismic refraction lines with both P-wave profiling and surface-wave analyses, geo-electrical profiles and seismic noise measurements. From the different approaches a consistent picture of the depths and seismic velocities for the landslide has emerged. Their estimates agree with resonance frequencies of seismic noise, and also with the logged depths to basement of 25 m at a new borehole and of 44 m at a pre-existing borehole. Velocities for S waves increase with depth, from 230 m/s at the surface to 625 m/s in basement immediately below the landslide.265 148 - PublicationOpen AccessItalian accelerometric archive: geological, geophysical and geotechnical investigations at strong-motion stations(2010)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Luzi, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Lovati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;D'Alema, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Marzorati, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Milano-Pavia, Milano, Italia ;Di Giacomo, D.; GFZ Potsdam ;Hailemikael, S.; UNIROMA1 ;Cardarelli, E.; UNIROMA1 ;Cercato, M.; UNIROMA1 ;Di Filippo, G.; UNIROMA1 ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Rainone, M.; UNICH ;Torrese, P.; UNICH ;Signanini, P.; UNICH ;Scarascia Mugnozza, G.; UNIROMA1 ;Rivellino, S.; UNIROMA1 ;Gorini, A.; DPC; ; ; ; ; ;; ; ; ; ; ; ; ; ; ; Geological, geophysical and geotechnical investigations, for the characterization of the strong-motion recording sitesmanaged by the ItalianCivil Protection, have been carried out in the framework of the project “Italian strong-motion database in the period 1972–2004”. The project aimed at creating an updated database of strong-motion data acquired in Italy by different institutions in the time span 1972–2004, and at improving the quality of disseminated data. This article illustrates the state of the recording site characterization before the beginning of the project, explains the criteria adopted to select the sites where geophysical/ geotechnical investigation have been performed and describes the results of the promoted field surveys.255 3437 - PublicationRestrictedGeophysical investigations for seismic zonation in municipal areas with complex geology: The case study of Celano, Italy(2008)
; ; ; ; ; ;Cardarelli, E.; Sapienza, Università di Roma, D.I.T.S. ;Cercato, M.; Sapienza, Università di Roma, D.I.T.S. ;De Nardis, R.; Dipartimento della Protezione Civile ;Di Filippo, G.; Sapienza, Università di Roma, D.I.T.S. ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; A quantitative prediction of seismic site effects requires the definition of a subsoil parametric model for ground motion numerical modelling. This paper describes an application of integrated geophysical methods to define an earthquake engineering parametric model for the seismic zonation of the municipal area of Celano, Italy. In municipal areas of such extent, particularly in case of complex geology, subsurface characterization is an optimization procedure, where the objective function to be minimized is the uncertainty related to the subsoil features, under the constraint of fixed resources and logistical limitations. In the particular case of Celano, correlation between different geophysical results was very profitable in discriminating different geological scenarios in the historical centre and in areas designed for urban expansion, while defining the elastic properties of the near-surface deposits throughout the municipal area.200 49 - PublicationRestrictedShear-wave velocity profiling at sites with high stiffness(2010-02)
; ; ; ; ; ; ;Cercato, M.; DITS, University La Sapienza of Rome, Italy ;Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cardarelli, E.; DITS, University La Sapienza of Rome, Italy ;Di Filippo, G.; DITS, University La Sapienza of Rome, Italy ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Milana, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ; ; Three sites of the Italian Strong Motion Network (RAN) have been selected for detailed S-wave profiling, using both borehole and surface wave seismic methods. At these sites, the presence of stiffness contrasts within the soil column is found to influence the surface wave propagation profoundly. Advanced aspects in surface wave inversion such as resolution, accuracy and higher-mode interpretation must be properly taken into account to obtain realistic results from the surface wave dispersion observations. The possibility of mode misidentification and the loss of resolution with depth in surface wave interpretation are explored using synthetic modelling together with active and passive seismic data sets. With high stiffness contrasts, the possibility of mode jumps and higher mode dominance over specific frequency ranges is very probable. This is true also for normally dispersive sites, where the shear velocity increases with depth, though higher mode dominance is recognized as more common in the case of a shear-wave velocity inversion within the soil column and the sensitivity of the dispersion curves with respect to those layers beneath the low-velocity zone may be significantly reduced. Pitfalls in the inversion resulting from mode misidentification can be avoided by investigating the effective phase velocity distribution, using active data sets and full waveform seismic modelling. When an unambiguous modal identification is achieved, the results obtained by surface wave inversion are very satisfactorily consistent with borehole data.168 43