Temporary dense seismic network during the 2016 Central Italy seismic emergency for microzonation studies

In August 2016, a magnitude 6.0 earthquake struck Central Italy, starting a devastating seismic sequence, aggravated by other two events of magnitude 5.9 and 6.5, respectively. After the first mainshock, four Italian institutions installed a dense temporary network of 50 seismic stations in an area of 260 km2. The network was registered in the International Federation of Digital Seismograph Networks with the code 3A and quoted with a Digital Object Identifier ( https://doi.org/10.13127/SD/ku7Xm12Yy9 ). Raw data were converted into the standard binary miniSEED format, and organized in a structured archive. Then, data quality and completeness were checked, and all the relevant information was used for creating the metadata volumes. Finally, the 99 Gb of continuous seismic data and metadata were uploaded into the INGV node of the European Integrated Data Archive repository. Their use was regulated by a Memorandum of Understanding between the institutions. After an embargo period, the data are now available for many different seismological studies.Publishedid 1825T. Sismologia, geofisica e geologia per l'ingegneria sismicaJCR Journa

High frequency attenuation of S waves in alluvial deposits of the central Po Plain (northern Italy)

This article has been accepted for publication in Geophysical Journal International ©:The Author(s) 2023. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.Uploaded in accordance with the publisher's self-archiving policy. All rights reserved.Estimation of local seismic response plays a key role in assessing local seismic hazard and particularly in the design of shaking scenarios. Modelling local seismic response involves knowing of the shear wave velocity (Vs) and quality factor (Qs) profiles for the site in question. The many techniques that have been developed to assess Vs in surface deposits produce reliable measurements of Vs , but these rarely correspond to direct measurements of Qs . The latter is often considered through damping measures from laboratory tests on small-scale soil samples, which can provide information primarily on intrinsic attenuation, neglecting the contribution of scattering effects. In this paper, using seismic recordings obtained at the surface and in boreholes at 100 m depth, we estimate an average value of Qs of some characteristic alluvial deposits of the Po Plain (northern Italy). Data come from a microseismic network which sampled an almost uniform lithology in the central Po Plain and consisted of three surface and four borehole stations with an interstation distance of about 2 km. The average value of Qs of the shallowest 100 m of the sedimentary strata, Qs100, is estimated by considering: (1) the high-frequency attenuation of seismic waves due to propagation through the corresponding stratigraphy and (2) the interference between incident and surface-reflected waves observed at borehole stations. We parametrize the first through k0_100, the difference between the values of the spectral decay parameter kappa (k) estimated at the surface and at the boreholes depth, respectively. We use the second in order to compute Vs100, the time-averaged Vs referred to the uppermost 100 m stratigraphy. We obtain: k0_100 = (11 ± 3) ms, Vs100 = (309 ± 11) m s −1 and Qs100 = 31 ± 10. At the surface, the estimated values of the site-specific kappa, k0, are found to range from 75 to 79 ms. As expected, these results are in good agreement with studies performed in other sites characterized by sandy or clayey lithologies, and can be usefully used in site response analysis at sites where the rigidity is mainly controlled by lithostatic pressure.Comune di Minerbio (grant: “Sperimentazione ILG Minerbio”; grant number: 0913.010).Published2075–2094OST2 Deformazione e Hazard sismico e da maremotoJCR Journa

EMPIRICAL EVALUATION OF THE HORIZONTAL-TO-VERTICAL SPECTRAL RATIO TECHNIQUE: RESULTS FROM THE “SESAME” PROJECT

In order to empirically evaluate the horizontal-to-vertical (H/V) spectral ratio technique, ambient noise measurements performed in about two hundred sites mainly in Europe where weak or/and strong motion data was recorded. Standard Information Sheets (SIS) and earthquake information data were included in the SESAME [Site EffectS assessment using AMbient Excitations] project database, specially designed to facilitate data selection. All noise recordings were processed with JSESAME software to calculate (H/V) spectral ratio, whereas weak and strong motion earthquake recordings were processed with a similarly standardized procedure. For the latter, (H/V) receiver function for all sites were calculated. Experimental site transfer functions obtained from earthquake recordings were compared with the (H/V) spectral ratios from noise recordings in terms of fundamental frequency, amplification bandwidth and amplification level. Similarities and differences between (H/V) spectral ratio of noise and earthquake recordings are presented and discussed. In addition, a dense grid of noise measurements were performed within urban environment of cities affected by strong earthquake (Greece: Thessaloniki, Kalamata, Italy: Palermo). It seems that the (H/V) spectral ratio may satisfactorily indicate areas favorable to the occurrence of higher damage in urban environment. However, quantitative correlation between (H/V) spectral ratio properties and damage distribution (macroseismic intensity, damage grades) in some cases, is difficult to be established given the complexity of parameters involved.PublishedVancouver, B.C., Canada4.1. Metodologie sismologiche per l'ingegneria sismicaope

Sesame Project - Deliverable D20-04 - WP04 H/V Technique : Empirical Evaluation - Comparisons of Damage Distribution in Modern Urban Areas with Results from (H/V) Spectral Ratio

In this Report comparisons of seismic damage distribution with the (H/V) spectral ratio results is attempted, under the framework of the SESAME Project (Site Effects Assessment Using Ambient Excitations, EC-RGD, Project No. EVG1-CT-2000-00026 SESAME), Task A (H/V technique), Work Package 04 (WP04– H/V Technique: Empirical Evaluation).European Commission – Research General Directorate Project No. EVG1-CT-2000-00026 SESAMEPublished4.1. Metodologie sismologiche per l'ingegneria sismicaope

Sesame Project - Deliverable D04-04 - Report of the WP04 H/V Technique : Empirical Evaluation - Homogeneous Data Set of Noise and Earthquake Recordings at Many Sites

In this Report the homogeneous data set of earthquake and noise recordings at many sites that is generated under the framework of the SESAME Project (Site Effects Assessment Using Ambient Excitations, EC- RGD, Project No. EVG1-CT-2000-00026 SESAME), Task A (H/V technique), Work Package 04 (WP04– H/V Technique: Empirical Evaluation), is presented. Three main topics are included in the Report: (a) The Standard Information Sheet (SIS) structure, (b) The SESAME Ascii Format (SAF) files, and (c) The SESAME SIS-database. The SIS compiled in this sub-task and SAF format adopted for all data, constitute a homogeneous data set to be processed for further scientific results in the framework of the WP04. In addition, the SIS-database is going to facilitate data selection and management.European Commission – Research General Directorate Project No. EVG1-CT-2000-00026 SESAMEPublished4.1. Metodologie sismologiche per l'ingegneria sismicaope

Temporary dense seismic network during the 2016 Central Italy seismic emergency for microzonation studies

AbstractIn August 2016, a magnitude 6.0 earthquake struck Central Italy, starting a devastating seismic sequence, aggravated by other two events of magnitude 5.9 and 6.5, respectively. After the first mainshock, four Italian institutions installed a dense temporary network of 50 seismic stations in an area of 260 km2. The network was registered in the International Federation of Digital Seismograph Networks with the code 3A and quoted with a Digital Object Identifier (https://doi.org/10.13127/SD/ku7Xm12Yy9). Raw data were converted into the standard binary miniSEED format, and organized in a structured archive. Then, data quality and completeness were checked, and all the relevant information was used for creating the metadata volumes. Finally, the 99 Gb of continuous seismic data and metadata were uploaded into the INGV node of the European Integrated Data Archive repository. Their use was regulated by a Memorandum of Understanding between the institutions. After an embargo period, the data are now available for many different seismological studies.</jats:p