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Dimitriu, Petros
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- PublicationOpen AccessSesame Project - Deliverable D04-04 - Report of the WP04 H/V Technique : Empirical Evaluation - Homogeneous Data Set of Noise and Earthquake Recordings at Many Sites(2003-07)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Atakan, Kuvvet; University of Bergen, Norway ;Azzara, Riccardo Mario; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Bard, Pierre-Yves; LGIT, Grenoble, France ;Cara, Fabrizio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cultrera, Giovanna; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Dimitriu, Petros; ITSAK, Thessaloniki, Greece ;Duval, Anne-Marie; CETE, Nice, France ;Faeh, Donat; ETHZ, Zurich, Swiss ;Di Giulio, Giuseppe; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Hagshenas, Ebrahim; LGIT, Grenoble, France ;Havskov, Jens; University of Bergen, Norway ;Koller, Martin; Resonance, Geneva, Swiss ;Pagani, Marco; CNR-IDPA, Milan, Italy ;Panou, Areti; ITSAK, Thessaloniki, Greece ;Papaioannou, Christos; ITSAK, Thessaloniki, Greece ;Rovelli, Antonio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Savvaidis, Alexandros; ITSAK, Thessaloniki, Greece ;Spohler, Eva; ETHZ, Zurich, Swiss ;Tento, Alberto; CNR-IDPA, Milan, Italy ;Daminelli, Rossella; CNR-IDPA, Milan, Italy ;Marcellini, Alberto; CNR-IDPA, Milan, Italy ;Theodoulidis, Nikos; ITSAK, Thessaloniki, Greece ;Zacharopoulos, Stratos; ITSAK, Thessaloniki, Greece; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; 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.284 441 - PublicationRestrictedEmpirical evaluation of microtremor H/V spectral ratio(2008-02-08)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Haghshenas, E.; International Institute of Earthquake Engineering and Seismology (IIEES), Tehran, Iran ;Bard, P. -Y.; Laboratoire de Geophysique Interne et Tectonophysique, Université Joseph Fourier, Grenoble, France ;Theodulidis, N.; ITSAK Institute of Engineering Seismology and Earthquake Engineering, Tessaloniki, Greece ;Atakan, K.; University of Bergen ;Cara, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cornou, C.; Laboratoire de Geophysique Interne et Tectonophysique, Université Joseph Fourier, Grenoble, France ;Cultrera, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Di Giulio, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Dimitriu, P.; ITSAK Institute of Engineering Seismology and Earthquake Engineering, Tessaloniki, Greece ;Fäh, D.; ETHZ ;De Franco, R.; CNR-IDPA ;Marcellini, A.; CNR-IDPA ;Pagani, M.; CNR-IDPA ;Rovelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Savvaidis, A.; ITSAK Institute of Engineering Seismology and Earthquake Engineering, Tessaloniki, Greece ;Tento, A.; CNR-IDPA ;Vidal, S.; CETE-Nice ;Zacharopoulos, S.; ITSAK Institute of Engineering Seismology and Earthquake Engineering, Tessaloniki, Greece; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The objective of this work is to perform a purely empirical assessment of the actual capabilities of the horizontal-to-vertical (H/V) spectral ratio technique to provide reliable and relevant information concerning site conditions and/or site amplification. This objective has been tackled through the homogeneous (re)processing of a large volume of earthquakes and ambient noise data recorded by different research teams in more than 200 sites located mainly in Europe, but also in the Caribbean and in Tehran. The original recordings were first gathered in a specific database with information on both the sites and recorded events. Then, for all sites close to an instrumented reference, average site-to-reference spectral ratios (“spectral ratio method” (SSR)) were derived in a homogeneous way (window selection, smoothing, signal-to-noise ratio threshold, averaging), as well as H/V ratios (“HVSRE–RF”) on earthquake recordings. H/V ratios were also obtained from noise recordings at each site (either specific measurements, or extracted from pre- or post-event noise windows). The spectral curves resulting from these three techniques were estimated reliable for a subset of 104 sites, and were thus compared in terms of fundamental frequency, amplitude and amplification bandwidth, exhibiting agreements and disagreements, for which interpretations are looked for in relation with characteristics of site conditions. The first important result consists in the very good agreement between fundamental frequencies obtained with either technique, observed for 81% of the analyzed sites. A significant part of the disagreements correspond to thick, low frequency, continental sites where natural noise level is often very low and H/V noise ratios do not exhibit any clear peak. The second important result is the absence of correlation between H/V peak amplitude and the actual site amplification measured on site-to-reference spectral ratios. There are, however, two statistically significant results about the amplitude of the H/V curve: the peak amplitude may be considered as a lower bound estimate of the actual amplification indicated by SSR (it is smaller for 79% of the 104 investigated sites), and, from another point of view, the difference in amplitude exhibits a questioning correlation with the geometrical characteristics of the sediment/basement interface: large SSR/HV differences might thus help to detect the existence of significant 2D or 3D effects.272 31 - PublicationOpen AccessStatistical study of epicentre alignment in the broader Aegean area(1994-09)
; ; ; ; ;Tosi, P.; Istituto Nazionale di Geofisica, Roma, Italy ;De Rubeis, V.; Istituto Nazionale di Geofisica, Roma, Italy ;Papadirnitriou, E.; Laboratory of Geophysics, Aristotelian University of Thessaloniki, Greece ;Dimitriu, P.; Laboratory of Geophysics, Aristotelian University of Thessaloniki, Greece; ; ; Accurate data concerning shallow (h = 60 km) earthquakes (Ms =4.5) that occurred in the broader Aegean area are used to point out the presence of linear seismogenic structures (seismolineaments). The earthquake data were analyzed by the use of a specific algorithm, and the directions of the best alignment of epicentres were found. The algorithm is based on statistical criteria applied within a circular area with the aim of searching for the best direction of alignment; this is then tested, to discriminate whether or not the pattern could stem from a random distribution of epicentres, or whether it is effectively the result of a linear seismic structure; the procedure is repeated to cover the whole area examined. The resulting lineaments can be regarded as individual tectonic units, as they usually coincide with known active faults or fault systems. An interpretation is given of the spatio-temporal evolution of the seismicity along the lineaments in terms of the asperity model.165 156 - PublicationOpen AccessSesame 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(2004-07)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Bordoni, Paola; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Cara, Fabrizio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cultrera, Giovanna; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Dimitriu, Petros; ITSAK, Thessaloniki, Greece ;Di Giulio, Giuseppe; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Hatzidimitriou, Panagiotis; ITSAK/AUTH-Geolab, Thessaloniki, Greece ;Lenti, Luca; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Marra, Fabrizio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Marcellini, Alberto; CNR, Milan, Italy ;Milana, Giuliano; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Oliveira, Carlos; Inst. Superior Tecnico, Lisbon, Portugal ;Pagani, Marco; CNR, Milan, Italy ;Panou, Areti; ITSAK, Thessaloniki, Greece ;Papazachos, Costas; ITSAK/AUTH-Geolab, Thessaloniki, Greece ;Rovelli, Antonio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Savvaidis, Alexandros; ITSAK, Thessaloniki, Greece ;Senos, M. Luisa; Inst. Meteorology, Lisbon, Portugal ;Tento, Alberto; CNR, Milan, Italy ;Tertulliani, Andrea; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Teves-Costa, Paula; ICTE/UL, Lisbon, Portugal ;Theodoulidis, Nikos; ITSAK, Thessaloniki, Greece; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; 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).239 127