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Cannelli, Valentina
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Cannelli, Valentina
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valentina.cannelli@ingv.it
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38 results
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- PublicationOpen AccessPost-seismic stress relaxation with a linear transient rheology(2010-04)
; ; ; ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; We performed an analysis of post-seismic stress relaxation, taking into account generalized linear rheologies. We compared the stress field (and its derived functions) obtained with a classical Maxwell rheology with that obtained with a transient Burgers body. From a set of synthetic case studies, we have revealed quantitative and qualitative differences both in relaxation times and in local stress values when a transient rheology is introduced. As a practical application, we modeled the time evolution of the Coulomb failure function following the 2009 L'Aquila earthquake, and we show that a transient rheology can lead to non-monotonic time dependence.309 202 - PublicationOpen AccessLong term continuous radon monitoring in a seismically active area(2015)
; ; ; ;Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Galli, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; We present the results of a long term, continuous radon monitoring experiment started in April 2010 in a seismically active area, affected during the 2010-2013 data acquisition time window by an intense micro seismic activity and by several small seismic events. We employed both correlation and cross-correlation analyses in order to investigate possible relationship existing between the collected radon data, seismic events and meteorological parameters. Our results do not support the feasibility of a robust one-to-one association between the small magnitude earthquakes characterizing the local seismic activity and single radon measurement anomalies, but evidence significant correlation patterns between the spatio-temporal variations of seismic moment release and soil radon emanations, the latter being anyway dominantly modulated by meteorological parameters variations.499 466 - PublicationOpen AccessMulti-level continuous monitoring of indoor radon activity(2022-05-27)
; ; ; ; ; ; ; We present the results of an experiment taking place inside the geophysical museum of Rocca di Papa (Rome, Italy), where the high radon levels detected might pose a risk to the health of workers and of the public audience. As a first step towards the mitigation of potential exposure risk, four active sensors were installed at different floors of the building, in order to continuously monitor not only radon exhalation from the soil but also its transport from the ground up to elevated floors. Collecting more than three years of data of radon concentration enables us to identify fluctuations over both short and seasonal scales and to elucidate the relation between radon variations and changes of internal temperature and relative humidity. The analysis of such dataset reveals how the healthiness of indoor environments in terms of radon concentration is controlled by a number of factors, including the environmental conditions and the use of heating and ventilation systems. Finally, the continuous radon monitoring at different levels of the building provides a unique chance to trace the vertical radon diffusion, allowing to make a first-order estimate of upward radon velocity.156 85 - PublicationOpen AccessApplication of the Post-Widder Laplace inversion algorithm to postseismic rebound models(2006-12-11)
; ; ; ; ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Spada, G.; Institute of Physics, University of Urbino, Italy; ; ; The computation of global postseismic rebound in a spherically symmetric, stratified, self-gravitating Earth with Maxwell viscoelastic rheology can be carried out semi-analytically with a normal-mode approach. The solution scheme usually involves the application of standard propagator techniques to the equivalent problem in the Laplace domain; to recover the temporal dependence a numerical Laplace anti-transform is required. This step involves the solution of the so-called “secular equation”, whose degree increases linearly with the detail of the stratification modeling, and whose coefficients become extremely ill-conditioned for high harmonic orders. As a result, the practically solvable models are limited to a few viscoelastic layers, and are anyway affected by severe numerical instabilities. To overcome these difficulties, alternative approaches have been explored by several authors, ranging from Runge-Kutta purely numerical integration to the evaluation of Laplace antitransform by a numerical discretization of the Bromwich integral. The Post-Widder algorithm allows the estimation of the Laplace antitransform by sampling numerically the transform on the positive real axis. This method, which has been recently applied to the computation of GIA viscoelastic Love numbers, allows to bypass completely the root-finding procedure while preserving at the same time the analytical normal-mode solution form. In this work, we apply the Post-Widder method to the computation of post-seismic rebound models. We perform a series of benchmarks to optimize the algorithm for speed while checking its stability against earlier results.180 382 - PublicationRestrictedCoseismic deformation pattern of the Emilia 2012 seismic sequence imaged by Radarsat-1 interferometry(2012-10)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Bignami, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Burrato, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Chini, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Falcucci, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Ferretti, A.; Tele-Rilevamento Europa s.r.l. ;Gori, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Kyriakopoulos, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Moro, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Novali, F.; Tele-Rilevamento Europa s.r.l. ;Saroli, M.; Università di Cassino e del Lazio Meridionale ;Stramondo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Valensise, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Vannoli, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ; ;; ;; ; ; ; ; ; ; ; On May 20th and 29th, 2012, two earthquakes having magnitude 5.9 and 5.8, respectively, and their aftershocks sequence hit the central Po Plain (Italy), about 40 km north of Bologna, in the northern Apennines. Following the main-shocks, more than 2,000 events were recorded by the INGV National Seismic Network (http://iside.rm.ingv.it/). During the seismic sequence, a pure compressional faulting was generated by the activation of blind thrusts of the western Ferrara Arc, thereby activating a 50 km-long stretch of this buried outer front of the northern Apennines. The focal mechanisms of the larger shocks agree with the compilation of present-day tectonic stress indicators, showing a ca. N-S oriented maximum horizontal stress in the area, i.e. oriented perpendicular to the main structural trends. Most of the seismic sequence was confined between 1 and 12 km depth, above the local basal detachment of the outer thrust front of the northern Apennines. The surface displacement pattern, associated with the mainshocks and some following minor events (some of which above M 5.0), has been measured by applying Interferometric Synthetic Aperture Radar (InSAR) technique to a pair of C-Band Radarsat-1 data. The coseismic movements detected overall the epicentral region have been here used as input information for the source inversion model.486 42 - PublicationOpen AccessImpact of Sumatra earthquake on CMB topography and core ellipticity(2006-11)
; ; ; ;Cannelli, Valentina; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Melini, Daniele; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piersanti, Antonio; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; Characterization of the global impact of 2004 Sumatra earthquake event through the investigation of its effects on core-mantle boundary (CMB) shape and on the elliptical part of the gravity field (J2)153 108 - PublicationOpen AccessMultiple seasonality in soil radon time series(2019-06-13)
; ; ; ; ; ; ; ; ; The dynamics governing the movement of the radon are complex and dependent on many factors. In the present study, we characterise the nature of temporal variations of 2-hourly and daily radon measurements in several monitoring sites of the Italian Radon mOnitoring Network (IRON) in Italy. By means of continuous wavelet transformation, a spectral analysis in time-frequency domain is performed. The results reveal that there are sub-daily, daily and yearly persistent periodicities that are common for all the stations. We observe structural seasonal breaks, that occur at the same frequency but at distinct time. Variations in radon concentration and local temperature are studied in terms of frequency contents and synchronicity. When analysing several long time series together, it is evident that the phase difference at low frequency movements (365-day period) between the radon and local temperature time series is depending on the sites' location and therefore strongly controlled by local factors. This could at least partially explain the apparently contrasting results available in the literature obtained investigating smaller dataset about the relationships between temperature and radon variations. On the other hand, results show that all radon time series are characterised by marked cycles at 1 and 365-days and less evident cycles at 0.5-day and 180-days. They would be all ascribable to environmental-climatic factors: the short-period cycles to temperature and pressure variations, the long-period cycles also to seasonal rainfall variations.624 40 - PublicationOpen AccessSignature of asthenospheric viscosity on long wavelength postseismic gravity perturbations after the 2004 Sumatra earthquake(2007-04)
; ; ; ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; Using a theoretical model of global postseismic deformation we computed the effect of 2004 Sumatra earthquake on the time evolution of the low degree zonal coefficients of the Earth gravity field (Jn). In fact, it is reasonable to expect that the exceptional energy release of the Sumatra event has given rise to a perturbation of the long wavelength Earth’s gravity field due to internal mass redistribution. Our analysis is performed varying asthenosphere viscosities, in order to show how the expected signature of the seismic event on the long wavelength deformation field is sensitive to mantle rheology. Low asthenospheric viscosities yield very large Jn variation rates in the first years after the event. Our results show that on the J2 time-series the postseismic effect remains comparable with the main secular trend for several years after the event if an asthenospheric viscosity of 10^18 Pa s is assumed, while for lower values the signature in the data should be even stronger. Since these short time-scale effects are not easily discernible from the available geodetic data because of large seasonal signals, we computed the expected contribution of postseismic relaxation to long term Jn trends as a function of asthenospheric viscosity. Our results show that the viscoelastic relaxation leaves a not negligible signature on the long term measured time-histories. In the forthcoming years, when geodetic data from recent missions (such as GRACE) will be available, it will be possible to establish if, after the Sumatra event, a significant deviation of Jn time series from its secular trend occurred. In this case it should be possible to infer or at least to put constrains to the mean asthenospheric viscosity that is still one of the big open issues in mantle rheology.152 223 - PublicationRestrictedThe October 23, 2011, Van (Turkey) earthquake and its relationship with neighboring structures(2014-02)
; ; ; ; ; ; ; ; ; ;Moro, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Chini, M.; Public Research Centre "Gabriel Lippmann" Belvaux, Luxembourg ;Bignami, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Stramondo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia ;Saroli, M.; Università degli Studi di Cassino e del Lazio Meridionale, DICeMDipartimento di Ingegneria Civile e Meccanica, Cassino ;Kyriakopoulos, C.; 4School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, Georgia (USA). ;Brunori, C. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; ;; ; ; ; ; The present work reports the analysis of a possible relationship due to stress transfer between the two earthquakes that hit the province of Van, Eastern Turkey, on October 23, 2011 (Mw 5 7.2) and on November 9, 2011 (Mw55.6). The surface displacement field of the mainshock has been obtained through a combined data set made up of differential interferograms from COSMO-SkyMed and ENVISAT satellites,integrated with continuous GPS recordings from the Turkish TUSAGA-AKTIF network. This allowed us to retrieve the geometry and the slip distribution of the seismic source and to compute the Coulomb Failure Function (CFF) variation on the aftershock plane, in order to assess a possible causal relationship between the two events. Our results show that the November 9 earthquake could have been triggered by the October 23 shock, with transferred stress values largely exceeding 1 bar.363 69 - PublicationOpen AccessPostseismic relaxation of the 2007 Central Peru earthquake(2007-12-10)
; ; ; ;Piersanti, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;Melini, D.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia; ; We present a comprehensive modeling of coseismic and postseismic effects of the 2007 Central Peru earthquake on deformation, gravity and stress fields obtained with a semi-analytical spherical self-gravitating Earth model. We discuss the expected signature of different stratification profiles including Maxwell and Burgers rheologies and find that measurements of short-term relaxation on horizontal deformations should provide a discrimination between different rheologies. We compute the time-dependent stress transfer of the 2007 earthquake on the 1868 and 1877 seismic gaps in terms of the Coulomb Failure Function (CFF). We find significant levels of stress transfer only on the 1868 seismic gap due to its proximity to the 2007 source, even if the sign of CFF variation is dependent on the depth of the receiver plane, which is not univocally fixed by geological evidences.133 96