Options
Cannelli, Valentina
Loading...
Preferred name
Cannelli, Valentina
Email
valentina.cannelli@ingv.it
Staff
staff
ORCID
38 results
Now showing 1 - 10 of 38
- PublicationOpen AccessApplication of the Post-Widder Laplace inversion algorithm to postseismic rebound models(2008-05)
; ; ; ;Spada, Giorgio ;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 ;Spada, Giorgio; Istituto di Fisica, Università di Urbino "Carlo Bo" - Urbino, Italy; ; ; Istituto di Fisica, Università di Urbino "Carlo Bo" - Urbino, ItalyThe postseismic response of a viscoelastic Earth can be computed analytically with a normal-mode approach, based on the application of propagator methods. This framework suffers from many limitations, mostly connected with the solution of the secular equation, whose degree scales with the number of viscoelastic layers so that only low-resolution models can be practically solved. Recently, a viable alternative to the normal-mode approach has been proposed, based on the Post-Widder inversion formula. This method allows to overcome some of the intrinsic limitations of the normal-mode approach, so that Earth models with arbitrary radial resolution can be employed and general linear non-Maxwell rheologies can be implemented. In this work, we test the robustness of the method against a standard normal-mode approach in order to optimize computation performance while ensuring the solution stability. As an application, we address the issue of finding the minimum number of layers with distinct elastic properties needed to accurately describe the postseismic relaxation of a realistic Earth model.221 125 - PublicationOpen AccessPostseismic signature of the 2004 Sumatra earthquake on low degree gravity harmonics(2008)
; ; ; ; ;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 ;Boschi, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; ; ; We perform an extensive analysis of the low degree gravitt field harmonics measured by the GRACE mission, in order to find a signature of the postseismic relaxation following the 2004 Sumatra earthquake. We find a statistically significant perturbation in the secular trend of low degree zonal coefficients ($J_l$) in correspondence of the 2004 Sumatra earthquake, and a similar perturbation, but with weak associated statistical significance, also in the non-zonal coefficients. Technical features and results of such analysis are discussed. The time-dependent postseismic evolution of harmonic coefficients is modeled for various asthenosphere viscosity values, using a theoretical model of global postseismic deformation. The observed change in secular trend is found to be consistent with our modeling results but it cannot be used to discriminate between viscosities. A forward modeling of the perturbations to time-dependent zonal variation rates following the Sumatra earthquake for various astenospheric viscosities is provided. As a result, an evident signature of the Sumatra earthquake on $\dot{J}_l$ time series is expected for asthenospheric viscosity values below $10^{18}$ Pa s. Therefore, long term $\dot{J}_l$ time histories from SLR geodetic missions will be able to put constraints on the asthenosphere viscosity, if such a signature is evidenced from data or, at least, put lower limits if no significant perturbation will be observed.259 231 - PublicationOpen AccessA relationship between giant earthquakes and core flow instabilities?(2008-12)
; ; ; ; ; ;Cannelli, V.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma1, Roma, Italia ;De Michelis, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, Roma, Italia ;Florindo, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Roma2, 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; ; ; ; Giant earthquakes of exceptional energy release induce large coseismic deformation field, with measured offsets of the order of millimeter recorded by GPS stations at distances of thousand kilometers from the epicenter. The recorded deformation field is just the surface expression of a volume deformation affecting the whole Earth. According to theoretical models of global coseismic deformation, the 2004 Sumatra-Andaman earthquake, which was the second-greatest occurred in the instrumental age, is expected to have affected the core-mantle boundary with static deformations of the order of millimeter over a large area. At the same time, high-resolution core magnetic-field models based on satellite observations evidenced a short-timescale geostrophic fluid acceleration at the top of the core. These anomalies are located in a region corresponding to the Indian ocean and occur in a time window containing the earthquake occurrence. More interestingly, the acceleration pattern is close to the modeled displacement due to earthquake coseismic effects. These evidences suggest us the possible existence of a relationship between giant earthquakes and rapid perturbations in the Earth core dynamics.191 126 - 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 - 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 AccessSoluzione GPS combinata degli spostamenti cosismici e stima preliminare dei parametri di sorgente - Terremoto Emilia 2012(2012-09)
; ; ; ;Devoti, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, 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; ; Miglioramento della copertura delle reti geodetiche GPS, soprattutto nelle regioni pedemontane della pianura Padana.Archivio dei caposaldi esistenti e loro misurazione periodica. Archivio dei caposaldi esistenti e loro misurazione periodica. Attivazione di procedure cooperative per la stima di prodotti geodetici di consenso (campo di spostamento cosismico, serie storiche, deformazione, ecc.). Tempo reale: stima dello spostamento cosismico GPS entro i primi 10 min dal terremoto.153 110 - PublicationOpen AccessItalian Radon mOnitoring Network (IRON): A permanent network for near real-time monitoring of soil radon emission in Italy(2018)
; ; ; ; ; ; ; We introduce the Italian Radon mOnitoring Network (IRON): a new nationwide permanent network for near real-time measurements of soil radon emissions in Italy. Deployed over the last 9 years, presently IRON consists of 26 stations mainly concentrated in the Central- Southern Apennines, but marginally covering the whole Italian peninsula. At present, most IRON stations have recorded radon concen- tration time-series for more than 4-5 years. With a standard sampling interval of about two hours, the whole IRON dataset consists of nearly 440,000 single radon concentration measurements. Here we present the network in terms of sites, installations types and collected time series. The amount of data, together with the systematic methods of measurements, allowed us to evaluate some significant aspects related both to the measurement methodology and to the complex dynamics of soil radon emanations. Two case studies show, respec- tively, how different observational setups impact on the features of the recorded signal, and how observed fluctuations in radon con- centration may be ascribed to geophysical processes taking place at depth in the crust. We discuss the potential suitability of IRON, in order to study the relation between radon variability and the preparation processes of strong earthquakes.500 168 - PublicationOpen AccessImplementing soil radon detectors for long term continuous monitoring(2019-07-14)
; ; ; ; ; ; ; The employment of different instruments for radon continuous measurements within the Italian Radon mOnitoring Network (IRON), mostly INGV, Algade AER and Airthings Corentium instruments, requires a uniform characterization and calibration protocol for the results to be comparable in a rigorous way. A 56 L stainless steel radon chamber with a sensitivity of 0.95 ± 0.01 Bq m-3 per pulse h-1 has been used and validation of Algade AER, Airthings Corentium and Durridge RAD7 radon monitors equipped with solid-state detectors operated at different absolute humidity values has been performed, extending their operative range. Robustness to atmospheric electromagnetic phenomena of INGV and Algade AER instruments has been investigated and, for the former instrument, improved.365 40 - 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 AccessApplication of the Post-Widder Laplace inversion algorithm to postseismic rebound models(2009)
; ; ; ; ;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.; Istituto di Fisica, Università di Urbino; ; ; The postseismic response of a viscoelastic Earth can be computed analytically with a normal-mode approach, based on the application of propagator methods. This framework suffers from many limitations, mostly connected with the solution of the secular equation, whose degree scales with the number of viscoelas- tic layers so that only low-resolution models can be practically solved. Recently, a viable alternative to the normal-mode approach has been proposed, based on the Post-Widder inversion formula. This method allows to overcome some of the intrin- sic limitations of the normal-mode approach, so that Earth models with arbitrary radial resolution can be employed and general linear non-Maxwell rheologies can be implemented. In this work, we test the robustness of the method against a stan- dard normal-mode approach in order to optimize computation performance while ensuring the solution stability. As an application, we address the issue of finding the minimum number of layers with distinct elastic properties needed to accurately describe the postseismic relaxation of a realistic Earth model.340 242