Options
Melini, Daniele
Loading...
Preferred name
Melini, Daniele
Email
daniele.melini@ingv.it
Staff
staff
ORCID
87 results
Now showing 1 - 10 of 87
- 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.180 381 - PublicationOpen AccessThe Campotosto Seismic Gap in Between the 2009 and 2016-2017 Seismic Sequences of Central Italy and the Role of Inherited Lithospheric Faults in Regional Seismotectonic Settings(2018-08)
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; The 2016-2017 seismic sequence, in central Italy, was caused by the Mt. Vettore-Mt. Bove active fault system, which generated three mainshocks, the largest one of M-w 6.6, on 30 October 2016. On 18 January 2017, four M-w 5-5.5 seismic events nucleated on the Campotosto active fault. The fault is considered as potentially responsible for M 6.6 seismic events and a seismic gap. The structure also nucleated a M-w 5.4 aftershock during the 2009 L'Aquila seismic sequence. We here combined new geological/geomorphological field data, 1945 aerial photographs interpretation, geodetic (Differential Interferometric Synthetic Aperture Radar and Global Positioning System) data, and local historical seismicity analysis to determine how much of the Campotosto seismogenic source ruptured during the 2009 and 2016-2017 seismic sequences. The obtained residual seismic moment of the Campotosto seismic gap is in the range M-w 6.4-6.6 earthquake. Moreover, the review of the regional tectonic setting and evolution allowed us a brand new and comprehensive reading of the seismotectonics for the region, in terms of both seismic potential and segmentation of the seismogenic sources, which results strictly connected to the long-term activity of inherited lithospheric discontinuities, among which the major Ancona-Anzio fault. We here first highlight that such regional structures strongly influenced the structural setting and evolution of the surrounding regions, in a progressive and continuous process of tectonic inversions, which implies that structural heritage must be understood and considered when dealing with seismotectonics of a given tectonically active region.424 56 - 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.152 222 - 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 - 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 AccessFEMSA: a finite element simulation tool for quasi-static seismic deformation modeling(2007-06)
; ; ; ;Volpe, M.; 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 set up a computational tool to numerically model static and quasi-static deformation generated by faulting sources embedded in plane or spherical domains. We use a Finite Element (FE) approach to automatically implement arbitrary faulting sources and calculate displacement and stress fields induced by slip on the fault. The package makes use of the capabilities of CalculiX, a non commercial FE software designed to solve field problems (see for details), and is freely distributed by request.2579 73508 - 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 AccessNew insights on the Messina 1908 seismic source from post-seismic sea level change(2013-08)
; ; ; ;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; ; The identification of a source model for the catastrophic 1908 December 28 Messina earth- quake (Mw = 7.2) has been the subject of many papers in the last decades. Several authors proposed different models on the basis of seismological, macroseismic and geodetic data sets; among these models, remarkable differences exist with regard to almost all parameters. We selected a subset of six models among those most cited in literature and used them to model the post-seismic sea level variation recorded at the tide gauge station of Messina (until 1923), to attempt an independent discrimination among them. For each model, we assumed a simple rheological structure and carried out a direct-search inversion of upper crust thickness and lower crust viscosity to fit the post-seismic sea level signal. This approach enabled us to iden- tify a class of fault geometries which is consistent with the post-seismic signal at the Messina tide gauge and with the known structural and rheological features of the Messina strait418 233 - PublicationOpen AccessHolocene relative sea-level changes along the Caribbean and Pacific coasts of northwestern South AmericaPredicting coastal change depends upon our knowledge of postglacial relative sea-level variability, partly controlled by glacio-isostatic responses to ice-sheet melting. Here, we reconstruct the postglacial relative sea-level changes along the Caribbean and Pacific coasts of northwestern South America by numerically solving the sea-level equation with two scenarios of mantle viscosity: global standard average and high viscosity. Our results with the standard model (applicable to the Pacific coast) agree with earlier studies by indicating a mid-Northgrippian high stand of ~2 m. The high-viscosity simulation (relevant to the Caribbean coast) shows that the transition from far- to intermediate-field influence of the Laurentide Ice Sheet occurs between Manzanillo del Mar and the Gulf of Morrosquillo. South of this location, the Colombian Caribbean coast has exhibited a still stand with a nearly constant Holocene relative sea level. By analyzing our simulations considering sea-level indicators, we argue that tectonics is more prominent than previously assumed, especially along the Caribbean coast. This influence prevents a simplified view of regional relative sea-level changes on the northwestern South American coast.
42 2