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Patella, Domenico
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Patella, Domenico
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Patella, D.
29 results
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- PublicationOpen AccessA physical pattern recognition approach for 2D electromagnetic induction studies(2000-04)
; ; ;Mauriello, P.; Istituto per le Tecnologie Applicate ai Beni Culturali, CNR, Roma, Italy ;Patella, D.; Dipartimento di Scienze Fisiche, Università «Federico II», Napoli, Italy; We present a new tomographic procedure for the analysis of natural source electromagnetic (EM) induction field data collected over any complex 2D buried structure beneath a flat air-earth boundary. The tomography is developed in a pure physical context and the primary goal is the depiction of the space distribution of two occurrence probability functions for the induced electrical charge accumulations on resistivity discontinuities and current channelling inside conductive bodies, respectively. The procedure to obtain tomographic image consists of a scanning operation governed analytically by a set of multiple interference cross-correlations between the observed EM components and the corresponding synthetic components of a pair of elementary charge and dipole. To show the potentiality of the proposed physical tomography, we discuss the results from three 2D synthetic examples.153 514 - PublicationOpen AccessExamples of application of tensorial resistivity probability tomography to architectonic and archaeological targets(2002)
; ; ; ; ;Di Fiore, B.; Dipartimento di Geofisica e Vulcanologia, Università «Federico II», Napoli, Italy ;Mauriello, P.; Istituto per le Tecnologie Applicate ai Beni Culturali, Consiglio Nazionale delle Ricerche, Roma, Italy ;Monna, D.; Istituto per le Tecnologie Applicate ai Beni Culturali, Consiglio Nazionale delle Ricerche, Roma, Italy ;Patella, D.; Dipartimento di Scienze Fisiche, Università «Federico II», Napoli, Italy; ; ; We present the results of the application of the tensor resistivity method to the assessment of the state of conservation of some architectonic features of the S.Giovanni a Carbonara monumental monastery (Naples, Italy) and to the recognition of buried remains in the archaeological site of the roman Port of Claudius at Fiumicino (Rome, Italy). The 3D tomographic approach, based on the concept of resistivity anomaly source occurrence probability, has been used for the analysis of the invariant parameter related to the trace of the determinant of the apparent resistivity tensor.148 280 - PublicationOpen AccessAbout the shallow resistivity structure of Vesuvius volcano(2008-02)
; ; ; ; ; ; ; ; ;Troiano, A.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Petrillo, Z.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Di Giuseppe, M. G.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Balasco, M.; Istituto di Metodologie per l’Analisi Ambientale (IMAA, CNR), Tito Scalo (Pz), Italy ;Diaferia, I.; Dipartimento di Geologia e Geofisica, Università degli Studi di Bari, Italy ;Di Fiore, B.; Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Vesuviano, Napoli, Italy ;Siniscalchi, A.; Dipartimento di Geologia e Geofisica, Università degli Studi di Bari, Italy ;Patella, D.; Dipartimento di Fisica, Università degli Studi di Napoli «Federico II», Napoli, Italy; ; ; ; ; ; ; Magnetotelluric (MT) soundings performed in the past in the volcanic area of Mt. Vesuvius by two independent research groups showed in the same places MT apparent resistivity curves with very similar shape, but statically shifted by one order of magnitude, at least. To try to resolve this ambiguity new controlled source audio-magnetotelluric (CSAMT) measurements have been carried out in the same MT sites. The interpretation of the CSAMT dataset, combined with that of two shallow dipole-dipole geoelectrical resistivity tomographies previously carried out in the area have allowed a reliable electrical structure to be recovered down to a few km of depth, which will next be used for a best constrained re-interpretation of the deep MT soundings.449 746 - PublicationOpen AccessA geophysical k-means cluster analysis of the Solfatara-Pisciarelli volcano-geothermal system, Campi Flegrei (Naples, Italy)(2018)
; ; ; ; ; ; ; ;; We present an application of the k-means cluster analysis technique to a trivariate geophysical parameter set dis- tributed over a 3 km thick and 1.2 km long section through the geothermally active Solfatara-Pisciarelli area of the Campi Flegrei caldera (Italy). The data set consists of resistivity, P-wave velocity and density parameters, ex- tracted from previously modeled univariate sections through the selected profile and mapped in a joint param- eter 3D space. Six compact and separated clusters have been identified. A subsequent linear regression statistics has allowed two distinct branches of clusters to be recognized, each represented in the joint parameter space by the equation of a plane. Each equation and its partial derivatives define the peculiar combinations among the used parameters. Once mapped back to the space domain, the final image has provided a grouping of the struc- tures in two superimposed blocks with an irregular interface located at 2 km mean depth. Based on drilling data, subsurface stratigraphy and recent seismic activity, the interface between the two blocks has been interpreted in terms of a substantial change in the rocks rheology inside the Solfatara-Pisciarelli volcano-geothermal system, namely the brittle-to-ductile transition.332 520 - PublicationOpen AccessModeling electrical dispersion phenomena in Earth materials(2008-02)
; ;Patella, D.; Dipartimento di Fisica, Università degli Studi di Napoli «Federico II», Napoli, ItalyIt is illustrated that IP phenomena in rocks can be described using conductivity dispersion models deduced as solutions to a 2nd-order linear differential equation describing the motion of a charged particle immersed in an external electrical field. Five dispersion laws are discussed, namely: the non-resonant positive IP model, which leads to the classical Debye-type dispersion law and by extension to the Cole-Cole model, largely used in current practice; the non-resonant negative IP model, which allows negative chargeability values, known in metals at high frequencies, to be explained as an intrinsic physical property of earth materials in specific field cases; the resonant flat, positive or negative IP models, which can explain the presence of peak effects at specific frequencies superimposed on flat, positive or negative dispersion spectra.183 310 - PublicationRestrictedSeparation of plain wave and near field contributions in Magnetotelluric time series: A useful criterion emerged during the Campi Flegrei (Italy) prospecting(2018)
; ; ; ; ; The presence of coherent noise in the Magnetotelluric time series greatly obstacles the application of this pow- erful technique in highly urbanized environments. Here the experiences gained during an intensive prospecting of the Campi Flegrei caldera (Italy) are described. In this area the presence of an extensive electrified railroad comports the contamination of the electromagnetic signal by high level of noise related to randomly moving sources. The main task consists in the search for a way to discern the plain wave signal from the noise. This has been achieved through a first application of the well-known Robust Multivariate Errors-in-Variables (RMEV) estimator to the time series collected in the area in order to characterize the global structure of the signal and then through various tests performed on both synthetic and real field Magnetotelluric data. In the end, an empirical criterion has been deduced, based on the rotational analysis of the dominant eigenvectors of the time series Spectral Density Matrix, apt to isolate the plain wave component of the Magnetotelluric data. A var- iation of the standard RMEV scheme has been successively applied in order to obtain a reliable estimate of the apparent resistivity curves. This application has proven its suitability for the time series collected in the Campi Flegrei area, but the logic at its basis could be a key to deal with more general cases.94 6 - PublicationOpen AccessAn integrated magnetotelluric study of the Mt. Etna volcanic structure(2000-04)
; ; ; ; ;Mauriello, P.; Istituto per le Tecnologie Applicate ai Beni Culturali, CNR, Roma, Italy ;Patella, D.; Dipartimento di Scienze Fisiche, Università «Federico II», Napoli, Italy ;Petrillo, Z.; Osservatorio Vesuviano, Ercolano, Napoli, Italy ;Siniscalchi, A.; Dipartimento di Geologia e Geofisica, Università di Bari, Italy; ; ; he results of a magnetotelluric (MT) survey performed at Mt. Etna (Sicily, Italy) are presented and discussed. The MT interpretation is preceded by the description of the data managing strategy used for the estimate of the impedance tensor and the computation of a rotationally invariant parameter. The 1D Bostick inversion of MT soundings located in the Etnean central area highlights the existence of a wide conductive zone in the depth range 15-30 km. Resistivities of a fewW×m are estimated in the southern part of this zone, while resistivities one order of magnitude higher are estimated in the northern part. In the central sector, the MT soundings are characterized by much higher resistivity values suggesting the presence of an E-W directed resistive barrier separating the two conductive deep zones. A two-feeding system is thus hypothesized as an extension of a previous 3D model deduced from regional earthquakes and teleseisms in the depth range 15-25 km. Moreover, the comparison with previous shallow seismic tomographies from local earthquakes within the first 11 km of depth allows us to distinguish inside the upper portion of the resistive barrier a central high velocity zone. This zone can likely be ascribed to a slowly cooled dike tending to become highly fractured at its western and eastern edges. Finally, the impedivity analysis based on the comparison with previous geoelectric dipole soundings allows us to exclude the existence of a permanent magma chamber within the first 5 km of depth and to argue the existence of a shallowplumbing system consisting of a medium-to-low temperature hydrothermally altered environment.270 719 - PublicationOpen AccessModelling earth current precursors in earthquake prediction(1997-03)
; ; ; ;Patella, D.; Dipartimento di Geofisica e Vulcanologia, Università di Napoli «Federico II», Napoli, Italy ;Tramacere, A.; Dipartimento di Geologia e Geofisica, Università di Bari, Italy ;Di Maio, R.; Dipartimento di Geofisica e Vulcanologia, Università di Napoli «Federico II», Napoli, Italy; ; This paper deals with the theory of earth current precursors of earthquake. A dilatancy-diffusion-polarization model is proposed to explain the anomalies of the electric potential, which are observed on the ground surface prior to some earthquakes. The electric polarization is believed to be the electrokinetic effect due to the invasion of fluids into new pores, which are opened inside a stressed-dilated rock body. The time and space variation of the distribution of the electric potential in a layered earth as well as in a faulted half-space is studied in detail. It results that the surface response depends on the underground conductivity distribution and on the relative disposition of the measuring dipole with respect to the buried bipole source. A field procedure based on the use of an areal layout of the recording sites is proposed, in order to obtain the most complete information on the time and space evolution of the precursory phenomena in any given seismic region.188 377 - PublicationOpen AccessElectrical resistivity tomography imaging of the near-surface structure of the Solfatara crater, Campi Flegrei (Naples, Italy)(2015)
; ; ; ; ; ; ; ; ; ; ; ;; We describe the results from an electrical resistivity tomography (ERT) survey performed inside the Solfatara cra- ter, located in the central part of the Campi Flegrei (CF) com- posite caldera. The Solfatara volcano represents the most ac- tive zone within the CF area, in terms of hydrothermal mani- festations and local seismicity. Eight dipole-dipole ERT lines have been measured with the aim of deducing a 3D resistivity model for the upper 80 m beneath the Solfatara. The results have allowed classification of the shallow structure below the crater into a low-resistivity (LR) class, up to about 4 Ωm, an intermediate resistivity (IR) class, from 5 Ωm up to 50 Ωm, and a high-resistivity (HR) class, from 60 Ωm onward. In order to solve the ambiguities arising in the interpretation of the nature of these bodies, a comparison has been done be- tween the 3D ERT model and the CO2 flux, soil temperature, and gravity maps over the same area. By combining all of these parameters, the whole LR body has been ascribed to a water-dominated geothermal basin and the HR body to a steam/gas-dominated reservoir. Finally, the IR class has been interpreted as a widespread background situation with inter- mediate character, where volatiles and condensates can coex- ist in the same volumes at variable percentages, coherently with the resistivity variation within this class. Since fluid dy- namics in the Solfatara crater change rapidly, ERT surveys repeated in the future are expected to be of great help in mon- itoring possible pre-eruptive changes, as well as in better fol- lowing evolution of the local geothermal system.340 65 - PublicationRestrictedImaging 2D structures by the CSAMT method: application to the Pantano di S. Gregorio Magno faulted basin (Southern Italy)(2009-03-24)
; ; ; ; ;Troiano, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Di Giuseppe, M. G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Petrillo, Z.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Patella, D.; Department of Physical Sciences, University Federico II, Naples, Italy; ; ; A controlled source audiofrequency magnetotelluric (CSAMT) survey has been undertaken in the Pantano di San Gregorio Magno faulted basin, an earthquake prone area of Southern Apennines in Italy. A dataset from 11 soundings, distributed along a nearly N-S 780 m long profile, was acquired in the basin’s easternmost area, where the fewest data are available as to the faulting shallow features. A preliminary skew analysis allowed a prevailing 2D nature of the dataset to be ascertained. Then, using a single-site multi-frequency approach, Dantzig’s simplex algorithm was introduced for the first time to estimate the CSAMT decomposition parameters. The simplex algorithm, freely available online, proved to be fast and efficient. By this approach, the TM and TE mode field diagrams were obtained and a N35!W ± 10! 2D strike mean direction was estimated along the profile, in substantial agreement with the fault traces within the basin. A 2D inversion of the apparent resistivity and phase curves at seven almost noise-free sites distributed along the central portion of the profile was finally elaborated, reinforced by a sensitivity analysis, which allowed the best resolved portion of the model to be imaged from the first few meters of depth down to a mean depth of 300 m b.g.l. From the inverted section, the following features have been outlined: (i) a cover layer with resistivity in the range 3–30 ! m ascribed to the Quaternary lacustrine clayey deposits filling the basin, down to an average depth of about 35 m b.g.l., underlain by a structure with resistivity over 50 ! m up to about 600 ! m, ascribed to the Mesozoic carbonate bedrock; (ii) a system of two normal faults within the carbonate basement, extending down to the maximum best resolved depth of the order of 300 m b.g.l.; (iii) two wedge-shaped domains separating the opposite blocks of the faults with resistivity ranging between 30 ! m and 50 ! m and horizontal extent of the order of some tens of metres, likely filled with lacustrine sediments and embedded fine gravels.380 41
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