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  • 1
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    The application of a denoising method aimed at reducing continuous gravity data (2008)
    Details
    Publication Date: 2020-12-01
    Description: This study summarizes the results obtained by using a processing method based on wavelet transform for noise-filtering of continuous gravity data. Continuous gravity recordings in vol- canic area could play a fundamental role in the monitoring of active volcanoes and in the prediction of eruptive events too. This geophysical methodology is used, on active volcanoes, in order to detect mass changes linked to magma transfer processes and, thus, to recognize forerunners to paroxysmal volcanic events. Spring gravimeters are still the most utilized in- struments for this type of microgravity studies. Unfortunately, spring gravity meters show a strong influence of meteorological parameters, especially in the adverse environmental condi- tions usually encountered at such places. As the gravity changes due to the volcanic activity are very small compared to other geophysical or instrumental effects, we need a new mathematical tool to get reliable gravity residuals susceptible to reflect the volcanic effect. The aim of the present work is to get a first evaluation about the comparison between the traditional filtering methodology and the wavelet transform. The overall results show that the performance of the wavelet-based filter seems better than the Fourier one. Moreover, the possibility of getting a multi-resolution analysis and study local features of the signal in the time domain makes the proposed methodology a valuable tool for gravity data processing.
    Description: Published
    Description: 1-10
    Description: 1A. Geomagnetismo e Paleomagnetismo
    Description: N/A or not JCR
    Description: open
    Keywords: wavelet transform ; volcanic monitoring ; gravimeter ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 2
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    An overview on wavelet multi-resolution decomposition compared with traditional frequency domain filtering for continuous gravity data denoising (2007)
    Details
    Publication Date: 2017-04-04
    Description: Continuous gravity recordings in volcanic area could play a fundamental role in the monitoring of active volcanoes and in the prediction of eruptive events too. This geophysical methodology is utilized, on active volcanoes, in order to detect mass changes linked to magma transfer processes and, thus, to recognize forerunners to paroxysmal volcanic events. Spring gravimeters are still the most utilized instruments for microgravity studies because of their relatively low cost and small size, which make them easy to transport and install. Continuous gravity measurements are now increasingly performed at sites very close to active craters, where there is the greatest opportunity to detect significant gravity changes due to a volcanic activity. Unfortunately, spring gravity meters show a strong influence of meteorological parameters (i.e. pressure, temperature and humidity), especially in the adverse environmental conditions usually encountered at such places. As the gravity changes due to the volcanic activity are very small compared to other geophysical or instrumental effects we need a new mathematical tool to get reliable gravity residuals susceptible to reflect the volcanic effect. In the following we present and discuss a preliminary work about the confrontation between the traditional filtering methodology and the Wavelet transform. The overall results show that the performance of the wavelet-based filter seems better than the Fourier one. Moreover, the possibility of getting a multi-resolution analysis and study local features of the signal in the time domain makes the proposed methodology a valuable tool for gravity data processing.
    Description: Submitted
    Description: open
    Keywords: Gravimeter ; wavelet transform ; filtering ; volcanic monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.05. Gravity variations ; 05. General::05.01. Computational geophysics::05.01.01. Data processing
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: manuscript
    Format: 363931 bytes
    Format: application/pdf
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  • 3
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    High Precision Tilt Observation at Mt. Etna Volcano, Italy (2012)
    Versita
    Details
    Publication Date: 2017-04-04
    Description: In 2007-2008, we installed on Mt. Etna two deep tilt stations using high resolution, self-leveling instruments. These installations are a result of accurate instrument tests, site selection, drilling and sensor positioning that has allowed detecting variations related to the principal diurnal and semidiurnal tides for first time on Mt. Etna using tilt data. We analyzed the tidal effects recorded on tilt signals and we removed tidal effects from signals, thereby allowing to detect changes of about 20 nrad with a considerable improvement in respect to the previous installation. Tilt changes have accompanied the Mt. Etna main eruptive phases and are generally related to the rapid rise of magma and formation of dikes and eruptive fissures. However, tilt changes may characterize lava fountains, earthquakes, and inflation-deflation phases. The 2008-2009 eruption represents an example of the potential of the tiltmeters we used, which provides new perspectives for highly precise monitoring of ground deformation on volcanoes.
    Description: Published
    Description: 618-632
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: tilt borehole tiltmeter, Earth tides, Mt. Etna, volcanic signals ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 4
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    Tidal gravity observations at Mt. Etna and Stromboli: results concerning the modeled and observed tidal factors (2009)
    Details
    Publication Date: 2019-11-21
    Description: Continuous gravity observations performed in the last few years, both at Mt. Etna and Stromboli, have prompted the need to improve the tidal analysis in order to acquire the best corrected data for the detection of volcano related signals. On Mt. Etna, the sites are very close to each other and the expected tidal factor differences are negligible. It is thus useful to unify the tidal analysis results of the different data sets in a unique tidal model. This tidal model, which can be independently confirmed by a modeling of the tidal parameters based on the elastic response of the Earth to tidal forces and the computation of the ocean tides effects on gravity, is very useful for the precise tidal gravity prediction required by absolute or relative discrete gravity measurements. The change in time of the gravimeters’ sensitivity is also an important issue to be checked since it affects not only the results of tidal analysis but also the accuracy of the observed gravity changes. Conversely, if a good tidal model is available, the sensitivity variations can be accurately reconstructed so as to retune observed tidal records with the synthetic tide, since the tidal parameters are assumed to be constant at a given location.
    Description: Published
    Description: 51-65
    Description: 2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attive
    Description: JCR Journal
    Description: open
    Keywords: Tidal gravity models ; Tidal loading ; 04. Solid Earth::04.03. Geodesy::04.03.04. Gravity anomalies
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 5
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    High precision tilt observation at Mt. Etna Volcano, Italy (2011)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: In 2007-2008, we installed on Mt. Etna two deep tilt stations using high resolution, self-leveling instruments. These installations are the result of accurate instrument tests, site selection, drilling and sensor positioning that has allowed detecting variations related to the principal diurnal and semidiurnal tides for first time on Mt. Etna using tilt data. We analyzed the tidal effects recorded on tilt signals and we removed tidal effects from signals, thereby allowing to detect changes of about 20 nanoradians with a considerable improvement respect to the previous installation. Tilt changes have accompanied the Mt. Etna main eruptive phases and are generally related to the rapid rise of magma and formation of dikes and eruptive fissures. However, tilt changes characterize lava fountains, earthquakes and inflation-deflation phases. The 2008-2009 eruption represents an example of the potential of these tiltmeters providing new perspectives for highly precise monitoring of ground deformation on volcanoes.
    Description: In press
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: open
    Keywords: Tilt borehole tiltmeter ; Earth tides ; 01. Atmosphere::01.01. Atmosphere::01.01.08. Instruments and techniques
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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