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Gagliardi, G.
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Gagliardi, G.
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- PublicationOpen AccessNovel laser-based techniques for monitoring of volcanoes(2005)
; ; ; ; ; ;De Natale, G.; Istituto Nazionale di Ottica Applicata, Comprensorio Olivetti, Pozzuoli (NA), Italy ;De Natale, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Gagliardi, G.; Istituto Nazionale di Ottica Applicata, Comprensorio Olivetti, Pozzuoli (NA), Italy ;Gianfrani, L.; Dipartimento di Scienze Ambientali, Seconda Università di Napoli, and INFM-Gruppo Coordinato Napoli 2, Caserta, Italy ;Rocco, A. S. D.; Istituto Nazionale di Ottica Applicata, Comprensorio Olivetti, Pozzuoli (NA), Italy; ; ; ; An overview of novel laser techniques suitable for volcanic monitoring, based on different kinds of infrared laser sources, is presented. Their main advantages and drawbacks are discussed focusing on the achievable sensitivity and precision levels in analysis of gaseous species. Some of the most recent experimental results obtained in laboratory development as well as in field tests of home-built laser spectrometers are reported. New perspectives in optical devices aimed at geochemical and geophysical applications are also considered.205 252 - PublicationRestrictedDesign and test of a laser-based optical-fiber Bragg-grating accelerometer for seismic applications(2008)
; ; ; ; ; ; ; ; ;Gagliardi, G.; CNR-Istituto Nazionale di Ottica Applicata, Sezione di Napoli, Comprensorio ‘A Olivetti’, Italy ;Salza, M.; CNR-Istituto Nazionale di Ottica Applicata, Sezione di Napoli, Comprensorio ‘A Olivetti’, Italy ;Ferraro, P.; CNR-Istituto Nazionale di Ottica Applicata, Sezione di Napoli, Comprensorio ‘A Olivetti’, Italy ;De Natale, P.; CNR-Istituto Nazionale di Ottica Applicata, Sezione di Napoli, Comprensorio ‘A Olivetti’, Italy ;Di Maio, A.; Ansaldo STS, Napoli, Italy ;Carlino, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;De Natale, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;Boschi, E.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione AC, Roma, Italia; ; ; ; ; ; ; We report on a proof-of-principle work aimed at the development of fast-response fiber-optic accelerometers for seismic monitoring. The system is based on a semiconductor diode-laser source that interrogates a newly devised two-dimensional inertial sensor suitable for measurement of horizontal ground accelerations. Plane acceleration components of the sensor’s mass are detected by two fiber Bragg gratings anchored to its structure. Calibration and comparison with a commercial accelerometer are presented. A great potential, in terms of frequency response and sensitivity, is demonstrated in view of possible field applications in active seismic areas.403 49 - PublicationRestrictedA diode-laser-based spectrometer for in-situ measurements of volcanic gases(2004)
; ; ; ; ; ;Rocco, A.; Istituto Nazionale di Ottica Applicata, Comprensorio Olivetti ;De Natale, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;De Natale, P.; Istituto Nazionale di Ottica Applicata, Comprensorio Olivetti ;Gagliardi, G.; Seconda Università di Napoli, Dipartimento di Scienze Ambientali ;Gianfrani, L.; Seconda Università di Napoli, Dipartimento di Scienze Ambientali; ; ; ; We report the first results of the field operation of a novel, portable diode-laser spectrometer for gasconcentration measurements in volcanic areas. Remote detection of direct absorption line shapes was possible thanks to a telecomsingle-mode optical fiber that delivered radiation from a room-temperature distributed-feedback diode laser, emitting at 1.997 µm, to an open-path multiple-reflection cell, placed on gas effluxes. The system was deployed on two different active volcanoes in Italy, where simultaneous and continuous monitoring of CO2 and H2O concentrations has been demonstrated.297 70 - PublicationOpen AccessContinuous in situ measurements of volcanic gases with a diode-laser-based spectrometer: CO2 and H2O concentration and soil degassing at Vulcano (Aeolian islands: Italy)(2007)
; ; ; ; ; ; ;De Rosa, M.; CNR, Istituto Nazionale di Ottica Applicata, Sezione di Napoli, I-80078 Pozzuoli (NA), Italy ;Gagliardi, G.; CNR, Istituto Nazionale di Ottica Applicata, Sezione di Napoli, I-80078 Pozzuoli (NA), Italy ;Rocco, A.; CNR, Istituto Nazionale di Ottica Applicata, Sezione di Napoli, I-80078 Pozzuoli (NA), Italy ;Somma, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia ;De Natale, P.; CNR, Istituto Nazionale di Ottica Applicata, Sezione di Napoli, I-80078 Pozzuoli (NA), Italy ;De Natale, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; ; ; ; ; We report on a continuous-measurement campaign carried out in Vulcano (Aeolian islands, Sicily), devoted to the simultaneous monitoring of CO2 and H2O concentrations. The measurements were performed with an absorption spectrometer based on a semiconductor laser source emitting around a 2-μm wavelength. The emitted radiation was selectively absorbed by two molecular ro-vibrational transitions specific of the investigated species. Data for CO2 and H2O concentrations, and CO2soil diffusive flux using an accumulation chamber configuration, were collected at several interesting sampling points on the island (Porto Levante beach- PLB, Fossa Grande Crater - FOG- and Valley of Palizzi, PAL). CO2/H2O values, measured on the ground, are very similar (around 0.019 (± 0.006)) and comparable to the previous discrete detected values of 0.213 (Fumarole F5 -La Fossa crater rim) and 0.012 (Fumarole VFS - Baia Levante beach) obtained during the 1977-1993 heating phase of the crater fumaroles. In this work much more homogeneous values are found in different points of the three sites investigated. The field work, although carried out in a limited time window (25th-28th August 2004), pointed out the new apparatus is suitable for continuous gas monitoring of the two species and their ratios, which are important geochemical indicators of volcanic activity, for which other reliable continuous monitoring systems are not yet available.222 349