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Roberts TJ, Lurton T, Giudice G, Liuzzo M, Aiuppa A, Coltelli M, Vignelles D, Salerno G, Couté B, Chartier M, Baron R, Saffell JR, Scaillet B. Validation of a novel Multi-Gas sensor for volcanic HCl alongside H 2S and SO 2 at Mt. Etna. Bull Volcanol 2017; 79:36. [PMID: 32025075 PMCID: PMC6979509 DOI: 10.1007/s00445-017-1114-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 03/16/2017] [Indexed: 06/10/2023]
Abstract
Volcanic gas emission measurements inform predictions of hazard and atmospheric impacts. For these measurements, Multi-Gas sensors provide low-cost in situ monitoring of gas composition but to date have lacked the ability to detect halogens. Here, two Multi-Gas instruments characterized passive outgassing emissions from Mt. Etna's (Italy) three summit craters, Voragine (VOR), North-east Crater (NEC) and Bocca Nuova (BN) on 2 October 2013. Signal processing (Sensor Response Model, SRM) approaches are used to analyse H2S/SO2 and HCl/SO2 ratios. A new ability to monitor volcanic HCl using miniature electrochemical sensors is here demonstrated. A "direct-exposure" Multi-Gas instrument contained SO2, H2S and HCl sensors, whose sensitivities, cross-sensitivities and response times were characterized by laboratory calibration. SRM analysis of the field data yields H2S/SO2 and HCl/SO2 molar ratios, finding H2S/SO2 = 0.02 (0.01-0.03), with distinct HCl/SO2 for the VOR, NEC and BN crater emissions of 0.41 (0.38-0.43), 0.58 (0.54-0.60) and 0.20 (0.17-0.33). A second Multi-Gas instrument provided CO2/SO2 and H2O/SO2 and enabled cross-comparison of SO2. The Multi-Gas-measured SO2-HCl-H2S-CO2-H2O compositions provide insights into volcanic outgassing. H2S/SO2 ratios indicate gas equilibration at slightly below magmatic temperatures, assuming that the magmatic redox state is preserved. Low SO2/HCl alongside low CO2/SO2 indicates a partially outgassed magma source. We highlight the potential for low-cost HCl sensing of H2S-poor HCl-rich volcanic emissions elsewhere. Further tests are needed for H2S-rich plumes and for long-term monitoring. Our study brings two new advances to volcano hazard monitoring: real-time in situ measurement of HCl and improved Multi-Gas SRM measurements of gas ratios.
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Affiliation(s)
- T. J. Roberts
- Institut Pierre Simon Laplace, CNRS/UPMC, 4 place Jussieu, 75252 Paris, France
| | - T. Lurton
- Institut Pierre Simon Laplace, CNRS/UPMC, 4 place Jussieu, 75252 Paris, France
| | - G. Giudice
- Istituto Nazionale di Geofisica e Vulcanologia, sezione di Palermo, Via La Malfa 153, 90146 Palermo, Italy
| | - M. Liuzzo
- Istituto Nazionale di Geofisica e Vulcanologia, sezione di Palermo, Via La Malfa 153, 90146 Palermo, Italy
| | - A. Aiuppa
- Istituto Nazionale di Geofisica e Vulcanologia, sezione di Palermo, Via La Malfa 153, 90146 Palermo, Italy
- Dipartimento DiSTeM, Università di Palermo, Via Archirafi 36, 90123 Palermo, Italy
| | - M. Coltelli
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Piazza Roma 2, 95125 Catania, Italy
| | - D. Vignelles
- Institut Pierre Simon Laplace, CNRS/UPMC, 4 place Jussieu, 75252 Paris, France
| | - G. Salerno
- Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Piazza Roma 2, 95125 Catania, Italy
| | - B. Couté
- Institut Pierre Simon Laplace, CNRS/UPMC, 4 place Jussieu, 75252 Paris, France
| | - M. Chartier
- Institut Pierre Simon Laplace, CNRS/UPMC, 4 place Jussieu, 75252 Paris, France
| | - R. Baron
- Alphasense Ltd, Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley, Braintree, Essex, CM77 7AA UK
| | - J. R. Saffell
- Alphasense Ltd, Sensor Technology House, 300 Avenue West, Skyline 120, Great Notley, Braintree, Essex, CM77 7AA UK
| | - B. Scaillet
- ISTO, CNRS/Université d’Orléans/BRGM, UMR 7327, 1a rue de la Férollerie, 45071 Orléans, France
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