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11 results on '"Tramontini, Matias"'

1. Atmospheric & geodesic controls on muon rate: a numerical study based on Corsika

Author

Cohu, Amélie, Tramontini, Matias, Chevalier, Antoine, Ianigro, Jean-Christophe, and Marteau, Jacques

Subjects
Physics - Geophysics, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

Muon rate models play a key role in converting measured data into information on the density distributions of a target. Any given muography measurement, either in transmission or in scattering mode, requires a proper modelization of the muon flux according to the localization and to the atmospheric conditions. Two approaches are commonly used: either through semi-empirical models calibrated on existing data or via Monte-Carlo simulations. The former requires extrapolations to the field experiment conditions while the latter offers the advantage of tackling down in an unique way all relevant parameters such as barometric conditions, geomagnetic field, atmosphere density etc. Although significant progress were made in the last decades, precision muography experiments require more and more accuracy on the models, especially for the muons close to the horizon where large disparities still remain. In this paper we present detailed results obtained with the CORSIKA simulation framework to emphasize and quantify the impact of the environmental conditions on the sensitivity of muography measurements.

Published
2021

2. Middle-atmosphere dynamics observed with a portable muon detector

Author

Tramontini, Matias, Rosas-Carbajal, Marina, Nussbaum, Christophe, Gibert, Dominique, and Marteau, Jacques

Subjects
Physics - Geophysics, High Energy Physics - Experiment, High Energy Physics - Phenomenology
Abstract

In the past years, large particle-physics experiments have shown that muon rate variations detected in underground laboratories are sensitive to regional, middle-atmosphere temperature variations. Potential applications include tracking short-term atmosphere dynamics, such as Sudden Stratospheric Warmings. We report here that such sensitivity is not only limited to large surface detectors under high-opacity conditions. We use a portable muon detector conceived for muon tomography for geophysical applications and we study muon rate variations observed over one year of measurements at the Mont Terri Underground Rock Laboratory, Switzerland (opacity of ~700 meter water equivalent). We observe a direct correlation between middle-atmosphere seasonal temperature variations and muon rate. Muon rate variations are also sensitive to the abnormal atmosphere heating in January-February 2017, associated to a Sudden Stratospheric Warming. Estimates of the effective temperature coefficient for our particular case agree with theoretical models and with those calculated from large neutrino experiments under comparable conditions. Thus, portable muon detectors may be useful to 1) study seasonal and short-term middle atmosphere dynamics, especially in locations where data is lacking such as mid-latitudes; and 2) improve the calibration of the effective temperature coefficient for different opacity conditions. Furthermore, we highlight the importance of assessing the impact of temperature on muon rate variations when considering geophysical applications. Depending on latitude and opacity conditions, this effect may be large enough to hide subsurface density variations due to changes in groundwater content, and should therefore be removed from the time-series., Comment: 16 pages, 8 figures

Published
2019
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5. Atmospheric & geodesic controls on muon rate: a numerical study based on Corsika

Author

Cohu, Am��lie, Tramontini, Matias, Chevalier, Antoine, Ianigro, Jean-Christophe, and Marteau, Jacques

Subjects
High Energy Physics - Experiment (hep-ex), High Energy Physics - Phenomenology (hep-ph), FOS: Physical sciences, Geophysics (physics.geo-ph)
Abstract

Muon rate models play a key role in converting measured data into information on the density distributions of a target. Any given muography measurement, either in transmission or in scattering mode, requires a proper modelization of the muon flux according to the localization and to the atmospheric conditions. Two approaches are commonly used: either through semi-empirical models calibrated on existing data or via Monte-Carlo simulations. The former requires extrapolations to the field experiment conditions while the latter offers the advantage of tackling down in an unique way all relevant parameters such as barometric conditions, geomagnetic field, atmosphere density etc. Although significant progress were made in the last decades, precision muography experiments require more and more accuracy on the models, especially for the muons close to the horizon where large disparities still remain. In this paper we present detailed results obtained with the CORSIKA simulation framework to emphasize and quantify the impact of the environmental conditions on the sensitivity of muography measurements.

Published
2021
Full Text
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6. Muographic long-term monitoring of the Soufrière of Guadeloupe with a system of coupled muon detection systems

Author

Marteau, Jacques, Rosas-Carbajal, Marina, tramontini, matias, Zyserman, Fabio, De Bremond D'Ars, Jean, Le Gonidec, Yves, Carlus, Bruno, Ianigro, Jean-Christophe, Deroussi, Sébastien, Gibert, Dominique, Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Universidad Nacional de la Plata [Argentine] (UNLP), Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Observatoire Volcanologique et sismologique de la Soufrière de Guadeloupe, American Geophysical Union, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
Abstract

International audience; We present novel developments in muography methods to combine continuous measurementsperformed by 2 independant muon detectors around the dome of an active volcano, the Soufrièreof Guadeloupe. The aim is to reach the best possible performances in the continuous monitoringof its hydrothermal system spatio-temporal dynamics.Volcanic hydrothermal systems give rise to unpredictable hazards such as hydrothermal explo-sions, partial edifice collapse, mudflows and sudden emission of toxic gases. Characterizing the dy-namics of these systems and constraining the models by real-time data is thus critical for develop-ing efficient risk assessment.Within the DIAPHANE project, funded by the french National Research Agency (ANR), 6 muontelescopes have been deployed around the dome since 2015 and acquire muon data continuouslywith a large duty cycle. In this work we show the results obtained with a set of more than 1.5years of continuous measurements acquired with 2 muon detectors scanning different zones of thedome with large overlapping volumes. Characterizing the time changes in the outgoing muon fluxin different regions allows us to study the density changes caused by steam formation, condensa-tion, water infiltration and storage.The details of the analysis is presented : region definition through common geological structures,principal component analysis of the temporal series, determination of the changes in opacity im-plied by the muon-flux changes observed. This strategy allows us to spatially constrain the three-dimensional location of the coherent density changes and to improve the quantification of the as-sociated mass changes. The obtained results on the active zone of the Soufrière of Guadeloupe’sSouth crater are presented in details.

Published
2019

8. Muon imaging and monitoring at the Mont Terri underground rock laboratory, Switzerland

Author

tramontini, matias, Rosas-Carbajal, Marina, Marteau, Jacques, Zyzerman, fabio, Carlus, Bruno, Ianigro, Jean-Christophe, Gibert, Dominique, Nussbaum, Christophe, Universidad Nacional de la Plata [Argentine] (UNLP), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique des 2 Infinis de Lyon (IP2I Lyon), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
VOLCANOLOGY, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Physics::Instrumentation and Detectors, GENERAL OR MISCELLANEOUSDE: 4315 Monitoring, NATURAL HAZARDSDE: 8419 Volcano monitoring, [SDU.STU.VO]Sciences of the Universe [physics]/Earth Sciences/Volcanology, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, forecasting, prediction, EXPLORATION GEOPHYSICSDE: 9805 Instruments useful in three or more fields, 0933 Remote sensing, Physics::Geophysics
Abstract

International audience; Imaging geological objects by quantifying the screening effect they have on the natural flux of cosmic muons is a powerful method that complements standard geophysical tools in the understanding of the Earth's subsurface. Radiographies of the average density of geological bodies along the muon paths can be retrieved from muon measurements, allowing to image large volumes of rock from a single observation point. Furthermore, continuous muon measurements allow us to monitor density variations in a geological object, by tracking the time changes in the outgoing flux of muons. The Mont Terri underground rock laboratory is located in the Jura Mountains range, at a depth of around 300 meters below the Earth's surface in north-western Switzerland. Its structural setting is dominated by an anticline of Triassic-Jurassic formations, whose spatial distribution is finely characterized given the numerous boreholes and outcrops studied inside and outside the tunnel. In this work we analyze 5 muon imaging experiences performed from inside the rock laboratory from 2013 to 2017. From this dataset we obtain corresponding muon radiographies of the average density between the tunnel and the surface of the Mont Terri site at extensive directions. Moreover, at one site the muon detector continuously recorded data for a whole year. We use these data to study the density variations due to changes on the rock's fluid saturation over time in different regions of the mountain. Finally, we perform a joint interpretation with complementary geological, meteorological and geophysical data from the site.

Published
2018

9. Long-term, coupled muon measurements to track density changes at La Soufrière de Guadeloupe volcano

Author

Rosas-Carbajal, Marina, Marteau, Jacques, tramontini, matias, Zyzerman, fabio, De Bremond D'Ars, Jean, Le Gonidec, Yves, Carlus, Bruno, Ianigro, Jean-Christophe, Deroussi, Sébastien, Gibert, Dominique, Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional de la Plata [Argentine] (UNLP), Géosciences Rennes (GR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Observatoire Volcanologique et sismologique de la Soufrière de Guadeloupe, Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Physics::Geophysics
Abstract

International audience; Volcanic hydrothermal systems give rise to unpredictable hazards such as hydrothermal explosions, partial edifice collapse, mudflows and sudden emission of toxic gases. Characterizing the dynamics of these systems is thus critical for developing efficient risk assessment.Here we present the use of continuous muon measurements at La Soufrière de Guadeloupe volcano as a novel methodology to characterize the spatio-temporal dynamics of its hydrothermal system. Six muon telescopes acquire data continuously around the lava dome since 2015. In this work a set of more than 1.5 years of continuous measurements acquired with two muon detectors is analyzed. The two telescopes scan two different zones of the dome with large overlapping volumes. Characterizing the time changes in the outgoing muon flux in different regions allows us to study the density changes caused by steam formation, condensation, water infiltration and storage. First, we define these regions according to the different geological structures in the volcano presenting characteristic behaviors: active/non-active fumarolic zones, and shallow/deeper sections of the system. We then perform a principal component analysis of the temporal series to identify which lines-of-sight of the two telescopes present coherent temporal variations. Finally, we make use of calibrated static muon radiographies to determine the changes in opacity implied by the muon-flux changes observed. This strategy allows us to spatially constrain the three-dimensional location of the coherent density changes and to improve the quantification of the associated mass changes.

Published
2018

10. Muon tomography of the La Soufrière de Guadeloupe hydrothermal system: 3-D structure and dynamics

Author

Rosas-Carbajal, Marina, Marteau, Jacques, tramontini, matias, Zyserman, Fabio, De Bremond D'Ars, Jean, Le Gonidec, Yves, Al., Et, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Universidad Nacional de la Plata [Argentine] (UNLP), Géosciences Rennes (GR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; Muon imaging has recently emerged as a powerful method to complement standard geophysical methods in volcanology.Muon measurements yield a radiography of the average density along the muon path, allowing to imagelarge volumes of a geological body from a single observation point. When multiple muon detectors surroundingthe volcano are available, it is possible to invert these data to retrieve the 3-D density distribution in the volcano.Long-term measurements of the muon flux allow to infer density changes in the system. In the context of volcanichydrothermal systems, this approach helps to characterize zones of steam formation, condensation, water infiltrationand storage. We present the results of imaging the La Soufrière de Guadeloupe shallow active hydrothermalsystem with a network of muon detectors scanning the lava dome from different positions around its base. First, wejointly invert the muon data from three different detectors with gravity data to obtain a three-dimensional densitymodel of the lava dome. The model reveals an extensive low-density region where the hydrothermal system ismost active. We then analyze the dynamics of the hydrothermal system from long-term measurements (more than2 years of almost non-interrupted acquisition), acquired by 2 simultaneous muon detectors. Shallow regions seemto evidence smaller density changes than deeper parts of the hydrothermal system (200-300 m below the summit).Among the most active regions, periods of relative calm can follow periods of quasi-periodical changes. Our simultaneousmuon detector strategy provides constraints on the three-dimensional location of the density changes andan improved quantification of the associated mass changes. This works characterizes for the first time the dynamicbehavior of an active hydrothermal system, at a volcano undergoing thermal and degassing unrest, at a large spatialscale and for a relatively long term (1.5 - 2 years), with a temporal resolution of 1 month.

Published
2018

11. Characterizing the dynamics of hydrothermal systems with muon tomography: the case of La Soufrière de Guadeloupe

Author

Rosas-Carbajal, Marina, Marteau, Jacques, Tramontini, Matias, de Bremond d'Ars, Jean, Le Gonidec, Yves, Carlus, Bruno, Ianigro, Jean-Christophe, Deroussi, Sébastien, Komorowski, Jean-Christophe, Gibert, Dominique, Institut de Physique du Globe de Paris (IPGP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Universidad Nacional de la Plata [Argentine] (UNLP), Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Observatoire Volcanologique et sismologique de la Soufrière de Guadeloupe, Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Physics::Geophysics
Abstract

International audience; Muon imaging has recently emerged as a powerful method to complement standard geophysical tools in the study of the Earth’s subsurface. Muon measurements yield a radiography of the average density along the muon path, allowing to image large volumes of a geological body from a single observation point. Long-term measurements allow to infer density changes by tracking the associated variations in the muon flux. In the context of volcanic hydrothermal systems, this approach helps to characterize zones of steam formation, condensation, water infiltration and storage. We present results of imaging the La Soufrière de Guadeloupe dome and shallow active hydrothermal system with a network of muon telescopes viewing the dome from different positions around its base. First, we jointly invert the muon radiographies of the different telescopes with gravity data to obtain a three-dimensional density model of the lava dome. The model reveals an extended low density region where the hydrothermal system is most active. We then analyze the dynamics of the hydrothermal system from long-term measurements (more than 2 years of almost non-interrupted acquisition) with 5 simultaneous muon telescopes. We identify a periodicity of ~1-2 months in the density increase/decrease in the most active zones below fumaroles and acid boiling ponds. Our simultaneous-muon telescope strategy provides constraints on the three-dimensional location of the density changes and an improved quantification of the associated mass flux changes. We compare the temporal trends acquired by the different muon telescopes to time-series of rainfall on the summit recharge area as well as to ground temperature profiles in the vicinity of thermal anomalies and high-discharge summit fumaroles.

Published
2017

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