Three‐dimensional density structure of La Soufrière de Guadeloupe lava dome from simultaneous muon radiographies and gravity data

Rosas‐Carbajal, Marina; Jourde, Kevin; Marteau, J.; Deroussi, Sébastien; Komorowski, Jean‐Christophe; Gibert, Dominique

doi:10.1002/2017gl074285

Cited by 88 publications

(69 citation statements)

References 42 publications

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“…Most of them were placed hundreds of meters underground, which improves data sensitivity to atmospheric effects by filtering out low-energy muons. The detection surface of these systems are huge compared to portable ones, which are used for geoscience applications such as characterizing the density structure of volcanoes (e.g., Rosas-Carbajal et al, 2017). Recently, muon rate variations following the passage of a thundercloud were reported by Hariharan et al (2019) using a relatively large detector (6×6×2 m 3 ).…”

Section: Introductionmentioning

confidence: 99%

Middle‐Atmosphere Dynamics Observed With a Portable Muon Detector

Tramontini

Rosas‐Carbajal

Nussbaum³

et al. 2019

Earth and Space Science

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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 1 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 are lacking such as midlatitudes, 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.

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Section: Introductionmentioning

confidence: 99%

Middle‐Atmosphere Dynamics Observed With a Portable Muon Detector

Tramontini

Rosas‐Carbajal

Nussbaum³

et al. 2019

Earth and Space Science

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“…the ideal scenario), (2) the porosity of a representative rock(s) is known and the GSI value(s) is unknown, (3) the porosity of a representative rock(s) is unknown but the GSI value(s) is known, and (4) both porosity and GSI are unknown. This approach can be used to provide a single value of Young's modulus for an elastic half-space or, if there is geological or geophysical justification for splitting the half-space into domains characterised by different porosity and/or GSI values (such as, for example low-density/high-porosity zones identified by muon tomography;Lesparre et al, 2012;Rosas-Carbajal et al, 2017; Le Gonidec et al, 2019), then the approach can also be used to assign Young's modulus values to the different domains within the half-space. TheJ o u r n a l P r e -p r o o f data and equations required for estimating rock mass Young's modulus in the four scenarios described below can be found in the Microsoft Excel© spreadsheet available as Supplementary Material.…”

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confidence: 99%

Towards more realistic values of elastic moduli for volcano modelling

Heap¹,

Villeneuve

Albino

et al. 2020

Preprint

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Highlights We provide porosity-Young's modulus data for 276 volcanic rock samples. We present a method to upscale these laboratory measurements to the rock mass scale. Young's modulus of a typical volcanic rock mass is 5.4 GPa. We provide methods to estimate depth-dependent rock mass Young's modulus. We provide a Microsoft Excel© spreadsheet with the relevant data and equations. J o u r n a l P r e -p r o o f AbstractThe accuracy of elastic analytical solutions and numerical models, widely used in volcanology to interpret surface ground deformation, depends heavily on the Young's modulus chosen to represent the medium. The paucity of laboratory studies that provide Young's moduli for volcanic rocks, and studies that tackle the topic of upscaling these values to the relevant lengthscale, has left volcano modellers ill-equipped to select appropriate Young's moduli for their models. Here we present a wealth of laboratory data and suggest tools, widely used in geotechnics but adapted here to better suit volcanic rocks, to upscale these values to the scale of a volcanic rock mass. We provide the means to estimate upscaled values of Young's modulus, Poisson's ratio, shear modulus, and bulk modulus for a volcanic rock mass that can be improved with laboratory measurements and/or structural assessments of the studied area, but do not rely on them. In the absence of information, we estimate upscaled values of Young's modulus, Poisson's ratio, shear modulus, and bulk modulus for volcanic rock with an average porosity and an average fracture density/quality to be 5.4 GPa, 0.3, 2.1 GPa, and 4.5 GPa, respectively. The proposed Young's modulus for a typical volcanic rock mass of 5.4 GPa is much lower than the values typically used in volcano modelling. We also offer two methods to estimate depth-dependent rock mass Young's moduli, and provide two examples, using published data from boreholes within Kīlauea volcano (USA) and Mt. Unzen (Japan), to demonstrate how to apply our approach to real datasets. It is our hope that the data and analysis presented herein will assist in the selection of elastic moduli for volcano modelling. To this end, we provide a Microsoft Excel© spreadsheet containing the data and necessary equations to calculate rock mass elastic moduli that can be updated when new data become available. The selection of the most appropriate elastic moduli will provide the most accurate model predictions and therefore the most reliable information regarding the unrest of a particular volcano or volcanic terrain. J o u r n a l P r e -p r o o f J o u r n a l P r e -p r o o fMagma". The experimental data presented in this study are, for the most part, unpublished data that were collected during mechanical studies performed in collaboration with many scientists. Although non-exhaustive, we thank

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“…The images revealed increased average rock densities across the east side of the activated Minamidake and underneath the deactivated Showa crater with a spatial resolution of ∼60 m. Despite the underestimated average densities due to the detection of energetic background muons, it is reasonable for us to interpret that the excessive density found in the current muographic image was produced by the formation of a volcanic plug. Multidirectional muography (Nagahara & Miyamoto, ) and its combination with high‐resolution gravity (Rosas‐Carbajal et al, ) are good candidates to achieve three‐dimensional monitoring of magma movements inside active volcanoes in the future.…”

Section: Discussionmentioning

confidence: 99%

“…Multidirectional muography (Nagahara & Miyamoto, 2018) and its combination with high-resolution gravity (Rosas-Carbajal et al, 2017) are good candidates to achieve three-dimensional monitoring of magma movements inside active volcanoes in the future.…”

Section: 1029/2019gl084784mentioning

confidence: 99%

Plug Formation Imaged Beneath the Active Craters of Sakurajima Volcano With Muography

Oláh

Tanaka

Ohminato

et al. 2019

Geophysical Research Letters

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Sakurajima Muography Observatory captured the formation of a volcanic plug beneath the Showa crater with a spatial resolution of ∼60 m in accordance with the end of the eruption episode of Showa crater and the reactivation of Minamidake crater. The increase of average density was observed with above 3 σ standard deviation for both above the floor of Minamidake crater and beneath the floor of Showa crater, respectively, being interpreted as volcanic ejecta deposition and the formation of a volcanic plug laterally extended within a few hundreds of meters.

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Three‐dimensional density structure of La Soufrière de Guadeloupe lava dome from simultaneous muon radiographies and gravity data

Cited by 88 publications

References 42 publications

Middle‐Atmosphere Dynamics Observed With a Portable Muon Detector

Middle‐Atmosphere Dynamics Observed With a Portable Muon Detector

Towards more realistic values of elastic moduli for volcano modelling

Plug Formation Imaged Beneath the Active Craters of Sakurajima Volcano With Muography

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