The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Patrick Richon - One of the best experts on this subject based on the ideXlab platform.
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Development of a highly sensitive Radon-222 amplifier (HiSRA) for low-level atmospheric measurements.
Journal of environmental radioactivity, 2017Co-Authors: Sylvain Topin, Patrick Richon, Vincent Thomas, Claire Gréau, Julie Pujos, J. Moulin, Alexandre Hovesepian, Ludovic DeliereAbstract:Abstract Radon ( 222 Rn), a radioactive gas with a half-life of 3.82 days, is continuously emanated from soil, rocks, and water by the radioactive decay of 226 Ra. Radon-222 is released from the ground into the atmosphere, where it is transported mainly by turbulent diffusion or convection. For precise measurement of Radon-222 atoms in the atmosphere, the detectors typically used present a small volume or surface area and are therefore not very sensitive, especially for online measurements and short sample intervals ( 3 h −1 ). The Radon-222 concentration is increased instantaneously by at least a factor of 30 across the HiSRA system. Therefore, in this study, when coupling to an ionization chamber (AlphaGUARDTM) at the outlet of the HiSRA system, the detection limit of the overall system is multiplied by factor of 30 and induces a new LD for a Radon 222 gas analyzer lower than 1 Bq m −3 for an integrating time of 10 min and 0.1 Bq m −3 for 1 h. We constructed one Radon amplifier prototype that provided the preliminary results for amplification efficiency and the initial measurements presented herein.
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Evidence of both M2 and O1Earth tide waves in Radon‐222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research: Solid Earth, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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evidence of both m2 and o1earth tide waves in Radon 222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Luc Moreau, J C Sabroux, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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Evidence of both M2 and O1 Earth tide waves in Radon-222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1-O1 and semidiurnal S2-M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentière glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2-O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m 3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2-O1 signatures in Radon signals recorded in other underground laboratories.
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Persistence of Radon-222 flux during monsoon at a geothermal zone in Nepal.
Journal of environmental radioactivity, 2009Co-Authors: Frédéric Girault, Patrick Richon, Frédéric Perrier, Bharat Prasad Koirala, Sudhir RajaureAbstract:Abstract The Syabru-Bensi hydrothermal zone, Langtang region (Nepal), is characterized by high Radon-222 and CO2 discharge. Seasonal variations of gas fluxes were studied on a reference transect in a newly discovered gas discharge zone. Radon-222 and CO2 fluxes were measured with the accumulation chamber technique, coupled with the scintillation flask method for Radon. In the reference transect, fluxes reach exceptional mean values, as high as 8700 ± 1500 g m−2 d−1 for CO2 and 3400 ± 100 × 10−3 Bq m−2 s−1 for Radon. Gases fluxes were measured in September 2007 during the monsoon and during the dry winter season, in December 2007 to January 2008 and in December 2008 to January 2009. Contrary to expectations, Radon and its carrier gas fluxes were similar during both seasons. The integrated flux along this transect was approximately the same for Radon, with a small increase of 11 ± 4% during the wet season, whereas it was reduced by 38 ± 5% during the monsoon for CO2. In order to account for the persistence of the high gas emissions during monsoon, watering experiments have been performed at selected Radon measurement points. After watering, Radon flux decreased within 5 min by a factor of 2–7 depending on the point. Subsequently, it returned to its original value, firstly, by an initial partial recovery within 3–4 h, followed by a slow relaxation, lasting around 10 h and possibly superimposed by diurnal variations. Monsoon, in this part of the Himalayas, proceeds generally by brutal rainfall events separated by two- or three-day lapses. Thus, the recovery ability shown in the watering experiments accounts for the observed long-term persistence of gas discharge. This persistence is an important asset for long-term monitoring, for example to study possible temporal variations associated with stress accumulation and release.
Anne Salaun - One of the best experts on this subject based on the ideXlab platform.
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Evidence of both M2 and O1Earth tide waves in Radon‐222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research: Solid Earth, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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evidence of both m2 and o1earth tide waves in Radon 222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Luc Moreau, J C Sabroux, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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Evidence of both M2 and O1 Earth tide waves in Radon-222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1-O1 and semidiurnal S2-M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentière glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2-O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m 3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2-O1 signatures in Radon signals recorded in other underground laboratories.
Marie Arnoux - One of the best experts on this subject based on the ideXlab platform.
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interactions between groundwater and seasonally ice covered lakes using water stable isotopes and Radon 222 multilayer mass balance models
Hydrological Processes, 2017Co-Authors: Marie Arnoux, Elisabeth Gibertbrunet, Florent Barbecot, Sophie Guillon, J J Gibson, Aurelie NoretAbstract:Interactions between lakes and groundwater are of increasing concern for freshwater environmental management but are often poorly characterized. Groundwater inflow to lakes, even at low rates, has proven to be a key in both lake nutrient balances and in determining lake vulnerability to pollution. Although difficult to measure using standard hydrometric methods, significant insight into groundwater–lake interactions has been acquired by studies applying geochemical tracers. However, the use of simple steady-state, well-mixed models, and the lack of characterization of lake spatiotemporal variability remain important sources of uncertainty, preventing the characterization of the entire lake hydrological cycle, particularly during ice-covered periods. In this study, a small groundwater-connected lake was monitored to determine the annual dynamics of the natural tracers, water stable isotopes and Radon-222, through the implementation of a comprehensive sampling strategy. A multilayer mass balance model was found outperform a well-mixed, one-layer model in terms of quantifying groundwater fluxes and their temporal evolution, as well as characterizing vertical differences. Water stable isotopes and Radon-222 were found to provide complementary information on the lake water budget. Radon-222 has a short response time, and highlights rapid and transient increases in groundwater inflow, but requires a thorough characterization of groundwater Radon-222 activity. Water stable isotopes follow the hydrological cycle of the lake closely and highlight periods when the lake budget is dominated by evaporation versus groundwater inflow, but continuous monitoring of local meteorological parameters is required. Careful compilation of tracer evolution throughout the water column and over the entire year is also very informative. The developed models, which are suitable for detailed, site-specific studies, allow the quantification of groundwater inflow and internal dynamics during both ice-free and ice-covered periods, providing an improved tool for understanding the annual water cycle of lakes.
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Interactions between groundwater and seasonally ice‐covered lakes: Using water stable isotopes and Radon‐222 multilayer mass balance models
Hydrological Processes, 2017Co-Authors: Marie Arnoux, Florent Barbecot, Sophie Guillon, J J Gibson, Elisabeth Gibert-brunet, Aurelie NoretAbstract:Interactions between lakes and groundwater are of increasing concern for freshwater environmental management but are often poorly characterized. Groundwater inflow to lakes, even at low rates, has proven to be a key in both lake nutrient balances and in determining lake vulnerability to pollution. Although difficult to measure using standard hydrometric methods, significant insight into groundwater–lake interactions has been acquired by studies applying geochemical tracers. However, the use of simple steady-state, well-mixed models, and the lack of characterization of lake spatiotemporal variability remain important sources of uncertainty, preventing the characterization of the entire lake hydrological cycle, particularly during ice-covered periods. In this study, a small groundwater-connected lake was monitored to determine the annual dynamics of the natural tracers, water stable isotopes and Radon-222, through the implementation of a comprehensive sampling strategy. A multilayer mass balance model was found outperform a well-mixed, one-layer model in terms of quantifying groundwater fluxes and their temporal evolution, as well as characterizing vertical differences. Water stable isotopes and Radon-222 were found to provide complementary information on the lake water budget. Radon-222 has a short response time, and highlights rapid and transient increases in groundwater inflow, but requires a thorough characterization of groundwater Radon-222 activity. Water stable isotopes follow the hydrological cycle of the lake closely and highlight periods when the lake budget is dominated by evaporation versus groundwater inflow, but continuous monitoring of local meteorological parameters is required. Careful compilation of tracer evolution throughout the water column and over the entire year is also very informative. The developed models, which are suitable for detailed, site-specific studies, allow the quantification of groundwater inflow and internal dynamics during both ice-free and ice-covered periods, providing an improved tool for understanding the annual water cycle of lakes.
Aurelie Noret - One of the best experts on this subject based on the ideXlab platform.
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interactions between groundwater and seasonally ice covered lakes using water stable isotopes and Radon 222 multilayer mass balance models
Hydrological Processes, 2017Co-Authors: Marie Arnoux, Elisabeth Gibertbrunet, Florent Barbecot, Sophie Guillon, J J Gibson, Aurelie NoretAbstract:Interactions between lakes and groundwater are of increasing concern for freshwater environmental management but are often poorly characterized. Groundwater inflow to lakes, even at low rates, has proven to be a key in both lake nutrient balances and in determining lake vulnerability to pollution. Although difficult to measure using standard hydrometric methods, significant insight into groundwater–lake interactions has been acquired by studies applying geochemical tracers. However, the use of simple steady-state, well-mixed models, and the lack of characterization of lake spatiotemporal variability remain important sources of uncertainty, preventing the characterization of the entire lake hydrological cycle, particularly during ice-covered periods. In this study, a small groundwater-connected lake was monitored to determine the annual dynamics of the natural tracers, water stable isotopes and Radon-222, through the implementation of a comprehensive sampling strategy. A multilayer mass balance model was found outperform a well-mixed, one-layer model in terms of quantifying groundwater fluxes and their temporal evolution, as well as characterizing vertical differences. Water stable isotopes and Radon-222 were found to provide complementary information on the lake water budget. Radon-222 has a short response time, and highlights rapid and transient increases in groundwater inflow, but requires a thorough characterization of groundwater Radon-222 activity. Water stable isotopes follow the hydrological cycle of the lake closely and highlight periods when the lake budget is dominated by evaporation versus groundwater inflow, but continuous monitoring of local meteorological parameters is required. Careful compilation of tracer evolution throughout the water column and over the entire year is also very informative. The developed models, which are suitable for detailed, site-specific studies, allow the quantification of groundwater inflow and internal dynamics during both ice-free and ice-covered periods, providing an improved tool for understanding the annual water cycle of lakes.
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Interactions between groundwater and seasonally ice‐covered lakes: Using water stable isotopes and Radon‐222 multilayer mass balance models
Hydrological Processes, 2017Co-Authors: Marie Arnoux, Florent Barbecot, Sophie Guillon, J J Gibson, Elisabeth Gibert-brunet, Aurelie NoretAbstract:Interactions between lakes and groundwater are of increasing concern for freshwater environmental management but are often poorly characterized. Groundwater inflow to lakes, even at low rates, has proven to be a key in both lake nutrient balances and in determining lake vulnerability to pollution. Although difficult to measure using standard hydrometric methods, significant insight into groundwater–lake interactions has been acquired by studies applying geochemical tracers. However, the use of simple steady-state, well-mixed models, and the lack of characterization of lake spatiotemporal variability remain important sources of uncertainty, preventing the characterization of the entire lake hydrological cycle, particularly during ice-covered periods. In this study, a small groundwater-connected lake was monitored to determine the annual dynamics of the natural tracers, water stable isotopes and Radon-222, through the implementation of a comprehensive sampling strategy. A multilayer mass balance model was found outperform a well-mixed, one-layer model in terms of quantifying groundwater fluxes and their temporal evolution, as well as characterizing vertical differences. Water stable isotopes and Radon-222 were found to provide complementary information on the lake water budget. Radon-222 has a short response time, and highlights rapid and transient increases in groundwater inflow, but requires a thorough characterization of groundwater Radon-222 activity. Water stable isotopes follow the hydrological cycle of the lake closely and highlight periods when the lake budget is dominated by evaporation versus groundwater inflow, but continuous monitoring of local meteorological parameters is required. Careful compilation of tracer evolution throughout the water column and over the entire year is also very informative. The developed models, which are suitable for detailed, site-specific studies, allow the quantification of groundwater inflow and internal dynamics during both ice-free and ice-covered periods, providing an improved tool for understanding the annual water cycle of lakes.
Eric Pili - One of the best experts on this subject based on the ideXlab platform.
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Evidence of both M2 and O1Earth tide waves in Radon‐222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research: Solid Earth, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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evidence of both m2 and o1earth tide waves in Radon 222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Luc Moreau, J C Sabroux, Eric Pili, Anne SalaunAbstract:[1] Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1–O1 and semidiurnal S2–M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentiere glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2–O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m−3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2–O1 signatures in Radon signals recorded in other underground laboratories.
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Evidence of both M2 and O1 Earth tide waves in Radon-222 air concentration measured in a subglacial laboratory
Journal of Geophysical Research, 2012Co-Authors: Patrick Richon, Jean-christophe Sabroux, Luc Moreau, Eric Pili, Anne SalaunAbstract:Many earthquake-related Radon-222 temporal changes have been recorded since the 1960s and are frequently discussed, sometimes initiating a controversial debate on the relevance of Radon-222 as an earthquake precursory signal. The diurnal S1-O1 and semidiurnal S2-M2 Earth tide signatures in Radon signals are acquired in a natural context. This can be used to calibrate the Radon changes under strain accumulation close to epicentral areas, which are often discussed but are rarely evidenced by experimental data. The analysis of a 10 month time series acquired in the subglacial laboratory of the Argentière glacier, Mont Blanc Massif, French Alps, demonstrates here the unambiguous episodic appearance of the M2-O1 waves in the Radon signal with significant amplitudes of 36 and 50 Bq m 3, respectively. We thus prove that Radon variations induced by gravitational M2 and O1 waves are detectable in a natural environment. In this particular place, the Radon response is probably amplified by cyclic stress variations applied on the upstream side of the natural rock dam into which the laboratory is drilled. The amplification of the Radon signal is induced by poroelastic deformation under this particular mechanical forcing. This can elucidate why most precedent studies failed to detect M2-O1 signatures in Radon signals recorded in other underground laboratories.
