Long term continuous radon monitoring in a seismically active area

Piersanti, Antonio; Cannelli, Valentina; Galli, Gianfranco

doi:10.4401/ag-6735

Cited by 10 publications

(2 citation statements)

References 41 publications

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“…This study is a more deterministic approach to the forecast with respect to the presently available purely probabilistic OEF models because it is more heavily based on the analysis of precursors in real time and offline. The Italian radon monitoring network of soil radon emission [2,3] or the continuous monitoring of soil CO 2 in Japan [4] are examples of such an approach. This does not exclude statistical analysis such as the detection of hydrogeochemical seismic precursors [5] or uncertainty evaluation in seismic risk assessments [6].…”

Section: Introductionmentioning

confidence: 99%

Monitoring of Gas Emissions in Light of an OEF Application

et al. 2020

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This study analyzes the possibility to use geophysical and geochemical parameters in an OEF (Operational Earthquake Forecasting) application correlated with short-term changes in seismicity rates using a magnitude–frequency relationship. Tectonic stress over the limits of rock elasticity generates earthquakes, but it is possible that the emission of gases increases as a result of the breaking process. The question is how reliable is the emission of radon-222 and Carbon Dioxide (CO2), with effects on air ionization and aerosol concentration, in an OEF application? The first step is to select the seismic area (in our study this is the Vrancea area characterized by deep earthquakes at the bend of the Carpathian Mountains), then determine the daily and seasonal evolution of the forecast parameters, their deviations from the normal level, the short-term changes in seismicity rates using a magnitude–frequency relationship and finally to correlate the data with recorded seismic events. The results of anomaly detection, effect evaluation and data analysis alert the beneficiaries specialized in emergency situations (Inspectorate for Emergency Situations, organizations involved in managing special events). Standard methods such as the standard deviation from the mean value, time gradient, cross correlation, and linear regression are customized for the geological specificity of the area under investigation. For detection we use the short-time-average through long-time-average trigger (STA/LTA) method on time-integral data and the daily–seasonal variation of parameters is correlated with atmospheric conditions to avoid false decisions. The probability and epistemic uncertainty of the gas emissions resulting from this study, in addition to other precursor factors such as air ionization, time between earthquakes, temperature in the borehole, telluric currents, and Gutenberg Richter “a-b” parameters, act as inputs into a logical decision tree, indicating the possibility of implementing an OEF application for the Vrancea area. This study is novel in its analysis of the Vrancea area and performs a seismic forecasting procedure in a new form compared to the known ones.

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Section: Introductionmentioning

confidence: 99%

Monitoring of Gas Emissions in Light of an OEF Application

et al. 2020

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“…Since gases, either dissolved in groundwater systems or as free gas phase emanating from fumarolic discharges, are highly mobile, it is possible that they can respond to even small crustal disturbances associated with seismicity. In this respect, several studies have mainly concentrated on the periodic and/or real-time monitoring of gas compositions, including concentrations of radon (Rn), carbon dioxide (CO 2 ), hydrogen sulfide (H 2 S), methane (CH 4 ), hydrogen (H 2 ), helium (He), gas concentration ratios (N 2 (Nitrogen)/Ar(Argon), He/Ar, CH 4 /Ar, H 2 /Ar, CO 2 /CH 4 ) , isotopic compositions ( 3 He/ 4 He, 13 C/ 12 C), and gas fluxes (Sugisaki 1978;Kawabe 1984;Reimer 1984;Hilton 1996;Sugisaki et al 1996;Sano et al 1998;Ito et al 1999;Colangello et al 2005;Weinlich et al 2006;Yang et al 2006;Cioni et al 2007;Einarsson et al 2008;Padron et al 2008;Miyakawa et al 2010;Brauer et al 2011;Ghosh et al 2011;Chaudhuri et al 2013;Umeda et al 2013;Aydın et al 2015;Piersanti et al 2015;Chowdhury et al 2017). Increasing or decreasing gas signals, which were mainly defined as "geochemical anomalies" observed in relation to local and/or regional earthquakes, were reported by such studies.…”

Section: Introductionmentioning

confidence: 99%

Real-time gas monitoring at the Tekke Hamam geothermal field (Western Anatolia, Turkey): an assessment in relation to local seismicity

et al. 2020

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This study presents the results of a real-time gas monitoring experiment conducted, via the use of a quadrupole mass spectrometer, in a mofette field within the Tekke Hamam geothermal site in western Anatolia (Turkey), a tectonically active region hosting several east-west trending grabens. The study is aimed to establish a baseline gas profile of the region. Within the framework of the experiment, gas compositions (CO 2 , N 2 , O 2 , H 2 , H 2 S, CH 4 , He, and Ar) and flow rate of a mofette were monitored during two observation periods: November 2007-January 2008 and April-July 2008. During the course of monitoring, the major gas component was CO 2 with concentration changing around 96 volume percent. Other gases, from the most abundant to the least, were N 2 , CH 4 , O 2 , H 2 S, Ar, H 2 , and He. The study produced a short-term, baseline gas profile of the region with daily/diurnal variations and temporal gas fluctuations appearing as instant signals. Although the temporal gas fluctuations did not reach the anomaly level (variations staying within the mean ± 2σ), some of the variations in more than one parameter in the gas compositions (exceeding the mean ± 1σ), accompanied by changes in the diurnal gas pulses lasting for long durations, were correlated with the seismic events selected according to the adopted seismic event elimination criteria. The variations were mainly attributed to changing gas mixing ratios in relation to porosity/permeability modifications possibly related to seismicity. Studies involving the continuous monitoring of meteorological parameters are necessary to assign these variations to geogenic events.

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Novel determination of radon‐222 velocity in deep subsurface rocks and the feasibility to using radon as an earthquake precursor

et al. 2016

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A novel technique utilizing simultaneous radon monitoring by gamma and alpha detectors to differentiate between the radon climatic driving forces and others has been improved and used for deep subsurface investigation. Detailed long‐term monitoring served as a proxy for studying radon movement within the shallow and deep subsurface, as well as for analyzing the effect of various parameters of the radon transport pattern. The main achievements of the investigation are (a) determination, for the first time, of the radon movement velocity within rock layers at depths of several tens of meters, namely, 25 m/h on average; (b) distinguishing between the diurnal periodical effect of the ambient temperature and the semidiurnal effect of the ambient pressure on the radon temporal spectrum; and (c) identification of a radon random preseismic anomaly preceding the Nuweiba, M 5.5 earthquake of 27 June 2015 that occurred within Dead Sea Fault Zone.

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Long term continuous radon monitoring in a seismically active area

Cited by 10 publications

References 41 publications

Monitoring of Gas Emissions in Light of an OEF Application

Monitoring of Gas Emissions in Light of an OEF Application

Real-time gas monitoring at the Tekke Hamam geothermal field (Western Anatolia, Turkey): an assessment in relation to local seismicity

Novel determination of radon‐222 velocity in deep subsurface rocks and the feasibility to using radon as an earthquake precursor

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