Anomalous decrease in groundwater radon before the Taiwan M6.8 Chengkung earthquake

Kuo, Tom Ming-Ching; Fan, Kai; Kuo-Chen, Hao; Han, Yuhui; Chu, Hao‐Tsu; Lee, Y.

doi:10.1016/j.jenvrad.2006.01.005

Cited by 52 publications

(27 citation statements)

References 17 publications

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“…However, this simplified picture is frequently contradicted by the lack of significant anomalies recorded before an earthquake (Kerr, 1978;King, 1981;Tsunogai and Wakita, 1995;Steinitz et al, 2003). Moreover, negative anomalies are sometimes measured at the seismic source (Hauksson, 1981;Kuo et al, 2006), while contemporaneous positive anomalies are inexplicably recorded at monitoring stations located hundreds of kilometres away (Kerr, 1978(Kerr, , 1981. Alternating increases and decreases of radon emissions are also measured prior to earthquakes (Wakita et al, 1980;Igarashi et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

Tuccimei

Mollo

Soligo

et al. 2015

Geosci. Instrum. Method. Data Syst.

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Abstract.Laboratory experiments can represent a valid approach to unravel the complex interplay between the geochemical behaviour of radon and rock deformation mechanisms. In light of this, we present a new real-time experimental setup for analysing in continuum the alpha-emitting 222 Rn and 220 Rn daughters over variable stress-strain regimes. The most innovative segment of this setup consists of the radon accumulation chamber obtained from a tough and durable material that can host large cylindrical rock samples. The accumulation chamber is connected, in a closed-loop configuration, to a gas-drying unit and to a RAD7 radon monitor. A recirculating pump moves the gas from the rock sample to a solid-state detector for alpha counting of radon and thoron progeny. The measured radon signal is enhanced by surrounding the accumulation chamber with a digitally controlled heating belt. As the temperature is increased, the number of effective collisions of radon atoms increases favouring the diffusion of radon through the material and reducing the analytical uncertainty. The accumulation chamber containing the sample is then placed into a uniaxial testing apparatus where the axial deformation is measured throughout a linear variable displacement transducer. A dedicated software allows obtaining a variety of stress-strain regimes from fast deformation rates to long-term creep tests. Experiments conducted with this new real-time setup have important ramifications for the interpretation of geochemical anomalies recorded prior to volcanic eruptions or earthquakes.

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Section: Introductionmentioning

confidence: 99%

Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

Tuccimei

Mollo

Soligo

et al. 2015

Geosci. Instrum. Method. Data Syst.

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show abstract

“…However, this simplified picture has been contradicted by the lack of significant anomalies recorded before an earthquake [Kerr, 1978;King, 1981;Tsunogai and Wakita, 1995;Steinitz et al, 2003]. Further, sometimes negative anomalies are measured at the seismic source [Hauksson, 1981;Kuo et al, 2006], while contemporaneous positive anomalies are inexplicably recorded at monitoring stations located hundreds of kilometres away [Kerr, 1978[Kerr, , 1981. Alternating increases and decreases have also been recorded prior to earthquake [Wakita et al, 1980;Igarashi et al, 1995].…”

Section: Introductionmentioning

confidence: 99%

Increase in radon emission due to rock failure: An experimental study

Mollo

Tuccimei

Heap

et al. 2011

Geophys. Res. Lett.

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Radon anomalies are commonly observed prior to dynamic failure in the crust and are interpreted as cracking of the medium, thus attracting considerable attention in understanding the precursory phenomena of earthquakes and volcanic activity. In this study we have compared the starting radon emissions from low porosity crystalline lava (phonolite) samples with those from damaged and failed samples. The damaged sample was loaded up to just beyond the end of the linear elastic phase, as evidenced by the output of AE energy, the increase in total porosity and a decrease in P‐wave and S‐wave velocity relative to the intact sample. Whereas, the failed sample showed deformation behaviour characteristically brittle with increasing values of AE output and porosity as the sample approached macroscopic failure. Radon measurements have evidenced that dilatational microcracking of deformed sample produced no significant variation in radon emanation with respect to the intact sample. In contrast, after macroscopic failure, radon emanation drastically increased. Therefore, major finding from this study is that, in the case of low porosity and relatively high strength crystalline lavas, the development of a macroscopic fracture provides new large exhaling surface resulting in a substantial increase in radon emission rate.

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“…For a count time of 50 min and background less than 6 cpm, a detection limit below 18 pCi/L was achieved using the sample volume of 15 mL. Details of the radon-monitoring station, sample collection, and radon determination were described by Kuo et al (2006a). Recurrent groundwater radon anomalies were observed to precede the earthquakes of magnitude Mw 6.8, Mw 6.1, Mw 5.9, and Mw 5.0 that occurred on December 10, , April 1, 2006, April 15, 2006, and February 17, 2008 at the Antung D1 monitoring well in eastern Taiwan.…”

Section: Radon-monitoring Methodsmentioning

confidence: 99%

“…Radon anomalies in groundwater have been observed prior to some earthquakes (Hauksson 1981;Igarashi et al 1995;Kuo et al 2006aKuo et al , 2009Liu et al 1985;Noguchi and Wakita 1977;Roeloffs 1999;Teng 1980;Wakita et al 1980). Most anomalies from these observations indicate a radon increase prior to the earthquake.…”

mentioning

confidence: 99%

Estimation of aseismic crustal-strain using radon precursors of the 2003 M 6.8, 2006 M 6.1, and 2008 M 5.0 earthquakes in eastern Taiwan

Kuo

Lin

Chang³

et al. 2009

Nat Hazards

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Aseismic crustal-strain signals prior to the 2003 Mw 6.8 Chengkung, 2006 Mw 6.1 Taitung, and 2008 Mw 5.0 Antung earthquakes with epicenters located 20, 55 and 11 km, respectively, from the Antung radon-monitoring station have been calculated using the radon anomalies recorded. Specifically, radon decreased from background levels of 791 ± 46, 762 ± 57, and 735 ± 48 pCi/L to minima of 326 ± 9, 371 ± 9, and 480 ± 43 pCi/L prior to the 2003, 2006, and 2008 earthquakes, respectively. The estimated aseismic crustal-strain maxima at the Antung hot spring during the rock dilation stage were 3.6, 2.7, and 1.3 ppm, respectively. The v-shaped radon pattern recognized in all three anomalies is valuable for detecting the aseismic strain precursory to disastrous earthquakes in the Antung hot spring which is situated in a brittle fractured aquifer of limited recharge surrounded by ductile mudstone.

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Anomalous decrease in groundwater radon before the Taiwan M6.8 Chengkung earthquake

Cited by 52 publications

References 17 publications

Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

Real-time setup to measure radon emission during rock deformation: implications for geochemical surveillance

Increase in radon emission due to rock failure: An experimental study

Estimation of aseismic crustal-strain using radon precursors of the 2003 M 6.8, 2006 M 6.1, and 2008 M 5.0 earthquakes in eastern Taiwan

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