A study of variation in soil gas concentration associated with earthquakes near Indo-Burma Subduction zone
© The Author(s). 2016
Received: 25 May 2016
Accepted: 11 November 2016
Published: 22 November 2016
In the recent past, several efforts have been made by a number of researchers to measure anomalous emanations of geo-gases in seismic prone regions of the world and radon has been the most preferred geo-gas as possible earthquake precursor since it is easily detectable.
In the present investigation, continuous measurements of radon concentration at 80 cm inside the soil has been carried out at Chite Fault (23.73°N, 92.73°E), Aizawl, Mizoram situated in the seismic zone V in North Eastern part of India near Indo-Burma subduction zone, using LR-115 Type-II nuclear track detectors manufactured by Kodak Pathe, France. During the investigation period, the radon concentration varied from 163.27 Bq/m3 to 2557.82 Bq/m3 with an average and standard deviation of 1116.15 Bq/m3 and 591.76 Bq/m3 respectively.
Certain anomalies observed in radon concentration have been correlated to the earthquakes within the range of magnitudes 4.7 ≤ M ≤ 5.5, while some other anomalies are due to the influence of meteorological parameters.
Migration of carrier gas by bubbles is considered to be an important transport mechanism governing distribution of carrier (CO2 and CH4) and trace (Rn, He) gases over wide areas on the earth surface. Soil-gas anomalies and chemical changes in groundwater, observed during seismic events may be attributed to gas carrier dynamics (Etiope and Martinelli, 2002). During the last several decades, analysis of earthquake precursory phenomena reveals that significant changes in geophysical and geochemical process may occur prior to intermediate and large earthquake. The behavior of the gas concentration anomalies has been quite variable. Several investigators have reported increase in gas concentrations before the occurrence of seismic events (Cai et al., 1984; Nersesov, 1984; Kawabe, 1985). Besides these, declines in radon concentration or concentration ratio immediately and prior to seismic events have also been reported (King et al., 1981; Barsukov et al., 1985; Sugisaki and Sugiura, 1986). In some cases, anomalies have also occurred contemporaneously with or after the events (Birchard and Libby, 1980; King, 1985; Thomas et al., 1986). Soil-gas concentrations are not sensitive to hydrologic changes as they are extremely susceptible to a number of other environmental effects. However, many authors in the past suggest that spatial and temporal variations in soil-gas concentrations are most intensively influenced by meteorological interferences (Kraner et al., 1964; Klusman, 1981; Fleischer, 1983; Robinson and Whitehead, 1986; Guedalia et al., 1970).
Radon emanation and earthquake
Seismicity of the study area
Experimental techniques and methods
Lists of earthquakes that occurred around the investigation area during the observation period (source: www.imd.gov.in)
Date of event
Date of anomaly observed
Epicenter distance (km)
Precursor/postcursor time (Days)
Results and Discussions
Now the CDF value of each Radon value is used for calculating the expected radon values and Z- score at each radon value by the following formulae.
NORMSINV (CDF at each radon value) for Z-score, and NORMINV (CDF at each radon value, mean, standard deviation) for expected values.
Effects of meteorological parameters on radon concentration
Descriptive statistics of radon and the meteorological parameters
Standard deviation (σ)
% Variation coefficient (σ/Avg.)
Correlation of radon concentration with seismic events
According to the characteristics trends of radon concentration as illustrated in Fig. 6, there are three positive peaks and three negative peaks recorded during the given time period. The first radon peak (negative anomaly) was observed on 9/6/2013 followed by an event of 4.8 M which occurred on 9/7/2013. Since the observed peak do not crosses the X-2σ limit, therefore it seems necessary to investigate the behavior of meteorological parameters carefully. During this period the relative humidity and rainnfall, which shows positive correlation with radon was quite low. Therefore, this decline in radon concentration is attributed and/or have caused by variation in meteorological parameters and not by seismic events. The second radon peak (negative) was recorded on 4/10/2013. During this time period a fair amount of rainfall was received and the temperature and humidity which shows positive correlation with radon were quite high indicating that this decline in radon concentration is caused by some other geophysical process which was not mature enough to produce an earthquake (Walia et al., 2009). Three consecutive positive radon peaks were recorded on 10/11/2013 and 10/25/2013 crossing the X + 2σ limit while the third peak on 11/8/2013 just exceeding X + 1σ level followed by two seismic events of 4.7 M and 5.5 M recorded on 10/29/2013 and 11/6/2013 with an epicenter distances of 176 km and 320 km from the measuring site. These positive anomalies may be due to the combining effects of these two earthquakes. The positive radon anomalies can be explained by the Dilatancy-diffusion model (Mjachkin et al., 1975) where the increase in radon content prior to earthquakes is connected with the amount of cracking of rocks and therefore is sharply increased and then flattens out due to relaxation of stress. Another sharp fall in radon concentration was observed on 11/22/2013 but no seismic events occurred during this period. Besides, it is quite difficult to explain such a large radon decrease by environmental parameters. This abrupt decrease in radon concentration may be either due to additional compression closing cracks and pores (Singh et al., 1991; Ramola et al., 2008) or from expansion causing under saturation of the pore volume (Whitcomb, 1983).
In the present study, the radon data generated during the mentioned time period have been analyzed with seismic events and meteorological parameters. Some considerable positive radon anomalies have been observed crossing the limits of X + 2σ before and after the earthquake of 4.7 and 5.5 magnitude. Such variation in radon concentration could be due to crustal deformation along Indo-Myanmar subduction zone during these two seismic events. Besides these, few abnormal declines in radon data having negative correlation with seismicity were also recorded. It can be concluded that these changes may be either because of meteorological parameters influencing radon concentration or due to the complexity of its transport mechanism from deeper soil. However, for better correlation and to pinpoint the seismic event with anomaly, longer periods of data collection along with measurements of other carrier and trace gases (like thoron).
This work was funded by the Ministry of Earth Sciences (MoES), Govt. of India, New Delhi; in the form of Major project vide Sanction Order No. MoES/P.O.(Seismo)/1(167)/2013 Dated 10.12.2013.
SS collected the data and drafted the manuscript. HPJ helped to collect the data and performed the statistical analysis. RPT helped to draft the manuscript and site selection. RCT helped in the experimental design, participated in the extensive revision and overall supervision. All authors read and approved the final manuscript.
The authors declare that they have no competing interests.
Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
- Ahrens, L.H. 1954. The lognormal distribution of the elements (a fundamental law of geochemistry and its subsidiary). Geochimica et Cosmochimica Acta 5: 49–73.View ArticleGoogle Scholar
- Barsukov, V.L., G.M. Varshal, and N.S. Zamokina. 1985. Recent results of hydrogeochemical studies for earthquake prediction in the USSR. Pure and Applied Geophysics 122: 143–156.View ArticleGoogle Scholar
- Birchard, G.F., and W.F. Libby. 1980. Soil radon concentration changes preceding and following four magnitude 4.2–4.7 earthquakes on the San Jacinto Fault in southern California. Journal of Geophysical Research 85: 3100–3106.View ArticleGoogle Scholar
- Cai Z, Shi H, Zhang W, Luo GEX, Shi X, Yang H. 1984. Some applications of fluid-geochemical methods to earthquake prediction in China: International symposium on continental seismology and earthquake prediction, 384–395. Beijing (China): Seismological Press.Google Scholar
- Etiope, G., and G. Martinelli. 2002. Migration of carrier and trace gases in the geosphere: an overview. Physics of the Earth and Planetary Interiors 129(3): 185–204.View ArticleGoogle Scholar
- Fleischer, R.L. 1981. Dislocation Model for radon response to distant earthquakes. Geophysical Research Letters 8(5): 477–480.View ArticleGoogle Scholar
- Fleischer, R.L. 1983. Theory of alpha recoil effects on radon release and isotopic disequilibrium. Geochimica et Cosmochimica Acta 47(4): 779–784.View ArticleGoogle Scholar
- Friedmann, H. 2012. Radon in earthquake prediction research. Radiation Protection Dosimetry 149: 177–184.View ArticleGoogle Scholar
- Fu, C.C., T.F. Yang, V. Walia, and C.H. Cheng. 2005. Reconnaissance of soil gas composition over the buried fault and fracture zone in southern Taiwan. Geochemical Journal 39(5): 427–439.View ArticleGoogle Scholar
- Guedalia, D., J.L. Laurent, J. Fontan, D. Blanc, and A. Druilhet. 1970. A study of radon 220 emanation from soils. Journal of Geophysical Research 75(2): 357–369.View ArticleGoogle Scholar
- Guerra, M., and S. Lombardi. 2001. Soil-gas method for tracing neotectonic faults in clay basin: the Pisticci field (southern Italy). Tectonophysics 339(3): 511–522.View ArticleGoogle Scholar
- Imme G, Morelli D. 2012. Radon as earthquake precursor. In: Earthquake Research and Analysis-Statistical Studies, Observation and Planning (Dr. Amico S.D., Ed.), ISBN: 978-953-51-0134-5, In Tech, Available from: http://www.intechopen.com/books/earthquake-research-and-analysis-statistical-studies-observations-and-planning/radon-as-earthquake-precursor.
- Jaishi, H.P., S. Singh, R.P. Tiwari, and R.C. Tiwari. 2013. Radon and thoron anomalies along Mat fault in Mizoram, India. Journal of Earth System Science 122(6): 1507–1513.View ArticleGoogle Scholar
- Jaishi HP, Singh S, Tiwari RP, and Tiwari RC (2014a) Correlation of radon anomalies with seismic events along Mat fault in Serchhip District, Mizoram, India. Applied Radiation and Isotopes 86:79–84.Google Scholar
- Jaishi HP, Singh S, Tiwari RP, and Tiwari RC (2014b) Temporal variation of soil radon and thoron concentrations in Mizoram (India), associated with earthquakes. Natural Hazards 72(2):443–454.Google Scholar
- Jaishi HP, Singh S, Tiwari RP, and Tiwari RC (2014c) Analysis of soil radon data in earthquake precursory studies. Annals of Geophysics 57(5): S0544; doi:10.4401/ag-6513.Google Scholar
- Jonsson, G. 1995. Radon gas- where from and what to do? Radiaiation Measurements 25: 1–4.View ArticleGoogle Scholar
- Kawabe, I. 1985. Anomalous changes of CH4/Ar ratio in subsurface gas bubbles as seismogeochemical precursors at Matsuyama, Japan. Pure and Applied Geophysics 122(2–4): 196–214.Google Scholar
- Kayal, J.R. 1998. Seismicity of Northeast India and surroundings: Development over the past 100 years. Journal of Geophysics 19(1): 9–34.Google Scholar
- King, C.Y. 1985. Impulsive radon emanation on a creeping segment of the San Andreas Fault, California. Pure and Applied Geophysics 122(2–4): 340–352.View ArticleGoogle Scholar
- King, C.Y., W.C. Evans, T. Presser, and R.H. Husk. 1981. Anomalous chemical changes in well water and possible relation to earthquakes. Geophysical Research Letters 8(5): 425–428.View ArticleGoogle Scholar
- Klusman, R.W. 1981. Variations in mercury and radon emission at an aseismic site. Geophysical Research Letters 8(5): 461–464.View ArticleGoogle Scholar
- Kraner, H.W., G.L. Schroeder, and R.D. Evans. 1964. Measurement of the effects of atmospheric variables on radon-222 flux and soil-gas concentrations. Symposium Proceedings Natural Radiation Environment, Houston, Texas, 10–13 April 1963, 191–214. Chicago: University of Chicago Press.Google Scholar
- Kristiansson K, Malmqvist L. 1984. The depth dependence of the concentration of sup Rn-222 in soil gas near the surface and its implication for exploration. Geoexploration 22:17–41.Google Scholar
- Mayya, Y.S., K.P. Eappen, and K.S.V. Nambi. 1998. Methodology for mixed field inhalation dosimetry in monazite areas using a twin-cup dosimeter with three track detectors. Radiation Protection Dosimetry 77(3): 177–184.View ArticleGoogle Scholar
- Mjachkin, V.I., W.F. Brace, G.A. Sobolev, and J.H. Dieterich. 1975. Two models for earthquake forerunners. Pure and Applied Geophysics 113: 169–181.View ArticleGoogle Scholar
- Nersesov IL. 1984. Development of earthquake prediction in the USSR. International symposium on continental seismicity and earthquake prediction, 373–383. Beijing (China): Seismological Press.Google Scholar
- Ramola, R.C., Y. Prasad, G. Prasad, S. Kumar, and V.M. Choubey. 2008. Soil-gas radon as seismotectonic indicator in Garhwal Himalaya. Applied Radiation and Isotopes 66(10): 1523–1530.View ArticleGoogle Scholar
- Robinson, R., and N.E. Whitehead. 1986. Radon variations in the Wellington region, New Zealand, and their relation to earthquakes. Earthquake Prediction Research 4: 69–82.Google Scholar
- Sarmah, S.K. 1999. The probability of occurrence of a high magnitude earthquake in Northeast India. Journal of Geophysics 20(3): 129–135.Google Scholar
- Scholz, C.H., L.R. Sykes, and Y.P. Aggarwal. 1973. Earthquake prediction: a physical basis. Science 181: 803–810.View ArticleGoogle Scholar
- Singh M, Ramola RC, Singh B, Singh S, Virk HS (1991) Subsurface soil gas radon changes associated with earthquakes. International Journal of Radiation Applications and Instrumentation. Part D. Nuclear Tracks and Radiation Measurements 19(1):417–420.Google Scholar
- Singh, S., H.P. Jaishi, R.P. Tiwari, and R.C. Tiwari. 2014. Variations of soil radon concentrations along Chite Fault in Aizawl district, Mizoram, India. Radiation Protection Dosimetry. doi:10.1093/rpd/ncu221.Google Scholar
- Sugisaki, R., and T. Sugiura. 1986. Gas anomalies at three mineral springs and a fumaroles before an inland earthquake, Central Japan. Journal of Geophysical Research 91(B12): 12296–12304.View ArticleGoogle Scholar
- Tanner, A.B. 1964. Radon migration in the ground: A review, Symposium Proceedings Natural Radiation Environment, 161–190. Chicago: University of Chicago Press.Google Scholar
- Thomas, D.M., K.E. Cuff, and M.E. Cox. 1986. The association between ground gas radon variations and geologic activity in Hawaii. Journal of Geophysical Research 91(B12): 12186–12199.View ArticleGoogle Scholar
- Virk, H.S. 1996. A critique of empirical scaling relationship between earthquake magnitude, epicentral distance and precursor time for interpretation of radon data. Journal of Earthquake Prediction Research 5: 574–583.Google Scholar
- Virk, H.S., V. Walia, A.K. Sharma, N. Kumar, and R. Kumar. 2000. Correlation of radon with microsiesmic events in Kangra and Chamba Valleys of N-W Himalaya. Geofisica Internacional 39(3): 222–227.Google Scholar
- Walia, V., H.S. Virk, T.F. Yang, S. Mahajan, M. Walia, and B.S. Bajwa. 2005. Earthquake prediction studies using radon as a precursor in NW Himalayas, India: a case study. Terristrial Atmospheric and Oceanic Sciences 16(4): 775–804.Google Scholar
- Walia, V., S.J. Lin, W.L. Hong, C.C. Fu, T.F. Yang, W.L. Wen, and C.H. Chen. 2009. Continuous temporal soil-gas composition variations for earthquake precursory studies along Hsincheng and Hsinhua faults in Taiwan. Radiation Measurements 44(9): 934–939.View ArticleGoogle Scholar
- Whitcomb JH. 1983. Modeling of tectonophysical distortion from measurements of long base-line geodetic data and other geophysical paramaters. NASA Grant No. NAG5-22 Semi-annual report, Colorado University. March-August 1980, 20p.Google Scholar
- Yang, T.F., V. Walia, L.L. Chyi, C.C. Fu, C.H. Chen, T.K. Liu, S.R. Song, C.Y. Lee, and M. Lee. 2005. Variations of soil radon and thoron concentrations in a fault zone and prospective earthquakes in SW Taiwan. Radiation Measurements 40(2): 496–502.View ArticleGoogle Scholar