Abstract
The Koyna region, located in the Deccan Flood Basalt Province of western peninsular India has been experiencing reservoir triggered seismicity since the impoundment of the Shivajisagar water reservoir in 1962. Scientific drilling carried out to 1522 m depth in the vicinity of the seismogenic zone exposed the granitic basement that lay below the Deccan Traps and provided a unique opportunity to study the rock types, petrological characteristics and microstructures. Cores obtained from drilling at four sites considered to be representative of the Koyna region, were studied. The boreholes include KBH-1 (Rasati) in the northern part, KBH-5 (Phansavle) in the western part, KBH-6 (Ukhalu) and KBH-7 (Panchgani) in the eastern part of the region. Each borehole penetrates the entire pile of Deccan basalt and pass through a few hundred metres of the granitic basement. The salient results are as follows: (i) The basement granitoids are dominantly composed of granite-gneiss, granite and migmatitic gneiss, typical of cratonic gneiss exposed in peninsular India. (ii) Petrology and microstructure study confirm the occurrence of strained quartz and unstrained plagioclase feldspars in the basement granitoids. (iii) Localized fault zones within the basement section, with prominent evidences of fault breccia, fault gouge, slicken lines with slickensides and pseudotachylite veins are observed in the individual boreholes. (iv) Anastomosing fracture network within these fault zones are good pathways for water channelization, which is supported by the higher abundances of ferruginous and siliceous secondary precipitations following the fractures.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Deere, D.U. (1963) Technical description of rock cores for engineering purposes. In Rock mechanics and engineering geology, Felsmechanik und Ingenieurgeologie (Rock Mechanics and Engineering Geology), v.1(1), pp.16–22.
Duncan, R.A. and Pyle, D.G. (1988) Rapid eruption of the Deccan flood basalts at the Cretaceous/Tertiary boundary. Nature, v.333, pp.841–843.
Gupta, H.K. (1992) Reservoir Induced Earthquakes. Elsevier, Amsterdam.
Gupta, H. (2002) A review of artificial reservoir triggered earthquakes with special emphasis on earthquakes in Koyna, India. Earth Sci. Rev., v.58, pp.279–310.
Gupta, H. (2011) Artificial water reservoir triggered earthquakes, In: H. Gupta (Ed.), Encyclopaedia of Solid Earth Geophysics. Springer, Berlin, pp.15–24.
Gupta, H.K., Rao, N.P., Roy, S., Arora, K., Tiwari, V.M., Patro, P.K., Satyanarayana, H.V.S., Shashidhar, D., Mallika, K., Akkiraju, V.V., Goswami, D., Vyas, D., Ravi, G., Srinivas, K.N.S.S.S., Srihari, M., Mishra, S., Dubey, S., Raju, C.P., Borah, U., Reddy, C.V., Babu, K.C., Rohilla, S., Dhar, U., Sen, M.K., BhaskarRao, Y.J., Bansal, B.K., and Nayak, S. (2015) Investigations related to scientific deep drilling to study reservoir-triggered earthquakes at Koyna, India. Internat. Jour. Earth Sci, v.104, pp.1511–1522, doi:10.1007/s00531-014-1128-0.
Gupta, H.K, Arora, K., Rao, N.P., Roy, S., Tiwari, V.M., Patro, P.K., Satyanarayana, H.V.S., Shashidhar, D., Mahato, C., Srinivas, K.N.S.S.S., Srihari, M., Satyavani, N., Srinu, Y., Gopinadh, D., Raza, H., Monikuntala, J., Akkiraju, V.V., Goswami, D., Vyas, D., Dubey, C.P., Raju, D., Borah, U., Raju, K., Chinnareddy, K., Babu, N., Bansal, B.K., and Nayak, S., 2016. Investigations of Continued Reservoir Triggered Seismicity at Koyna, India. Geol. Soc. London Spec. Publ, v.445, doi:10.1144/SP445.11.
Kaila, K.L., Reddy, P.R., Dixit, M.M. and Lazarenko, M.A. (1981) Deep crustal structure at Koyna, Maharashtra, indicated by deep seismic soundings. Jour. Geol. Soc. India, v.22, pp.1–16.
Kailasam, L.N., Reddi, A.G.B., Joga Rao, M.V., Satyamurthy, K. and Murthy, B.S.R. (1976) Deep electrical resistivity soundings in the Deccan Trap region. Curr. Sci., v. 45, pp. 9–13.
Misra, S., Roy, S., Bartakke, V., Athavale, G., and Gupta, H. (2017) Fissures and fractures in the Koyna Seismogenic zone, Western India. Jour. Geol. Soc. India, v.90, pp.131–137.
Roy S., Rao, N.P., Akkiraju, V.V., Goswami, D., Sen, M., Gupta, H.K., Bansal, B.K. and Nayak, S. (2013) Granitic basement below Deccan Traps unearthed by drilling in the Koyna Seismic Zone, western India. Jour. Geol. Soc. India, v.81, pp.289–290.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Misra, S., Bartakke, V., Athavale, G. et al. Granite-gneiss basement below Deccan Traps in the Koyna region, western India: Outcome from scientific drilling. J Geol Soc India 90, 776–782 (2017). https://doi.org/10.1007/s12594-017-0790-9
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12594-017-0790-9