The Borehole Geophysics Research Laboratory (BGRL) situated in Karad, Maharashtra is a first of a kind and the only laboratory in India that has been helping scientists to study earth’s deep secrets for nearly five years now (Fig 1). Set up in 2014, BGRL has enabled scientists to get access to a variety of samples from depths of up to three kilometers (km) below the earth’s surface. “Deep boreholes are like telescopes that look down into the earth’s deep interior. It is proposed to drill down to the earthquake source zone at 5-7 km depth and set up a Deep Borehole Observatory in the Koyna region(Fig 2). This is highly challenging. A pilot borehole to 3 km depth has been completed successfully and measurements have revealed valuable new information that could not be obtained otherwise. The goal is to equip BGRL with an elaborate and unique scientific infrastructure that only a few other countries have”, said Dr Sukanta Roy, scientist and Project Director at BGRL.
Fig 1. Location of the three km deep borehole at Gothane (marked as a red dot) in Maharashtra.
An initiative of the Ministry of Earth Sciences (MoES), Govt of India, BGRL was primarily aimed to understand why the Koyna region witnesses recurrent and intense earthquakes ever since the Shivaji Sagar reservoir was impounded in 1962. “Although reservoir-triggered earthquakes generally die down with time, Koyna continues to experience such earthquakes to date. We want to know the reason behind this phenomenon”, remarked Dr Roy. This could be possible by analysing the changes in the physical and chemical properties of rocks deep down where the earthquakes originate. To accomplish this, in the first phase, BGRL relies on a three km deep borehole near Gothane located near the Koyna dam. It is proximate to the Donichawadisurface rupture zone, which was caused by the magnitude 6.3 Koyna earthquake of 1967 and one that remains active even today. So far, BGRL has provided insights into what makes a region prone to earthquakes regarding rock characteristics, fault zones, stress regime, fracture orientations, and temperature in the earth’s deep layers of this region (Goswami et al. 2020, Roy and Bansal 2020).
In addition to studies on earthquakes, BGRL has helped gather data of soil, drilling fluid, gases, and living microbes in earth’s deep layers—all of which have helped scientists to uncover mysteries surrounding the evolution of earth and life (Bose et al., 2020; Goswami et al., 2020; Podugu et al. 2020). This includes understanding the formation of rocks and soil to know more about the earth’s geological past, deciphering the survival tactics of microbes in deep pockets where environmental conditions are harsh such as high temperature and pressure.
Fig 2. The drilling site of the BGRL near Koyna, Maharashtra.
BGRL research has yielded more than 25 research papers so far, with researchers from institutes such as the Indian Institute of Technology (IIT) in Kharagpur, National Centre for Seismology in Delhi, National Centre for Ocean and Polar Research in Goa, Council for Scientific and Industrial Research-National Geophysical Research Institute in Hyderabad, Council for Scientific and Industrial Research-Central Institute of Mining and Fuel Research in Jharkhand and Atomic Minerals Directorate in Hyderabad as collaborators. Researchers from different institutions and universities are working on core samples and data sets generated under the Koyna programme(Fig 3,4 &5). Expertise is also shared with the International Continental Scientific Drilling Programme—a multinational continental drilling programme—of which India is a member since 2011.
Fig 3. Granite rock core samples from the site.
Fig 4. Display of scientific drilling core samples for academia and the public.
Dr B K Bansal, scientist at the MoES headquarters in New Delhi, and Director of the National Centre for Seismology, Delhi, who has been instrumental in setting up and working of the BGRL, said, “BGRL has enabled scientists to access valuable samples for studying the earth’s geological past. In addition to enabling ongoing research activities, upcoming labs at BGRL will offer immense potential for young researchers to carry out innovative and socially-relevant projects.” His team is setting up procedures to provide study samples to scientific groups in both India and abroad.
Fig 5. Rock and soil cutting samples collected from scientific drilling at BGRL in 2017.
A digital core library under BGRL is also upcoming.(Fig 7) When functional, it would enable scientists to collate, catalogue, scan, and store core samples. (Contd)
Fig 6. A representative optically scanned image of core sample.
With this, high resolution and three-dimensional images of samples from drilling projects will be available in an online format. (Fig 6 & 8) “It will be a first of its kind, world class physical repository and digital library for drilled samples in the country”, exclaimed Dr Roy.
Fig 7. Upcoming Digital Core Library at Karad, Maharashtra.
Most importantly, scientific drilling will be expanded up to a depth of seven km into the earth’s interior to set up an observatory, going forward. This will bring several of the earth’s deep hidden secrets to life. “Moreover, it will aid evidence-based decision making for building infrastructure projects such as dams and reservoirs in India”, said Dr Bansal.
Fig 8. The optical core scanning system at BGRL
The author is a scientist, Ministry of Earth Sciences, Govt of India. firstname.lastname@example.org
Bose H., A. Dutta, A. Roy, A. Gupta, S. Mukhopadhyay, B. Mohapatra, et al. (2020). Microbial diversity of drilling fluids from 3000 m deep Koyna pilot borehole provides insights into the deep biosphere of continental earth crust. Sci. Dril., 27, 1-23. doi:10.5194/sd-27-1-2020
Goswami D., P. Hazarika, and S.Roy. (2020). In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment. Tectonics, 39 (1). doi:10.1029/2019tc005647
Podugu N., S. Mishra, T. Wiersberg, and S. Roy. (2019). Chemical and Noble Gas Isotope Compositions of Formation Gases from a 3 km Deep Scientific Borehole in the Koyna Seismogenic Zone, Western India. Geofluids, 2019, 1078942. doi:10.1155/2019/1078942
Roy S., and B. K. Bansal. (2020). Ministry of Earth Sciences Borehole Geophysics Research Laboratory, Karad, Maharashtra. Proceedings of the Indian National Science Academy, 86. doi:10.16943/ptinsa/2020/49825