newsletter-bgrl 6p re14.139.119.10/bgrl/newsletters/jan-2015.pdf · activity within ~50 km of the...
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Vol 1, Issue 1, January 26, 2015
e‐NEWSLETTER Borehole Geophysics Research Laboratory
Earth System Science Organisation (ESSO),
Ministry of Earth Sciences, Government of India
Dr. Shailesh Nayak Chairman, Earth System Science Organisation
Secretary to Govt. of India, Ministry of Earth Sciences
“It gives me immense pleasure to note that the Borehole Geophysics Research Laboratory (BGRL) is functional and has started an e‐Newsletter to report its activities.
Globally, the causes for intraplate earthquakes have remained an enigma for scientists. In several developing countries, such as India, the impacts of such earthquakes are often quite alarming because of high population density and the prolif‐eration of buildings which are not earthquake resistant. Reservoir‐triggered earthquakes are a special case. Existing models do not explain the genesis of such earthquakes due to lack of observations in the near‐field. Therefore, scientific deep drilling to gain access to the near‐field of earthquakes is an emerging frontier area of seismological research.
The Earth System Science Organization (ESSO) – Ministry of Earth Sciences has recently launched a major national programme “Scientific Deep Drilling in the Koyna Intra‐plate Seismic Zone, Maharashtra”. The BGRL has been established at Karad (near Koyna) to implement this project, which includes setting up a state‐of‐the‐art deep borehole obser‐vatory and a core repository. The laboratory is dedicated to deep borehole investigations and advanced studies on core samples. The immediate need is to set up the infrastructure and capacity building in these areas of study.
I complement the staff of the Borehole Geophysics Research Laboratory for the efforts to launch the inaugural issue of their e‐Newsletter. I wish them success in their endeavours”.
The Koyna region located in the ~65 Ma old Dec‐can Traps of western India is a classical site of artificial water reservoir triggered seismicity (RTS) because of (i) persistent seismicity in the vicinity of the reservoir for the past five decades since the impoundment of the Shivajisagar lake in 1962, with 22 M≥5 earthquakes, more than 200 M~4 earthquakes and several thousand smaller earthquakes, (ii) the largest RTS earthquake so far – M6.3 on 10 Dec 1967, (iii) strong association of the earthquake activity with the annual loading and unloading cycles of the Koyna and nearby Warna reservoirs, and (iv) isolated nature of the
seismic zone, restricted to ~20 x 30 km2 area and up to 10 km in depth, with no other source of activity within ~50 km of the Koyna Dam. There‐fore, the Koyna RTS site is an excellent natural laboratory to test various earthquake prediction models and hypothesis. A deep fault zone obser‐vatory at Koyna would facilitate study of pre‐seismic, co‐seismic and post‐seismic changes in physical and chemical parameters in an intra‐plate, active, fault zone in the near‐field. This experiment would provide important constraints to comprehend the genesis of RTS.
Harsh Gupta
Inside… Project Director’s desk
Studies in progress
Field visits
Moments to cherish
Team-Koyna
SCIENTIFIC DRILLING TO INVESTIGATE RESERVOIR‐TRIGGERED EARTHQUAKES IN KOYNA
Source: Atlas Copco
Koyna Dam
It is a proud moment for the project staff “TEAM‐KOYNA” of the Borehole Geophysics Re‐
search Laboratory to bring out the inaugural issue of our Newsletter on the occasion of the
66th Republic Day of our country. Within a short span of time since its inception on October
7, 2014, the laboratory has made considerable progress in setting up its office from ground‐
zero and initiating a number of scientific activities including studies on cores, planning for
pilot boreholes and capacity building for carrying out scientific deep drilling investigations
to study reservoir‐triggered earthquakes in the Koyna intra‐plate seismic zone, western In‐
dia. The seed for establishing the laboratory has been sown. This has been possible due to
the unstinted support of ESSO‐Ministry of Earth Sciences (MoES), Government of India. The
National Centre for Antarctic and Ocean Research (NCAOR), Goa has extended valuable
operational support for setting up the office, hiring of scientific and administrative staff, and
in carrying out the project activities. Through this brief e‐newsletter, we wish to provide a
snapshot of our activities during the past four months and the challenges that lay ahead.
Looking back, it has been an exciting journey since the conceptualization of the project in
January 2010. Extensive discussions with national and international scientists including an
International Workshop, organized by the MoES and CSIR‐NGRI with support from Interna‐
tional Continental Scientific Drilling Program (ICDP) at Hyderabad and Koyna in March
2011, provided the necessary inputs for development of a project on scientific drilling to
study reservoir triggered earthquakes occurring in the Koyna region for the past five dec‐
ades. It was clear that existing models to comprehend the genesis of triggered earthquakes
suffer from lack of observations in the near‐field. At this time, the MoES formulated the de‐
tailed project plan including scientific deep drilling, setting up a deep fault zone observatory
and establishing a dedicated laboratory for borehole geophysics and core studies at Karad
(near Koyna). The project was later approved by the Government of India. The first phase of
the project was launched by MoES in the year 2012. In this phase, land as well as airborne
geophysical investigations (including LiDAR) and drilling at nine sites up to a maximum
depth of 1522 m was carried out by the CSIR‐National Geophysical Research Institute during
2012‐14. During the second International ICDP Workshop held at Koyna in May 2014, the
specifications for deep scientific drilling down to 5 km, borehole measurements and moni‐
toring experiments were finalized in consultation with experts. On this day, we record our
deep sense of gratitude to Dr Shailesh Nayak, Secretary to Govt. of India, MoES under
whose dynamic leadership this laboratory has been established. We remain indebted to
Prof. Harsh Gupta, former Member, National Disaster Management Authority for his vision
and untiring efforts towards developing and guiding the Koyna Scientific Drilling Pro‐
gramme. Dr. B.K. Bansal, Advisor (Geosciences), MoES has been instrumental in planning
and execution of the project. Dr. S. Rajan, Director, NCAOR has provided valuable guidance
for carrying out the operations of the project office.
The immediate challenges for the office are three‐fold: (i) finalization of plans and scientific
drilling of pilot borehole(s) to a depth of 3 km, measurements and monitoring, (ii) establish‐
ment of infrastructure and facilities for a borehole geophysics and core studies laboratory,
and (iii) capacity building in areas relevant to scientific deep drilling investigations. TEAM‐
KOYNA is gearing up to meet these challenges, and seeks the help and cooperation from
one and all in making this national scientific effort a success.
Welcome to the inaugural issue of our biannual newsletter!
From the Project Director’s desk
Page 2 e-Newsletter Borehole Geophysics Research Laboratory
To succeed in your mission, you must have single-minded devotion to your goal. APJ Abdul Kalam
In the history of science, we often find that the study of some natural phenome-non has been the starting point in the development of a new branch of knowledge. CV Raman
Discipline is the bridge between goals and accom-plishment.
Jim Rohn
Detailed geological investigations of core samples from bore‐
holes KBH‐05 and KBH‐07, drilled previously in the Koyna re‐
gion, have been initiated. In both boreholes, Deccan basalt is
found to overlie granitic basement rock, without the occurrence
of infra‐Trappean sediments. The basement rocks comprise
predominantly granite‐gneiss alternating with migmatitic‐
gneiss. Near the basalt‐basement contact, the granitoids are
highly deformed, represented as mylonite and ultramylonite
followed by breccia and gouge at places. The deformation pat‐
tern varies with stress localizations and strain gradients within
the basement rock. Gneissosity is preserved as remnant within
less deformed zones and reoriented along the shear planes.
Deformation related phyllosilicates and clay minerals are en‐
riched along these sheared and fractured planes. Cataclasite is
present at places within the granitic basement. Rocks are highly
fractured with clear evidences of reddish iron staining at places.
Slickenlines are commonly observed along these fractures, and
are sometimes associated with gouge. Cementation, mineral
precipitation and lithification are found to occur along fractures.
Activities in progress ...
Page 3
Geological studies on core samples
Core sample of a breccia showing angular fragments of basement rock entrapped within a fine grained matrix
Core shows direct contact between basalt and granitic basement
Laboratory set-up for unconfined compressive strength (UCS) test: (a) Test specimen during the test, and (b) fracture developed on the test speci-men after the test.
-0.004 -0.002 0 0.002 0.004 0.006Diametrical strain Axial strain
0
20
40
60
80
Str
ess,
MP
a
-0.004 -0.002 0 0.002 0.004Diamertical strain Axial strain
0
40
80
120
160
200
Str
ess
, MP
a
Plot showing stress-strain response of granite-gneiss basement rocks from borehole KBH-7 (c), and borehole KBH-1 (d).
Rock mechanical properties
Rock physical and mechanical properties play a critical role in
processes controlling the origin of earthquakes and deformation
behavior of rocks. Laboratory measurements provide important
constraints to determine the strength of intact rock mass, i.e.,
the maximum strength beyond which deformation initiates. A
combination of laboratory derived stress values with the in‐situ
measurements of stress magnitude helps in understanding the
effect of pore fluid pressure in lowering the tensile strength of
the intact rock mass, which provides critical insights to triggered
seismicity.
Measurements of rock mechanical properties on the core sam‐
ples from the Koyna region have been initiated, utilizing the
facility at CSIR‐Central Institute for Mining and Fuel Research,
Dhanbad. A set of 18 samples of basement granite‐gneiss have
been tested so far. The measurements include compressive
strength, tensile strength, Young’s modulus, Poisson’s ratio,
cohesive strength of rocks and angle of internal friction.
Preliminary results from the limited UCS tests carried out so far
indicate variations in the compressive strength of basement
rock as a function of distance from the seismically active zone.
This is consistent with structural deformation observed in core
samples of basement granitoids in the vicinity of the Koyna seis‐
mic zone. Further detailed studies are underway.
Contact
Basalt Basement
Granite-gneiss
Clast
Gouge
Fracture
Clast
Matrix
Granite-gneiss
Slickenline
Core showing fractured granite-gneiss and fragmented clasts en-trapped within gouge
Slickenlines present on a fractured surface of granite-gneiss basement rock
a b
c d
Page 4 e-Newsletter Borehole Geophysics Research Laboratory
The entire staff appreciated the hard work put in by the drilling crew of M/S Mining Associates Private Limited to present the most valuable information in the form of core, unmasking the na‐ture of basement rock underneath the thick pile of Deccan flood basalt.
Earlier, another short field trip was car‐ried out to the Koyna dam and Rasati borehole (KBH‐1) sites. Core drilling down to 1522 m at Rasati was carried out by CSIR‐NGRI during 2012‐13 and a 4.5 Hz seismometer was installed in the granitic basement during February 2014.
TEAM‐KOYNA had discussions about the role of artificial water‐reservoir trig‐gered seismicity in the Koyna‐Warna region, core drilling to constrain subsur‐face geology and structure, and the need for installation of borehole seis‐mometers in the granitic basement rock.
Field Visits ...
Research is a field which allows scientists to put in all their thoughts, ideas, and imagination to paint the big picture. Carl Sagan (astronomer and science commu‐nicator) had said – “If you wish to make an apple pie from scratch, you must first invent the universe”. Team‐Koyna made a short educational tour to Khadi‐Kolvan, the site of borehole KBH‐9 in Ratnagiri District of Maharashtra, to get an over‐view of on‐site drilling and operational activities. The field party benefited from the experience of Shri R B Chakraborty, former General Manager (Drilling), ONGC Ltd. who has recently joined TEAM‐KOYNA. The scientists were introduced to various drilling and coring techniques, types of drill rigs, drill rods, drill and core bits, and casing liners.
Site selection for pilot borehole near Koyna
Scientific deep drilling down to ~5 km in the Koyna area and setting up a deep fault zone observatory to study pre‐seismic, co‐seismic and post‐seismic changes in physical and chemical parameters in the near‐field is planned. Prior to undertaking deep drilling, a pilot borehole phase has been initiated with the aim of acquiring critical information through drilling of two 3km‐deep pilot boreholes, measurements and monitor‐ing. Monitoring of seismicity using borehole arrays installed in the base‐ment rocks at a depth of 3 km, together with the NGRI network of 6‐8 seismometers in the granitic basement in exploratory boreholes sur‐rounding the seismic zone, would provide a better assessment of focal parameters. Information obtained in this phase will guide the trajectory
Team visit to proposed pilot hole site
Panoramic view of proposed pilot hole site near Koyna
of the main holes. Installation of temperature and pore pressure sensors will also be carried out.
The first site is located next to the seismic cluster in the Koyna area. The second site is located in close proximity to the seismic
cluster located to the south of the Warna reservoir. Reconnaissance surveys are ongoing to identify approx. 100m x 100m area
for each drill site and their suitability for carrying out deep drilling.
Page 5 Volume 1, Issue 1
Moments to cherish ...
The biannual e-Newsletter is brought out by Borehole Geophysics Research Laboratory, Karad, Maharashtra.
For e-Newsletter enquiries, contact:
Dr. Pinki Hazarika, Scientist C Phone: 02164-255060 Email: [email protected]
Team-Koyna
From left, 1st row: Amol Patil, Akshwant Pansare, Nagaraju Podugu, Vikrant Bartakke, Satyabrata Das, Gaurav Athavale 2nd row: Surajit Misra, Vyasulu V. Akkiraju, Sukanta Roy, Ram Bikash Chak-raborty, G. Srihari Prasad, Abhijeet Patil 3rd row: Shruti Shukla, Nisha Tamse, Pallavi B. Tembhurni-kar, Pinki Hazarika, Saraswati Girap, Anjana Vaditale. 4th row: Girish Dantkale, Digant K. Vyas, Rakesh Kumar Tiwari, Deepjyoti Goswami (Amrita Yadav is not present in the picture).
Fill the brain with high thoughts, highest ideals, place them day and night before you and out of that will come great work. (Swami Vivekananda) If you follow the crowd, you will go no further than the crowd. But if you walk alone, and find your own way, you will likely find yourself in places no one has ever been before. (Albert Einstein) A slip of foot you may soon recover, but a slip of the tongue you may never get over. (Benjamin Franklin)
Contact: Project Director, Borehole Geophysics Research Laboratory, ESSO-Ministry of Earth Sciences, Near RTO office, Padali (Kese), Karad-Patan Road, P.O. Supane 415114, Karad, Maharashtra (India). Tel +91-2164-255060; Email: [email protected]