Dr. M.S. Krishnan (October 1961-March 1964)

Maharajapuram Seetaraman Krishnan (born on 24th august 1898), awardee of the prestigeous Padma Bhushan from Government of India, was the moving force behind the beginning of NGRI, was the Director of the Institute during 1961-1964.He was the President of the Geology Section of the then prestigious Indian Science Congress. He was the first Indian to head the Geological Survey of India and served the nation by being the Director of the Indian Bureau of Mines (New Delhi), Indian School of Mines (Dhanbad), Head of the Geology and Geophysics in Andhra University, Waltair before joining NGRI. The classic text book authored by Dr.Krishnan titled "Geology of India Burma" is a bible for every geology student in India

Dr.Hari Narain (April 1964-March 1983)

Born on 21st September 1922, earned his B. Sc. (Hons), M. Sc. (Physics) and D. Phil at Allahabad University (1950) under supervision of Professor K. S. Krishnan., PhD (Geophysics) at Sydney University (1954). Superintending Geophysicist, Oil and Natural Gas commission (ONGC), Dehra Dun (1957-62) ; Director, Institute of Petroleum Exploration, ONGC, Dehra Dun (UNSF Project) (1962-64), Director National Geophysical Research Institute (1964-78; 1981-1983), Concurrently Surveyor-General of India (1972-76) ; Vice Chancellor, Banaras Hindu University, Varnasi (1978-81) ; Chief Coordinator, UNDP Project, NGRI (1983-86) ; Chairman of the Board of Directors of the National Institute of Technology Warangal (2001-2009) member of the Advisory Council of the Directorate General Hydrocarbons, Government of India (2001-09) . Dr. Hari Narain has carried out extensive gravity and magnetic surveys in Austraila and his pioneering work the eastern and central parts of Australia has thrown new light on the tectonics and subsurface geological and crustal structures. As the first Director of Research and Training Institute, now known as Keshava Deva Malaviya Institute of Petroleum Exploration, ONGC, Dehra Dun, Dr. Narain established research facilities in petroleum, geology, basin studies, geophysical interpretation and carried out extensive integrative studies for petroleum exploration. As the Director of NGRI Dr. Hari Narian has established several new research groups like seismology, exploration geophysics, airborne magnetic surveys, geophysical instrumentation, rock mechanics, high-pressure physical properties of rocks and minerals, paleomagnetic laboratory, magnetic observatory, geochemistry, geochronology and geological studies division. Dr. Hari Narain has published over 200 research papers and articles in Indian and foreign journals, and supervised about 30 students for their PhD. Degree. His work in seismology has established new criteria for reservoir associated earthquakes and has determined upper mantle structures in and around Indian subcontinent. He has prepared quantitative seismicity maps, heat flow map of India. The research and development work in indigenous airborne surveys and results obtained in Mysore and Madhya Pradesh States have thrown new light on mineral exploration. Under his stewardship the project team of UNDP has brought out many publications on the mineral resources of Cudappah region of Andhra Pradesh. The most exciting achievement was the finding of a new Kimberlite with maximum gem quality diamond production in Southern India. The methodology of stream sampling was further handed over to GSI. Awards and Honours: Among the various awards and honours received by him, mention must be made of the President, Geology and Geography Section, Indian Science Congress Association (1972) ; First UGC National Lecturer in Earth Sciences (1973) ; President of Indian Geophysical Union (1973-1975) ; Padma Shri, Government of India (1974) ; Decennial Award of Indian Geophysical Union (1976), Honorary professorship of Andhra University (1977), DSc, Indian School of Mines, Dhanbad (1978); President of the National Academy of Sciences, India (1979-80) ; Fellowship of Indian National Science Academy (1981) ; M. N. Saha Birth Centenary Award, Indian Science Congress (1994) ; First Petrotech Life time Achievement Award (1999) ; National Mineral Award of Excellence, Ministry of Mines, Government of India (2002) ; General President Medal, Indian Science Congress Association, from the Hon'ble Prime Minister of India Dr. Manmohan Singh (2007)

Prof. V.K. Gaur (April 1983-September 1989)

Vinod K Gaur Distinguished Professor Indian Institute of Astrophysics, Bangalore-560 034 Also Adjunct Professor Indian Institute of Science, Education and Research (IISER), Kolkata Vinod Gaur studied Geophysics at Banaras University and at Imperial College where he discovered the hitherto unsuspected ‘host rock effect’ in geo-electromagnetics. For this discovery in 1959, he earned the degree of Doctor of Philosophy from the University of London. His academic career began, immediately thereafter, as a Scientist at the National Physical Laboratory, UK. Later in 1966, he joined the University of Roorkee as Professor where he initiated a modern academic programme in Geophysics incorporating the insightful contents of signal analysis, inverse theory and computational geophysics. These were subsequently propagated by the UGC to other universities by sponsoring short- term intensive courses that were organized by Gaur at Roorkee. In 1983, he moved to Hyderabad as Director of the National Geophysical Research Institute and set about restructuring the Institute’s research programmes with scientific rigour, guided by hypothesis formulation and experiment design (Nature, April 12, 1984) Gaur’s landmark contributions to science include: i) discovery and explanation of the host-rock effect in the electromagnetic response of subsurface geological conductors (1959), ii) experimental ation of the hypothesis that the Indian plate under-thrusts the Asian plate @ ~ 1 cm /year, along the Main Himalayan Fault (1971) by direct measurement of slow deformation across a tunnel in the Tons valley, Uttaranchal , iii) discovery of the thick Deccan lithosphere, using the first seismic tomography experiments in India (1986) , iv) the first quantitative measurement of the Indian plate velocity with respect to the Eurasian, using Global Positioning System (GPS) Geodesy and an upper bound for the strain rate in the Southern Peninsula (1995), v) the first high resolution crustal images using broadband seismology, of the south Indian shield (1996) and of northeastern India (2005), and vi) the first Indian experiment to constrain global Carbon fluxes (2007) , over India and Central Asia, through inversion of ultra-high precision atmospheric concentration data (0.1 ppm), generated at the WMO accredited CO2 laboratory established by him at the Indian Astronomical Observatory, Hanle, Ladakh. His contributions (PHYSICS TODAY, 2001) to advancing Scientific endeavours include: i) design of modern Geophysics curricula (UGC,1970s), ii) restructuring of NGRI research programmes, iii) integrated design and writing of CBSE VIII and X class Science books (1990), design and implementation of Marine Satellite and Ocean Information Services, and modern Antarctic Research (1989-92), as Secretary to the Government of India, and v) founding of a Science to People programme in Hyderabad (1984), now matured in a vibrant State- wide movement. Professor Gaur is a fellow of the Indian National Science Academy (INSA), the Indian Academy of Sciences and the Third World Academy of Sciences. His awards include the Bhatnagar Prize (1980), the Flinn Award of the American Geophysical Union (2000), the Saha Birth Centenary Award of the Indian Science Congress (2006), and INSA Lecture Awards: the GP Chatterji Memorial Lecture(1991) and the D N Wadia Medal Lecture(2007). He has also been conferred Doctorate of Science Degrees (Honoris Causa) by the Banaras Hindu University, the Andhra University at Waltair and the Jawahar Lal Nehru Technical University at Hyderabad.

Prof. D. Guptasarma (October 1989-June 1992)

Dharmajit Guptasarma was born on 16 July, 1932, in Serajgunj, Dt. Pabna (now in Bangladesh). He obtained BSc with Physics Honours in 1950, and MSc in Radiophysics & Electronics in 1952, from Calcutta University, securing first rank in the university in both. He was awarded a Scientific Manpower Committee research fellowship of the Govt. of India, and worked as a research scholar for about 2 years under Prof Arun K. Chaudhury at the Inst. of Radiophysics & Electronics (RPE), and was then appointed a lecturer at the RPE without completing a PhD. He worked in the Geological Survey of India (GSI), Calcutta, from 1956 to 1965, and then joined the National Geophysical Research Institute (NGRI), Hyderabad, under the Council of Scientific and Industrial Research (CSIR), from where he retired as Director in June 1992. ACADEMIC AND RESEARCH CONTRIBUTION: Professor Guptasarma pioneered the development of geophysical exploration instruments in India at GSI, and then at NGRI. He designed many instruments for land, airborne and ship-borne operations that were extensively used. With his team he discovered a diamond-rich kimberlite in Wajrakarur, Andhra Pradesh. He carried out theoretical and physical scale modeling to interpret geophysical measurements; invented faster, more accurate digital numerical filter operators; showed that low frequency electrical resistivity modeling in electrolytic tanks goes wrong due to surface polarization; that a published 'theorem' using the concept of contribution to the electric potential at a point by the electric fields around was wrong; that the transient response of a coincident-loop EM system cannot change its sign except in the presence of electrochemical polarizability. He discovered a novel method for computation of the magnetic field due to an arbitrary polyhedral object; this was then applied for computation of the gravity field due to any polyhedral object. He discovered a relationship between the frequency spectra of true and apparent polarizability of a buried target. He authored 43 research articles. OTHER CONTRIBUTIONS He showed the need, and importance, of Very Long Baseline Interferometry (VLBI) measurements of the relative motion of the Indian tectonic Plate with respect to the Eurasian tectonic Plate for the proper understanding of the nature of the ongoing continent-continent convergence. He computed the sensitivity of missile launch systems to the gravity field of the earth structures. He showed that the seismic risk is not the same everywhere along the Himalayan collision belt. Awards Elected to fellowship of INSA (1987);Council Member (1991-93). Elected fellow of IASc, Bangalore (1987). Among the various other fellowships, awards and honours he received are: Father La Font Gold Medal (1950), Ganga Prasad Gold Medal (1952), Tripundeshwar Mitra Gold Medal (1952), Calcutta University Gold medal for MSc (1952), Krishnan Gold Medal (1972), UGC National Lecturer (1985-86), Decennial Award of IGU (1986), National Mineral Award (1986-87), Adjunct Professor in IIT, Kharagpur (1989).

Dr. Harsh K. Gupta (July 1992-February 2001)

Padmashri Dr. Harsh Gupta (born in 1942) served as the Director of the National Geophysical Research Institute (NGRI) Hyderabad for nearly a decade from 1992. Under his stewardship, NGRI rose to be the top geosciences research institute in India. His visionary leadership led NGRI to use the pool of basic research capabilities to address the country’s needs in hydrocarbons, minerals, and groundwater resources, a crucial question for agriculture in India. Positions held by Dr. Gupta: Member of the National Disaster Management Authority of India (Status: Minister of State, Government of India, 2011-2014); Secretary to Government of India, Department of Ocean Development (2001- 2005); Director, N.G.R.I. (1992- 2001); Advisor, Department of Science and Technology, Government of India (1990- 1992); Vice Chancellor, Cochin University of Science and Technology (1987- 1990); Director, Centre of Earth Science Studies, Trivandrum (1982- 1987); and Project Director, Kerala Mineral Development and Exploration Project (1982- 1987); Adjunct Professor, University of Texas at Dallas (1978- 2001); Research Scientist, University of Texas at Dallas (1972-1977); Senior UNESCO Fellowship, International Institute of Seismology and Earthquake Engineering (IISEE), Tokyo (1971-1972); Scientist N.G.R.I. (1967-1971); UNESCO Fellowship, IISEE, Tokyo (1966-1967); Scientist NGRI (1964-1966). Visiting Professor at a number of Universities and Institutes in Europe and USA. Advisor/Consultant to UNESCO, Common Wealth Science Council, International Atomic Energy Authority, ICSU etc on several occasions. Major Scientific Contributions: Prof. Gupta’s work is globally recognized for 1) Providing the first evidence of an extremely thick crust (65~70 km) below Himalaya and Tibet Plateau region in 1967, later ed by seismic surveys in 1980’s 2) Developing criteria to discriminate artificial water reservoir triggered earthquakes from normal earthquakes, which are globally applied and finding safe sites for construction of reservoirs, 3) Making a medium term forecast of an M~8 earthquake in north-east India region in 1986 which came true on August 6,1988, 4) Chairing the Steering Committee of the Global Seismic Hazard Assessment Program (G-SHAP) where some 500 scientists worked from 1992 to 1999 and produced the Global Seismic Hazard map, 5) Pioneering the Gas Hydrate program and delimiting the zones for stability of gas hydrates within the exclusive economy zone of India, 6) Taking up detailed studies of genesis of triggered earthquakes in the Koyna region and making successful short term earthquake forecasts. Indian Tsunami Warning System: After the occurrence of the devastating December 26, 2004 Mw 9.3 Sumatra earthquake and the resultant tsunami that claimed over 250,000 human lives in south and south east Asia,Prof. Gupta spear headed setting up India’s tsunami warning system, which was completed in just 30 months time. This is now assessed to be among the best tsunami warning systems globally. Low Temperature Thermal Desalination: Under the stewardship of Prof. Gupta, the first low-temperature thermal desalination plant was set up in Kavaratti, Lakshadweep in 2005. This is the first of its kind anywhere in the world and has been producing over 100,000 liters/day for the past 7 years. Kavaratti has a population of about 10,000 people. Consequently, the cases reported in the hospital have dropped to less than one-half in the subsequent years as most cases were related to water borne deceases. Legal Continental Shelf: Prof. Gupta directed the Legal Continental Shelf program of India, where 31,000 line km of seismic date, intense gravity, magnetic and other geo-data were collected. This has led to India’s submitting a claim to the UN Commission on the Limits of the Continental Shelf. Publications: Dr. Gupta has published over 200 scientific papers in internationally reputed journals, has authored 5 books, published by Elsevier and Springer, and edited 21 volumes. One of his papers was adopted as a chapter in the Open University (U.K.) text book on Geophysics. His first book, “Dams and Earthquakes”, published in 1976 was translated into Russian and Chinese languages. Prof Gupta compiled and edited “Encyclopedia of Solid Earth Geophysics”. This monumental 1500+ pages two volume treatise, published by Springer is globally a landmark (website: www.spinger.com external link ). ANTARCTICA: Prof Gupta was the Leader of the Third Indian Scientific Expedition to Antarctica (1983- 1984), which succeeded in establishing a permanent base station for scientific research in a record time of one Antarctic Summer, against very heavy odds. This record still holds good. This led to India joining the exclusive club of nations as a member of “Antarctic Treaty”. IUGG/ICSU/AGU/AOGS Etc. Long time involvement with IUGG (President 2011-2015, Vice President 2007-2011, Bureau Member for two terms, 1999- 2003 and 2003- 2007); IASPEI (Vice President, 1995- 1999, Executive Committee Member 1991- 1995); Chair, Steering Committee of Global Seismic Hazard Program (GSHAP), 1992- 1999; ICSU (Member CSPR, two terms, 2005-2008 and 2008- 2011); Chair, Hazards Group, ICSU Regional Office for Asia and Pacific; ILP (Bureau Member, 1986- 1989; and was made a Bureau Member of ILP for life in 1996); Founder President of the Asian Seismological Commission (1996- 2000); IUGS (Councilor, 2000- 2004); Vice President and President AOGS (2010-2013); Member Scientific and Technical Committee of ISDR (2009- ); Member AGU Committee on Public Affairs, The New AGU and a member of AGU Committee on International Participation, etc. International Union of Geodesy and Geophysics (IUGG) has over 70 countries as members. In its history of 96 years, Prof Gupta is the second scientist from India to have been elected as its president. Asia Oceania Geoscience Society (AOGS) has jurisdiction from Japan in the north to New Zealand in the south involving over 40 countries. Prof Gupta is the only scientist from India to have been elected as its President. Institution Building Dr. Gupta has been involved from a very young age in senior administrative positions of institution building. He built Centre for Earth Science Studies at Trivandrum from a scratch. This included development of a whole campus in a short time of two years (1984-86). He also had the responsibility of building Indian Scientific Station in Antarctica which he did with distinction and completed all the tasks in a record time of one Antarctic summer (1983-84). In his capacity as Vice-Chancellor of Cochin University of Science and Technology (at the age of 45 years he was the youngest Vice-Chancellor in the country at that time), among several things, he created DRDO – Cochin University of Science & Technology, Computer Centre equipped with the then latest available computers for joint research projects. He also hosted the Science Congress in January 1990, the first Science Congress in Kerala, which, people still remember as one of the best conducted Science Congress meetings. At DST, during his stay of two years (1990-92) he initiated many new programmes including consolidating DST inputs on IGBP projects. During 1992-2001, Dr Gupta was the Director at the National Geophysical Research Institute (NGRI), Hyderabad. NGRI has risen to the position of one of the top few CSIR laboratories. From a meager rupees one crore external cash flow during 1993-94, it has grown to 11 crores during 1996-97. NGRI won the prestigious Technology Prize for Business Development and Technology Marketing during 1997. At NGRI, Dr Gupta has revolutionized application of earth sciences to the basic needs of the country. This has included delineation of Mesozoic sediments (which could be petroliferous) under Deccan Trap cover, and a new chapter has been opened in looking for Gas Hydrates in offshore region of India. NGRI has also significantly contributed in water resource finding, rain water harvesting and water pollution related studies as well as ways and means of assessing and safeguarding against earthquake hazards. Indian Science Congress Association: As the Vice Chancellor of the Cochin University of Science and Technology, Prof. Gupta hosted the Science Congress in 1990 at Cochin. He was the President of Earth Science Section in 1993/1994. He was elected General President of ISCA and organized a very successful Science Congress at Annamalai University in 2007 with the theme “Planet Earth”. The previous earth scientist to hold this position was Prof W. D. West in 1972. Awards: Many, including:

1977	Indian School of Mines Golden Jubilee “Outstanding Alumni” Award
1978	Krishna Gold Medal of the Indian Geophysical Union
1983	Shanti Swarup Bhatnagar Prize for Science & Technology in Earth Sciences
1985	USSR Academy of Sciences “100 Years of International Geophysics” Memorial Medal
1989	The first “Dr Anil Kumar Ganguli” Memorial Oration Award, BARC, Bombay
1991	National Mineral Award, Government of India
1993	The Department of Atomic Energy, Government of India “C.V. Raman Lectureship”.
1995	Indian Science Congress Association Jubilee Lecture
1995	CSIR Technology Prize for Business Development and Technology Marketing
1997-98	Ninth Professor K.P. Rode Memorial Lecture of the Indian Science Congress Association
1998	Second Outstanding performance Award by the 11th International Kharazmi Festival of Iranian Research Organization for Science and Technology, Teheran,Iran
1998	Indian Geophysical Union Decennial Award
1999	Federation of Indian Chambers of Commerce and Industry, New Delhi, Award for Physical Sciences,1998-99
1999	IGU Millennium Award
2000	Indian Society of Applied Geochemists Millennium Award
2001	Vikram Sarabhai Memorial Lecture, Department of Space
2001	First Dr. H.N. Siddiquie Memorial Lecture, Indian Geophysical Union
2002	22nd G.P. Chatterjee Memorial Award, Indian Science Congress Association
2003	Jawaharlal Nehru Visiting Fellowship 2003, Indian National Science Academy
2003	The 4th Prof. C. Karunakaran Endowment Lecture
2003	Bruun Memorial Lecture, 22nd session of the Assembly of International Oceanographic Commission, Paris.
2003	National Mineral Award for Excellence-2002
2004	Prof. K. Naha Memorial Medal (2004) of INSA
2004	Sir Alladi Krishnaswamy Aiyer Endowment Lecture 2004
2005	Prof. J.B. Auden Memorial Lecture 2005
2005	Prof. M. Kurup Memorial Lecture 2005
2005	Prof. Y. Nayudamma Memorial Lecture 2005
2006	Padma Shri 2006
2008	Prof. Y. Nayudamma Memorial Gold Medal Award for 2008 from APAS
2008*	Waldo E. Smith Medal Award for 2008 from AGU
2008	Rotary Vocational Excellence Award 2009 by Rotary Club of Hyderabad Deccan
2009	Sivananda Eminent Citizen Award 2009 by Sanathana Dharma Charitable Trust
2012	Distinguished Alumnus Award, I. I. T. Roorkee; 2012
2013	Basant Samman (Outstanding Alumnus award), Indian School of Mines,
2014	The Daulat Singh Kothari Memorial Lecture (2014) of Indian National Science Academy

* Prof Gupta is the first so far and the only scientist from the developing world to be awarded Waldo Smith Medal by the American Geophysical Union. He is also the second from Asia, the only other awardee being from Japan.

Dr. V.P. Dimri (October 2001-February 2010)

Dr. Vijay Prasad Dimri served as the Director of the Institute from October 2001 to February 2010. Under his leadership, NGRI's achievements were significant in geosciences. NGRI is ranked No.1 in the research output among the geosciences institutions in the country (June 2006, NISCAIR, New Delhi). During 2005-06 NGRI was no.1 among all CSIR laboratories in earning external cash flow from the sponsored projects. Also NGRI was placed among the top 1% institutions in the world in term of citation according to the analysis carried out by the SCOPUS 2007. Earlier, Dr. Dimri joined theoretical geophysics group at NGRI in 1970 as a Junior Research Fellow, after his post graduation in applied geophysics from Indian School of Mines, Dhanbad in 1969. Dr. Dimri reformulated the problems of geophysics for realistic geology after careful analysis of physical properties such as density, susceptibility, reflectivity etc from several deep boreholes including German Continental Deep Drilling Project (KTB), which follow fractal distribution rather than hitherto assumed random distribution for mathematical simplicity. His theoretical work established a relation between potential field and their sources and thus developed a new technique of scaling spectral analysis to delineate subsurface complex geological structures for hydrocarbon exploration. A new way for modelling of any complex object lying beneath the earth surface by using fractal geometry, has been granted as US patent and has many applications like Enhanced Oil Recovery, Aquifer Modelling etc. Earlier Dr. Dimri established a parallelism between deconvolution and inversion, two important tools of signal processing, and thus results and concepts of one can be applied to another and vice versa. The Wiener filter which is commonly used in seismic deconvolution procedure was modified to apply in inversion of gravity & magnetic measurements to map the subsurface density and susceptibility respectively. One of the significant findings of Dr. Dimri was to show that a single channel time varying filter is equivalent to multi-channel time invariant filter so that the well developed algorithms for processing of the stationary data could be easily applied to non-stationary geophysical data. Dr. Dimri extended the well known maximum entropy method to nonstationary and complex geophysical data analysis. All these new findings he wrote in form of a book entitled “Deconvolution and Inverse Theory” published by Elsevier, 1992 and Prof. M. Koch declared the book as a didactical master piece and reference book in the field of Inverse theory. Dr. Dimri has edited two books on “Applications of fractal in Geosciences, Balkema, USA, 2000” and “Fractal Behaviour in Earth Science System, Springer, 2005”. Dr. Dimri was the first person to quantify the well known ambiguity of gravity interpretation in terms of number of false gravity anomalies associated with gravity measurement using the concept of entropy and channel capacity of Information theory, which is a part of his PhD work. Later he hypothesized covariance gravity model for the Bay of Bengal, Indian Ocean. Dr. Dimri made significant contributions in geophysical data analysis and interpretation for a variety of applications to Indian earthquakes and exploration of hydrocarbons and groundwater. His significant finding is self organized fractal seismicity of reservoir triggered earthquakes in Koyna-Warna, India. Currently Dr. Dimri along with others is modelling Tsunami Wave Propagation from sea earth quakes originated from Sumatra and Makran subduction regions. Dr. Dimri, with more than 4 and 1/2 years of R&D experience in Norway and Germany, has designed major scientific programmes in sectors of ‘Energy security’, ‘Water security’, ‘Risk assessment’ ‘Ocean studies’ and ‘Frontier research areas of international repute’. Awards & Honours Padma Shri award by the Govt. of India in 2010. First Asian to get Lorenz Award Lecturer in American Geophysical Union in the field of non-linear geophysics in December, 2007. G.P.Chatterjee Award of Indian Science Congress Association, presented by the Prime Minister of India Dr. Manmohan Singh in 2007. Outstanding Scientist award of FAPCCI, presented by the Chief Minister of Andhra Pradesh in 2008. Department of Ocean Development Award, Govt. of India, 2004. Fellow, Third World Academy of Sciences, Italy Fellow, Indian National Science Academy (INSA), New Delhi Fellow, National Academy of Sciences, Allahabad Fellow, AP Akademy of Sciences, Andhra Pradesh President, AP Academy of Sciences (2010-Continued) Indian Geophysical Union, 2006-2010 Sectional President, Earth Science section of Indian Science Congress Association, 2007 Chairman, member of several governing council and research advisory council of many earth science institutions in the country. Served as member of several national and international committees such as Chair, National Committee on International Union of Geodesy and Geophysics (2005-07). CSIR-Distinguished Scientist in CSIR-National Geophysical Research Institute, Hyderabad (October,2010-Octber,2013) Currently, he is serving as INSA Senior Scientist from 07/11/2013

Prof. Mrinal Kanti Sen (January 2012-January 2014)

Prof. Mrinal K. Sen received B.Sc and M.Sc degrees from the Indian School of Mines and Ph.D from the University of Hawaii at Manoa. Prior to joining graduate school, Prof. Sen worked in the oil industry as an exploration geophysicist. After spending two years working on seismic hazard estimation in Los Angeles Basin in Pasadena, California, he joined the University of Texas at Austin Institute for Geophysics. He moved up the ranks there and became a full professor and was awarded Jackson chair in Applied Seismology at the University of Texas. Prof. Sen’s research areas include seismic wave propagation, inverse problems, seismic imaging, reservoir characterization and computational geophysics. He is an expert on seismic wave propagation including anisotropy and fracture characterization, and develops analytic and numerical techniques for forward and inverse modeling. Prof. Sen is well known for his work on global optimization methods for geophysical inversion. Over the years, he worked on several geophysical parameter estimation problems. He and his colleagues were able to demonstrate that global optimization methods such as simulated annealing (SA) and genetic algorithms (GA) can be used effectively for several geophysical applications such as seismic waveform inversion, gravity interpretations, and seismic migration velocity analysis. He also showed how one could apply Gibbs' sampling and the Metropolis rule to characterize uncertainties and the posterior probability density function (PPD) in model space. He has extended seismic plane wave analysis methods to anisotropic media and developed techniques for estimating the parameters that determine the degree of anisotropy. His most recent accomplishments in exploration seismology include developing novel methods for characterizing reservoirs using seismic and well log data, estimating P- and S-wave velocity models for sediments containing gas hydrates from seismic reflection data, and, improving seismic imaging and velocity estimation methods in structurally complex areas. In whole earth seismology, he has estimated the anisotropy in the D" region of the earth's deep interior. He is continuing to actively pursue research problems that require development of new analytic and numerical methods in both exploration and whole earth seismology. For example using seismic reflection data he is attempting to estimate high resolution reservoir properties using deterministic and stochastic algorithms. Prof. Sen has supervised over fifty doctoral and post-doctoral students. He and his students have carried out rigorous error analysis of finite difference and finite element methods. They have also developed new methods for computing synthetic seismograms based on path integral formulation, full waveform inversion and reservoir characterization including time lapse seismics. Prof. Sen serves on several national and international committees and is an associate editor of some leading journals such as Geophysics, Journal of seismic exploration and International Journal of Geophysics. He routinely serves on the SEG and SPG technical committees. He has been an instructor of several industry short courses including an SEG short course on ‘Full Waveform Inversion’.

Dr. V.M Tiwari (July 2016- November 2022)

Dr. Virendra M. Tiwari obtained his post-graduate degree in Geophysics from Banaras Hindu University (BHU), Varanasi. He took up a scientific career at CSIR-National Geophysical Research Institute (CSIR-NGRI), after receiving a Ph.D. in Geophysics from NGRI-BHU. He has worked as a Post-Doctoral Researcher at the IPGP, Paris, France, and LAGOS-CNES, Toulouse, France, and as Visiting Scientist at the GEOMAR/CU Kiel, Germany, and CU, Boulder, USA. His academic excellence has been recognized by National Merit Scholarship; ONGC-AEG Best Thesis Award; the Young Scientist Awards from INSA, CSIR, UP S&T; Krishnan Gold Medal by IGU, National Mineral Award by Ministry of Mines, GoI, to name a few. With well recognized scientific contributions, Dr. Tiwari is an elected Fellow of the Indian National Science Academy (FNA), National Academy of Sciences India (FNASc), Indian Academy of Sciences (FASc), and Telangana Academy of Sciences (FTAS). He is a recipient of the SERB J C Bose Fellowship (2022). He is also a member of several national and international committees. His research focuses on deciphering the mass distribution and mass transport related to the geophysical phenomenon on the surface and at depth in the Earth. Besides well-cited research papers in leading journals; he has contributed significantly to the important R&D projects for the groundwater and the Oil and Mineral Industries in India.