Dhananjay Ravat

drava2's picture
Education: 
Ph.D., Purdue University, Geophysics, 1989 M.S., Purdue University, Geophysics, 1985 B.Sc., Maharaja Sayajirao University of Baroda, Geology, 1981
Biography: 

 

Professor Dhananjay Ravat received his B.Sc. degree in geology from Maharaja Sayajirao University of Baroda, India, and M.S. and Ph.D. degrees in geophysics from Purdue University, USA.  He has taught and conducted research at Southern Illinois University Carbondale in Illinois, USA (1991-2007) and University of Kentucky on topics pertaining to exploration of the earth and planets with gravity and magnetic fields, solid-earth geophysics, tectonics and environmental geophysics. From August 2007, he joined University of Kentucky, where he has been the Chair of Department of Earth & Environmental Sciences. He is presently an associate editor of Near Surface Geophysics, has been an associate editor of Geophysics (2001-2005), and has edited special issues of Seismological Research Letters and The Leading Edge. He is a life member of Geological Society of India (Fellow), American Geophysical Union, Society of Exploration Geophysicists, International Association of Mathematical Geology and a member of American Association for Advancement of Science.

Research: 

Potential fields (gravity, magnetics, heat flow) geophysics theory and its global/planetary, regional, geo-hazards, tectonic and environmental applications.

Research interests of Professor Ravat, his students, and research associates range from global and planetary geophysics and tectonics, regional-scale geophysics to solving environmental and engineering geophysical problems.

 

Current  Projects

The most exciting recent project we have been involved with is using high-resolution spectral magnetic methods to study the thermal structure of Aeolian volcanoes in Italy. The reference to our De Ritis et al. (2013) paper on this topic can be found in the Academics section.

Currently, we are also involved in a NSF-funded project on Deciphering the Structure and Evolution of North America’s Cratonic Core using EarthScope seismic and potential-field data. In this context, we have already developed a new spectral magnetic depth determination method (Salem et al., 2013) and also a method for computing geotherms with the constraints from the Curie-depths found from magnetic anomaly data. 

We have also been involved in the preparation of the World Digital Magnetic Anomaly Map published in 2007 by UNESCO and CGMW and initiated by IAGA/IUGG. The data and maps are available at: http://ftp.gtk.fi/WDMAM2007/. Interpretation of this map in the context of the geology and geophysics of the world and improvements to these data to facilitate the second edition of this map are underway.

In addition, we are also involved in improving magnetic anomaly data for the United States collected during the National Uranium Resource Evalutation (NURE) project during 1970s using new methodologies. Our long-wavelength corrected US magnetic database and report is presently available at: http://pubs.usgs.gov/of/2009/1258/

 

Selected Publications: 
  • E-mail Prof. Ravat, at dhananjay.ravat@uky.edu for electronic copies of publication.
  • De Ritis, R. , D. Ravat, G. Ventura, and M. Chiappini, 2013, Curie isotherm depth from aeromagnetic data constraining shallow heat source depths in the central Aeolian Ridge (Southern Tyrrhenian Sea, Italy), Bull. Volcanol, 75, 710-xxx, DOI 10.1007/s00445-013-0710-9.
  • Ravat, D., A. Salem, A.M.S.Abdelaziz, E. Elawadi, and P. Morgan, 2011, Probing magnetic bottom and crustal temperature variations along the Red Sea margin of Egypt, Tectonophysics, 510, 337-344.
  • Ravat, D., 2011, Interpretation of Mars southern highlands high amplitude magnetic fieldwith total gradient and fractal source modeling: New insights into the magneticmystery of Mars, Icarus, 214, 400-412.
  • Ravat, D., 2011, Magnetic Methods, Satellite, Encyclopedia of Solid Earth Geophysics, Gupta, H.K. (ed.), Springer, 771-774.
  • Salem, A., Williams, S., Samson, E., Fairhead, D., Ravat, D., and R.J. Blakely, 2010, Sedimentary basins reconnaissance using the magnetic Tilt-Depth method, Exploration Geophysics, 41, 198-209.
  • Ravat, D., Finn, C., Hill, P., Kucks, R., Phillips, J., Blakely, R., Bouligand, C., Sabaka, T., Elshayat, A., Aref, A., and Elawadi, E.(2009) A preliminary, full spectrum, magnetic anomaly grid of the United States with improved long wavelengths for studying continental dynamics--A website for distribution of data: U.S. Geological Survey Open-File Report 2009–1258.
  • Hill, P.L., Kucks, R.P., and Ravat, D.(2009) Aeromagnetic and aeroradiometric data for the conterminous United States and Alaska from the National Uranium Resources Evaluation (NURE) Program of the U.S. Department of Energy: U.S. Geological Survey Open-File Report 2009–1129.
  • Wang, B., E.S. Krebes, D. Ravat (2008) High-precision potential-field and gradient-component transformations and derivative computations using cubic B-splines, Geophysics, 73 (I35), I42
  • Salem, A., S. Williams, J.D. Fairhead, R. Smith, D. Ravat (2008) Interpretation of magnetic data using tilt-angle derivatives, Geophysics, 73 (L1), L10
  • Korhonen, J., (and the rest alphabetically), J.D. Fairhead, M. Hamoudi, K. Hemant, V. Lesur, M. Mandea, S. Maus, M. Purucker, D. Ravat, T. Sazonova, E. Thebault, World Digital Magnetic Anomaly Map, 1:50 000 000, 1 sheet and 1 DVD, First Edition, Paris, CCGM-CGMW/UNESCO, 2007
  • Salem, A., S. Williams, J.D. Fairhead, D. Ravat, R. Smith (2007) Tilt-depth method: A simple depth estimation method using first order magnetic derivatives, The Leading Edge, 26, 1502-1505
  • Hemant, K., E. Thébault, M. Mandea, D. Ravat, S. Maus (2007) Magnetic anomaly map of the world: merging satellite, airborne, marine and ground-based magnetic data sets, Earth and Planetary Science Letters, 260, 56-71
  • Maus, S., T. Sazonova, K. Hemant, J. D. Fairhead, D. Ravat (2007) National Geophysical Data Center candidate for the World Digital Magnetic Anomaly Map, Geochemistry, Geophysics, Geosystems, 8 (Q06017), doi:10.1029/2007GC00
  • Ravat, D., A. Pignatelli, I. Nicolosi, M. Chiappini (2007) A study of spectral methods of estimating the depth to the bottom of magnetic sources from near-surface magnetic anomaly data, Geophysical Journal International, 169, 421-434
  • Bektas, O., D. Ravat, A. Büyüksarac, F. Bilim, A. Ates (2007) Regoinal geothermal characterization of East Anatolia from aeromagnetic, heat flow and gravity data, Pure and Applied Geophysics, 164, 975-998
  • Ravat, D. (2007) Upward and downward continuation, Encyclopedia of Geomagnetism and Paleomagnetism (Editors: D. Gubbins E. Herrero-Bervera), First Edition, Springer, 1020 pages, In Press, ISBN=1402039921 (bookchapter)
  • Ravat, D. (2007) Reduction to pole, Encyclopedia of Geomagnetism and Paleomagnetism (Editors: D. Gubbins E. Herrero-Bervera), First Edition, Springer, 1020 pages, In Press, ISBN=1402039921 (bookchapter)
  • Ravat, D. (2007) Crustal Magnetic Fields, Encyclopedia of Geomagnetism and Paleomagnetism (Editors: D. Gubbins E. Herrero-Bervera), First Edition, Springer, 1020 pages, In Press, ISBN=1402039921 (bookchapter)
  • Hinze, W.J., B. Coakley, T. Hildenbrand, G.R. Keller, X. Li, D. Plouff, D. Ravat, M. Webring (2006) Reply to "Vasanthi, A., Sharma, K.K., and Mallick, K., Discussion on the paper `New standards for reducing gravity data: The North American gravity database' by Hinze, W.J, Aiken, C.J. and 20 others: Geophysics, v. 70, No. 4, pp. J25-J32, 2005, Geophysics, 71, X32-X33
  • Bexfield, C.E., J.H. McBride, A.J.M. Pugin, D. Ravat, S. Biswas, W.J. Nelson, T.H. Larson, S.L. Sargent, M.A. Fillerup, B.E. Tingey, L. Wald, M.L. Northcott, J.V. South, M.S. Okure, and M.R. Chandler (2006) Integration of P- and SH-wave high resolution seismic reflection and micro-gravity techniques to improve interpretation of shallow subsurface structure: New Madrid seismic zone, Tectonophysics, 420, 5-21
  • Gaya-Pique, L.R., D. Ravat, A. De Santis, and J.M. Torta (2006) New model alternatives for improving the representation of the core magnetic field of Antarctica, Antarctic Science, DOI: 10.1017/S0954102006000095, 18, 101-109
  • Hinze, W.J., C. Aiken, J. Brozena, B. Coakley, D. Dater, G. Flanagan, R. Forsberg, T. Hildenbrand, G. R. Keller, J. Kellogg, R. Kucks, X. Li, A. Mainville, R. Morin, M. Pilkington, D. Plouff, D. Ravat, D. Roman, J. Urrutia-Fucugauchi, M. Véronneau, M. Web (2005) New standards for reducing gravity data: The North American gravity database, Geophysics, DOI: 10.1190/1.1988183, 70, J25-J32
  • Salem, A., D. Ravat, R. Smith, and K. Ushijima (2005) Interpretation of magnetic data using an enhanced local wavenumber (ELW) method, Geophysics, DOI: 10.1190/1.884828, 70, L7-L12
  • Salem, A., D. Ravat, T.J. Gamey, K. Ushijima (2005) Chapter 16: Detection of buried steel drums from magnetic anomaly data using an artificial intelligence technique, pp.513-523, In D.K. Butler (eds), Near-Surface Geophysics, Investigations in Geophysics No. 13, Tulsa, Society of Exploration Geophysicists, 732p. pages, ISBN=1-56080-130-1 (bookchapter)
  • Salem, A., D. Ravat, M.F. Mushayandebvu, K. Ushijima (2004) Linearized least-squares method for interpretation of potential-field data from sources of simple geometry, Geophysics, 69, 783-788
  • Milligan, P.R., R. Franklin, D. Ravat (2004) A new generation of Magnetic Anomaly Grid Database of Australia (MAGDA) - use of independent data increases the accuracy of long wavelength components of continental-scale merges, Preview, 113, 25-29
  • Ravat, D., and P.S. Millegan (eds.), Geophysics from Space (special Grav/Mag section), The Leading Edge, 22(8), 2003
  • Salem, A., and D. Ravat (2003) A combined analytic signal and Euler Method (AN-EUL) for automatic interpretation of magnetic data, Geophysics, 68, 1952-1961
  • Ravat, D., T.G. Hildenbrand, and W. Roest (2003) New way of processing near-surface magnetic data: The utility of the Comprehensive Magnetic Field Model, The Leading Edge, 22, 784-785
  • Ravat, D., and P.S. Millegan (2003) An introduction - Geophysics: Doing it in space, The Leading Edge, 22, 757-758
  • Ravat, D. (2003) New uses of continuous coverage satellite magnetic field data in studying the Earth's lithosphere In P. Stauning, H. Lühr, P. Ultre-Guerard, J. LaBrecque, M. Purucker, F. Primdahl, J. Jorgensen, F. Christiansen, P. Hoeg, and K. Lauritsen (eds), OIST-4 Proceedings, Copenhagen, Narayana Press, 79-82 pages (bookchapter)
  • Bankey, V., and 17 others, Digital data grids for the magnetic anomaly map of North America (http://pubs.usgs.gov/of/2002/ofr-02-414/), U.S. Geological Survey Open-File Report, 02-414, 2002
  • Wheeler, R.L., and D. Ravat (editors, special issue), The Illinois basin: Seismicity, Quaternary faulting, and Seismic Hazard, Seismological Research Letters, 73(5), 2002
  • Wheeler, R.L., and D. Ravat (2002) Introduction to the special issue on Seismic hazards of the Illinois basin, Seismological Research Letters, 73, 590-596
  • Hildenbrand, T.G., J.H. McBride, and D. Ravat (2002) The Commerce geophysical lineament and its possible relation to Mesoproterozoic igneous complexes and large earthquakes in the central Illinois Basin, Seismological Research Letters, 73, 640-659
  • Salem, A., D. Ravat, T.J. Gamey, and K. Ushijima (2002) Analytic signal approach and its applicability in environmental magnetic investigations, Journal of Applied Geophysics, 49, 231-244
  • Ravat, D., K. Kirkham, and T.G. Hildenbrand (2002) A source-depth separation filter: Using the Euler method on the derivatives of total intensity magnetic anomaly data, The Leading Edge, 21, 360-365
  • Ravat, D., K.A. Whaler, M. Pilkington, T. Sabaka, and M. Purucker (2002) Compatibility of high-altitude aeromagnetic and satellite-altitude magnetic anomalies over Canada, Geophysics, 67, 546-554
  • Ravat, D. B. Wang, E. Wildermuth, P.T. Taylor (2002) Gradients in the interpretation of Satellite-altitude Magnetic Data: An Example from Central Africa, J. Geodynamics, 33, 131-142
  • Ravat, D. and M. Purucker (2002) Unraveling the Magnetic Mystery of the Earth's Lithosphere: The Background and the Role of the CHAMP Mission In C. Reigber, H. Luehr, P. Schwintzer (eds), In: C. Reigber, H. Luehr, P. Schwintzer (Eds.), First CHAMP Mission Results for Gravity, Magnetic and Atmospheric Studies, Springer-Verlag, Heidelberg, Heidelberg, Springer-Verlag, 251-260 pages (bookchapter)
  • Salem, A., D. Ravat, R. Johnson, and K. Ushijima (2001) Detection of Buried Steel Drums from Magnetic Anomaly Data using a Supervised Neural Network, Journal of Environmental Engineering and Geophysics, 6, 115-122
  • Salem, A., K. Ushijima, T.J. Gamey, and D. Ravat (2001) Automatic detection of UXO from airborne magnetic data using a neural network, Journal of Subsurface Sensing Technologies and Applications, 2 (3), 193-215
  • Purucker, M., D. Ravat, H. Frey, C. Voorhies, T. Sabaka, and M. Acuna (2000) An altitude-normalized magnetic map of Mars and its interpretation, Geophysical Research Letters, 27, 2449-2452
  • Ravat, D. (2000) Magnetohydrodynamic Waves in the Earth In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 632 pages (bookchapter)
  • Ravat, D. (2000) Magnetic Field: Origin of Internal Field In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 631 pages (bookchapter)
  • Ravat, D. (2000) Magnetic Pole In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 630-631 pages (bookchapter)
  • Ravat, D. (2000) Geomagnetism: Polarity Reversals In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 422-423 pages (bookchapter)
  • Ravat, D. (2000) Geomagnetism: Main Field, Secular Variation and Westward Drift In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 421-422 pages (bookchapter)
  • Ravat, D. (2000) Geomagnetism: External Fields In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 420-421 pages (bookchapter)
  • Ravat, D. (2000) Geomagnetic Measurement, Techniques and Surveys In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 417-420 pages, ISBN=978-0-19-8540 (bookchapter)
  • Ravat, D. (2000) Curie Temperature In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 202-203 pages, ISBN=978-0-19-8540 (bookchapter)
  • Ravat, D. (2000) Aeromagnetic Surveying In P.L. Hancock and B.J. Skinner (eds), The Oxford Companion to the Earth, P.L. Hancock and B.J. Skinner (eds.), Oxford University Press, Oxford, U.K., Oxford, U.K., Oxford University Press, 6-7 pages, ISBN=978-0-19-8540 (bookchapter)
  • Ravat, D., and M. Purucker (1999) The future of satellite magnetic anomaly studies is bright!, The Leading Edge, 18, 326-329
  • Ravat, D., Z. Lu, and L.W. Braile (1999) Velocity-density relationships and modeling the lithospheric density variations of the Kenya Rift, Tectonophysics, 302, 225-240
  • Ravat, D., and P.T. Taylor (1998) Determination of depths to centroids of three-dimensional sources of potential-field anomalies with examples from environmental and geologic applications, Journal of Applied Geophysics, 39, 191-208
  • Hildenbrand, T.G. and D. Ravat (1997) Geophysical Setting of the Wabash Valley Fault System, Seismological Research Letters, 68, 567-585
  • Taylor, P.T., and D. Ravat (1997) Reply to comments by R. Pucher and T. Wonik on 'An interpretation of the Magsat anomalies of central Europe, J. Applied Geophys., 34, 83-91,', Journal of Applied Geophysics, 36, 217-219
  • Ravat, D. (1996) Analysis of the Euler method and its applicability in environmental magnetic investigations, Journal of Environmental Engineering and Geophysics, 1, 229-238
  • Ravat, D. (1996) Magnetic properties of unrusted steel drums from laboratory and field-magnetic measurements, Geophysics, 61, 1325-1335
  • Taylor, P.T., and D. Ravat (1995) An interpretation of the Magsat anomalies of central Europe, Journal of Applied Geophysics, 34, 83-91
  • Ravat, D., R.A. Langel, M. Purucker, J. Arkani-Hamed, and D.E. Alsdorf (1995) Global vector and scalar Magsat magnetic anomaly maps, Journal of Geophysical Research - Solid Earth, 100, 20111-20136
  • Ravat, D., W.J. Hinze, and P.T. Taylor (1993) European tectonic features observed by Magsat, Tectonophysics, 220, 157-173
  • Ravat, D. and W.J. Hinze (1993) Considerations of variations in ionospheric field effects in mapping equatorial lithospheric Magsat anomalies, Geophysical Journal International, 113, 387-398
  • Taylor, P.T., W.J. Hinze, and D. Ravat (1992) The Search for Crustal Resources: Magsat and Beyond, Adv. Space Res., 12, (7)5-(7)15
  • Ravat, D., W.J. Hinze, and R.R.B. von Frese (1992) Analysis of MAGSAT Magnetic Contrasts across the African and South American Lithospheric Plates, Tectonophysics, 212, 59-76
  • Hinze, W.J., R.R.B. von Frese, and D. Ravat (1991) Mean Magnetic Contrasts between Oceans and Continents, Tectonophysics, 192, 117-128
  • Ravat, D., W.J. Hinze, R.R.B. von Frese (1991) Lithospheric Magnetic Property Constrasts within the South American Plate Derived from Damped Least-Squares Inversion of Satellite Magnetic Data, Tectonophysics, 192, 159-168
  • Goyal, H.K., R.R.B. von Frese, W.J. Hinze, and D. Ravat (1990) Statistical Prediction of Satellite Magnetic Anomalies, Geophysical Journal International, 102, 101-111
  • von Frese, R.R.B., W.J. Hinze, C.A. McGue, and D. Ravat (1989) Use of Satellite Magnetic Anomalies for Tectonic Lineament Studies, in Qureshy, M.N., and W.J. Hinze (eds.), Regional Geophysical Lineaments - Their Tectonic and Economic Significance, Geol. Survey of India Memoir, 12, 171-180
  • von Frese, R.R.B., D. Ravat, W.J. Hinze, and C.A. McGue (1988) Improved Inversion of Geopotential Field Anomalies for Lithospheric Investigations, Geophysics, 53, 375-385
  • Ravat, D., L.W. Braile, and W.J. Hinze (1987) Earthquakes and Plutons in the Midcontinent - Evidence from the Bloomfield Pluton, Seismological Research Letters, 58, 41-52
Honors

Outstanding Alumnus Award from Purdue University Department of Earth & Atmospheric Sciences and the College of Science

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