Regional and residual gravity anomaly separation using the singular spectrum analysis-based low pass filtering: a case study from Nagpur, Maharashtra, India
K. Satish Kumar 1 Rekapalli Rajesh 1 2 Rama Krishna Tiwari 1
+ Author Affiliations
- Author Affiliations
1 Council of Scientific and Industrial Research – National Geophysical Research Institute, Hyderabad 500 007, India.
2 Corresponding author. Email: rekapalli@gmail.com
Exploration Geophysics 49(3) 398-408 https://doi.org/10.1071/EG16115
Submitted: 6 October 2016 Accepted: 12 April 2017 Published: 13 June 2017
Abstract
We present here a singular spectrum analysis (SSA)-based low pass filtering algorithm for regional and residual gravity anomaly separation. The data adaptive decomposition in SSA frequency filtering algorithm facilitates reduction of the artefacts in the filtering of the non-linear and non-stationary gravity data. Initially, the method was tested on synthetic gravity data representing combined response of regional and residual components derived from the geological structures like infinite horizontal layers, intrusive dykes, deep-seated faults and volcanic intrusive bodies and compared with fast Fourier transform (FFT) wavenumber and wavelet-based filtering techniques. The results show that SSA-based filtered output exhibits a better match with pure synthetic data than the output generated from the FFT and wavelet filtering methods. The underlying method was then applied to two parallel gravity profiles of real data from the Umred coalfield, Nagpur, Maharashtra, India. Further, the SSA-based filtered regional anomaly was modelled using Geosoft GM-SYS software to construct the model of crustal structure of the study region. In essence, the modelling results suggest the following: (i) a basin-type graben structure with variable trap and sedimentary thicknesses and (ii) deep seated faults on either sides of the basin. These results correlate fairly well with known regional geology attesting the authenticity of the regional models generated from the two gravity profiles, which also agree well with each other. We, therefore, conclude that the SSA-based filtering technique is robust for regional gravity anomaly separation and could be effectively exploited for filtering other geophysical data.
Key words: gravity anomaly, regional and residual anomalies, SSA filtering.
References
Bhattacharyya, B. K., 1966, Continuous spectrum of the total-magnetic field anomaly due to a rectangular prismatic body: Geophysics, 31, 97–121| Continuous spectrum of the total-magnetic field anomaly due to a rectangular prismatic body:Crossref | GoogleScholarGoogle Scholar |
Chamoli, A., Bansal, A. R., and Dimri, V. P., 2007, Wavelet and rescaled range approach for the Hurst coefficient for short and long time series: Computers & Geosciences, 33, 83–93
| Wavelet and rescaled range approach for the Hurst coefficient for short and long time series:Crossref | GoogleScholarGoogle Scholar |
Daubechies, I., 1992, Ten lectures on wavelets, CBMS-NSF conference series in applied mathematics: Society for Industrial and Applied Mathematics.
De, S., Ghosh, D., and Rao, K. J., 1982, Report on geophysical investigations for delineating Gondwana below traps in Umred trough in NW extension for Wardha valley coal field, Nagpur district, Maharashtra: Unpublished Report, Geological Survey of India.
DGM, 2009, Report on exploration for coal in Dahegaon-Makardhokada, Block-IV, Umred coal field district, Nagpur. Unpublished report.
Fedi, M., and Quarta, T., 1998, Wavelet analysis of the regional-residual and local separation of potential field anomalies: Geophysical Prospecting, 46, 507–525
| Wavelet analysis of the regional-residual and local separation of potential field anomalies:Crossref | GoogleScholarGoogle Scholar |
Geosoft, 2008, Oasis Montaj, GM-SYS version 7.0: gravity and magnetic modelling software user guide: Geosoft, Inc.
Ghil, M., Allen, M. R., Dettinger, M. D., Ide, K., Kondrashov, D., Mann, M. E., Robertson, A. W., Saunders, A., Tian, Y., Varadi, F., and Yiou, P., 2002, Advanced spectral methods for climatic time series: Reviews of Geophysics, 40, 3-1–3-41
| Advanced spectral methods for climatic time series:Crossref | GoogleScholarGoogle Scholar |
Golyandina, N., Nekrutkin, V. V., and Stepanov, D. V., 2003, Variants of the Caterpillar SSA-method for analysis of multidimensional time series [in Russian]. Availalable at: http://www.gistatgroup.com/cat/
Hahn, A., Kind, E. G., and Mishra, D. C., 1976, Depth estimation of magnetic sources by means of Fourier amplitude spectra: Geophysical Prospecting, 24, 287–306
| Depth estimation of magnetic sources by means of Fourier amplitude spectra:Crossref | GoogleScholarGoogle Scholar |
Hassani, H., Mahmoudvand, R., and Zokaei, M., 2011, Separability and window length in singular spectrum analysis: Comptes Rendus Mathematique, 349, 987–990
| Separability and window length in singular spectrum analysis:Crossref | GoogleScholarGoogle Scholar |
Hassani, H., Heravi, S., and Zhigljavsky, A., 2013, Forecasting UK industrial production with multivariate singular spectrum analysis: Journal of Forecasting, 32, 395–408
| Forecasting UK industrial production with multivariate singular spectrum analysis:Crossref | GoogleScholarGoogle Scholar |
Jogarao, M. V., Ghatak, S. K., and Rammohan, P. K., 1975, Progress report on reconnaissance gravity, magnetic and electrical resistivity surveys for coal in the Chandra-Wardha valley coal fields area, Chandrapur district, Maharashtra: Unpublished Report of the Geological Survey of India.
Jogarao, M. V., Pathak, C. S., Ghosh, D., and Ghosh, D. C., 1984, Report on geophysical surveys to trace Gondwana below Deccan traps under project deep geology in Hinganghat area of Wardha valley, Chandrapur district, Maharashtra: Unpublished Report of the Geological Survey of India.
Kailasam, L. N., 1948, Report on electrical resistivity surveys of the Kamptee coal field area, Nagpur district, Maharashtra: Unpublished Report of the Geological Survey of India.
Kumar, D., Bastia, R., and Guha, D., 2004, Prospect hunting below Deccan basalt: imaging challenges and solutions: First Break, 22, 35–39
| Prospect hunting below Deccan basalt: imaging challenges and solutions:Crossref | GoogleScholarGoogle Scholar |
Mallat, S., 1989, A theory for multiresolution signal decomposition: the wavelet representation: IEEE Transactions on Pattern Analysis and Machine Intelligence, 11, 674–693
| A theory for multiresolution signal decomposition: the wavelet representation:Crossref | GoogleScholarGoogle Scholar |
Meyer, Y., 1995, Wavelets and operators (Vol. 1). Cambridge University Press.
Naidu, P. S., 1970, Statistical structure of aeromagnetic field: Geophysics, 35, 279–292
| Statistical structure of aeromagnetic field:Crossref | GoogleScholarGoogle Scholar |
Naskar, D. C., and Saha, D. K., 2015, Geophysical investigations for delineation of Gondwana sediments below Deccan trap beyond the western limit of Wardha Valley coalfields, Yeotmal and Wardha districts, Maharashtra: a comprehensive analysis of case studies: Journal of the Indian Geophysical Union, 19, 433–446
Padilha, A. L., Trivedi, N. B., Vitorello, I., and da Costa, J. M., 1992, Upper crustal structure of the northeast Parana Basin, Brazil, determined from integrated magnetotelluric and gravity measurements: Journal of Geophysical Research, 97, 3351–3365
| Upper crustal structure of the northeast Parana Basin, Brazil, determined from integrated magnetotelluric and gravity measurements:Crossref | GoogleScholarGoogle Scholar |
Prieto, C., Perkins, C., and Berkman, E., 1985, Columbia River basalt plateau – an integrated approach to interpretation of basalt-covered areas: Geophysics, 50, 2709–2719
| Columbia River basalt plateau – an integrated approach to interpretation of basalt-covered areas:Crossref | GoogleScholarGoogle Scholar |
Raja Rao, C., 1982, Coalfields of India: Geological Survey of India, Bulletin Series A, No. 45.
Rajesh, R., and Tiwari, R. K., 2015, A short note on the application of singular spectrum analysis for geophysical data processing: Journal of the Indian Geophysical Union, 19, 77–85
Rama Krishna, T. S., Ramarao, M. S. V., Bhaskar Rao, K. V. S., and Punekar, D. V., 1999a, Geophysics of the Mahrashtra Gondwana: GSI special publication, 47.
Rama Krishna, T. S., Ramarao, M. S. V., Bhaskar Rao, K. V. S., and Punekar, D. V., 1999b, Geophysics of the Mahrashtra Gondwana: GSI special publication, 49.
Rekapalli, R., and Tiwari, R. K., 2016, Singular spectral analysis based filtering of seismic signal using new Weighted Eigen Spectrogram: Journal of Applied Geophysics, 132, 33–37
| Singular spectral analysis based filtering of seismic signal using new Weighted Eigen Spectrogram:Crossref | GoogleScholarGoogle Scholar |
Rekapalli, R., Tiwari, R. K., Dhanam, K., and Seshunarayana, T., 2014, T-x frequency filtering of high resolution seismic reflection data using singular spectral analysis: Journal of Applied Geophysics, 105, 180–184
| T-x frequency filtering of high resolution seismic reflection data using singular spectral analysis:Crossref | GoogleScholarGoogle Scholar |
Sarma, S. V. S., Harinarayna, T., Virupakshi, G., Someswara Rao, M., Rao, M., Nagarajan, N., Sastry, T. S., and Rao, S. P. E., 2004, Magnetotelluric investigations in Deccan trap covered areas of Nagpur-Wardha region, India: Journal of Geophysics, XXV, 87–91
Skeels, D. C., 1967, What is residual gravity?: Geophysics, 32, 872–876
| What is residual gravity?:Crossref | GoogleScholarGoogle Scholar |
Spector, A., and Grant, F. S., 1970, Statistical models for interpreting aeromagnetic data: Geophysics, 35, 293–302
| Statistical models for interpreting aeromagnetic data:Crossref | GoogleScholarGoogle Scholar |
Stanley, W. D., Saad, A. R., and Ohofugi, W., 1985, Regional magnetotelluric surveys in hydrocarbon exploration, Parana Basin, Brazil: AAPG Bulletin, 69, 344–360
Talwani, M., and Heirtzler, J. R., 1964, Computation of magnetic anomalies caused by two dimensional bodies of arbitrary shape, in G. A. Parks, ed., Computers in the mineral industries, part 1: Stanford University Publications in the Geological Sciences, 9, 464–480.
Talwani, M., Worzel, J. L., and Landisman, M., 1959, Rapid gravity computations for two dimensional bodies with application to the Mendocino submarine fracture zone: Journal of Geophysical Research, 64, 49–59
| Rapid gravity computations for two dimensional bodies with application to the Mendocino submarine fracture zone:Crossref | GoogleScholarGoogle Scholar |
Won, I. J., and Bevis, M., 1987, Computing the gravitational and magnetic anomalies due to a polygon: algorithms and FORTRAN subroutines: Geophysics, 52, 232–238
| Computing the gravitational and magnetic anomalies due to a polygon: algorithms and FORTRAN subroutines:Crossref | GoogleScholarGoogle Scholar |