Abstract
The Delhi Seismic Zone (DSZ) is a seismically highly active intraplate region that keeps experiencing recurrent seismicity of minor to moderate nature. The seismic activity in the DSZ in recent times has evoked concerns about the vulnerability of the region due to potential earthquakes. Although the spatial distribution of recorded earthquakes gives a fairly good idea about the zone of the seismicity, the information about the underlying crustal structure and seismogenic faults is largely missing. In the present work, we have revisited the MT data acquired at various locations across Haryana to understand whether there are any anomalous features in the crust that might correlate with the seismicity in the western part of the DSZ. The MT data recorded at six groups of sites yielded good impedance tensors in the period range of 0.001–1000 s. A significant result obtained by 2-D inversion of distortion corrected impedance tensors is the presence of a northward dipping electrical conductor (<10 Ωm) from the surface down to about 20–25 km depth. The surface location of this conductor is in the proximity of the northern edge of the inferred Delhi–Sargodha Ridge. The DSZ earthquakes, when projected onto the MT profile, coincide with the north dipping conductor. We infer that the conductor is possibly extending into the DSZ and has an important role in the occurrence of the seismicity, at least in the western part of the region and that the increased electrical conductivity is possibly due to the presence of crustal fluids.
Similar content being viewed by others
References
Bansal B K and Verma M 2012 The M 4.9 Delhi earthquake of 5 March 2012; Curr. Sci. 102(12) 1704–1708.
Becken M and Burkhardt H 2004 An ellipticity criterion in magnetotelluric tensor analysis; Geophys. J. Int. 159 69–82.
Caldwell T G, Bibby H M and Brown C 2004 The magnetotelluric phase tensor; Geophys. J. Int. 158 457–469.
Chopra S 1990 A geological cum geomorphological framework of Haryana and adjoining areas for land use appraisal using landsat imagery; J. Ind. Soc. Remote Sens. 18(1&2) 15–22.
Chouhan P K S, Mohanty W K and Roonwal G S 1998 In: The Indian Precambrian (ed.) Paliwal B S, Sci. Publish. Jodhpur, pp. 523–530.
Datta A K and Sastri V V 1977 Tectonic evolution of the Himalaya and the evaluation of petroleum prospects of the Punjab and Ganga Basins and the Foot Hill Belt; Him. Geol. 7 296–325.
Demudu Babu M, Manglik A, Thiagarajan S and Suresh M 2020 Electrical resistivity image of a basement ridge in the foreland central Ganga basin; J. Appl. Geophys. 104097.
Dwivedi D, Chamoli A and Pandey A K 2019 Crustal structure and lateral variations in Moho beneath the Delhi fold belt, NW India: Insight from gravity data modelling and inversion; Phys. Earth Planet. Inter. 297 106317.
Gokarn S G, Rao C K and Singh B P 1995 Continental Crust of NW and Central India; Geol. Soc. India Mem. 31 373–381.
GSI-NGRI 2006 Gravity Map Series of India, Geological Society of India and National Geophysical Research Institute, Hyderabad, India.
Gupta A K, Chopra S, Prajapati S K, Sutar A K and Bansal B K 2013a Intensity distribution of M 4.9 Haryana–Delhi border Earthquake; Nat. Hazards 68 405–417.
Gupta S, Mohanty W K, Prakash R and Shukla A K 2013b Crustal Heterogeneity and Seismotectonics of the National Capital Region, Delhi, India; Pure Appl. Geophys. 170 607–616.
Iyenger R N 2000 Seismic status of Delhi megacity; Curr. Sci. 78 568–574.
Iyengar R N and Ghosh S 2004 Microzonation of earthquake hazard in greater Delhi area; Curr. Sci. 87 1193–1202.
Joshi G C and Sharma M L 2008 Uncertainties in the estimation of Mmax; J. Earth Syst. Sci. 117 671–682.
Kamble V P and Chaudhary H M 1979 Recent seismic activity in Delhi and neighborhood; Mausam 30 305–312.
Lilley F E M, Singh B P, Arora B R, Srivastava B J, Prasad S N and Sloane M N 1981 A magnetometer array study in northwest India; Phys. Earth Planet. Inter. 25 232–240.
Mandal B, Sen M K, Vijaya Rao V and Mann J 2014 Deep seismic image enhancement with the common reflection surface (CRS) stack method: Evidence from the Aravalli–Delhi fold belt of northwestern India; Geophys. J. Int. 196(2) 902–917.
Manglik A, Arora T, Thiagarajan S and Mallick A 2009 Intraplate stresses due to crustal heterogeneities along the Nagaur–Jhalawar transect, northwestern India; Curr. Sci. 96(6) 838–843.
Manglik A, Muralidharan D, Arora T, Ramakrishna N, Pavan Kumar G, Mann M, Rajakishore K V and Praveen Kumar 2010a Geophysical investigations of an earth electrode station site at Mohindergarh, Haryana, for 500 kV HVDC transmission system; Tech. Rep. Nr. NGRI-2010-LITHOS-723, 27p.
Manglik A, Arora T, Pavan Kumar G and Swetha G 2010b Geophysical investigations of an earth electrode station site at Bhiwani, Haryana, for 500 kV HVDC transmission system; Tech. Rep. Nr. NGRI-2010-LITHOS-722, 20p.
Manglik A, Pavan Kumar G, Swetha G and Bindu P 2010c Magnetotelluric investigations around Kaithal for an earth electrode station site in Haryana for 500 kV HVDC transmission system; Tech. Rep. Nr. NGRI-2010-LITHOS-736, 21p.
Manglik A, Adilakshmi L, Suresh M and Thiagarajan S 2015 Thick sedimentary sequence around Bahraich in the northern part of the central Ganga foreland basin; Tectonophys. 653 33–40.
Mishra D C, Singh B, Tiwari V M, Gupta S B and Rao M B S V 2000 Two cases of continental collisions and related tectonics during the Proterozoic period in India – insights from gravity modelling constrained by seismic and magnetotelluric studies; Precamb. Res. 99 149–169.
Prakash R and Shrivastava J P 2012 A Review of the Seismicity and Seismotectonics of Delhi and Adjoining Areas; J. Geol. Soc. India 79 603–617.
Prakash R, Singh R K, Shukla A K, Singh D, Rana B S, Jariyal J S, Bhatnagar A K and Bali S 2011 Intensity and isoseismal map of 25th November 2007 Delhi earthquake; Mausam 62 417–424.
Ramachandra Rao M B 1973 The subsurface geology of the Indo-Gangetic plains; J. Geol. Soc. India 14(3) 217–242.
Reuter H I, Nelson A and Jarvis A 2007 An evaluation of void filling interpolation methods for SRTM data;. Int. J. Geogr. Inform. Sci. 21(9) 983–1008.
Rodi W and Mackie R L 2001 Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion; Geophysics 66 174–187.
Shukla A K, Prakash R, Singh R K, Mishra P S and Bhatnagar A K 2007 Seismotectonic implications of Delhi region through fault plane solutions of some recent earthquakes; Curr. Sci. 93(12) 1848–1853.
Sinha-Roy S, Malhotra G and Guha D B 1995 A transect across Rajasthan Precambrian terrain in relation to geology, tectonics and crustal evolution of south-central Rajasthan; Memoir Geol. Soc. India 31 63–89.
Tewari H C, Dixit M M, Rao N M, Venkateswarlu N and Vijaya Rao V 1997 Crustal thickening under the Paleo/Mesoproterozoic Delhi Fold Belt in NW India: Evidence from deep reflection profiling; Geophys. J. Int. 129 657–668.
Thussu J L 2006 Geology of Haryana and Delhi; Geol. Soc. Ind., Bangalore, 191p, ISBN: 81-85867-75-5.
Verma R K, Roonwal G S, Kamble V P and Mohanty W K 1995 Seismicity of Delhi and its surrounding region; Himal. Geol. 6 75–82.
Vijaya Rao V, Rajendra Prasad B, Reddy P R and Tiwari H C 2000 Evolution of Proterozoic Aravalli Delhi Fold Belt in the northwestern Indian shield from seismic studies; Tectonophys. 327 109–130.
Acknowledgements
These results are an offshoot of the MT surveys carried out by CSIR-National Geophysical Research Institute (CSIR-NGRI) under a project sponsored by M/s. Siemens Limited (SL) to investigate HVDC earth electrode station sites in Haryana. We are grateful to SL for sponsoring the project SSP-569-28(AM). AM is thankful to Drs V M Tiwari, D Srinagesh and Vineet K Gahalaut for stimulating discussions on DSZ seismicity. We are thankful to the Editor and an anonymous reviewer for their valuable comments that have helped in improving the manuscript. CSIR-NGRI contribution number (NGRI/Lib/2020/Pub-155) under the project MLP6404-28(AM).
Author information
Authors and Affiliations
Contributions
Ajay Manglik conceived the idea, arranged the MT datasets, and supervised results and manuscript writing. G Pavankumar analyzed datasets, performed inversion, prepared results and wrote the manuscript. M Demudu Babu and N N Chakravarthi digitized datasets, prepared figures, and assisted in manuscript writing.
Corresponding author
Additional information
Communicated by Arkoprovo Biswas
Rights and permissions
About this article
Cite this article
Pavankumar, G., Manglik, A., Babu, M.D. et al. Magnetotelluric evidence for the presence of a deep electrical conductor in the vicinity of the Delhi Seismic Zone, India. J Earth Syst Sci 130, 79 (2021). https://doi.org/10.1007/s12040-021-01565-7
Received:
Revised:
Accepted:
Published:
DOI: https://doi.org/10.1007/s12040-021-01565-7