Frequency characteristics of geomagnetic induction anomalies in Saurashtra region

  • P V Vijaya Kumar
  • P B V Subba RaoEmail author
  • C K Rao
  • A K Singh
  • P Rama Rao


Magnetovariational studies were carried out along four different EW profiles in Saurashtra region in different phases, during January 2007–March 2012. Transient geomagnetic field variations (X, Y horizontal field and Z vertical field components) recorded along these profiles are analyzed to infer the electrical conductivity distribution of the region. The vertical field transfer functions which depict the characteristics of electrical conductivity distribution are presented in the form of induction arrows. From the spatial distribution of these arrows, it is inferred that the sediments filling the offshore basins have more conductivity than those basins in Saurashtra region. Z/H pseudo sections along the four profiles in conjunction with tectonics and other geophysical methods permit to infer that the conductivity anomaly in the eastern part of the profiles is associated with the crustal/lithosphere thinning. The possible cause for these anomalies may be explained in terms of partial melts associated with mafic intrusions, related to Deccan and pre-Deccan volcanism. High resistive block related to underplating mantle material has been reflected in 1D models of long period magnetotelluric data and its thickness reduces from west to east. Lithosphere–asthenosphere boundary varies from 80 to 100 km.


Magnetovariational studies Saurashtra rifting magmatic underplating transient thermal effects Reunion hotspot 



The authors are grateful to Prof. D S Ramesh, Director, IIG, for his kind interest and constant support and permission to publish this paper. They thank the reviewers for their constructive comments and suggestions that improved the manuscript and the Associate Editor, Prof. N Purnachandra Rao for his encouragement. The authors also wish to thank Mr. N K Gadai and other colleagues of Rajkot Magnetic Observatory, Saurashtra University, for logistic support.


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Copyright information

© Indian Academy of Sciences 2017

Authors and Affiliations

  • P V Vijaya Kumar
    • 1
  • P B V Subba Rao
    • 1
    Email author
  • C K Rao
    • 1
  • A K Singh
    • 1
  • P Rama Rao
    • 2
  1. 1.Indian Institute of GeomagnetismPanvelIndia
  2. 2.Department of GeophysicsAndhra UniversityVisakhapatnamIndia

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