delineation of electrical resistivity structure using magnetotellurics: a case study from dholera...
DESCRIPTION
Electromagnetic (EM) induction technique is one of the most important geophysical techniques in understanding thesubsurface structure. The magnetotelluric (MT) method uses naturally occurring electromagnetic (EM) waves assources to map the resistivity structure. MT time-series data are decomposed into spectra, providing “apparentresistivity” as a function of frequency. The depth of penetration is inversely proportional to frequency and theconductivity of the subsurface; thus lower frequencies can be used to map the deeper resistivity structures. During theperiod, we have carried out MT investigation in Dholera Special Economic Zone (SEZ) situated in south Gujarat,Sourasthra with an objective of delineating the electrical resistivity structure of the region using broadbandmagnetotelluric investigations and to map the sedimentary thickness of the region and the basement depth. Naturalelectromagnetic signal in the form of time series are recorded in broad-frequency range (1000Hz-1000sec) along thegeological strike of the region. The MT time series is processed by the processing software (Mapros) through whichapparent resistivity and phase vs. period curves are obtained. The resultant curves are used as the input for inversionroutine implemented in data interpretation software ‘WingLink’. The resultant geoelectric structure of the region fromthe Bostick inversion infers the sedimentary thickness of about 200-300 m (might be a mixture of saline water withsediments) with a resistivity of 0.1-1.5 ohm.m overlaying by a basement of resistivity 20k ohm-m with a thickness of32-35 km.TRANSCRIPT
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5/28/2018 Delineation of electrical resistivity structure using Magnetotellurics: a case study from Dholera coastal region, Gujarat, India
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*Corresponding author, E-mail address: [email protected]
Phone: +91 9566928959
2014 Journal of Coastal Sciences. All rights reserved
: ...
: 2348 6740 1 . 1 2014 4146
A B A C A I C L E I N F
28 2013
4 2014 7 2014
Dholera
Gujarat
India
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