Titre du document / Document title
An analysis of magnetotelluric (MT) data over geothermal region of Bakreshwar, West Bengal
Auteur(s) / Author(s)
SINHARAY Rajib K. (1) ;
SHALIVAHAN (1) ;
BHATTACHARYA Bimalendu B. (1) ;
Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)
(1) Department of Applied Geophysics, Indian School of Mines, Dhanbad - 826004, INDE
Résumé / Abstract
Magnetotelluric (MT) reconnaissance survey has been carried out over the geothermal region of Bakreshwar, West Bengal to study the resistivity, strike direction and dimensionality of the subsurface conductivity structure. This paper is an effort to get most from the already acquired data before planning for more data. The results of sequential analysis of polar diagrams, Swift's strike, rotation angle, tipper magnitude and skew have been presented for three MT soundings: (1) 500 m NE, (2) 1.2 km SW and (3) 9 km away in NE direction from the hot spring respectively. 1-D models have been prepared by very fast simulated annealing (VFSA), a nonlinear inversion technique, for both transverse electric (TE) and transverse magnetic (TM) modes and their resolutions at different depths have been compared. The nearest sounding to the hot spring shows two low resistive zones of about 100 ohm-m and 15 ohm-m at a depth of about 8 km and 12 km respectively in TM mode. The thicknesses of these two low resistive zones are 2.3 km and 3.4 km respectively. These zones, however, are local in nature as they are not seen even in the sounding 1.2 km away on the other side of the hot spring. It is seen that the TM mode gives better resolution at shallower depths than TE mode. Tipper and skew parameters indicate that near surface structure is 1-D or 2-D in nature but for larger depths it is 3-D in nature.
Revue / Journal Title
Journal of geophysics
ISSN
2230-9497
Source / Source
2001, vol. 22, n
o1, pp. 31-39 (10 ref.)
Langue / Language
Anglais
Editeur / Publisher
Association of Exploration Geophysicists, Hyderabad, INDE
(1997)
(Revue)
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Localisation / Location
INIST-CNRS, Cote INIST : 20057, 35400009928871.0050
Nº notice refdoc (ud4) : 1145977
