Studies on multiple electric discontinuities and dipping anisotropic conditions using multifrequency magnetotellurics

• Autorzy: Nagubai D. , Saraf P.
• Języki publikacji: EN

Abstrakty

EN

The Earth is characterized by many irregulars in its physical parameters. Recent deep EM and MT investigations have established that the upper crustal layers are inhomogeneous and anisotropic in their electrical properties. The problem of incorporating inhomogeneities (both in vertical and horizontal directions) is of considerable interest to geophysicists. Hence, an attempt has been made to compare the influence of dipping anisotropy in layers at different depth. Emphasis has also been given to explore the approximate frequency ranges needed to resolve the anisotropy in the subsurface layers at different depths. To achieve this, several numerical studies have been carried out in a three-layer Earth model for different meaningful combinations of thickness of the layers, conductivities, and frequencies of the EM wave parameters Our results show that the negligence of anisotropy nay produce serious errors in delineating subsurface structures. It is also shown that the electrical discontinuities played a major role in mapping anisotropic and dipping subsurface conditions.

Słowa kluczowe

EN

multiple electrical discontinuities; multifrequency magnetotellurics

• Wydawca: Instytut Geofizyki PAN
• Czasopismo: Acta Geophysica Polonica
• Rocznik: 2003
• Tom: Vol. 51, nr 3
• Strony: 323--335
• Opis fizyczny: Bibliogr. 5 poz.

Twórcy

autor

Nagubai D.

• National Geophysics Research Institute Hyderabad - 500 007, India

autor

Saraf P.

• National Geophysics Research Institute Hyderabad - 500 007, India

Bibliografia

• 1. Eramanko, A.N., and A.K. Datta, 1968, Tectonic framework of outer Himalayas (India), Oil. Naturl. Gas Bull. 4, 65-73.
• 2. Negi, J.G., and P.D. Saraf, 1973, Inductive sounding of a stratified earth with transition layer resting on dipping anisotropic beds, Geophys. Prosp. 21, 635-646.
• 3. Negi, J.G., and P.D. Saraf, 1976, Possibility of deep crustal probing in orogenic regions by studying variations of the surface impedance parameter of natural electromagnetic fields, Radio Science 11, 787-793.
• 4. Negi, J.G., and P.D. Saraf, 1989, Anisotropy in Geo-electromagnetism, Elsevier, Amsterdam.
• 5. Saraf, P.D., and J.G. Negi, 1986, On mapping multiple electrical discontinuities associated with deep seated anisotropic oblique zones using magnetotelluric frequency sounding, Phys. Earth Planet. Inter. 44, 324-331.