GEOPHYSICAL RESEARCH, 2017, vol. 18, no. 3, pp. 81-94. DOI: 10.21455/gr2017.3-7
UDC 550.837
Abstract References Full text (in Russian)
FEATURES OF REGIONAL AND LOCAL COAST EFFECTS IN MAGNETOTELLURIC FIELD OF KAMCHATKA
Yu.F. Moroz(1,2), O.M. Samoylova(1)
(1) Institute of Volcanology and Seismology FEB RAS, Petropavlovsk-Kamchatsky, Russia
(2) Institute of Geology SB RAS, Ulan-Ude, Russia
Abstract. The results of three dimensional numerical modeling of Kamchatka magnetotelluric (MT) field are considered in the study of three dimensional coast effect. We used two models. The first one has conductivity rising with the depth, the second one includes conductive layer in the crust. We attempted to divide the coast effect into regional and local components and present the analysis of MT polar diagrams that characterize the medium dimensionality at the boundary between the Okhotsk Sea and Pacific Ocean and the distant coastline. Also we give detailed description of modelled amplitude and phase MT curves obtained in western, central, southern, and eastern Kamchatka areas. The behavior of these curves outlines peculiarities of regional and local coast effects. The periods of the coast effect manifestation are determined and possible reasons for its origin are discussed.
Kewwords: magnetotelluric sounding, impedance tensor polar diagrams, conductivity, coast effect.
References
Berdichevsky, M.N. and Dmitriev, V.I. Models and Methods of Magnetotellurics, Berlin: Springer, 2008.
Berdichevsky M.N., Koldaev D.S., and Yakovlev A.G. Magnetotelluric soundings of an oceanic coast, Izv. Phys. Solid Earth, 1992, no. 6, pp. 87-96.
Berdichevsky M.N., Vanyan L.L., and Nguen Than Van. Polar phase diagrams of MT impedance, Izv. Phys. Solid Earth, 1993, no. 2, pp. 19-28.
Geologya SSSR. Severo-Vostok SSSR. Geologycheskoe opysanie (Geology of the USSR. North-East of the USSR. Geological description), vol. 30, book I, Moscow: Nedra, 1970a.
Geologya SSSR. Severo-Vostok SSSR. Geologycheskoe opysanie (Geology of the USSR. North-East of the USSR. Geological description), vol.30, book II, Moscow: Nedra, 1970b.
Mackie K.L., Smith J.T., and Madden T.R. Three-dimensional electromagnetic modeling using finite difference equations: the magnetotelluric example, Radio Science, 1994, no. 4, pp. 923-935.
Moroz Yu.F. Electroprovodnost zemnoi kory i verhnei mantii Kamchatky (Conductivity of Kamchatka crust and upper mantle), Moscow: Nayka, 1991.
Moroz Yu.F. and Kobzova V.M. Physical and numeric modeling of the magnetotelluric field of Kamchatka, Volcan. Seismol., 1994, no. 2, pp. 86-98.
Moroz Yu.F. and Moroz T.A., Numerical 3D modeling of the magnetotelluric field in Kamchatka, Izv. Phys. Solid Earth, 2011, vol. 47, no. 2, pp. 138-146.
Parkinson W.D. The influence of continents and oceans on geomagnetic variations, Geophys. J. Roy. Astr. Soc., 1962, vol. 6, pp. 441-449.
Parkinson W.D. and Jones F.W. The geomagnetic coast effect, Reviews of geophysics and space physics, 1979, vol. 17, no. 8, pp. 1999-2015.
Seliverstov N.I. Podvodnye morphostructury Kurilo-Kamchatskoi i Aleutskoi ostrovnyh dug (Underwater morphostructures of Kurilo-Kamchatskaya and Aleutstkaya island arc). Petropavlovsk-Kamchatskii: IVS FEB RAS, 2013.
Smirnov Ya.B. Karta glubinnyh temperatur territorii SSSR i sopridelnykh raionov v masshtabe 1:100000 (Map of deep temperatures of USSR territories and adjacent regions in scale of 1:100000), Мoscow: GUGL, 1980.
Vanyan L.L. Electromagnitnye zondirovaniya (Electromagnetic soundings), Moscow: Naychnyi mir, 1977.
Vanyan L.L. and Shilovskii P.P. Glubinnaya electroprovodnost okeanov i kontinentov (Deep conductivity of oceans and continents), Moscow: Nayka, 1983.
Varentsov Iv.M., Golubev N.G., Gordienko V.V., and Sokolova E.Yu. Study of the deep geoelectrical structure along Linkoln Line profile (EMSLAB experiment), Izv. Phys. Solid Earth, 1996, no. 4, pp. 124-144.