+ Site Statistics
References:
52,572,879
Abstracts:
28,705,754
PMIDs:
27,750,366
DOIs:
25,464,004
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Magnetovariational sounding; new possibilities



Magnetovariational sounding; new possibilities



Izvestiya - Russian Academy of Sciences Physics of the Solid Earth



Geoelectric research provides unique information on the stratification of the Earth and its deep structures. A basic geoelectric method is believed to be magnetotelluric sounding (MTS), underlain by the inversion of frequency responses of the impedance tensor, which are determined from the electric and magnetic fields. The MTS data interpretation is complicated due to near-surface inhomogeneities distorting the electric field. Modern geoelectric methods allow more or less reliable identification of these distortions and their elimination. The MTS method is complemented by magnetovariational profiling (MVP) using the tipper (the Wiese-Parkinson vector), which is determined from the magnetic field alone. The MVP role reduces to the recognition and localization of geoelectric structures disturbing the horizontal homogeneity of the medium studied. However, the theorem of uniqueness proved in this paper for the 2-D magnetovariational inversion problem indicates that the tipper not only reflects the geoelectric asymmetry of the medium but also provides constraints on its stratification, i.e., enables the construction of layered inhomogeneous sections. Thus, local magnetovariational sounding (MVS) based on the straightforward inversion of frequency responses of the tipper can be applied together with the MTS. The main distinctive MVS feature is the fact that distortions of the magnetic field caused by near-surface inhomogeneities attenuate with decreasing frequency and do not spoil the information on deep structures. Evidently, local MVS allows one to avoid the difficulties inherent in the MTS due to the near-surface distortion of apparent resistivity curves, which are constructed from frequency responses of the impedance tensor. We arrive at the conclusion that MVS can substantially improve the reliability of geoelectric reconstructions. In this respect, several problems related to the combination of the MVS and MTS methods arise. In this paper, we analyze an MVS-MTS complex in which the MVS plays the role of a basic method and the MTS is employed for checking and refining MVS data. An algorithm based on the principle of successive inversions is proposed for the integrated interpretation of MVS and MTS characteristics. The paper consists of theoretical and experimental parts. The uniqueness theorem is proven in the theoretical part for the 2-D MVS inversion problem. The experimental part of the paper describes model experiments on the interpretation of MVS and MTS synthetic data and presents a geoelectric model of the Cascadian subduction zone constrained primarily by MVS data.

Please choose payment method:






(PDF emailed within 1 workday: $29.90)

Accession: 019361275

Download citation: RISBibTeXText


Related references

Mathematical modeling of a source in the auroral zone in order to evaluate the possibilities of local magnetovariational sounding. Physics of the Solid Earth: 1, Pages 839-841. 1979., 1979

Results of magnetovariational sounding in Cuba. Physics of the Solid Earth 15(5): 377-380, 1979

Deep magnetovariational sounding in Pribaikalia. Pages 184-193 1967, 1967

Magnetovariational sounding in the Baikal region. Abstracts - Workshop on Electromagnetic Induction in the Earth and Moon 9: 93, 1988

Magnetovariational gradient sounding the Tyrrhenian Basin. Physics of the Solid Earth 31(4): 352-355, 1995

Experimental data on global magnetovariational sounding. Geomagnetism and Aeronomy 26(1): 98-102, 1986

Effect of the world ocean on the results of global magnetovariational sounding. Physics of the Solid Earth 17(7): 519-523, 1981

Magnetovariational sounding of the Earth using observatory and MAGSAT satellite data. Physics of the Earth and Planetary Interiors 78(1-2): 119-130, 1993

The effect of the relief of high-impedance basins on magnetovariational sounding curves. Physics of the Solid Earth: , Pages 353-359. 1977., 1977

On the radial geoelectrical structure of the mid-mantle from magnetovariational sounding using MAGSAT data. Journal of Geomagnetism and Geoelectricity 45(11-12): 1415-1423, 1993

Electromagnetic depth-sounding possibilities for groundwater in India. Pages 153-168 1975, 1975

Possibilities and limitations for the application of geoelectric vertical sounding on Malta. Geologisches Jahrbuch Reihe E: Geophysik, 1974

Possibilities of using results of seismic sounding to reveal local inhomogeneities. Soviet Geology and Geophysics 30(3): 89-97, 1989

Possibilities of identifying faults by point sounding with refracted waves. Geologiya i Geofizika 1(Pages 92-102, 1967

The possibilities and limitations of the methods for the personality identification from the voice and sounding speech characteristics. Sudebno-Meditsinskaia Ekspertiza 58(4): 32-36, 2015