8.2. ARS study near Moscow (with low anisotropy of morain sediments) -
at the place Alexandrovka.
Near Alexandrovka
place in 200 km from Moscow glacial and moraine sediments are widespread.
In connection with their origin from horizontal water flows or physical
displacement with ice sheet it is possible to assume presence of a weak
anisotropy in such sediments. Therefore we tried to study their anisotropy
with the help of Y-array. The results are shown in fig.1, azimuthal diagrams
are displayed here in three forms: for each MN line and as average diagram
(A). Below there are graphs of some interpretational parameters along profile:
strike azimuths (B), ratio of odd to even harmonics (C) (Bolshakov et al.,
1997). These allow to estimate relative influence of inhomogeneity and
anisotropy. Six graphs of "true" resistivity (longitudinal, transversal
and mean square root of them) for two MN lines are displayed at the next
picture (D). The last graph (E) shows anisotropy coefficient with greater
values at the left part of the profile and the lowest ones at the right
part. The mean value for anisotropy coefficient of glacial sediments is
about 1.05. Such weak anisotropy can be estimated only with non-linear
arrays.
119899, Russia, Moscow, Moscow State University, Geological
Faculty, Department of Geophysics
V.A. Shevnin, I.N. Modin
Tel. & fax: (7-095) 939 49 63
E-mail: sh@geophys.geol.msu.ru
Please feel free to send us
your comments.