JOURNAL OF THE BALKAN GEOPHYSICAL
SOCIETY, Vol. 1, No 4, November 1998, p. 53-59, 7 figs.
Calculation of the
azimuthal inhomogeneity ratio response of
3-D structures using
an analytical forward modelling scheme
K.M.Ermokhin *, G.N.Tsokas
**, P. Tsourlos **, V.V. Glasunov*
*Geophysical Faculty, St.Petersburg
Mining Institute, St.Petersburg, Russia
**Geophysical Laboratory, Aristotelian
University of Thessaloniki, Thessaloniki 54006,Greece
(Received 17 September 1998; accepted
20 October 1998 )
Azimuthal Inhomogeneity Ratio (A.I.R.) can be obtained by measuring
the three possible modes of connection for resistance measurements
with the square array and it reflects the presence of subterranean
lateral inhomogeneities. The A.I.R. anomalies form a signal of dipolar
pattern and have relatively large amplitude.
The expected A.I.R. pattern
of two models was computed in the framework of the present study
together with the respective resistance anomalies for all three
possible modes. The method of "dipole sources" was applied for the
computation of the response of the 3-D models. The models that simulate
the targets commonly encountered in archaeological exploration were
selected to test the validity of the suggested method.
The calculated A.I.R. patterns
delineate very well the edges of the disturbing bodies. Moreover,
they present an intricate pattern suitable that can be handled by
the pattern recognition schemes.
Key Words: Azimuthal Inhomogeneity
Ratio, Resistivity Modelling, Dipole Sources.