Electrical Tomography Software Res2dinv0 pages
ELECTRICAL IMAGING SYSTEM 16G
DATA INVERSION SOFTWARE
FOR ELECTRICAL IMAGING AND
INDUCED POLARIZATION (IP) RES2DINV
This very popular software, developped by M.H.Loke, uses
the method involving the Sasaki minimum squares inversion
(1992) to produce a 2D sub-soil model starting from the
data of apparent resistivity (up to 2000 electrodes). It is
completely automatic and does not require that the user
formulates a starting model. When using a normal computer
equipped with a Pentium' microprocessor, the inversion of
a single pseudosection will require only a few minutes.
RES2DINV supports spreading types like Wenner,
Schlumberger, Pole-Pole, Pole-Dipole, line Dipole, equatorial
Dipole and other non-conventional spreading types. The
program automatically selects the best inversion parameters
for a certain set of data (those parameters may anyway be
modified by the user). Three different versions of the minimum
squares method are available for the inversion: a fast
'almost-Newton* method, a slower and more accurate
'Gauss-Newton* method, and finally a hybrid technique,
rather fast and accurate at the same time.
The 'smoothing* filter may be adjusted in order to emphasize
the variations of relative resistivity in vertical or horizontal
direction; furthermore, it may be optimized for the obtainment
of models with rounded edges (e.g. for pollution plumes in
the ground) or net edges (e.g. for fracture areas).
You may also enter information concerning the electrical
resistivity coming from investigations in wells or from other
sources. Furthermore, three different techniques concerning
topographical correction (Loke 2000) are available. For
Windows 95/98/2000/NT/XP8'
-H.B
■ ' ■ ■
flatticroghan Mound
28. a
60.a
-36.
1.0
3.1;
5-1 ;
Measured Apparent Resistivity Pseudosection
Inverse Model Resistivity Section with topography
Iteration 5 RMS error - 3.S
Elevation
1.6
-1.9
-5.5
-0.0
02.an.
™™™!Z3[ZZIiZZ!I=!iZZ!CZHZZHZZl[=
5B.o -tee see 4ee see lose
_Besistioitu in Ohin.Keter_
3288
eneo
Archaeological research (grave) - Topview: pseudosection of apparent resistivity Downview: Inversion result
evidencing the sepulchral chamber (Waddell, J. and Barton, K, 1955, Seeing beneath Rathcroghan, Archaeology
Ireland, Vol.9, No. 1,38-41)
12.7
42.5
71i.li
Mineral exploration on the Magusi River (apparent
resistivity+IP): a) apparent resistivity b) section of the model
c)apparent'metal factor* d) model of the section (Edwards,
L.S., 1977, A modified pseudosection for resistivity and
nduced-polarization. Geophysics, 42, 1020-1036)
-935.3
-213.4
Hagusi River survey
-91.4 SB.5
152
274
396
112
Measured Apparent Resistivity Pseudosection
5.2
45.2
9B.5
122
Iteration 5 RMS error = 14.S % body 457.2 -335.3 -213.4 -91.4 30 ................ | .5 152 ...... | 27k 396 _^_i_i_._,_:_i_, |
Inverse Model Resistivity Section
■ 1M M B [ZZI [ZZ! IZZJ ZZ3 H IZZJ ZZ] EZZI [ZZI BS
10. B 28.B 48. B 88.a 168 320 648
Resistivity in ohn.M
1280
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