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'

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flatticroghan Mound

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60.a

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Measured Apparent Resistivity Pseudosection

Inverse Model Resistivity Section with topography

Iteration 5 RMS error - 3.S

Elevation

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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

Inverse Model Resistivity Section

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10. B 28.B 48. B 88.a 168 320 648

Resistivity in ohn.M

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