P R E F A C EGratitude belongs only to Almighty God, who has
given his affection to the author for taking the time to complete
the paper titled "Resistivity Method". The author also thank those
who have assisted in the completion of this paper.
The authors are aware that this paper is still far from perfect.
Therefore, the authors expect criticism and suggestions either in
writing or orally, in particular course to the Communication
geophysic technique lecturer. Haddy Suprapto, Dr.Ms, so that
writers can develop science, especially science Geophysical.
Yogyakarta, 17 May 2014 Compiler
FAISAL AHMAD
ABSTRACTResistivity method is one of the geoelectric method used
to study the condition of subsurface flow by studying the
properties electricity in the rock beneath the earth's surface.
Geoelectric method is one of way of geophysical methods to detect
rock layers the subsurface. The value resistivity can be derived
from the value of the current and potential difference from a
variety of different distances electroda. In the resistivity method
is assumed to be homogeneous isotropic earth where resistivity
values measured is not an true value but it is apparent resistivity
values (apparent resistivity). Surface electrical resistivity
surveying is based on the principle that the distribution of
electrical potential in the ground around a current-carrying
electrode depends on the electrical resistivities and distribution
of the surrounding soils and rocks. The usual practice in the field
is to apply an electrical direct current (DC) between two
electrodes implanted in the ground and to measure the difference of
potential between two additional electrodes that do not carry
current. All analysis and interpretation are done on the basis of
direct currents. The distribution of potential can be related
theoretically to ground resistivities and their distribution for
some simple cases, notably, the case of a horizontally stratified
ground and the case of homogeneous masses separated by vertical
planes (e.g., a vertical fault with a large throw or a vertical
dike). For other kinds of resistivity distributions, interpretation
is usually done by qualitative comparison of observed response with
that of idealized hypothetical models or on the basis of empirical
methods.
TABLE OF FIGURE
II.1. Variation of water resistivity with concentration
.....5
of dissolved NaCl II.2. Archies law variation of bulk
resistivity....6 III.1. Some common electrode arrays and their
...............................11 geometric factors III.2.
Variation in gradient array geometric factor ....11 with distance
along and across line III.3. Current flow patterns.....14 III.4.
Signal contribution sections...15 III.5. layer apparent resistivity
type curves .......16 III.6. Relative effect of a thin.....17
III.7. Construction of a complete Schlumberger ...22 depth-sounding
curve III.8. Offset Wenner sounding.....23 III.9. Sequential curve
matching..25 III.10. Wenner array pseudo-sections.....26iii
