THE SMOOTH SOUNDING GRAPH. A Manual for Field Work ... - BGR
THE SMOOTH SOUNDING GRAPH. A Manual for Field Work ... - BGR
THE SMOOTH SOUNDING GRAPH. A Manual for Field Work ... - BGR
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Preface<br />
2<br />
This manual shall be a practical guide to surveyors, field operators, tech-<br />
nical assistants, i.e. to all those who have to do the "dirty" work collecting<br />
field data under more or less bad conditions.<br />
Suffering under rough roads, hard climate and very often the lack of suffi-<br />
cient support by local officials a team "is thrown" into an area to be inves-<br />
tigated. Such a team has to provide its office or company with field data.<br />
In our case these field data are so-called resistivity sounding graphs. A<br />
graph is a sequence of data, which can be combined (by hand) to a more<br />
or less smooth curve. This procedure is not possible, if the data <strong>for</strong>m a<br />
"cloud". Knowing that a cloud will not be accepted by the interpreter in<br />
the office the field group has to offer in any case rather smooth curves.<br />
This is their problem. Provided with a map where a grid of measuring<br />
points is plotted -often following the 1 inch-1 mile network- they start.<br />
Comparing their map (usually many years old) they find out, that an ac-<br />
curate measurement with the prescribed lay-out of say 500 m will end in<br />
a lake or in a new industrial plant or in a green paddy-field. The chance of<br />
shifting the measuring point is usually very low, because the grid may not<br />
be disturbed. Now it depends on the conscience of the chief surveyor in<br />
the field, to tell the truth, i.e. that a smooth curve at the prescribed point<br />
and also in its neighbourhood is impossible. His scientific opinion cannot<br />
allow him to "cook data" even when being sure, that the interpreter will<br />
never control him.<br />
Thinking on his own promotion the "field-man" is really in a bad situation.<br />
The authors know from experience collected in many countries all over<br />
the world about just this situation.<br />
In order to make the best of it from the technical point of view this man-<br />
ual was written hoping that it may be a real help.<br />
A short remark has to be added. Only real direct current is concerned<br />
here. There are equipments using alternating current with very low fre-<br />
quencies. Those equipments may get sufficiently good results using rela-