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
23 to 1 2 we will get twice the current density at the centre point. This means that the ascending branch of our sounding graph will continue under an angle of 45° in the bi-log. diagram. If ρ2 has a finite value greater than ρ1 then the sounding graph has to run ρ 2 asymptotically into the horizontal line .Thus the question asked by aid ρ1 of Fig.11 in chapter 1.4. is answered. Since the zooming process is a steady one the sounding graph combining ρ1 and ρ2 asymptotically must be a smooth curve. Any breaks or steps are impossible. On one side this is a great advantage in field work: If the curve on a horizontally layered earth is not a smooth one, it is either disturbed by lateral effects, inho- mogeneities in the underground or mistakes in the record. On the other hand difficulties arise in the interpretation because interfaces of
24 Fig17 layers with different resistivities cannot be seen just looking at the curve (as f.i. possible in refraction seismics from the travel time record). Master
- Page 1 and 2: THE SMOOTH SOUNDING GRAPH A Manual
- Page 3 and 4: Preface 2 This manual shall be a pr
- Page 5 and 6: 1. Basic rules 4 The first chapter
- Page 7 and 8: This current density is marked as j
- Page 9 and 10: 8 Fig.2 Fig.3 Fig.4 Fig.5
- Page 11 and 12: 10 1.3. The four-electrode arrangem
- Page 13 and 14: 12 Fig.6 Fig.7 Fig.8
- Page 15 and 16: 14 If we compare equations (10) and
- Page 17 and 18: Case 2 (Fig. 10) 16 Now we observe
- Page 19 and 20: 1.5. The fundamental principle for
- Page 21 and 22: Case 3 (Fig.14) 20 The electrode di
- Page 23: with just the same factor K. 22 Aft
- Page 27 and 28: 26 Simulating this zooming by enlar
- Page 29 and 30: 28 1.6. Shifting of potential elect
- Page 31 and 32: 30 Fig.21 Fig.22 Fig23
- Page 33 and 34: 32 2.1. How to carry out a field me
- Page 35 and 36: L/2 a/2 1,5 6,28 2 11,8 2,5 18,9 34
- Page 37 and 38: 36 Fig.27 Fig.28 Before we start th
- Page 39 and 40: 38 fence, ditch) especially, if the
- Page 41 and 42: 40 by experience. The measurement i
- Page 43 and 44: 42 2.2. Possible errors influencing
- Page 45 and 46: 2.2.4. Crossing a ditch (Fig.26/29)
- Page 47 and 48: 46 accuracy is not so important the
- Page 49 and 50: 2.2.8. Insulation and leakage curre
- Page 51 and 52: 50 Fig.31. They are ascending with
- Page 53 and 54: 52 If j' is negative, i.e. the dist
23<br />
to 1<br />
2 we will get twice the current density at the centre point. This means<br />
that the ascending branch of our sounding graph will continue under an<br />
angle of 45° in the bi-log. diagram.<br />
If ρ2 has a finite value greater than ρ1 then the sounding graph has to run<br />
ρ 2<br />
asymptotically into the horizontal line .Thus the question asked by aid<br />
ρ1<br />
of Fig.11 in chapter 1.4. is answered. Since the zooming process is a<br />
steady one the sounding graph combining ρ1 and ρ2 asymptotically must<br />
be a smooth curve. Any breaks or steps are impossible. On one side this<br />
is a great advantage in field work: If the curve on a horizontally layered<br />
earth is not a smooth one, it is either disturbed by lateral effects, inho-<br />
mogeneities in the underground or mistakes in the record. On the other<br />
hand difficulties arise in the interpretation because interfaces of
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