TABLE OF FIGURE

II.1. Variation of water resistivity with concentration ..3

of dissolved NaCl II.2. Archies law variation of bulk resistivity....4 III.1. Some common electrode arrays and their geometric factors................6 III.2. Variation in gradient array geometric factor ..7 with distance along and across line III.3. Current flow patterns.......3

III.4. Signal contribution sections......4 III.5. layer apparent resistivity type curves ......6

III.6. Relative effect of a thin...7

III.7. Construction of a complete Schlumberger ...7 depth-sounding curve III.8. Offset Wenner sounding...7

III.9. Sequential curve matching7 III.10. Wenner array pseudo-sections...7