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Homework #7: Due Saturday March 23 by 12noon.
- sections 5.1 and 5.2
- section 5.3.1, 5.3.2 and 5.3.3. Note especially Eq. (5.8), which is what I used in the example in class, and which is discussed in fig. 5.5
- I can't emphasize enough Eq. (5.15). This is a completely general equation, and is the basis for all 4-electrode (2 current electrodes, 2 potential electrodes) resistivity work.
- section 5.5
- section 5.8.2 These are the 4 basic electrode configurations. Note that th edipole-dipole does not have to have all 4 electrodes co-linear.
- section 5.10 is all about field surveys with examples
That's all for homework #7 (yes, just two problems).
- problem 5.1 Show your work here, and use basic geometry to get the distances between the current electrodes ("C" on the surface) and the potential points ("P" in the subsurface).
- problem 5.14 Use a spreadsheet to do this. Make 3 graphs: ρ vs. z with a linear scale for z; ρ vs. z with a logarithmic scale for z (ask me if you don't know how); and Σρ vs. z with a linear scale for z. You will use the cumulative resistivity graph to get the depth to the top and the bottom of the clay layer. Turn in your graphs and your data table (save paper--print them all on one page). Show your work (lines) on your (cumulative resistivity) graph. Your data table should have 4 columns as we had in class: electrode spacing, resistivity, z, and cumulative resistivity. Center your columns, and have appropriate significant figures for z and Σρ (you'll have to use theirs for a and ρ).