Week 4

Lec: 9/16

• More details on resistivity as an inherent material property.

• Review of Wenner VES sounding - reprocesses out Dog Leg data

• Schlumberger VES sounding concept (see your reading for the Schlumberger geometric factor:

  $$K_{Sch}=\pi \frac{L^2}{2l}$$

  whereas for the Wenner array the geometric factor is:

  $$K_{Wenner}=2\pi a$$

• Briefly mentioned the idea of a CST or constant spread traverse. Note that by employing both VES and CST you can begin to build of two-dimensional sets of image points. You should sketch this.

• Compared the inversions of a W-VES and a Sch-VES from Fall 2024 over a profile near our Wenner VES.

  • We inferred that their differences may be enough to conclude that superimposed on the broadly layered structure we envision at the Dog Leg (why do we envision that?) there is at least one more isolated inhomogeneity of geologic material. But, we don't know where under the profile it would be, or how many others there may be. We just know that something exists. Can you make an informed set of possibilities for what geologic inhomogeneities at the Dog Leg could be?

Lab: 9/17

• Collect a 2D ERT profile at the Dog Leg over the same profile as the Wenner-VES data.

• We have the same goals: layers and their thicknesses and resistivities, what is the bedrock and how deep, where is the best place for a well (note that this requires minimally two-dimensional data)