Introduction
- Active and Passive Geophysical Methods
- Advantages and Disadvantages of Each Method
- Electrical Methods Overview
Resistivity Basics
- Current Flow and Ohm's Law
- The Fundamental Electrical Property is Resistivity, NOT Resistance
- Resistivities for Common Earth Materials
- Current Density and Electric Field
- A First Estimate of Resistivity
- Current Flow From Two Closely Spaced Electrodes
- A Practical Way of Measuring Resistivity
Resistivity Surveys and Geology
- Sources of Noise
- Depth of Current Penetration Versus Current Electrode Spacing
- Current Flow in Layered Media
- Variation in Apparent Resistivity: Layered Versus Homogeneous Media
- Current Flow in Layered Media Versus Electrode Spacing
- A Second Example of Current Flow in Layered Media
Resistivity Equipment and Field Procedures
- Equipment
- Survey Types Overview: Soundings and Profiles
- Soundings: Wenner and Schlumberger
- Electrode Spacings and Apparent Resistivity Plots
- Advantages and Disadvantages of Each Survey Type
- Profiles