Many things are underneath the earth’s surface, hidden from normal view. Geophysical resistivity and induced polarization (IP) imaging allows geoscientists to create pictures of subsurface structures using special equipment. Advanced Geosciences Inc. (AGI) is an example of a company that manufactures these imaging systems.
Geophysical resistivity and IP imaging has many applications, including archeological surveys. Archeologists use resistivity imaging to find archeological remains, such as buried remains beneath ancient dwellings. The AGI website at aitusa.com explains how archeologists use the two-dimensional (2D) imaging systems that the company pioneered.
Cave and Void Detection
Cave and void detection is another popular application for 2D resistivity imaging. Geophysical surveys were used during World War II to find the tunnel used by Germans for V-1 rocket production. Today, scientists use similar geophysical instruments to find caves and other voids under the earth’s surface.
Dam and levee engineers use geophysical imaging to investigate structures and detect leakage. In some cases, this is accomplished through resistivity imaging and spontaneous potential (SP) surveys. Also called self potential, spontaneous potential measures an aspect of the earth’s electromagnetism.
Engineers use resistivity and IP imaging to explore the earth. The images help them see subsurface structures that help them understand bedrock topography. Images on the AGI website show how well engineering drill logs match resistivity images.
Two-dimensional resistivity imaging is also used for environmental surveys. Geophysical imaging systems can detect radioactive waste leakage at disposal sites, pollution at municipal landfills and hydrocarbon contamination beneath old gas stations. The AGI website features several case studies.
Engineers use geophysical resistivity and IP imaging for groundwater exploration programs. By combining arrays, they can produce high-resolution images deep beneath the earth’s surface. Various image colors represent the surface materials, clay levels and bedrock. Several images and case studies appear on agiusa.com.
Marine exploration is another geophysical imaging application. Engineers use imaging surveys to study currents, design marine park water wells, and determine limestone quality in seafront canals. The possibilities are endless.
The imaging systems created by AGI and other companies have many other uses. Bridge and tunnel investigations, groundwater-related subsidence in residential areas, cable installation and pipelines are a just a few examples. Geophysical resistivity and IP imaging can also map the earth’s resources. Visit the Advanced Geosciences website more information.