Introduction to Environmental Geophysics
Geophysics lets us image the subsurface without digging: every method measures a physical field at the surface and infers what property contrasts below could produce it. The central skill of this module is matching the right method to the right problem, because target depth, target size, and property contrast decide what is detectable.
Learning Objectives
Undergraduate Core: By the end of this module, you will be able to:
- Match a subsurface target to the physical property contrast a method senses.
- Explain the trade-off among depth of investigation, resolution, and signal-to-noise ratio.
- Propose a defensible first-pass survey method and spacing for a stated target.
- Distinguish measured data, an inverted physical-property model, and a geological interpretation.
Graduate Extension
Analyze method selection as a non-unique decision problem: compare sensitivity, expected data error, prior information, and the value of collecting complementary data.
Practice this module Teach with active-learning slides
Interactive Lecture
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๐ฅ๏ธ Geophysical Method & Spacing Simulator
Explore how survey geometry and method choice control what you can resolve at depth.
Demo
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โก Depth of Investigation vs. Resolution Explorer
Compare the depth ranges and resolving power of gravity, magnetics, seismic, ERT, EM, and GPR side by side.
Why This Matters: Hydrogeophysics
Turning geophysical images into hydrology
A resistivity or velocity image is only a means to an end. The goal in much of modern near-surface work is to watch water move through the subsurface: soil moisture, groundwater, and the weathered "critical zone" where rock becomes soil. Doing that means combining several methods and linking them to hydrological models.
PyHydroGeophysX, developed in Dr. Chen's group, is built for exactly this. It converts hydrological model outputs (MODFLOW, ParFlow) into ERT, seismic, and EM responses, and inverts field data back to water content.
- Hydrology to multi-method geophysics: one workflow, several methods.
Orientation reading: Binley et al. (2015) and Parsekian et al. (2015) on the References page.
Keep Going
- ๐ Continue with Gravity Methods, the first method module.
- ๐ Set up Google Colab so you are ready for the notebook exercises.