As an undergraduate student pursuing a degree in theoretical physics at the University of Guelph over a dozen years ago, I would have never expected to find an almost purely classical physics career in the 21st century. However, I had not yet discovered the world of geophysics, which uses the classical field theories of gravity, electromagnetics and wave phenomena to understand the Earth. While such classical subjects are often only starting points for the modern concepts found in many other branches of physics, in geophysics it is these subjects themselves that are really our window into geology.
In a number of ways the discipline of geophysics has many similarities to medical imaging, and in the natural resource business geophysics can be thought of as "preparing for surgery", where geological targets such as mineral deposits, oil & gas reservoirs and fresh water are identified remotely prior to drilling expensive exploration wells. On the smaller scale geophysical methods are often used for archeological, forensic and geotechnical investigations, while on the larger scale geophysics is used to understand such problems as plate tectonics, the composition of the Earth’s core, mantle and lithosphere, and the critical issue of climate change. All of these applications require a strong foundation in physics and a wide spectrum of career opportunities are available in academia, government and industry, ranging from basic earth science research to earthquake hazard assessment all the way to shipwreck exploration.
In this talk I will outline the fundamentals of applied geophysics, focusing on gravity, magnetic, electrical, seismic and ground-penetrating radar methods - the main tools of the exploration geophysicist. I will then describe a short example where we image the internal structure of a seafloor mud volcano located offshore Egypt for the purposes of gas exploration and production. In this problem, Maxwell’s classical equations are central in developing the electromagnetic theory and experiments needed to map the electrical resistivity of the seafloor - a proxy for the presence of hydrocarbons within marine reservoir rocks.