Geophysics 2

The aim of this module is to present the geoelectrical and electromagnetic methods most commonly used today to explore and analyze the subsoil, as well as the basics of seismic reflection. The main differences between these methods depend on the physical parameter measured (electro-magnetic field, electrical resistivity, seismic wave, etc.), the depth of investigation (shallow, semi-deep, deep) and the field of application or purpose (environmental issues, oil and mineral exploration, hydrogeology and thermalism, public works, archaeology and ocean research, volcanology, seismology, etc.). ).
Geoelectric, electromagnetic, magnetic, seismic refraction and georadar methods are mainly used for environmental issues: natural hazards, detection of underground cavities, polluted water tables, etc...
Seismic reflection is the most widely used method for analyzing sedimentary basins, since it can image the subsoil at great depths (up to several tens of kilometers) and with greater resolution than other methods. Among other things, seismic reflection makes it possible to analyze the geometry (structural and stratigraphic) of geological layers in the subsurface, and thus interpret the tectonic-sedimentary evolution of basins and reservoir architecture (2D and 3D models).
The theoretical and practical foundations of these geophysical methods will be covered, from data acquisition and processing to interpretation. Applications will take the form of numerous tutorials and a field day.
Minimum skills to be acquired:
Mastery of the theoretical bases and geophysical methods used in geo-environment.

Basic knowledge of earth sciencesMatrix calculusDifferential and integral calculusDifferential equationsLeast squares method

Geoelectrical methods (electrical resistivity, spontaneous polarization, induced polarization) (10h): physical principles of electrical signals, main applications, introduction to modeling and 1D inversion.
Electromagnetism (low frequency and high frequency) (10h): physical principles of electromagnetic signals, acquisition and processing techniques, introduction to modeling and 1D inversion.
Seismic reflection (10h): acquisition methods and fundamental principles of seismic reflection data processing. Origin and properties of seismic reflections, notions of resolution. Introduction to geological interpretation of seismic data (structural and stratigraphic). Numerous application exercises.