58358 - Earth Physics

Learning outcomes

At the end of the course the student has the basic knowledge of the structure and dynamics of the Earth, the gravitational field and the magnetic field of the Earth.

Course contents

The course provides the basic knowledge on the shape and dynamics of our planet, in view of the solid Earth and in the context of modern Earth System Physics. In the five parts of the course the structure of the Earth will be described through the study of seismic waves, gravity field, heat flow, rheology and the Earth's magnetic field. Starting from multiple experimental data, the theoretical foundations were laid and the physical models useful for the quantitative analysis of the relevant geodynamic processes are introduced. Pragmatically, case studies and classic examples shall be presented, shedding light on the interconnections between Solid Earth and the various parts of the Earth System. The topics covered in the parts of the course will be seen in the great scenario of Plate Tectonics, which shall be illustrated in its essence.  

Part 1: "Seismic waves, internal structure of the Earth and earthquakes" Recall, Motivations, Stress and deformation, Elastic behaviour, Elastic waves, Volume waves, Surface waves, Densities and elastic constants inside the Earth, Seismic velocities, Wave fronts and rays, Energy of seismic waves, Earthquakes.

Part 2: "The shape of the Earth and its gravity field" Background, Motivations, The gravity field, Mass distributions, Multipoles of a mass distribution, Moments of inertia, The gravitational field, The gravity field and the shape of the Earth, Anomalies of gravity, Isostasy, Flexion of the lithosphere.

Part 3: "The thermal structure and rheological behavior of the Earth" Terrestrial heat flux, Conduction and convection, Stationary one-dimensional conduction and continental geothermal, Cooling of a half-space, Subsolar temperatures, Oceanic lithosphere, Topography of ocean floors.

Part 4: "Rheology of the earth" Basics of rheology, Elastic behavior, Newtonian fluid behavior, Plastic and non-Newtonian behavior, Maxwell's visco-elastic model, Stationary and transient rheological models, The Kelvin-Voigt element, Generalized Maxwell bodies.

Part 5: "The Earth's magnetic field" Introductory notes, observations, historical digression and motivations, Elements of the Earth's magnetic field, Magnetostatics and dipolar magnetic field, The magnetosphere, Temporal variations of the Earth's magnetic field, Origin of the Earth's magnetic field.

Readings/Bibliography

The slides can be used as study texts, if accompanied by in-depth readings recommended by the teacher. Texts and online resources will be suggested (scientific articles, tools and web sites of interest for understanding the interactions between the Solid Earth and the various components of the Earth System), useful as a complement to the lessons. Lecture notes.

Teaching methods

Classroom lessons in which students actively participate, taking part in discussions on the topics covered.

Assessment methods

The verification consists of a final oral exam, fixed by appointment with the teacher. The student will be asked to discuss three topics among those covered in the course. The student will be able to prepare one of the three topics in the form of a short written dissertation.

Teaching tools

Computer and beamer, blackboard.

Office hours

See the website of Giorgio Spada