00903 - Seismology

Learning outcomes

The student acquires knowledge about the theoretical, computational and data-processing aspects of seismology, focusing on the physics of seismic sources and the generation, propagation and recording of seismic waves.

Course contents

Seismology represents one of the fundamental disciplines in the study of Earth sciences as it includes the study of the elastic and inelastic processes that characterize the solid earth and materials, at time scales ranging from microseconds to years.

Seismology also represents an introduction for Earth Physicists to Time Series Analysis and Signal Processing, which take on crucial importance in the training of scientists who want to work at the interface between the solid earth, the atmosphere and marine environments.

Introduction to seismology - topics presented.

Time series analysis: temporal series as a mathematical and physical tool for the study of waves.

Signal processing: creation of time filters and application to geophysical time series.

The seismic source: description of the earthquake as seismic source, the spectrum of seismic waves, magnitude, energy and focal mechanism of earthquakes.

Seismic waves: propagation in inhomogeneous media, seismic rays in the Earth, surface waves and dispersion, absorption of seismic waves, elastic reflection and refraction.

Effects of earthquakes: the Earth's free oscillations, the change in the Earth's rotation due to earthquakes.

Seismic imaging techniques: seismic tomography; use of phase and amplitude information, interferometry and ambient noise tomography.

It is assumed that the student has a good preliminary knowledge of the basic concepts of thermodynamics, fluid mechanics and theory of elasticity.

The course provides the first elements of data processing and computational analysis of signals to the students of the CdS. The topics covered provide the first skills to work in an applied seismological environment, especially in research institutes and companies interested in the assessment of resources and seismic risk.

The course comprises computational laboratories that will provide the first training for students on software and programming languages used by the seismological community.

Readings/Bibliography

Each lesson is delivered by the projection of a file PowerPoint. The collection of files, divided into chapters, contains an exhaustive treatment of the program and can be used as a textbook for the study of the subject. The files in PowerPoint format are available since the beginning of the course and can be reached from the web page of the course.

If students wish to go deeper into the topics of the course, they can consult the following textbooks:

- K. Aki e P. G. Richards, Quantitative Seismology, 2a edizione, University Science Books, Sausalito CA, 2002.

- F. A. Dahlen e J. Tromp, Theoretical Global Seismology, Princeton University Press, Princeton NJ, 1998.

- E. Boschi e M. Dragoni, Sismologia, UTET, Torino, 2000.

- D. Gubbins, Time Series Analysis and Inverse Theory, Cambride University Press, Cambridge UK, 2004.

- T. Lay e T. C. Wallace, Modern Global Seismology, Academic Press, San Diego California US, 1995.

The following books are available by request to lecturers: 

- H. Igel, Computational Seismology, A Practical Introduction, Oxford University Press Books, Oxford UK, 2017.

Teaching methods

The course is presented in the form of a "frontal lectures" accompanied by visual documentation in PowerPoint.

The course includes computer exercises with introductory programming in Julia, Matlab, and Python; relative to these methods, active participation is expected from the attending students.

Assessment methods

The exam will be oral and will generally last about 30 minutes.

The student will be asked to analyse a portion of the seismogram, describing the components that constitute it and connecting it to the theoretical topics covered in the course.

The student will be asked in sequence to illustrate two topics, among those considered in the course. For each topic, the student will be first asked to expose the general framework, then to go into details on some specific aspects.

The student will be requested to know the main equations of the physical theories employed and to know how they are derived; to be able to apply them to specific cases; to know the orders of magnitude of the employed physical quantities.

Teaching tools

The course uses presentations that will have connections to online resources, such as seismological databases and codes, which will contribute to the student's computational and data training.

The exercises include instructions given in advance for installing codes and downloading datasets on a personal computer, for in-class exercises and, optionally, outside of course time.

Office hours

See the website of Luca De Siena