Define, derive and analyse the impact of lateral inhomogeneities and anisotropy on propagation and scattering of seismic waves and generation of coda waves. Analyse and discuss local coda waves. Describe generation and derive the equations of free oscillations of the Earth. Discussion of characteristics of free oscillations of the Earth.
Fundamentals of theory of scattering of elastic waves in inhomogeneous media. Coda waves of local earthquakes. Quality factor (Qc) of coda waves, measurements and interpretation. Dependence of Qc on frequency and elapsed time. Seismic anisotropy. Tensor ofelasticity and fundamental properties of seismic plane waves in homogeneous anisotropic media. Equations of motion in 1-D and 2-D and in Earth as a uniform elastic sphere. Determination of eigen values and eigen functions of free oscillations. Spherical harmonics.
After completing the course Seismology IV (6 ECTS) the student should be able to:
1. Outline generation and characteristics of local coda waves.
2. Measure, calculate and interpret Qc of coda waves.
3. Analyse frequency and time dependence of the Qc factor.
4. Discriminate isotropic and anisotropic media.
5. Describe seismic anisotropy and its causes.
6. Define anisotropic structures in Earth's crust and mantle.
7. Define and describe basic systems of symmetry important for seismology.
8. Derive and discuss equations of free oscillations of Earth.
Attending of lectures, study notes and study literature.Derivation of the equations and analysis of examples.
- Lectures, discussion.
- Derivation of the equations.
- Solving problems regarding determination of Qc quality factor of coda waves.
- Teleseismic shear wave splitting analysis
METHODS OF MONITORING AND VERIFICATION:
Homework, oral exam.
TERMS FOR RECEIVING THE SIGNATURE:
Solved 2 homework assignments, and 2 problems solved. Oral exam.
- Aki, K., P.G. Richards: Quantitative Seismology, 2nd Ed., University Science Books, Sansalito, California 2002.
- Sato, H., M. C. Fehler: Seismic Wave Propagation and Scattering in the Heterogeneous Earth, Springer Verlag, Berlin 1997.
- Stein, S. & Wysession: An introduction to Seismology, Earthquakes and Earth Structure, Blackwell Publ. 2003.