SubjectsSubjects(version: 964)
Course, academic year 2024/2025
   Login via CAS
Modelling Seismic Wave Fields - NDGF003
Title: Modelování seismických vlnových polí
Guaranteed by: Department of Geophysics (32-KG)
Faculty: Faculty of Mathematics and Physics
Actual: from 2023
Semester: both
E-Credits: 3
Hours per week, examination: 2/0, Ex [HT]
Capacity: unlimited
Min. number of students: unlimited
4EU+: no
Virtual mobility / capacity: no
State of the course: not taught
Language: Czech, English
Teaching methods: full-time
Note: you can enroll for the course in winter and in summer semester
Guarantor: RNDr. Luděk Klimeš, DrSc.
Class: DS, geofyzika
Classification: Physics > Geophysics
Annotation -
Viscoelastodynamic equations. seismic model of the medium. Green tensor. Travel times. Initial value ray-tracing. Calculation of ray-theory travel times. Calculation of first-arrival travel times. Ray-theory synthetic seismograms. Accuracy and validity conditions of asymptotic ray methods. Full-wave finite differences in 3-D. Ray method for surface waves in Cartesian and curvilinear coordinates.
Last update: T_KG (10.05.2002)
Aim of the course -

Acquiring knowledge of methods for calculating seismic waves or their properties, and knowledge of applicability and accuracy of these methods.

Last update: T_KG (14.04.2008)
Course completion requirements -

Oral exam

Last update: Gallovič František, prof. RNDr., Ph.D. (10.06.2019)
Literature - Czech

Červený, V.: Seismic Ray Theory. Cambridge Univ. Press, Cambridge, 2001.

Last update: T_KG (14.04.2008)
Teaching methods -

Lecture

Last update: T_KG (11.04.2008)
Requirements to the exam - Czech

Zkouška je ústní, požadavky odpovídají sylabu v rozsahu prezentovaném na přednášce.

Last update: Gallovič František, prof. RNDr., Ph.D. (06.10.2017)
Syllabus -
Viscoelastodynamic equations:

Linear constitutive equations for viscoelastic medium, relaxation functions. Anisotropic and isotropic viscoelastodynamic equations. Dispersion and attenuation.

Seismic model of the medium (macro model):

Coordinate systems and metric tensors. Computer representation of the model.

Green tensor.

Travel times:

Kinds of travel times. Isotropic and anisotropic eikonal equations. First-arrival travel times. Ray-theory travel times, elementary waves.

Initial-value ray tracing:

Hamiltonian ray tracing, rays as geodesics, wave-propagation metric tensor. Kinematic and dynamic ray tracing. Second and higher partial travel-time derivatives.

Calculation of ray-theory travel times:

Two-point ray tracing, shooting methods, bending methods. Computation of travel times on regular rectangular grids. Ray cells, weighting of paraxial ray approximations. Wavefront tracing.

Calculation of first-arrival travel times:

Network shortest-path ray tracing, grid travel-time tracing.

Ray-theory synthetic seismograms:

Isotropic and anisotropic ray theories. Weak anisotropy. Complex-valued rays and travel times. Space-time ray theory. Gaussian beams and packets, Chapman-Maslov asymptotic theory.

Accuracy and validity conditions of asymptotic ray methods:

Kirchhoff integrals, Fresnel zones, representation theorems, Fresnel volumes.

Full-wave finite differences in 3-D:

Accuracy of various finite-difference schemes, grid dispersion. Waves as structural interfaces. Fast calculation of the first-arrival waveforms.

Ray method for surface waves in Cartesian and curvilinear coordinates.

Last update: T_KG (11.04.2008)
 
Charles University | Information system of Charles University | http://www.cuni.cz/UKEN-329.html