Modules in Advanced Studies and Specialisation in Geophysics

After successful completion of the module, students are familiar with the causes and effects of elastic anisotropy in the context of seismic wave propagation and imaging of the subsurface.

Contents: Physical principles of wave propagation in anisotropic media

• Causes of seismic anisotropy
• Symmetries
• Parameterisation
• Weak anisotropy
• Normal moveout
• Nonhyperbolic moveout
• Parameter estimation
• Shear waves

• Dellinger, J.A., 1991, Anisotropic Seismic Wave Propagation; Ph.D. thesis, Stanford University.
• Fedorov, F.I., 1968, Theory of Elastic Waves in Crystals; Plenum Press.
• Helbig, K., 1994, Foundations of Anisotropy for Exploration Seismics: Pergamon Press.
• Musgrave, M.J.P, 1970, Crystal Acoustics; Holden-Day.
• Thomsen, L., 2002, Understanding Seismic Anisotropy in Exploration and Exploitation: SEG-DISC.
• Tsvankin, I., 2001, Seismic Signatures and Analysis of Reflection Data in Anisotropic Media: Pergamon Press.

Upon successful completion, the students are familiar with the most abundant measurement devices used at volcanoes worldwide. They have identified the physical parameters, relevant to volcanological research and know how to retrieve them. They gained overview on the measurement principles and function of devices and their installation in the field. In addition, an introduction to general periphery (electronic and IT), power supply, data storage and transmission, as well as accurate timing of instruments will enable students to plan their own campaigns.

Contents: 

• Volcano seismology
• Infrasound
• Deformation
• Radar
• Gas and temperature measurement
• Remote sensing
• Data storage and transmission
• Isolated power supply

• Will be announced at the beginning of the course.

After successful completion of the module, the students are able to recognise simple lithologies and hydrocarbon contents on the basis of borehole measurements.

Contents: 

• Drilling and coring
• Depth and depth measurement
• Caliper and quality control
• Gamma ray
• Electrical resistivity
• Rock density
• Seismic velocities
• Case studies

Will be announced at the beginning of the lecture.

After completing the module, the students have gained an overview of 'advanced' borehole sensors. They have learned to evaluate borehole field measurements regarding fluid detection as applied by the carbohydrate industry as well as geothermic applications. They are able to recognise simple lithologies and calculate fluid contents.

Contents: 

• Borehole Imaging (SHDT, FMS, FMI, ...)
• Vertical Seismic Profiling (VSP)
• Nuclear Magnetic Resonance (NMR)
• Temperature Measurements (DTS)
• Borehole Gravity, Magnetic Susceptibility
• Formation Testing and Sampling (RFT, MDT)
• Evaluation Methods, Software

Will be announced at the beginning of the lecture.

After completing the module, students have gained a solid background in the fundamental methods of signal processing and the analysis of data in different domains.

Contents: 

• Geophysical time series
• Analog-to-digital conversion
• Representation of numbers
• Fourier series and Fourier transform
• Laplace Transform
• Sampling theoreme
• Uncertainty relations
• Convolution
• Causality
• Linear filters
• Window functions and tapering
• Z-transform
• Hilbert transform
• τ-p transform
• Phase properties of wavelets

• Buttkus, B., 2000, Spectral Analysis and Filter Theory in Applied Geophysics: Springer.

After completing the module, students will be able to describe the earthquake source mechanism. Students will be familiar with the processes driving earthquakes. Students will have explored different aspects of current research on earthquake source processes.

Contents:

• Focal parameters and source mechanism of earthquakes
• Models of fracture, nucleation, propagation and arrest of a rupture
• Methods of determination of source mechanisms
• Different types of earthquakes: tectonic, volcanic, induced
• Seismicity, seismotectonics and seismic risk
• Current research in earthquake characterization and simulation
• The exact contents of the course will be adapted to the interest of the participating students.

Will be announced at the beginning of the course.

 After successfully completing the module, students are able to locate an Earthquake, determine its focal mechanism, and relate this to the moment tensor. They have an understanding of the physical processes occurring during earthquake rupture. This includes a base understanding of processes that happen on the micro scale when materials break, and how this relates to phenomena at larger scales. Students are able to place the understanding gained in this course within the framework of open questions and challenges in seismology. They are able to answer the question ”why can earthquakes not be predicted?”

Contents:

• Earthquake sources: localization, focal solution, moment tensor
• Earthquake rupture processes: how does a rupture start (and stop)?
• Micro-scale fracture processes and non-linea relasticity
   
   

Will be announced at the start of the course.

After completing the module, students are familiar with concepts, theory and limitations of linear and non-linear inversion methods and algorithms. They have inverted diverse data sets using self-written programs and gained experience in the application of established inversion methods. They are capable of solving inverse problems efficiently on their own. They are familiar with confidence intervals and the concept of errors and recognize instabilities and non-unique solutions.

Contents: 

• Linear inverse problems:
  • Least squares method, incl. weighting
  • Errors and norms
  • Under- and overdetermined problems
  • Damping
  • Generalized inverse
  • (In-)equality constraints
  • Interpolation and model fitting
  • Hypothesis testing
• Non-linear inverse problems:
  • Gradient methods, incl. conjugate gradients
  • Grid search
  • Monte Carlo methods
  • Simulated Annealing
  • Evolutionary Algorithms

• Menke (2012): Geophysical Data Analysis: Discrete Inverse Theory

After successful completion of the module, students are familiar with the foundations of subsurface imaging by depth conversion of poststack and prestack seismic reflection data.

Contents:

• Wavefields
• Modelling
• Time migration
• Geometric migration
• Summation migration
• Imaging condition
• Kirchhoff migration
• Frequency-wavenumber migration
• Migration with finite differences
• Full-waveform migration
• Migration velocity analysis

• Bancroft, J., 1997/98, A Practical Understanding of Pre- and Poststack Migration, Vol. I and II: SEG, Tulsa.
• Claerbout, J.F., 1985, Imaging the Earth's Interior: Blackwell.
• Scales, J.A., 1995, Theory of Seismic Imaging: Springer.

After successful completion of the module, students will have an overview of machine learning, including theory and specific applications in Geophysics. They have applied various machine learning techniques to geophysical problems using self-written programs but also get to know several open source machine learning frameworks. They learned how to evaluate the performance of their implemented algorithms.

Contents:

• Machine learning
• Objects and features
• Supervised and unsupervised methods
• Deep learning
• Applications in geophysics

• Will be announced at the beginning of the course.

After completing the module, students have a firm understanding of the basics of potential theory. They are able to answer fundamental questions in potential theory. They will have written a code by themselves to numerically calculate gravity anomalies of arbitrarily shaped bodies.

Contents: 

• Potentials
• Greens functions
• Newtonian potential
• Magnetic potential
• Spherical harmonics
• Laplace equation
• Gravity of the Earth

• Blakely, Potential Theory in gravity & magnetic applications, Cambridge Univ. Press, 1995.
• John Wahr, Geodesy and Gravity, Samizdat Press, 1996.

After completing the module, the students should understand the fundamental concepts of seismic wave propagation and put these concepts into practice. They will be familiar with the theory, analysis, and application of surface waves. Through computer exercises, they will have some practical experience in the application of several seismological methods.

Contents:

• Basic theorems in dynamic elasticity
• Wave potentials
• Wave excitation from a point source
• Representation of the seismic source
• Surface waves; surface wave modes
• Dispersion 
• Surface wave tomography
• Earth's normal modes

Most material will be provided, but the following references contain helpful background information:

• Aki, K., & Richards, P. G. (2002). Quantitative seismology.
• Shearer, P. M. (2019). Introduction to seismology. Cambridge University Press.

After completing the module, students will be able to locate sources of ambient seismic noise and compute Green’s functions between station pairs. Students will be very familiar with the most important sources of ambient seismic noise and their mechanisms. Students will have broad knowledge about common applications of ambient noise in modern seismology (tomography, structural monitoring), and will have basic knowledge of more exotic applications (amplitudes, other celestial bodies).

Contents: 

• Sources of ambient seismic noise: global, regional, local; Source mechanisms
• Methods for source identification and localization: Beamforming and Matched Field Processing
• Interferometry of seismic noise for retrieval of estimated Green’s functions
• Applications of estimated Green’s functions: Tomography, amplitudes
• Monitoring approaches, coda sensitivity, environmental monitoring
• Seismic noise on Moon and Mars

Will be announced at the beginning of the course.

After completing this course students will have acquired a basic understanding of the physics of volcanological processes. They will be able to address interdisciplinary volcanological questions and to model volcanological processes.

Contents: 

• Overview plate tectonics
• Volcano types
• Phase diagrams
• Crystallisation processes
• Lava lakes
• Rheology of magma
• Conduit flow
• Eruption dynamics

• Schmincke, Volcanism, Springer, 2004.
• Philpotts, Principles of igneous and metamorphic petrology, Prentice Hall, 1990.
• Okrusch, Matthes, Mineralogie, Springer, 2005.