• Startseite

• Institut

• Einleitung

• OnSITE - On-line seismic imaging for tunnel seismic exploration

• Time-Domain Full Waveform Tomography

• Seismic Prediction Ahead of Boreholes

• Inversion of Surface Waves

Finite-Difference Seismic Wave Simulation

In order to extract information about the 3-D structure and composition of the crust from seismic observations, it is necessary to be able to predict how seismic wavefields are affected by complex structures. Since exact analytical solutions to the wave equations do not exist for most subsurface configurations, the solutions can be obtained only by numerical methods.

Seismic modelling is helpful for predicting and understanding the kinematic and dynamic properties of seismic waves propagating through models of the crust. With the increased amount of detailed information required from seismic data, seismic modelling has become an essential tool for the evaluation of seismic measurements. It helps in every stage of a seismic investigation. It can help determine optimal recording parameters in data acquisition. Synthetic datasets can be computed to test processing procedures. The comparison of synthetic and field seismograms leads to a better understanding of seismic measurements and thus, finer details can be extracted from seismic field recordings. In seismic inversion procedures, modeling is the kernel of the inversion process.

The seismic working group concentrates on the optimization of 2-D and 3-D time domain finite-difference numerical methods, since these methods are applicable to arbitrary complex media. Domain-decomposition allows to use modern cluster technology.  By using the free and portable message passing interface (MPI) the simulations are distributed on our in-house Linux PC cluster.  The codes also show  good performance on massive parallel supercomputers.

The following finite-difference modelling codes are currently being optimized:

• FDMPI - 3-D viscoelastic, elastic, and acoustic  wave simulations
  
• FDVEPS - 2-D viscoelastic and elastic wave simulations
• FDANISO - 2-D elastic wave simulations for anisotropic media

They are applied and further developed in various research projects of our group. For software inquiries please contact Thomas Bohlen.

Work group

Thomas Bohlen
Denise De Nil
Stefan Jetschny
Daniel Köhn
Andre Kurzmann
Nhi Xuan Ngyen
Olaf Hellwig

Funding

The methodological developments are financially supported by WesternGeco (Houston), Verbundnetz Gas AG (Leipzig), Baker Hughes INTEQ (Celle), and the Technical University Bergakademie Freiberg.

 References

Bohlen, T., Lorang, U., Rabbel, W., Müller, C., Giese, R., Lüth, S., Jetschny, S., 2007, Rayleigh-to-shear wave conversion at the tunnel face - from 3D-FD modeling to ahead-of-drill exploration, Geophysics, in press.

Köhn, D., Bohlen, T., 2007, On the numerical stability of spatial variable finite-difference grids in seismic modelling, Geophysical Journal International, submitted.

Essen, K., Bohlen, T., Friederich, W., Meier, T., 2007, Modelling of Rayleigh-type seam waves in disturbed coal seams and around a coal mine roadway, Geophysical Journal International, 170, 511-526 (abstract)

Huang, J.-W., Bohlen, T., Milkereit, B., 2006, Numerical Solutions of Seismic Scattering in Heterogeneous Media, Canadian SEG Recorder, November 2006, Vol. 31, 44-47.

Bohlen, T. and Saenger, E.H., 2006, Accuracy of heterogeneous staggered-grid finite-difference modeling of Rayleigh waves, Geophysics, Volume 71, No. 4, Pages T109-T115 (pdf)

Bohlen, T.,  2004, Analysis of Seismic Waves in the Presence of Small-Scale Strong Material Discontinuities, Habilitation (professorial dissertation) (pdf)

Saenger, E. and Bohlen T., 2004, Finite-difference modeling of viscoelastic and anisotropic wave propagation using the rotated staggered grid, Geophysics, 69, No. 2, 583-591 (pdf)

Bohlen, T., 2002, Parallel 3-D viscoelastic finite-difference seismic modelling , Computers@Geosciences, 28 (8) pp. 887-899 (pdf)