Studia Geophysica et Geodaetica

, Volume 51, Issue 1, pp 141–164

Inversion of travel times obtained during active seismic refraction experiments CELEBRATION 2000, ALP 2002 and SUDETES 2003

  • B. Růžek
  • P. Hrubcová
  • M. Novotný
  • A. Špičák
  • O. Karousová
Article

Abstract

A series of kinematic inversions based on robust non-linear optimization approach were performed using travel time data from a series of seismic refraction experiments: CELEBRATION 2000, ALP 2002 and SUDETES 2003. These experiments were performed in Central Europe from 2000 to 2003. Data from 8 profiles (CEL09, CEL10, Alp01, S01, S02, S03, S04 and S05) were processed in this study. The goal of this work was to find seismic velocity models yielding travel times consistent with observed data.

Optimum 2D inhomogeneous isotropic P-wave velocity models were computed. We have developed and used a specialized two-step inverse procedure. In the first “parametric” step, the velocity model contains interfaces whose shapes are defined by a number of parameters. The velocity along each interface is supposed to be constant but may be different along the upper and lower side of the interface. Linear vertical interpolation is used for points in between interfaces. All parameters are searched for using robust non-linear optimization (Differential Evolution algorithm). Rays are continuously traced by the bending technique. In the second “tomographic” step, small-scale velocity perturbations are introduced in a dense grid covering the currently obtained velocity model. Rays are fixed in this step. Final velocity models yield travel time residuals comparable to typical picking errors (RMS ∼ 0.1 s).

As a result, depth-velocity cross-sections of P waves along all processed profiles are obtained. The depth range of the models is 35–50 km, the velocity varies in the range 3.5–8.2 km/s. Lowest velocities are detected in near-surface depth sections crossing sedimentary formations. The middle crust is generally more homogeneous and has typical P wave velocity around 6 km/s. Surprisingly the lower crust is less homogeneous and the computed velocity is in the range 6.5–7.5 km/s. The MOHO is detected in the depth ≈30–45 km.

Keywords

seismic tomography kinematic velocity inversion Bohemian Massif CELEBRATION 2000 ALP 2002 SUDETES 2003 

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References

  1. Běhounková M., Čížková H. and Matyska C., 2005. Resolution tests of global geodynamic models by travel-time tomography. Stud. Geophys. Geod., 49, 343–363.CrossRefGoogle Scholar
  2. Brückl E., Bodoky T., Hegedüs E., Hrubcová P., Gosar A., Grad M., Guterch A., Hajnal Z., Keller G.R., A. Špičák A., Sumanovac F., Thybo H., Weber F. and ALP 2002 Working Group, (2003). ALP 2002 seismic experiment. Stud. Geophys. Geod., 47, 671–679.CrossRefGoogle Scholar
  3. Efron B. and Tibshirani R., 1991. Statistical Data Analysis in the Computer Age. Science, 253, 390–395.CrossRefGoogle Scholar
  4. Grad M., Špičák A., Keller G.R., Brož M., Hegedüs E. and SUDETES 2003 Working Group, 2003. SUDETES 2003 seismic experiment. Stud. Geophys. Geod., 47, 681–689.CrossRefGoogle Scholar
  5. Guterch A., Grad M., Keller G.R., Posgay K., Vozár J., Špičák A., Brückl E., Hajnal Z., Thybo H., Selvi O. and CELEBRATION 2000 Working Group, 2003a. CELEBRATION 2000 seismic experiment. Stud. Geophys. Geod., 47, 659–669.CrossRefGoogle Scholar
  6. Guterch A., Grad M., Špičák A., Brückl E., Hegedüs E., Keller G.R., Thybo H. and CELEBRATION 2000, ALP 2002, SUDETES 2003 Working Groups, 2003b. An overview of recent seismic refraction experiments in Central Europe. Stud. Geophys. Geod., 47, 651–657.CrossRefGoogle Scholar
  7. Hole, J.A., 1992. Nonlinear high resolution three-dimensional seismic travel time tomography. J. Geophys. Res., 97(B5), 6553–6562.Google Scholar
  8. Hrubcová P., Šroda P., Špičák A., A. Guterch, M. Grad, G. R. Keller, E. Brückl, and H. Thybo, 2005. Crustal and uppermost mantle structure of the Bohemian Massif based on CELEBRATION 2000 data. J. Geophys. Res., 110, B11305, doi:10.1029/2004JB003080.Google Scholar
  9. Landes M., O’Reilly B.M., Readman P.W., Shannon P.M. and Prodehl C., 2003. VARNET-96: three-dimensional upper crustal velocity structure of SW Ireland. Geophys. J. Int., 153, 424–442.CrossRefGoogle Scholar
  10. Majdañski M, Grad M, Guterch A, and the SUDETES 2003 Working Group, 2006. 2-D seismic tomographic and ray tracing modelling of the crustal structure across the Sudetes Mountains basing on SUDETES 2003 experiment data. Tectonophysics, 413, 249–269.CrossRefGoogle Scholar
  11. Málek J., Brož M., Fischer T., Horálek J., Hrubcová P., Janský J., Novotný O., Růžek B. and the CELEBRATION Working Group, 2001. Seismic measurements along short profiles in Western Bohemia during the CELEBRATION 2000 experiment. Acta Montana IRSM AS CR, 18, 15–28.Google Scholar
  12. Michelini A., Živčič M. and Suhadolc P., 1998. Simultaneous inversion for velocity structure and hypocenters in Slovenia. J. Seismol., 2, 257–265.CrossRefGoogle Scholar
  13. Press W.H., Teukolsky S.A., Vetterling W.T. and Flannery B.P., 1992. Numerical Recipes in C. The Art of Scientific Computing. Second Edition. Cambridge University Press.Google Scholar
  14. Price K. and Storn R., 1997. Differential Evolution. Dr. Dobb’s Journal, April 1997, 18–24.Google Scholar
  15. Puliam R.J., Vasco D.W. and Johnson L.R., 1993. Tomographic inversion for mantle P wave velocity structure based on the minimization of L2 and L1 norms of International Seismological Centre travel time residuals. J. Geophys. Res., 98(B1), 699–734.CrossRefGoogle Scholar
  16. Puliam R.J. and Start P.B., 1994. Confidence regions for mantle heterogeneity. J. Geophys. Res., 99, 6931–6943.CrossRefGoogle Scholar
  17. Růžek B. and Kvasnička M., 2001. Differential evolution algorithm in the earthquake hypocenter location. Pure Appl. Geophys., 158, 667–693.CrossRefGoogle Scholar
  18. Růžek B. and Kvasnička M., 2005. Earthquake hypocenter location: a challenge for the differential evolution algorithm. In: K. Price, R. Storn and J. Lampinen (Eds.), Differential Evolution, A Practical Approach to Global Optimization, Springer-Verlag Berlin, 379–392.Google Scholar
  19. Růžek B., Vavryčuk V., Hrubcová P. and Zedník J. and the CELEBRATION 2000 working group, 2003. Crustal anisotropy in the Bohemian Massif, Czech Republic: observations based on Central European Lithospheric Experiment Based on Refraction (CELEBRATION) 2000. J. Geophys. Res., 108(B8), 2392, oi:10.1029/2002JB002242.CrossRefGoogle Scholar
  20. Scarpa R., 1993. Seismic tomography and modeling of complex geological structures. J. of Appl. Geophys., 30, 119–130.CrossRefGoogle Scholar
  21. Song L.P., Koch M., Koch K. and Schlittenhardt J., 2004. 2D-anisotropic Pn-velocity tomography underneath Germany using regional traveltimes. Geophys. J. Int., 157, 645–663.CrossRefGoogle Scholar
  22. Stark P.B., 1992. Inference in infinite-dimensional inverse problems: discretization and duality. J. Geophys. Res., 97(B10), 14055–14082.Google Scholar
  23. Storn R. and Price K., 1997. Differential Evolution — A simple and efficient heuristic for global optimization over continuous spaces. J. Glob. Optim., 11, 241–354.CrossRefGoogle Scholar
  24. Tichelaar B.W. and Ruff L.J., 1989. How good are our best models? Jackknifing, bootstrapping, and earthquake depth. EOS Trans. AGU, 16, 593.CrossRefGoogle Scholar
  25. Um J. and Thurber C., 1987. A fast algorithm for two-point seismic ray tracing. Bull. Seismol. Soc. Amer., 77, 972–986.Google Scholar
  26. Vavryčuk V., Hrubcová P., Brož M. and Málek J. and the ALP 2002 working group, 2004. Azimuthal variation of Pg velocity in the Moldanubian, Czech Republic: observation based on a multiazimuthal common-shot experiment. Tectonophysics, 387, 189–203.CrossRefGoogle Scholar
  27. Wessel P. and Smith W.H.F., 1991. Free software helps map and display data. EOS Trans. AGU, 441, 72.Google Scholar
  28. Zelt C.A., 1998. Lateral velocity resolution from three-dimensional seismic refraction data. Geophys. J. Int., 135, 1101–1112.CrossRefGoogle Scholar
  29. Zelt C.A., Sain K., Naumenko J.V. and Sawyer D.S., 2003. Assessment of crustal velocity models using seismic refraction and reflection tomography. Geophys. J. Int., 153, 609–626.CrossRefGoogle Scholar
  30. Zhang H. and Thurber C., 2005. Adaptive mesh seismic tomography based on tetrahedral and Voronoi diagrams: Application to Parkfield, California. J. Geophys. Res., 110(B4), B04303, doi:10.1029/2004JB003186.Google Scholar

Copyright information

© StudiaGeo s.r.o. 2007

Authors and Affiliations

  • B. Růžek
    • 1
  • P. Hrubcová
    • 1
  • M. Novotný
    • 1
  • A. Špičák
    • 1
  • O. Karousová
    • 1
  1. 1.Geophysical InstituteAcad. Sci. Czech RepublicPrague 4Czech Republic

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