pure and applied geophysics

, Volume 133, Issue 1, pp 103–115 | Cite as

Interpretation of seismic reflection records: Direct calculation of interval velocities and layer thicknesses from travel times

  • Ali A. Nowroozi
Article

Abstract

In reflection surveys and velocity analysis, calculations of interval velocities and layer-thicknesses of a multilayered horizontal structure are often based on Dix's equation which requires the travel times at zero offsets and a prior estimate of the root mean squared velocities.

In this paper a method is presented which requires only the reflection travel-time data. A set of equations are derived which relate the interval velocity and thickness of a layer to the reflection travel time from the top and the bottom of that layer, the offset distances and the ray parameter. It is shown that the difference of the offset distances and the difference of the picked travel times of any reflected rays with the same value of ray parameter from the top and the bottom of a horizontal layer can be used to calculate the interval velocity and thickness of that layer.

Key words

Reflection travel time interval velocities layer thickness 

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References

  1. Al-Chalabi, M. (1974),An Analysis of Stacking, rms, Average, and Interval Velocities Over a Horizontally Layered Ground, Geophysical Prospecting22, 458–475.Google Scholar
  2. Claerbout, J. F.,Imaging the Earth's Interior (Blackwell Scientific Publications 1985).Google Scholar
  3. Dix, C. H. (1955),Seismic Velocities from Surface Measurements, Geophysics20, 68–86.Google Scholar
  4. Diebold, J. B., andStoffa, P. L. (1981),The Travel-Time Equation, τ-P Mapping and Inversion of Common Midpoint Data, Geophysics46, 238–254.Google Scholar
  5. Gonzalez-Serrano, A., andClaerbout, J. F. (1984),Wave Equation Velocity Analysis, Geophysics49, 1432–1456.Google Scholar
  6. Nowroozi, A. A. (1989),Generalized Form of the Dix Equation for Calculation of Interval Velocities and Layer Thicknesses, Geophysics54, 659–661.Google Scholar
  7. Robinson, E. A.,Seismic Velocity Analysis of the Convolution Model (International Human Resources, Development Corporation, Boston 1983).Google Scholar
  8. Schultz, P. S. (1982),A Method of Direct Estimation of Interval Velocities, Geophysics47, 1657–1671.Google Scholar
  9. Shah, M. P., andLevin, F. K. (1973),Gross Properties of Time-distance Curves, Geophysics38, 643–656.Google Scholar

Copyright information

© Birkhäuser Verlag 1990

Authors and Affiliations

  • Ali A. Nowroozi
    • 1
  1. 1.Department of Geological SciencesOld Dominion UniversityNorfolkUSA

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