Traveltime for velocity linear with depth
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| Series | Geophysical References Series |
|---|---|
| Title | Digital Imaging and Deconvolution: The ABCs of Seismic Exploration and Processing |
| Author | Enders A. Robinson and Sven Treitel |
| Chapter | 2 |
| DOI | http://dx.doi.org/10.1190/1.9781560801610 |
| ISBN | 9781560801481 |
| Store | SEG Online Store |
The traveltime is
$ {\begin{aligned}t&{\rm {=}}\int _{{\theta }_{0}/pa}^{\theta {\rm {/}}pa}{\frac {ds}{v}}{\rm {=}}{\frac {\rm {1}}{a}}\int _{{\theta }_{0}}^{\theta }{\frac {d\theta }{{\rm {\ sin\ }}\theta }}.\end{aligned}} $ ()
Integration gives the traveltime as
$ {\begin{aligned}&t{\rm {=}}{\left[{\frac {\rm {l}}{a}}{\rm {\ log\ }}{\frac {{\rm {1}}-{\rm {\ cos\ }}\theta }{{\rm {\ sin\ }}\theta }}\right]}_{{\theta }_{0}}^{\theta }{\rm {=}}{\left[{\frac {\rm {l}}{a}}{\rm {\ log\ \ tan\ }}{\frac {\theta }{\rm {2}}}\right]}_{{\theta }_{0}}^{\theta }{\rm {=}}{\frac {\rm {l}}{a}}{\rm {\ log\ }}{\frac {{\rm {\ tan\ }}\left(\theta {\rm {/2}}\right)}{{\rm {\ tan\ }}\left({\theta }_{0}{\rm {/2}}\right)}},\end{aligned}} $ ()
which gives
$ {\begin{aligned}at&{\rm {=\ log\ }}{\frac {{\rm {\ tan\ }}\left(\theta {\rm {/2}}\right)}{{\rm {\ tan\ }}\left({\theta }_{0}{\rm {/2}}\right)}}\end{aligned}} $ ()
If we take the exponential of both sides, we obtain the implicit equation for traveltime given by
$ {\begin{aligned}e^{at}&{\rm {=}}{\frac {{\rm {\ tan\ }}\left(\theta {\rm {/2}}\right)}{{\rm {\ tan\ }}\left({\theta }_{0}{\rm {/2}}\right)}}.\end{aligned}} $ ()
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Also in this chapter
- Reflection seismology
- Digital processing
- Signal enhancement
- Migration
- Interpretation
- Rays
- The unit tangent vector
- Traveltime
- The gradient
- The directional derivative
- The principle of least time
- The eikonal equation
- Snell’s law
- Ray equation
- Ray equation for velocity linear with depth
- Raypath for velocity linear with depth
- Point of maximum depth
- Wavefront for velocity linear with depth
- Two orthogonal sets of circles
- Migration in the case of constant velocity
- Implementation of migration
- Appendix B: Exercises