Refraction Seismics: The Lateral Resolution of Structure and Seismic Velocity

120 Distance metres amplitude anisotropy factor apparent velocities approximation attenuation average velocity blind zone computed convenient conventional reciprocal method corrections Crampin equation critical angle critically refracted depth conversion factor depth section detector determined dip angles Equation 8-1 errors exploration forward and reverse geological geophone Geophysical Prospecting Hatherly head waves horizontal Huygens intercept time method interface irregular isotropic layer model layer thicknesses measured medium migration milliseconds model in Figure nomograms obtained offset distance optimum XY value parameters phase velocity surface plane layering plotted pulse broadening ray paths raypaths reflection reflection seismology refraction data refractor surface refractor velocity sedimentary basins seismic refraction surveys seismic velocity seismic wave seismograms shear waves shot point shown in Figure sin² Snell's law target techniques time-depths travel time curves travel time data travel time graphs undetected layers upper layer V₁ variable velocity media velocity analysis function velocity contrasts velocity layer vertical wavelets