As shown in Figure 4.26, a vertically propagating upgoing plane wave is incident on a sediment-basement interface where the seismic velocity drops from 4 km/s to 2 km/s. A cylindrically shaped...

As shown in Figure 4.26, a vertically propagating upgoing plane wave is incident on a

sediment-basement interface where the seismic velocity drops from 4 km/s to

2 km/s. A cylindrically shaped depression (with radius of curvature r = 1 km)

focuses (approximately) the ray paths to a focus point within the sediments. Solve

for the height of the focus point above the lowest point of the interface. Hint: Assume that the maximum slope of the depression is sufficiently small that sin θ ≈ θ

when considering the ray angles.