You have collected a reversed P-wave refraction survey and a reversed SH-wave refraction survey over the same surface locations (referred to as Line 2 in this problem) at the Norman Landfill. In the field, you picked the first-arrival traveltimes from both surveys. You are to invert the traveltimes from each survey using the delay-time method as described in Burger, Chapter 3. To do this you will use dynamic Table 3-9.

The traveltimes and distances of the first arrival picks must be determined from the plots (click on the hyperlinks below). These traveltimes come from an earlier survey done in exactly the same location as we used, but the station ("geophone") spacing is 3 m (remember, we used 3 ft) and there are only 24 traveltimes (we collected 48). The vertical scale is in [ms].

Questions to answer:

1. What is the assumption about the layering at the Landfill that allows you to use Table 3-9?
2. What is the geological identity of the P-wave refractor? How can you verify this from its apparent velocity?
3. What is the geological identity of the SH-wave refractor? How can you verify this from its apparent velocity? Is the SH-wave refractor the same as the P-wave refractor? Explain.
4. Make a cross-sectional plot showing the boundaries for both refractors beneath the appropriate stations. Can you explain why the station spacing doesn't come directly into the calculation of depth by the delay-time method (look at the equation in the dynamic table)?