1. Find the velocities (in meters per second) of the three layers shown in the graph.

(The answer choices are listed as V1, V2, and V3).

2. The crossover point xco1 is at 230 meters. What is h1?

3. Find the intercept time for line 3 (green line) on the graph by laying a ruler along the line and seeing where it intercepts the Y-axis. Now you have enough information, find the thickness of layer 2 (h2).

4. Now we can calculate θic. Critical refraction is 90° because the interface is horizontal. Use Snell's Law to determine critical incident angle.

5. Last but not least, we can calculate θi. Use Snell's law.

Part 2

1. If an underground explosion has an initial energy (Io) of 1000 db (decibles) what is the energy at 10 meters if the wave is traveling through a material with an absorbtion coefficient of 0.6 db/???

2. We use signal conditioning to _________ the recorded data: Why?

3. A P-wave that strikes a contact generates how many and what types of waves: Why?

4. You have been hired to do a seismic survey of the caldera in Yellowstone National Park. Which energy sources should you not consider using (from table on page 49)? Why?