Answer the following questions on the same page:

For each of the following statements indicate the lineation pattern that best matches. Mid-ocean Ridge A.Mid-ocean Ridge B.Mid-ocean Ridge C. 31.Ridge with slowest rate of seafloor spreading. 32.Ridge with moderate rate of seafloor spreading. 33.Ridge with fastest rate of seafloor spreading. 34) Ridge whose 2 spreading rate (rate of spreading for one side of the plate) for the last 5 Ma(million years) is approximately 28 km/Ma. 35.Ridge with line showing longest length of seafloor.

Answer the following questions on the same page: 15. Based on the location and magnitude of your earthquake, speculate on the type of damages your earthquake might have caused. 16. Now compare this to the Mercalli Intensity scale. What classification is your earthquake based on this scale? 17. How did the different waves (P, S & Surface Waves) assist you in determining the epicenter and the amount of damage caused? 18. Was your location in an area prone to earthquakes? Speculate on what might have caused this earthquake (be specific). 19. Why is it so difficult for geologists to predict when and where an earthquake will occur? 20. What connections can you make between the behavior of the seismic waves and the Earth's interior? 21. Make sure your name is ON your document before submitting. Tips and hints can be found here (Links to an external site.). This assessment is adapted from "Virtual Earthquake" by Gary Novack, originally found here (Links to an external site.).

1.(6 pts). a) Using the travel-times curves (Figure 3.5-4) for earthquakes at the surface and at a depth of 600 km, estimate the ray parameters in s/degree for direct P waves at 60° distance. b) Find angles of incidence at the earthquake source for these two rays by converting ray parameter values to s/radian and using the velocities estimated from Figure 3.5-1 (also attached). c) In words and with a sketch, explain how and why the angle of incidence for rays reaching a given distance varies with the depth of the earthquake.

3.(4 pts) The travel-times for PcP, PKiKP, and PKIKP are shown in Figures 3.5-4 and 3.5-7 which are attached. You can use an outer core radius of 3482 km, and an inner core radius of 1217 km. a) Use the travel-times for PCP and PKiKP (Figure 3.5-4) at vertical incidence (incidence angle = 0°) to estimate the average P-wave velocity in the outer core. Include a sketch that explains your reasoning. b) Use the travel-times for PKIKP and PKIKP (Figures 3.5-4 and 3.5-7) at vertical incidence to estimate the average P-wave velocity in the inner core. Include a sketch that explains your reasoning.

2. (8 pts). The travel-time curve for Pdiff (sometimes labeled just Pa), the P wave that diffracts along the core-mantle boundary, directly tells us the P-wave velocity at the base of the mantle. The Pdiff travel-time curve is linear, with a ray parameter p = dT/dA = Temb/vcmb, where remb is the radius of the core-mantle boundary, and Vemb is the velocity at the base of the mantle. a) Measure the ray parameter (in s/degree) for the Pdiff phases shown in the record section of Figure P3.4 (attached). Pdiff is the one prominent phase seen on each seismogram. How does this value compare to the slope of the Pdiff travel-time curve in Figure 3.5-4? (Incidentally, I published a paper in 2004 using seismograms from these stations, which were part of MOMA, a PASSCAL experiment spanning the eastern US that predated EarthScope. Station CCM is in Missouri, and station HRV is in Massachusetts. My paper focused on surface waves, not core diffractions.) b) Convert the Pdiff ray parameter to s/radian, and find the velocity at the base of the mantle. c) Using values of dT/dA from Figure 3.5-4 for Pdiff and Sdiff, find the average ratio of P to S velocity (Vp/Vs) in the mantle. d) Compare the travel-times of PcP and ScS at zero epicentral distance for an earthquake at the surface (0 km depth). What is the average ratio of P to S velocity in the mantle (Vp/Vs)?