Project VESE (very expensive seismic experiment) deployed 60 seismometers in a linear array extending 240 km away
Question:
Project VESE (very expensive seismic experiment) deployed 60 seismometers in a linear array extending 240 km away from a large surface explosion. Despite careful picking of the resulting seismograms, the first-arrival P -wave travel times (plotted in Fig. 5.16 and also given in the supplemental web material) show considerable scatter. Fit these points with a series of straight lines and compute the ray parameter p and the delay time ? for each line. The first of these lines should go through the origin (zero time and range). Be sure to take into account the reduction velocity of 8 km/s in computing p . Using equation (5.12), invert these results for a layer-cake P -velocity model of the crust and uppermost mantle. List your model in a table, starting with the surface layer and continuing downward, with each line consisting of a depth (km) and a velocity (km/s). Specify the velocity discontinuities between layers by listing the depth twice, with the first line containing the velocity in the upper layer and the second line the lower layer velocity. Make sure that the first column of your table is absolute depth and not layer thickness. For example, a three-layer model with a 2 km thick top layer of 4 km/s, a 4 km thick middle layer of 6 km/s, and a bottom layer of 8.1 km/s would be written as: 0.0 4.0 2.0 4.0 2.0 6.0 6.0 6.0 6.0 8.1 What is the Pn crossover distance? How thick is the crust in your model? How much uncertainty would you assign to your crustal thickness estimate? Note: Not everyone will get the same answer to this exercise! It?s fun to plot the different models to see how well they agree.?
Expert Answer:
Answer In the above seismic experiment 60 seismometers have been plotted in a linear way ... View the full answer
