AP's+Post-activity+Assessment


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1. Use Google Maps (or Google Earth—your pick) to calculate the distance from the quake’s epicenter to LIGO.** First I went to Google Earth and plugged in the coordinates for the quake. Then I plugged in the coordinates for Hanford, Wa. I used the ruler tool to measure the distance to be 10,933.5 km.

P waves = 5-8 km sec. Seismic Y 10,933.5 km / 8 km sec = 22.78 min. The quake occurred at 03:50:40.80. Its difficult to tell by the graphs but it appears that the spike starts at about 4:13. That would perfectly match the speed of the P wave traveling from the origin of the quake. Seismic Z 10,933.5 km / 10 km sec = 18.22 min. Again, The quake occurred at 03:50:40.80. Its difficult to tell by the graphs but it appears that the spike starts at about 4:07. That would be an extremely close match with the speed of the P wave traveling from the origin of the quake.
 * 2. Calculate the seismic wave speed twice, once for each of the LIGO plots shown.**

For some reason, the Seismic Z graph had an earlier spike. That means that the Z graph may have picked up on a wave slightly before the Y. The spikes on the two graphs also differ from each other.
 * 3. Comment on any difference you see between the LIGO plots, and between the wave speed estimates obtained using each plot.**