Post-lab+for+LIGO

Back =**1. Use Google Maps (or Google Earth—your pick) to calculate the distance from the quake’s epicenter to LIGO.**=

All I did was go on Google Maps and plug in the Latitude (34.5390) and the Longitude (73.5880), and into Google Maps, and did the distance tool from the earthquake, to Hanford. Then converted the miles (6791.85) to kilometers using Google.

=**2. Calculate the seismic wave speed twice, once for each of the LIGO plots shown.**= ==Seismic Y Graph:    == It occurred at 3:50:40.80, and hit LIGO (Hanford) at about 4:12. This means that it took about 22 minutes 20 seconds (1340 seconds) to get to Hanford. So now, you use the distance, which is 10,930.4357km and you divide it by t, or time (1340sec) to get the wave speed.

Seismic Z Graph:
The earthquake occurred at 3:50:40.80 and this time, the Z graph shows that it arrived around 4:10. This means it took 18 minutes and 20 seconds to get to LIGO, or 1100 seconds. So again, you use the distance, which is 10,930.4357km and you divide it by t, or time (1100sec in this case) to get the wave speed. =**3. Comment on any difference you see between the LIGO plots, and between the wave speed estimates obtained using each plot.**= The main difference really noticeable between the two graphs is the obvious one of time difference; the Y being at 4:12, and the Z being 4:10. This difference in 2 minutes, makes the wave speed faster. Another difference, is that the Z seems to have picked up some more Earthquakes, or tremors maybe, than the Y did. One more noticeable difference, is the difference in... power shown, or magnitude maybe... I don't know, but the Y is at a high of 250, whereas the Z is only at 100. If anyone knows what these numbers mean, let me know. I think that the main reason that two detectors got different times, is because each of them pick up different times. An earthquake can occour for a long time, so therefore, there is no set time as top when EXACTLY the earthquake hit. The main reason they are different, is because they are different detectors, and they pick up different parts of the earthquake.

What kind of wave do you think this must be, from this quake, detected at LIGO?
They must be P-waves because they typically move from about 5-8km/sec

What route do you think it would have traveled?
P-waves are faster, because they go directly through the earth, whereas, S-waves to the typical earthquake up and down thing. Here is a link that helps to explain this: http://www.seismo.unr.edu/ftp/pub/louie/class/100/seismic-waves.html Purdue does a good job showing what the [|P-wave] and [|S-wave] look like as well

How do waves propagate from a quake epicenter--can you say?
Now I am not sure if this is the correct answer to the question, but it starts when the plates move, and the energy is [|displaced].

Is it like a laser, coherent and pointed in a single direction, E/W/N/S? How about up and down?
Well P-waves move sort of like a laser, only in one direction, and S-waves move more like a grenade, moving all over the place, up/down, and spreading out. And it is notP-waves that move up and down, it is S-waves.