Time transcripts of tsunamiArrivalPick

[00:00:00:010]	Can I just say before we even start that this is such cool data!

[00:00:04:020]	First of all, this station is really close

[00:00:08:030]	to the earthquake and it is sitting at the bottom of the ocean. You can tell that

[00:00:12:040]	because the y axis here is water column height. This thing is a pressure sensor

[00:00:16:040]	sitting in five and a half kilometers of water, which is pretty amazing

[00:00:20:050]	that we can even build something that will work at five and half kilometers down, don't you think?

[00:00:24:070]	Anyway, in part one you were looking at tide gauges

[00:00:28:080]	and those are really cool, but they are just at the surface, so all they can do is record the

[00:00:32:080]	height of the water, whereas this thing, since it's a pressure sensor on the ocean floor,

[00:00:36:090]	it can record the seismic waves themselves and the tsunami, which is really neat.

[00:00:40:100]	The x axis here is the Julian day of 2011

[00:00:44:110]	and it is in these fractional parts. That's helpful since we already

[00:00:48:110]	know how to do that and work with those numbers. Let's look at the data itself.

[00:00:52:120]	This wiggly line. Right here is

[00:00:56:120]	the first big excursion from nothing happening. That is actually

[00:01:00:130]	the seismic waves from the earthquake, not the tsunami itself.

[00:01:04:140]	(which is awesome) The tsunami itself actually comes in right here.

[00:01:08:150]	And I would mark it down as 70.26 as the arrival time.

[00:01:12:160]	What's really neat is that when you look at

[00:01:16:160]	stations that are farther and farther away in the rest of this problem set, you are going to see that the 

[00:01:20:180]	time between the earthquake arrival and the tsunami gets bigger and bigger and bigger.

[00:01:24:190]	That's because the seismic waves are just faster. The tsunami is pretty fast

[00:01:28:190]	but not as fast as seismic waves. I feel like if I were a

[00:01:32:200]	high school physics teacher and I wanted students to do those boring problems

[00:01:36:200]	where two trains leave a station and one is traveling at this speed and the other one is traveling at some other

[00:01:40:200]	speed, and how far apart will they be at time x, y, and z?

[00:01:44:210]	Well, this is that exact problem, it's just cool because it's real data; it's a real thing that happens

[00:01:48:220]	in the Earth. So, check it out! You'll see it when you look at this data.

[00:01:52:230]	It's just so neat. It's awesome.