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Speaker 1: Brought to you by the reinvented two thousand twelve Camray.

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Speaker 1: It's ready. Are you get in touch with technology? With

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Speaker 1: tech Stuff from how stuff works dot com. Hello again, everyone,

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Speaker 1: and welcome to tech stuff. My name is Chris Poulette

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Speaker 1: and I am an editor at how stuff works dot com.

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Speaker 1: Sitting across from me, as always, is senior writer Jonathan Strickland.

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Speaker 1: The governor and I aren't even in the same party.

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Speaker 1: If this turns out to be a false alarm, he'll

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Speaker 1: make me out to be the biggest fool west of

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Speaker 1: the Mississippi. Hey, nice Mississippi. Yeah, you know what. That's

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Speaker 1: the site of several faults, actually one great, big fault.

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Speaker 1: There are lots of faults everywhere, and it's not my fault. No,

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Speaker 1: before we get into whose fault it is, let's talk

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Speaker 1: about listener mail. By the way, this is not his fault.

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Speaker 1: This listener mail comes from Joe, and Joe says earthquake. No,

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Speaker 1: just kidding. I live in Christchurch, New Zealand, and I've

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Speaker 1: been through two major earthquakes and I was wondering if

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Speaker 1: you could do a podcast on how they measure earthquakes.

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Speaker 1: Cheers Joe, Joe, we're very glad that you are okay. Definitely,

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Speaker 1: so definitely, So that was a scary situation if you

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Speaker 1: don't know. Um uh, just a few weeks ago, as

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Speaker 1: I when we're recording this, in very late February two eleven,

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Speaker 1: there was a pretty significant earthquake, to say the very least,

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Speaker 1: that hit New Zealand. Um and uh, you know, several

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Speaker 1: people lost their lives as a result of this. Um

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Speaker 1: And of course these things are very damaging, both to

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Speaker 1: people and property. So it's a it would be nice

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Speaker 1: if we could do a lot of prediction and give

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Speaker 1: you a heads up from when these things are coming,

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Speaker 1: but I'm afraid at this point about the best we

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Speaker 1: can do is let you know how big they were

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Speaker 1: and maybe get an idea of what you might expect

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Speaker 1: from an aftershock. Yeah. As it turns out, predicting an

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Speaker 1: earthquake is not exact science, but we have learned quite

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Speaker 1: a bit about earthquakes. And before we get too far

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Speaker 1: into this, I should just point out that a couple

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Speaker 1: of our sister podcasts have covered similar topics. Stuff you

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Speaker 1: Should Know has done an entire episode on how earthquakes work.

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Speaker 1: It's actually one of their older episodes, but it's it's excellent,

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Speaker 1: so you can listen to that if you are interested

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Speaker 1: in the topic and the stuff of Genius did an

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Speaker 1: episode about an early pioneer in seismology, which and we'll

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Speaker 1: talk about him in a little bit, just because it's

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Speaker 1: it's too cool not to talk about, right, Oh yeah, yeah,

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Speaker 1: definitely so so an earthquake. You know, we most of

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Speaker 1: us probably know exactly what someone means when they say earthquake.

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Speaker 1: It's it's an event in which the ground is shaking

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Speaker 1: right right, the earth thing. Yeah, yeah, Um, they can

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Speaker 1: be caused from from many many different related types of

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Speaker 1: movement in the Earth. Um, it's pretty well, uh, pretty

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Speaker 1: well known at this point that the Earth's crust is

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Speaker 1: made up of many plates, and there are different kinds

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Speaker 1: of they're they're moving in different ways. Um. I'm going

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Speaker 1: back to my undergraduate days when I actually took a

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Speaker 1: geology class, which I found fascinating but didn't go into

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Speaker 1: it obviously as a career field. But um, in some cases,

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Speaker 1: one plate is going underneath another plate. In other cases,

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Speaker 1: they're rubbing against one another in a and you know

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Speaker 1: along you know, one is going north while the other

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Speaker 1: is going south. And and gradually what happens is tension

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Speaker 1: builds up. I'm oversimplifying here, but tension builds up, and

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Speaker 1: when the tension is released, that causes an earthquake. And

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Speaker 1: they can be you know, small enough that you don't

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Speaker 1: even notice it. Um. But some of the equipment we're

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Speaker 1: going to talk about today can detect that. Of course, others, um,

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Speaker 1: like the earthquake in New Zealand and and famous earthquakes

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Speaker 1: like in Haiti and uh in California, in Japan, um

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Speaker 1: and and my favorite fault, the New Madrid fault in

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Speaker 1: the middle of the United States. Again, that would be

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Speaker 1: the one near Mississippi and all the others around it. Um.

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Speaker 1: You know, those can can be very very serious. So uh,

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Speaker 1: you know, scientists have been trying to figure out for

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Speaker 1: a long time, we'll say a very very very long

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Speaker 1: time millennia in fact, yes, exactly how to measure the

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Speaker 1: effect of the earth shaking. So let's talk about what

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Speaker 1: actually happens and then we can talk about how we

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Speaker 1: how we measure it. Now you gave a good overview. Yeah, there's,

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Speaker 1: like I said, that's just a nutshell, very very very

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Speaker 1: basic version, right, Yeah, three basic ways that plates move

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Speaker 1: against each other. Right, they either move apart, or they

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Speaker 1: move together, or they slide against each other. Right, that's

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Speaker 1: about it. The by the way, if you're talking about

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Speaker 1: a plate going underneath another, that's called subducting. Um, just

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Speaker 1: so you guys know. And when plates, when plates meet, uh,

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Speaker 1: it pushes rock and dirt together. That's what actually forms mountains. Besides,

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Speaker 1: there's also volcanic mountains, so there's some mountains that are

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Speaker 1: formed through volcanic activity. But in general, mountains are formed

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Speaker 1: when two plates pressed up against each other and they

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Speaker 1: crinkle essentially. Um. Now, when these these uh, these events happen,

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Speaker 1: these these plate events. By the way, there are other

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Speaker 1: things that can cause an earthquake, like an explosion can

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Speaker 1: cause the essentially a localized earthquake, and meteoric impact can

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Speaker 1: cause an earthquake, that kind of thing. But most of

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Speaker 1: them are caused by these these plate movements. Um. There's

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Speaker 1: about eight thousand of them each day, and most of

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Speaker 1: them are uh beneath our level of being able to

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Speaker 1: perceive them. And of course lots of them are happening

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Speaker 1: in places where there's really little to know human habitat there,

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Speaker 1: so we wouldn't necessarily notice it even if it were

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Speaker 1: a significant earthquake, because one is there, right, might be

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Speaker 1: under the ocean or anything like that. Um. And like

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Speaker 1: you were saying, where the plates meet, that's a fault.

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Speaker 1: That's you know, any place where two two plates are meeting,

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Speaker 1: that's a fault. When when there is an earthquake, energy

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Speaker 1: radiates out from the center of that earthquake in seismic waves. Yes,

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Speaker 1: and these waves are what you would you know, when

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Speaker 1: you think of a wave, that's what we're talking about.

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Speaker 1: It's energy moving in a wavelength. There's there's a peak

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Speaker 1: and there's a trough through this wave. And uh, there's

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Speaker 1: actually two waves that move out from an earthquake. Yes,

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Speaker 1: he's talking about the PEA wave in which those those

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Speaker 1: waves move in the direction that they're they're being propagated.

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Speaker 1: Um and then the S wave, which is perpendicular to that, right,

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Speaker 1: And the PEA wave moves faster than the S wave.

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Speaker 1: It actually goes about between one to five miles per second.

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Speaker 1: It tends to be one point seven times faster than

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Speaker 1: the than the S wave. So this has become a

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Speaker 1: key for us to figure out where earthquakes are originating. Right,

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Speaker 1: because you measure the time between the primary wave and

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Speaker 1: the secondary wave, and that will tell you, in general

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Speaker 1: how far away the focus is. It doesn't tell you

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Speaker 1: the direction. It will just tell you. You know, you

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Speaker 1: feel a shaking, and then you feel a second shaking.

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Speaker 1: You take the time between that, you do a little calculation.

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Speaker 1: You figured, all right, so the center of this earthquake

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Speaker 1: is fifty miles away, but it could literally be fifty

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Speaker 1: miles in any direction on the surface. You can discount

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Speaker 1: the directions that are directly below you and directly above you,

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Speaker 1: and all that like anything in the air, not gonna matter. Um.

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Speaker 1: So that's that's the basics of earthquakes. We'll talk a

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Speaker 1: little bit about the measuring. Let's let's let's take a

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Speaker 1: little walk back into history by a couple of millennia.

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Speaker 1: This is the guy that we were talking about and

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Speaker 1: the stuff of genius who came up with an interesting seismoscope. Now,

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Speaker 1: a seismoscope is a an instrument, any instrument that indicates

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Speaker 1: that motion has occurred. But it does not give you

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Speaker 1: more information than that, right right. It can't necessarily tell

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Speaker 1: you where it was coming from. It can't necessarily tell you, um,

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Speaker 1: it can't give you like a reading over a duration

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Speaker 1: of time, it just tells you, hey, stuff moved around.

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Speaker 1: So basically, if you've seen Jurassic Park, when that dinosaur

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Speaker 1: is coming up on you and you watch the motion

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Speaker 1: in the glass of water, in the glass of water,

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Speaker 1: that wop. Yes, it's a very primitive seismoscope, but as

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Speaker 1: slightly and I stress slightly more sophisticated seismoscope was invented

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Speaker 1: by a Chinese philosopher named Chong Hang Yes, and one

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Speaker 1: thirty two. Yeah, one thirty two a d Yes, that's

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Speaker 1: not that, that's not one thirty two in the afternoon.

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Speaker 1: That's the year. Um No, Chang hangg came up with

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Speaker 1: this really cool design. And we we've actually seen examples

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Speaker 1: of this and you know, uh, not just it's it's

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Speaker 1: not just a theory that these things actually existed. Though

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Speaker 1: they're they're actual, the way they worked is somewhat of

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Speaker 1: a mystery. We've got a couple of ideas of how

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Speaker 1: they could have worked, but but we'll get to that.

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Speaker 1: So basically, what you had was a wine jar. Yes,

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Speaker 1: it was. It was cylinder. You know, think of it

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Speaker 1: as a sort of cylindrical shape standing on in so

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Speaker 1: like a jar. Yes, six ft in diameter, so we're

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Speaker 1: not talking like a little jar, No, this would be

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Speaker 1: a big jar. And mounted to the jar on the

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Speaker 1: jar were eight dragon head spouts that faced in the

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Speaker 1: cardinal directions. Yes, and that would be at the very

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Speaker 1: top of the jar from what from what I understand,

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Speaker 1: it can be anywhere from the above the middle to

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Speaker 1: the top of anything on the top half of the jar.

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Speaker 1: Is that's because I've actually seen pictures of these. There

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Speaker 1: are images of these on the Internet of various people

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Speaker 1: have made recreations of these things. Um. So within that

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Speaker 1: each dragon's mouth there's essentially a marble or stone, and

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Speaker 1: so those are balanced within the mouths of the dragons.

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Speaker 1: And then underneath the dragon mouths are these little ceramic

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Speaker 1: frogs with open mouths. And the idea here is that

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Speaker 1: if there's an earthquake that is significant enough for it

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Speaker 1: to set this seis muscope off, it'll rattle the pebbles,

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Speaker 1: and the pebbles that are facing the direction that the

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Speaker 1: earthquake is coming from, uh would theoretically fall out the

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Speaker 1: dragon's mouth into the frog mouth. So then you could

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Speaker 1: look in and say, all right, this is coming from

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Speaker 1: somewhere the north northeast region. Um, it doesn't tell you

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Speaker 1: how far away it's gonna the earthquake was. But let's

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Speaker 1: say that you're in ancient China and you are overseeing

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Speaker 1: a large amount of land. Communication is not fast. But

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Speaker 1: seeing something like that happened, you could say, well, now

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Speaker 1: I know that there's some problems to the north of us.

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Speaker 1: I should expect some people to come and ask me

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Speaker 1: for help, or maybe I should send Uh perhaps it

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Speaker 1: came from the direction that an enemy is in. Perhaps

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Speaker 1: you would want to send a group of troops out

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Speaker 1: there to see, like, hey, were they weakened enough for

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Speaker 1: us to kind of come in and mop up? Right?

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Speaker 1: So this isn't this isn't just a diversion, uh, you know,

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Speaker 1: just something that you do for fun. They really had

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Speaker 1: a practical use. Now, now, the point where I said

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Speaker 1: it might be a bit of a mystery is that

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Speaker 1: we're not sure what was inside the jar. There are

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Speaker 1: some who think that the jar had perhaps a pendulum

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Speaker 1: suspended from the top of the jar. That so it's

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Speaker 1: it's actually you know, the base of the weight of

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Speaker 1: the pendulum would be inside the jar. That's funny that

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Speaker 1: you have mentioned that, because I have the feeling that

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Speaker 1: will come up again. Yes, and this is because you

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Speaker 1: need an inertial mass in most of these seismoscopes. You

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Speaker 1: need something that is not going to move in relation

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Speaker 1: to the rest of the instrument because one of the

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Speaker 1: big challenges of measuring earthquakes, I mean it sounds silly,

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Speaker 1: but it's true, is that you have to design a

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Speaker 1: tool that can measure something even when the uh the

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Speaker 1: tool itself is moving right like, you know, if the

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Speaker 1: earth is quaking and the tool is on the earth,

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Speaker 1: then how do you get a reliable measurement. Well, this

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Speaker 1: idea of an inertial mass becomes very important with later

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Speaker 1: size seismometers. So um, yeah, there was one possibility. Another

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Speaker 1: possibility was a reverse pendulum. And a reverse pendulum is

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Speaker 1: essentially a flexible pole with a weight at the end

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Speaker 1: of it. The weight is on the top right, And

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Speaker 1: the idea here is that a significant UH quake would

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Speaker 1: cause the pendulum to swing, perhaps hitting the inside of

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Speaker 1: the jar, and that's what would then cause the stone

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Speaker 1: in that dragon's mouth to fall into the the frog's mouth,

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Speaker 1: and then it's six more weeks of winter. Uh, okay, stuff,

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Speaker 1: I'm a little bit I'm on cold medication. So yeah,

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Speaker 1: And in doing some research I read in in Britannica

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Speaker 1: that in Italy in the seventeenth century, um a seismoscope.

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Speaker 1: They're used spilling water to show you know what was

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Speaker 1: going on, whether there was an earthquake taking place. And

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Speaker 1: another they also used a lot of mercury. I know

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Speaker 1: that's probably not a surprise, but yeah, a cup of mercury,

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Speaker 1: which would be would probably be a pretty good indicator

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Speaker 1: given its color. Um. Yeah, too bad, you'd be crazy

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Speaker 1: by the time the earthquake hit. Now see you're getting

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Speaker 1: into the tiny details that are just just ruined them

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Speaker 1: the magic for me. Um and uh. And then there

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Speaker 1: was a Luigi Palmieri who had a seized seismometer to detect,

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Speaker 1: you know, the motion during an earthquake. He had a

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Speaker 1: series of use you shaped tubes that again used mercury. Um.

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Speaker 1: And then there was a clock hooked up to that

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Speaker 1: and um, what would happen is the motion would cause

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Speaker 1: an electrical clock to stop and to start a recording drum. Um. Basically,

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Speaker 1: there was a float on top of the mercury and

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Speaker 1: the drum was keeping track of the floats motion as

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Speaker 1: it moved. It would tell you the time and intensity

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Speaker 1: of the earthquake. That makes it more that. That's why

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Speaker 1: we would refer to that as a seismoment or even

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Speaker 1: a seismograph, because seismograph essentially that that graph means to draw,

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Speaker 1: but it's it's essentially meaning that you are recording the

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Speaker 1: event of the earthquake and there's some element of time

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Speaker 1: there or you can actually see the earthquakes movements over

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Speaker 1: time and be able to say this is when it started,

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Speaker 1: this is when it ended, and um. And that's what

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Speaker 1: sets it apart from the seismoscopes, which essentially just tell you, hey,

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Speaker 1: something's moving out there, yes, which you know a lot

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Speaker 1: of us can do on a good day. I can

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Speaker 1: do it. The rabbits, they're agitated. So let's let's talk

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Speaker 1: a little bit about what it takes to get uh.

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Speaker 1: One of some of the challenges in creating a seismic graph, Well,

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Speaker 1: there's one very big challenge, which is to overcome friction.

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Speaker 1: That's a big one because see, and in a seismograph,

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Speaker 1: in a lot of cases, especially the earlier seismographs, you

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Speaker 1: would want to use a marketing device, a pen and

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Speaker 1: a piece of paper essentially, um and uh. The problem

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Speaker 1: is that the in order to be sensitive, the pen

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Speaker 1: is marking on the paper right right to record the

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Speaker 1: Earth's motion UM. But the problem is that it has

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Speaker 1: to overcome the friction of the pen on the paper

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Speaker 1: right and if it's a very very subtle quake, then

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Speaker 1: the friction may be too great for the pen to

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Speaker 1: move UM. And that that is a very big challenge.

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Speaker 1: It it doesn't seem like it would be that big,

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Speaker 1: but if you think about it, uh, you know, if

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Speaker 1: you had a UM I would imagine too for older

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Speaker 1: pens before ballpoint type technology it's created. If you had

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Speaker 1: something like some of these UM seismographs where it was

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Speaker 1: constantly moving UM, when the paper was constantly moving under

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Speaker 1: the pen, I'm not sure how you would distribute inc

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Speaker 1: to it unless it worked sort of like a fountainin

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Speaker 1: And I didn't actually research that. I wish I had

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Speaker 1: because now I'm kind of intrigued the podcast. But yeah,

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Speaker 1: I mean that the seismograph is not a twentieth century innovation,

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Speaker 1: and you know the ballpoint pen, well it wasn't either,

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Speaker 1: but the seismograph goes back farther. So another big challenge

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Speaker 1: is that you have to you have to segregate the

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Speaker 1: seismograph from other structures. Yes, So for example, here in

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Speaker 1: our building, it wouldn't do us much good to have

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Speaker 1: a seismograph here because the vibrations that we would create

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Speaker 1: in the building, the vibrations from traffic passing outside. The

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Speaker 1: seismograph would pick all that up and we get a

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Speaker 1: lot of false readings, false positives. Yeah, if you've ever

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Speaker 1: been on the top floor of a parking deck when

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Speaker 1: people are leaving at rush hour, I mean you'll feel

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Speaker 1: the motion of the cars moving and sometimes they'll you know,

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Speaker 1: you can bounce around a little bit, depending on the

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Speaker 1: parking deck. So the key to having a very good

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Speaker 1: seismograph is finding a way so that you can you

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Speaker 1: can connect it to the bedrock of whatever region you're in.

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Speaker 1: I will I will try to do flint stones. I

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Speaker 1: hated that cartoon really, Yeah, despised it with the heat

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Speaker 1: of a thousand exploding suns. Well, we won't get into

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Speaker 1: that um. But yes, you have to connect it to

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Speaker 1: the bedrock and then once sits connect to the bed

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Speaker 1: bedrock and and completely separate from other buildings. So it's

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Speaker 1: not getting essentially uh pollution really because vibration vibration, then

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Speaker 1: you can be more more sure that the readings you

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Speaker 1: get reflect what's actually going on with the Earth as

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Speaker 1: opposed to localized events. And it's interesting, this idea of

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Speaker 1: the inertial mass ends up being really really important. Yes,

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Speaker 1: and there's it's it's funny because um pendulums have been

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Speaker 1: used for a very very very long time in UH

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Speaker 1: seismological circles. UM. Because if you have a pendulum hanging

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Speaker 1: and and it's free of vibration pollution, then um, it's

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Speaker 1: just going to hang there until something acts on it

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Speaker 1: because of the laws of inertia. Basically, an object at

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Speaker 1: rest tends to stay at rest. Um. But there's something

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Speaker 1: else too. You also have to have a damper because

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Speaker 1: of the laws of inertia, because an object in motion

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Speaker 1: tends to stay in motion. So you have to have

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Speaker 1: both if you're going to have an accurate UH seismometer,

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Speaker 1: because you if once the pendulum starts to move with

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Speaker 1: the earth as it starts to shake, it will continue

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Speaker 1: to do that. And from from what i've from what

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Speaker 1: I understand, you need some kind of dampening material in

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Speaker 1: order for it to get an accurate representation of how

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Speaker 1: much the Earth is moving, which is kind of funny.

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Speaker 1: I wouldn't necessarily have thought about that, but yes, the

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Speaker 1: pendulum is just gonna keep swinging and you'll you really

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Speaker 1: won't have an idea and it's okay, well, this is it.

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Speaker 1: Was it a serious earthquake or was it a very

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Speaker 1: very mild earthquake? And you can tell both from the

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Speaker 1: pendulum moving and the inertial damper that's that stops it

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Speaker 1: from moving as much. Right, Uh. One one way to

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Speaker 1: imagine there are a couple of different variations on the

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Speaker 1: seize mobter basic design. But one way to imagine it

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Speaker 1: is imagine you've got a stand and from the stand

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Speaker 1: hangs a very very sense of spring, a very tight spring,

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Speaker 1: and there's a weight on the end of that spring,

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Speaker 1: so it's above the ground. It's just it's hanging there.

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Speaker 1: It's not moving up and down. It's it's at rest.

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Speaker 1: It's just the weight is hanging from the spring, not

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Speaker 1: moving at all. There is a pen attached to the weight,

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Speaker 1: and the pens the top of the pen is or

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Speaker 1: the the ink is rested the nib thank you like

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Speaker 1: words gone, Jonathan. The ap upset. The nib of the

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Speaker 1: pen is resting against a piece of paper that's on

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Speaker 1: a spool that's constantly turning giving fresh paper to the pen.

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Speaker 1: So when there's an earthquake, if there's up and down motion,

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Speaker 1: this is, you know, a vertical seismometer. There are different kinds,

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Speaker 1: so the weight tends to stay still. Uh. You're you

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Speaker 1: have to step outside the context of the Earth, which

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Speaker 1: is kind of weird to say, but you have to

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Speaker 1: do it. Like the Earth, the the mass is maintaining

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Speaker 1: its space, uh, and then the the everything else is

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Speaker 1: moving up and down in relation to the weight. And

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Speaker 1: that's the basis for most seismometers. There's also a kind

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Speaker 1: where it's similar except the the it's it's a horizontal seismometer,

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Speaker 1: in which there's a imagine a stand. Okay, but now

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Speaker 1: you've got a long pole that sticks out halfway through

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Speaker 1: the stand, right, So it's a horizontal pole that's connected.

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Speaker 1: It's got a it's got a hinge on it so

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Speaker 1: it can move left and right in relation to the stand.

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Speaker 1: And then there's also a spring attached from the top

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Speaker 1: of the stand to the the far end of the pole. Right.

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Speaker 1: All right, You've got you've got your weight there at

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Speaker 1: the far end of the pole. And again you've got

364
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Speaker 1: your pen attached to it. The pen's nib is against

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Speaker 1: the paper. Now, when there's an earthquake that does side

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Speaker 1: to side motion, the lever can swing to the left

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Speaker 1: and to the right. The the spring acts as the

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Speaker 1: dampener it amount because it's it's a high tension spring.

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Speaker 1: So the weight will move back and forth again again. Really,

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Speaker 1: the the paper is moving back and forth against the weight. Uh.

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Speaker 1: And that's how you get your readings for horizontal waves. UM. Now,

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Speaker 1: a good seismometer actually has will have a three axes

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Speaker 1: UH detector on it. Yes, Now, what do you were

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Speaker 1: just I'm sorry, go ahead, and I was gonna say

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Speaker 1: what you were describing before was the strained seismograph if

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Speaker 1: I'm not mistaken. Yes, Um, from from some of the

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Speaker 1: research that I had done, I understand that it really

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00:22:20,680 --> 00:22:25,520
Speaker 1: you really need to measure basically, just for the simplification

379
00:22:25,720 --> 00:22:27,480
Speaker 1: of this and and the fact that we're trying to

380
00:22:27,520 --> 00:22:31,359
Speaker 1: describe it in an UH in an audio track, left

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Speaker 1: to right, up and down, so I'm not up and

382
00:22:34,320 --> 00:22:37,600
Speaker 1: down but left and right, north to south. Uh. So

383
00:22:37,640 --> 00:22:40,240
Speaker 1: you have two different directions, and X axis and y

384
00:22:40,320 --> 00:22:43,199
Speaker 1: axis you're measuring those two and then you do have

385
00:22:43,320 --> 00:22:47,800
Speaker 1: a vertical access to UM. And you're you have pendulums

386
00:22:47,800 --> 00:22:50,680
Speaker 1: for each of those three and so really we should

387
00:22:50,680 --> 00:22:52,880
Speaker 1: say instead of left right, we should say north south

388
00:22:52,960 --> 00:22:57,440
Speaker 1: east west. Sorry, yes, that's much better, UM and UM

389
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Speaker 1: And yes, so I totally lost my train of thought. Sorry,

390
00:23:02,480 --> 00:23:04,200
Speaker 1: but yes, you have to have the three axes to

391
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Speaker 1: be able to detect, uh, what kind of earthquake is

392
00:23:07,560 --> 00:23:09,360
Speaker 1: hitting you, like, what kind of waves are moving through

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Speaker 1: the ground. Yes, And they have found another way to

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00:23:13,480 --> 00:23:18,240
Speaker 1: solve the pen on paper UH problem because some optical

395
00:23:18,359 --> 00:23:23,639
Speaker 1: seismographs use mirrors to reflect light onto photosensitive paper has

396
00:23:23,680 --> 00:23:28,240
Speaker 1: mounted on the drum. Now there the drum in in UH.

397
00:23:28,440 --> 00:23:32,639
Speaker 1: Seismographs that use a drum of paper basically have a

398
00:23:33,800 --> 00:23:35,800
Speaker 1: if you think about it as a recording point that

399
00:23:36,000 --> 00:23:40,880
Speaker 1: is gradually moving around the drum. So it starts it.

400
00:23:40,560 --> 00:23:44,000
Speaker 1: It's sort of like a recording drum that you might

401
00:23:44,480 --> 00:23:50,119
Speaker 1: see UM in those early audio recorders or a version

402
00:23:50,200 --> 00:23:52,920
Speaker 1: of the long playing vinyl record. It starts at one

403
00:23:52,960 --> 00:23:56,560
Speaker 1: point and gradually goes in a spiral around as the

404
00:23:56,640 --> 00:24:00,560
Speaker 1: drum goes So it's recording the movement of the as

405
00:24:00,840 --> 00:24:06,040
Speaker 1: time goes on, and the the fact that it is moving. UM.

406
00:24:06,720 --> 00:24:11,919
Speaker 1: And distance to shows you roughly when those uh, those

407
00:24:11,960 --> 00:24:16,400
Speaker 1: seismological waves are taking place. UM, And I think that's

408
00:24:16,440 --> 00:24:20,119
Speaker 1: really that the optical seismograph is an elegant solution to

409
00:24:21,119 --> 00:24:24,400
Speaker 1: the problem. Of course, es since you're using photosensitive paper,

410
00:24:24,440 --> 00:24:26,439
Speaker 1: that means you also have to be recording this in

411
00:24:26,480 --> 00:24:28,639
Speaker 1: the dark. Yeah, there are there are quite a few

412
00:24:29,160 --> 00:24:35,160
Speaker 1: seismic uh seismoscopes and seismommits that no longer use pen

413
00:24:35,280 --> 00:24:39,480
Speaker 1: or paper at all. They're just using various sensors, so

414
00:24:39,560 --> 00:24:41,919
Speaker 1: that I mean, there's some where they have the paper

415
00:24:42,160 --> 00:24:44,600
Speaker 1: counterpart as well to show off to the public whenever

416
00:24:44,600 --> 00:24:46,280
Speaker 1: the public wants to watch it, because it's a lot

417
00:24:46,280 --> 00:24:49,200
Speaker 1: more interesting to see the pen against paper, especially since

418
00:24:49,240 --> 00:24:53,360
Speaker 1: that's such an iconic image for size seismographs. I remember

419
00:24:53,480 --> 00:24:56,639
Speaker 1: seeing the little needle like pens, you know then and

420
00:24:56,760 --> 00:25:01,200
Speaker 1: watching the paper tape scroll through any united is scratching

421
00:25:01,760 --> 00:25:06,400
Speaker 1: seismology and light detectors many so it is a very

422
00:25:06,440 --> 00:25:09,240
Speaker 1: it is there is something very satisfying about seeing that.

423
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Speaker 1: But the truth is is that a lot of the

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00:25:11,280 --> 00:25:14,960
Speaker 1: modern ones just use sensors. Now, let's talk about um

425
00:25:15,840 --> 00:25:18,800
Speaker 1: identifying where the focus of an earthquake is, because here's

426
00:25:18,840 --> 00:25:23,440
Speaker 1: another thing. You can have the most advanced seismicograph or

427
00:25:23,520 --> 00:25:26,720
Speaker 1: seismometer in the world, and it's not necessarily going to

428
00:25:26,760 --> 00:25:29,440
Speaker 1: tell you where the focus is. What it's gonna tell

429
00:25:29,480 --> 00:25:32,840
Speaker 1: you is how far away the earthquake is, right, and

430
00:25:33,080 --> 00:25:35,560
Speaker 1: we're how far away the focus of the earthquake is right.

431
00:25:35,600 --> 00:25:39,760
Speaker 1: And I think that's um that's sort of a frustrating

432
00:25:39,880 --> 00:25:43,160
Speaker 1: point for geologists because as much as they know, they

433
00:25:43,200 --> 00:25:49,320
Speaker 1: still have difficulty um being pinpoint accurate too. And they're

434
00:25:49,359 --> 00:25:51,919
Speaker 1: they're very good at what they do, but they're very

435
00:25:51,920 --> 00:25:55,840
Speaker 1: good at measuring, yes, But there I think the material

436
00:25:56,320 --> 00:25:59,640
Speaker 1: inside the earth is difficult for them. Makes it makes

437
00:25:59,640 --> 00:26:03,400
Speaker 1: life because when you talk about the epicent of the earthquake,

438
00:26:03,400 --> 00:26:04,800
Speaker 1: you're not saying, well, you know it's down at the

439
00:26:04,800 --> 00:26:07,160
Speaker 1: corner of Fifth and Maine. You also have to figure

440
00:26:07,160 --> 00:26:10,560
Speaker 1: out how deep within the earth it is. And that

441
00:26:10,680 --> 00:26:14,080
Speaker 1: also it's you know, once it gets down to a

442
00:26:14,160 --> 00:26:17,760
Speaker 1: certain point, it's very very it's sort of is a fustcutory.

443
00:26:17,840 --> 00:26:22,320
Speaker 1: You can't really tell as accurately as you would like to. Um. Yeah,

444
00:26:22,359 --> 00:26:24,480
Speaker 1: and then that just that just makes these tools the

445
00:26:24,600 --> 00:26:28,320
Speaker 1: more accurate they become. There's still an element of difficulty,

446
00:26:28,760 --> 00:26:32,119
Speaker 1: and and and to make matters even more difficult. Um,

447
00:26:32,240 --> 00:26:36,960
Speaker 1: the primary waves and secondary waves have different different traits.

448
00:26:37,320 --> 00:26:41,480
Speaker 1: Primary waves can move through anything. They move through solids, liquids,

449
00:26:41,480 --> 00:26:44,880
Speaker 1: and gas. Secondary waves, however, can only move through solids.

450
00:26:45,520 --> 00:26:49,800
Speaker 1: So once they hit the liquid center, the delicious liquid

451
00:26:49,800 --> 00:26:52,320
Speaker 1: center of the Earth, that they don't go any further

452
00:26:52,359 --> 00:26:57,960
Speaker 1: than that. Um. But you know, there are there seismographs

453
00:26:57,960 --> 00:27:01,040
Speaker 1: out there that are sensitive enough to, at least in theory,

454
00:27:01,119 --> 00:27:03,320
Speaker 1: detect an earthquake even if it's happening on the other

455
00:27:03,400 --> 00:27:07,560
Speaker 1: side of the world. So how do earthquake scientists figure

456
00:27:07,560 --> 00:27:11,080
Speaker 1: out where the epicenter of an earthquake is. They have

457
00:27:11,160 --> 00:27:16,480
Speaker 1: to consult multiple seismic graphs, and they they do it

458
00:27:16,560 --> 00:27:19,359
Speaker 1: with three of them. And this is going to be

459
00:27:19,400 --> 00:27:23,080
Speaker 1: familiar to anyone who has done any kind of navigation. UM.

460
00:27:23,200 --> 00:27:25,960
Speaker 1: The reason here is that, like I said before, that

461
00:27:26,080 --> 00:27:28,679
Speaker 1: you measure the difference between the primary wave that the

462
00:27:28,680 --> 00:27:30,840
Speaker 1: time it takes a primary wave and a secondary wave

463
00:27:30,880 --> 00:27:32,760
Speaker 1: to hit you, and that's how you can figure out

464
00:27:33,119 --> 00:27:36,360
Speaker 1: how far away the thing is. Right. Well, that creates

465
00:27:37,160 --> 00:27:41,640
Speaker 1: a sphere, a virtual sphere around the seismic graph. Okay,

466
00:27:41,920 --> 00:27:44,679
Speaker 1: let's say that we know that the epicenter of the

467
00:27:44,720 --> 00:27:49,200
Speaker 1: earthquake is twenty five miles away from our seismic graph,

468
00:27:49,320 --> 00:27:51,600
Speaker 1: So that's twenty five miles in every direction. We we

469
00:27:51,640 --> 00:27:55,080
Speaker 1: don't know the origin of this. Now, of course, you

470
00:27:55,119 --> 00:27:56,680
Speaker 1: can go ahead and say, all right, it's not gonna

471
00:27:56,680 --> 00:28:00,520
Speaker 1: be the sky, but at any rate, can imagine that.

472
00:28:01,640 --> 00:28:04,560
Speaker 1: So you then call up your buddy who's a couple

473
00:28:04,560 --> 00:28:07,240
Speaker 1: of cities away, and say, hey, we just had an earthquake.

474
00:28:07,240 --> 00:28:09,399
Speaker 1: Do you guys have an earthquake registered on there too?

475
00:28:09,400 --> 00:28:12,040
Speaker 1: And he says, yeah, yeah, it's seventy five miles away. Well,

476
00:28:12,080 --> 00:28:15,280
Speaker 1: now you take the intersection of your sphere and their

477
00:28:15,359 --> 00:28:18,800
Speaker 1: sphere at every point where it's you know where where

478
00:28:18,840 --> 00:28:22,320
Speaker 1: those two spheres connect, and say, okay, the epicenter is

479
00:28:22,320 --> 00:28:24,600
Speaker 1: somewhere in here. Then you call up a third well,

480
00:28:24,640 --> 00:28:27,280
Speaker 1: a third person. It's your second buddy. You call up

481
00:28:27,280 --> 00:28:30,160
Speaker 1: your second buddy, he's in another city. He said, hey,

482
00:28:30,240 --> 00:28:32,640
Speaker 1: we have an earthquake. Do you guys notice anything? So, yeah,

483
00:28:32,680 --> 00:28:35,840
Speaker 1: it was thirty miles away. And you take those three uh,

484
00:28:36,000 --> 00:28:38,040
Speaker 1: those those three measurements, and that's going to give you

485
00:28:38,080 --> 00:28:41,000
Speaker 1: a point on the map. It'll actually give you two

486
00:28:41,120 --> 00:28:43,640
Speaker 1: you'll get two connections that it could possibly be, but

487
00:28:43,680 --> 00:28:44,920
Speaker 1: one of them is going to be in the sky,

488
00:28:45,880 --> 00:28:48,240
Speaker 1: and that means you can count that one out. The

489
00:28:48,240 --> 00:28:51,320
Speaker 1: one that's in the earth. That's the epicenter of the

490
00:28:51,320 --> 00:28:56,720
Speaker 1: earthquake's triliteration. Okay, I'll try it. No, no, no no, that's

491
00:28:56,840 --> 00:28:59,840
Speaker 1: t r I. But yeah, it's you know, it's this

492
00:29:00,040 --> 00:29:02,480
Speaker 1: idea of it's something that we've used, like I said,

493
00:29:02,480 --> 00:29:05,600
Speaker 1: in navigation, where you it's like triangulating. It's the same

494
00:29:05,640 --> 00:29:08,920
Speaker 1: sort of principles that you need three points and from

495
00:29:08,920 --> 00:29:11,760
Speaker 1: those three points, once you've made the measurements, you can

496
00:29:11,760 --> 00:29:16,520
Speaker 1: figure out where that epicenter is. Yeah, and that's that's important.

497
00:29:16,560 --> 00:29:21,360
Speaker 1: That's why so many scientists, especially around the uh what

498
00:29:21,520 --> 00:29:24,040
Speaker 1: is known as the Ring of Fire, an area of

499
00:29:24,080 --> 00:29:28,080
Speaker 1: intense geologic activity. They're scientists all over the world who

500
00:29:28,160 --> 00:29:32,959
Speaker 1: have access to this kind of equipment and that's so

501
00:29:33,080 --> 00:29:37,840
Speaker 1: very important to determining um. There are a lot of

502
00:29:37,840 --> 00:29:39,959
Speaker 1: things that that go into this in addition to just

503
00:29:40,040 --> 00:29:43,960
Speaker 1: the earthquake and finding out where the epicenter is. Because

504
00:29:44,280 --> 00:29:47,920
Speaker 1: if you have earthquakes, say off the coast in the

505
00:29:47,920 --> 00:29:53,480
Speaker 1: middle of the ocean, they might produce tsunami and uh,

506
00:29:53,680 --> 00:29:56,800
Speaker 1: knowing roughly where the epicenter is can give you an

507
00:29:56,840 --> 00:30:01,320
Speaker 1: idea of where you might expect to see a tsunami

508
00:30:01,440 --> 00:30:05,520
Speaker 1: and and roughly how long you might have until you

509
00:30:05,560 --> 00:30:11,040
Speaker 1: would expect it on shore. UM. So that's very very important, UM,

510
00:30:11,160 --> 00:30:14,920
Speaker 1: and is really really useful in enable you know, in

511
00:30:15,080 --> 00:30:17,560
Speaker 1: enabling people to do that. UM. And you can use

512
00:30:17,800 --> 00:30:21,360
Speaker 1: you can use a seismological equipment to do all kinds

513
00:30:21,360 --> 00:30:23,920
Speaker 1: of other things too. They use it in patroleum exploration,

514
00:30:24,760 --> 00:30:28,440
Speaker 1: monitoring volcanic activity. Of course, these these two are actually

515
00:30:28,520 --> 00:30:32,520
Speaker 1: very very closely related. UM. That's because sound will move

516
00:30:32,560 --> 00:30:35,480
Speaker 1: at a different speed depending upon the medium it's moving through.

517
00:30:36,200 --> 00:30:39,840
Speaker 1: And by knowing the speeds that sound moves in and

518
00:30:39,880 --> 00:30:43,800
Speaker 1: the various medium or media that it can that you

519
00:30:43,840 --> 00:30:47,640
Speaker 1: could possibly encounter, you can start to narrow down like, oh,

520
00:30:47,800 --> 00:30:51,000
Speaker 1: this is a likely place for oil versus this it

521
00:30:51,080 --> 00:30:53,160
Speaker 1: is unlikely that we would find oil it were we

522
00:30:53,240 --> 00:30:55,880
Speaker 1: to drill here. And we talked about a little bit

523
00:30:55,880 --> 00:30:59,000
Speaker 1: about that in our Auto Tune podcast. Yeah yeah, and

524
00:30:59,040 --> 00:31:03,600
Speaker 1: the oil drilling episode two. UM. So yeah, these are

525
00:31:03,640 --> 00:31:06,920
Speaker 1: these are certainly very important devices and UM, you know,

526
00:31:07,880 --> 00:31:09,520
Speaker 1: can you think of anything else that we need to. Yeah,

527
00:31:09,560 --> 00:31:12,520
Speaker 1: let's let's talk really quickly about the Richter scale. Oh,

528
00:31:12,520 --> 00:31:14,680
Speaker 1: the Richter scale, we haven't even touched on that. So

529
00:31:14,920 --> 00:31:17,480
Speaker 1: Richter scale is you may have heard about the Richter scale,

530
00:31:17,600 --> 00:31:19,920
Speaker 1: about that being a way of measuring the magnitude of

531
00:31:19,960 --> 00:31:23,960
Speaker 1: an earthquake. The Richter scale is a scale in which

532
00:31:24,560 --> 00:31:30,320
Speaker 1: each whole number is uh ten times more powerful. I

533
00:31:30,320 --> 00:31:33,200
Speaker 1: guess you could say or has a magnitude of ten

534
00:31:33,280 --> 00:31:37,440
Speaker 1: times the previous whole number. So a magnitude to earthquake

535
00:31:37,960 --> 00:31:42,320
Speaker 1: has ten times the magnitude of a one earthquake excellent,

536
00:31:42,400 --> 00:31:45,720
Speaker 1: and three would have ten times that the two and um,

537
00:31:45,800 --> 00:31:50,680
Speaker 1: So these numbers get big really quickly. Anything below of

538
00:31:50,760 --> 00:31:53,680
Speaker 1: four is pretty much a minor earthquake, and in fact

539
00:31:53,880 --> 00:31:58,000
Speaker 1: three or lower you're not likely to feel. Anything that's

540
00:31:58,040 --> 00:32:00,400
Speaker 1: a seven or higher is a major earth wake. That's

541
00:32:00,440 --> 00:32:03,080
Speaker 1: that's going to cause lots of damage should it hit

542
00:32:03,120 --> 00:32:08,320
Speaker 1: any populated area. Um and some serious side effects can

543
00:32:08,360 --> 00:32:10,920
Speaker 1: happen to We're talking about things like a fissure opening

544
00:32:11,000 --> 00:32:15,200
Speaker 1: up and magma pouring out, or the tsunami, as Chris

545
00:32:15,240 --> 00:32:18,240
Speaker 1: was mentioned, that could also be a byproduct. Those are

546
00:32:18,320 --> 00:32:19,959
Speaker 1: those are the really bad ones. Anything that's in the

547
00:32:20,000 --> 00:32:22,800
Speaker 1: six to seven range is still bad bad, it's just

548
00:32:22,840 --> 00:32:25,840
Speaker 1: not considered a major earthquake. Now, that's not the only

549
00:32:25,880 --> 00:32:28,360
Speaker 1: scale we used to measure earthquakes, or at least not

550
00:32:28,360 --> 00:32:32,280
Speaker 1: the effects of earthquakes. Do you know of the Marcali scale? No,

551
00:32:32,440 --> 00:32:37,640
Speaker 1: I don't, Okay, So the Richter scale is more it's scientific, right,

552
00:32:37,720 --> 00:32:40,800
Speaker 1: you are actually taking measurements of the earthquake and you're saying,

553
00:32:40,800 --> 00:32:44,280
Speaker 1: based upon this magnitude, this is how powerful this earthquake was.

554
00:32:44,920 --> 00:32:48,200
Speaker 1: So it's a scientific measurement. The Marcali scale is more

555
00:32:48,280 --> 00:32:52,560
Speaker 1: of a subjective measurement. Marcali scale is the scale of

556
00:32:52,760 --> 00:32:59,240
Speaker 1: damage done by an earthquake. Now, for earthquakes where where

557
00:32:59,280 --> 00:33:03,200
Speaker 1: you can feel the earth shaking, but but it's not

558
00:33:03,320 --> 00:33:05,840
Speaker 1: strong enough to actually damage anything. That would be a

559
00:33:05,920 --> 00:33:11,280
Speaker 1: category two on the Mercaulli scale. So one would be

560
00:33:11,320 --> 00:33:14,280
Speaker 1: an earthquake you couldn't even feel. Now it goes up

561
00:33:14,320 --> 00:33:17,360
Speaker 1: to all the way up to twelve. That's a quake

562
00:33:17,400 --> 00:33:21,160
Speaker 1: that's so powerful that's doing major structural damage in the area.

563
00:33:21,360 --> 00:33:23,520
Speaker 1: So let's look, I'm gonna finish up here with one

564
00:33:23,600 --> 00:33:25,960
Speaker 1: other thing that we we talked that I wanted to

565
00:33:25,960 --> 00:33:30,480
Speaker 1: talk about. There was a discussion recently online about the

566
00:33:30,480 --> 00:33:36,280
Speaker 1: possibility that solar flares could somehow induce earthquakes and predict earthquakes. Yes,

567
00:33:36,320 --> 00:33:38,880
Speaker 1: we we had a solar flare not too long ago,

568
00:33:38,960 --> 00:33:41,520
Speaker 1: and then there was the earthquake in christ Church, and

569
00:33:41,600 --> 00:33:45,040
Speaker 1: so some have said that that that the solar flare

570
00:33:45,080 --> 00:33:49,040
Speaker 1: in in effect predicted the earthquake. I'm not so quick

571
00:33:49,080 --> 00:33:52,440
Speaker 1: to jump on this. I've done some research, alcoholic preliminary.

572
00:33:52,720 --> 00:33:55,520
Speaker 1: I've done some preliminary research into this, and I can't

573
00:33:55,600 --> 00:34:01,120
Speaker 1: find any um accepted scientific study that really points to

574
00:34:01,200 --> 00:34:05,120
Speaker 1: a connection. There's some that seemed to say there's some

575
00:34:05,200 --> 00:34:09,560
Speaker 1: sort of uh connection there, but nothing that's actually, you know,

576
00:34:09,719 --> 00:34:12,759
Speaker 1: really like, nothing that that really grabs me and says

577
00:34:12,880 --> 00:34:16,400
Speaker 1: this is this is proof. Most of it seems circumstantial.

578
00:34:16,400 --> 00:34:18,640
Speaker 1: A lot of it has confirmation bias written all over it,

579
00:34:18,640 --> 00:34:21,840
Speaker 1: which is a logical fallacy. And I was trying to

580
00:34:21,840 --> 00:34:24,839
Speaker 1: search around to find because I saw things saying that

581
00:34:24,840 --> 00:34:29,440
Speaker 1: that that the solar flare did in effect predict the

582
00:34:29,520 --> 00:34:32,880
Speaker 1: earthquake in christ Church. One of them, one of the

583
00:34:32,960 --> 00:34:36,799
Speaker 1: sources I found made at error that I just wanted

584
00:34:36,800 --> 00:34:38,239
Speaker 1: to point out. And I'm not saying that this is

585
00:34:38,280 --> 00:34:42,160
Speaker 1: necessarily the the crux of the entire argument, or that

586
00:34:42,239 --> 00:34:45,040
Speaker 1: this is the source. But it was a blog that

587
00:34:45,040 --> 00:34:51,120
Speaker 1: that quoted a NASA UM scientist, and you think, okay,

588
00:34:51,239 --> 00:34:54,160
Speaker 1: NASA people, they know a lot about solar flares. Well,

589
00:34:54,200 --> 00:34:57,960
Speaker 1: the quote was the total energy in a space quake, which,

590
00:34:58,000 --> 00:35:00,960
Speaker 1: by the way, that's what happens when the energy from

591
00:35:00,960 --> 00:35:04,680
Speaker 1: a solar flare and encounters the Earth's magnetosphere. The total

592
00:35:04,760 --> 00:35:08,359
Speaker 1: energy in a spacequake can rival that of a magnitude

593
00:35:08,440 --> 00:35:13,680
Speaker 1: five or six earthquake. Now, the blogger chose to interpret

594
00:35:13,760 --> 00:35:19,480
Speaker 1: this as saying that space quakes cause magnitude five or

595
00:35:19,560 --> 00:35:23,719
Speaker 1: six earthquakes. That's not the case. What the scientist said

596
00:35:23,920 --> 00:35:27,800
Speaker 1: was that the amount of energy is equivalent to an earthquake,

597
00:35:27,880 --> 00:35:31,480
Speaker 1: not that one causes the other. Right, And I made

598
00:35:31,520 --> 00:35:35,799
Speaker 1: a I just made up an analogy that said, if

599
00:35:35,840 --> 00:35:39,920
Speaker 1: we said that a redwood, fully mature redwood falling in

600
00:35:40,000 --> 00:35:42,400
Speaker 1: the forest and hitting the ground had the same amount

601
00:35:42,440 --> 00:35:44,879
Speaker 1: of of energy to it, the same amount of force

602
00:35:44,960 --> 00:35:48,560
Speaker 1: to it that a locomotive moving at seventy five miles

603
00:35:48,640 --> 00:35:51,160
Speaker 1: per hour has, we would not say that a tree

604
00:35:51,239 --> 00:35:53,960
Speaker 1: falling in the forest causes the locomotive to go seventy

605
00:35:54,000 --> 00:35:56,919
Speaker 1: five miles per hour. There's no connection between the two

606
00:35:56,960 --> 00:35:59,400
Speaker 1: other than the fact that the magnitude of the energy

607
00:35:59,520 --> 00:36:02,920
Speaker 1: is the same. Aim. So now I'm not saying that

608
00:36:03,000 --> 00:36:05,680
Speaker 1: there is no connection. I'm saying I can't find any

609
00:36:05,719 --> 00:36:09,640
Speaker 1: scientific study that gives me a very definitive answer, or

610
00:36:09,640 --> 00:36:14,600
Speaker 1: even a semi definitive answer. So but from the geologists

611
00:36:14,600 --> 00:36:18,640
Speaker 1: that I referenced, most of them seem skeptical, saying that

612
00:36:19,000 --> 00:36:24,040
Speaker 1: really earthquakes mostly that mostly are caused by these plate movements,

613
00:36:24,080 --> 00:36:29,520
Speaker 1: which are not affected by magnetic phenomena. Okay, I just

614
00:36:29,520 --> 00:36:34,919
Speaker 1: wanted to head that off a well, let's clarified nicely. Yeah, well,

615
00:36:35,280 --> 00:36:37,200
Speaker 1: I didn't write a blog post this time. At least

616
00:36:37,920 --> 00:36:41,880
Speaker 1: I've been doing that. Jonathan responds to people who have

617
00:36:41,960 --> 00:36:44,160
Speaker 1: no interest in what he has to say. I guess

618
00:36:44,200 --> 00:36:45,879
Speaker 1: that's what blogging is all about, really, when I get

619
00:36:45,880 --> 00:36:49,240
Speaker 1: down to it. Okay, so let's wrap this up, guys. Uh,

620
00:36:49,520 --> 00:36:53,600
Speaker 1: that's our our discussion on seismology and seismological equipment. If

621
00:36:53,600 --> 00:36:56,200
Speaker 1: you have any questions or you want to share some stories,

622
00:36:56,239 --> 00:36:58,920
Speaker 1: if you've been in an earthquake and you got some

623
00:36:58,920 --> 00:37:02,240
Speaker 1: some tales to hell. You can let us know on

624
00:37:02,239 --> 00:37:06,120
Speaker 1: Facebook and Twitter are handled. There is tech Stuff hs W,

625
00:37:06,480 --> 00:37:08,560
Speaker 1: or you can shoot us an email. That address is

626
00:37:08,760 --> 00:37:11,120
Speaker 1: tech stuff at how stuff works dot com and Chris

627
00:37:11,120 --> 00:37:15,160
Speaker 1: and I will taught to you again really soon. For

628
00:37:15,280 --> 00:37:17,640
Speaker 1: more on this and thousands of other topics, visit how

629
00:37:17,680 --> 00:37:20,360
Speaker 1: stuff works dot com. So learn more about the podcast,

630
00:37:20,560 --> 00:37:23,080
Speaker 1: click on the podcast icon in the upper right corner

631
00:37:23,120 --> 00:37:27,240
Speaker 1: of our homepage. The how Stuff Works iPhone app has arrived.

632
00:37:27,360 --> 00:37:34,600
Speaker 1: Download it today on iTunes, brought to you by the

633
00:37:34,640 --> 00:37:38,000
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