How would you know if you were experiencing an...
EARTHQUAKE!
WELL, BESIDES THE OBVIOUS, THERE'S THIS!
This is the Raspberry Shake, and you can use it to monitor seismic activity at your home,
and you can also contribute to ShakeNet, a global database with nearly 2000 stations!
This thing was designed by a team in Panama, and they wanted to make it so anyone could
participate in a global citizen science project: listening to the earth as it moves!
But wait, listening to the earth?
The earth doesn't talk, does it?
Well, prepare for your mind to be blown: the earth transmits its own kind of sound, in
waves, just like the ocean.
It's way more complex than that, but for now, bear with me.
Have you ever seen one of these?
It's a seismograph.
But technology has come a long way since the days of a giant drum and a mechanical arm
scribbling earth's movements on paper.
The Raspberry Shake I have is the most basic model, the 1D.
It has one geophone that measures vertical earth motion, the 'waves' of up and down motion
that happen whenever the earth vibrates.
Just like those old seismographs, it records a one-dimensional value on a graph over time.
But unlike those old seismographs, that data is stored on the Pi locally, and also aggregated
online with thousands of other Shakes, in real-time.
And this system is helping extend the digital revolution of seismology.
But I know next to nothing about seismology, so I thought I'd call up an expert.
My name is Bob Herman.
I'm a professor emeritus of geophysics at St. Louis University And I've been looking
at seismograms since 1964, so I think I've seen a few over the years.
I actually went to Saint Louis University—or SLU as we call it—and took meteorology and
oceanography, but I had no idea about the history of earthquake research on campus—or
the fact that Dr. Herrmann had already been studying earthquakes decades before I was
born!
Not only that, the university has operated seismographs on-campus since 1909, starting
with this Wiechert seismograph!
So we've had instruments here since 1909, the first instrument which we'll show you
shortly recorded on smoke paper.
[Jeff] I don't know what it is.
[Bob] Well, you take a piece of paper, you hold it over an alcohol lamp, puts soot on
it.
You put on a drum, and then on the drum, there's a little stylus.
And as the stylus drags, it lifts the soot off.
And what you'll then see is a little white stripe on the black background.
If there's no earthquake, you recycle it by smoking again the next day.
If there is an earthquake, they would run this through shellac to permanently bond the
soot to the paper.
That... sounds like a lotta work.
He also had some examples of photographic recordings made with seismographs like this
one, which used light and a mirror to expose paper and produce permanent records like these,
from Florissant, Missouri in the 1950s.
If they wanted to record different frequencies, to get more information about an earthquake,
they had to have multiple instruments, so they might have four or more sheets of paper
they'd have to look at to study any single earthquake.
And I asked Dr. Herrmann about how that worked in the 60s and 70s, and he said:
I started this as an undergraduate at Xavier University in Cincinnati, where my job was
to drive 20 miles one way each day to a place go into a dark room, change the paper, and
then come back and process this.
So this, you know, it's a photographic record, photographic smelly, chemicals, and we're
doing things with big sheets of paper.
It's like doing laundry.
And studying historic earthquakes was even more work.
I asked him what it was like when he got his doctorate back in 1974 and he said this:
Okay, what was my dissertation?
I studied 10 earthquakes, and to study one earthquake took at least a month to get the
data, because I had to write letters to different seismograph stations, have them copied.
When I got the paper records back, we had to convert the squiggles to numbers, and we
had a digitizer, and that all went on to IBM cards.
And then you have to take them over across campus to the computer on campus.
So you spend a lot of time writing programs, maybe thinking more about the programs and
a lot of time just preparing the data.
That sounds like a lotta work, when nowadays, we're used to just pressing a button and the
computer does everything for us!
Even without devices like the Raspberry Shake, the digital revolution meant researchers like
Dr. Herrmann can devote more time to studying data and improving outcomes.
So, yeah, I can do more.
I can do it faster.
But then what I'm interested in doing or what I do is somewhat routine.
And then you provide all these results, and then someone else can then use this to do
their research studies.
So nobody uses those old seismographs.
I asked Dr. Herrmann if I could see the instruments they're using today, and he brought me to
SLU's Seismic Vault, which was set up on a concrete slab on bedrock in 1927, and has
been recording data 24x7 for almost a hundred years now.
Right now I just have my Raspberry Shake sitting on the concrete floor in my basement.
But if you wanna isolate just the earth's movement and not have a bunch of background
noise, like the vibration from household appliances, you need to put a seismometer as close to
bedrock as possible.
Heck, you can see exactly when the washer started its spin cycle here, and then whenever
the dryer goes on it creates a constant 30 hertz vibration.
So to try to cancel out the effect of road noise, weather patterns, and even humans walking
around, SLU set up their vault on bedrock.
[Jeff] So that brings me to an interesting point.
Like the one in my basement.
I put it on the slab, but I can watch my washing machine when it turns on and see the oscillation
of the motor spinning and stuff.
So I see all that local noise.
This is still seemingly connected somehow.
Like what is the special thing about setting it here?
[Bob] Well, one thing is, even though it's dirty down there, if you look down there,
this [slab] is not connected to the building.
There's a crack down there between the floor of the building and this.
Okay, so this is then concrete which is poured onto the hard rock.
[Jeff] Okay.
So it goes down further.
[Bob] Yeah.
But still, it will pick up local noise.
So at one time, I was interested in quantifying the noise that certainly one could tell around
here whether it's a weekday or a weekend by how much traffic is on I-64.
You could also talk about how much you know—hey, Sunday mornings on campus, students are not
awake, so it's quiet on campus.
So anything that generates noise will be picked up and recorded.
And weather fronts coming by will make signals because what weather fronts will do to the
building is they will cause the building to tilt, and so the horizontals, after long periods,
will pick that up.
And the seismometers are so sensitive that they even had to worry about things like the
atmosphere rushing into the room too quickly, so they even have these double doors just
to get into the room.
And later, when we were back in Dr. Herrmann's office, he even showed how when we went into
the vault, the seismometers picked up that change in pressure.
They're really sensitive.
On the slab, they had a Raspberry Shake in the middle, but it was surrounded by a bunch
of other seismographs.
In addition to the old Wiechert that's in storage, they had old analog electromagnetic
seismographs, nicknamed "Big Benioff" and "Little Benioff".
This one here in the round one is called a Baby Benioff because it's smaller than this.
It also means it's a lot lighter.
These have been here since 1960 and they've never really been moved.
One reason is they're very heavy.
So the reason they're still here is that this stuff is heavy.
Then over next to the Raspberry Shake, there are a couple broadband seismometers by Trillium,
those things cost like ten thousand bucks!
The big difference between a ten thousand dollar broadband seismometer and the little
geophone in the shake is you can measure a lot more earthquakes.
So these things will have a good response so that we could go down to maybe periods
as long as 100 seconds.
So this would be good for distant earthquakes or for regional earthquakes.
But they also are sensitive at high frequencies, so they provide the information to locate
small earthquakes nearby.
[Jeff] High frequencies, being still...
[Bob] High frequencies would be below the frequency that the human ear can hear.
Dogs might hear it, but not us.
And you know what?
You can actually see the live data from all of SLU's instruments on their Earthquake Center
website.
Just...
don't all go at once, I don't know how many concurrent users Wiggles can handle.
Wiggles.
[Jeff] Is that the name of the server?
[Bob] Yeah, or Shake or whatever or Query is a good one."
Heh, can't stop a programmer from having a little fun naming things.
Anyways, that's a bit about SLU's seismographs.
They had a Raspberry Shake sitting in the middle of all those expensive seismographs.
So, can the Shake hold its own?
Well, for starters, here's a closeup of the hardware you get if you buy the Shake 1D,
like I have.
It has a Raspberry Pi, the Shake sensor HAT, a vertical geophone, that's this round cylinder
thing, and a bull's eye level, to help you make sure you place your Shake on a flat surface.
And all that comes in this clear acrylic case.
But you might go on Raspberry Shake's website and wonder, why does this thing start at almost
$400?
Well, yeah, if you add up the price of each of the components, and we're generous saying
the geophone's about fifty bucks, the custom case is fifty, the custom HAT is fifty, and
the Pi is ... wait, 90 bucks now!?
Well, even with the insane scalping going on, that doesn't all add up to four hundred
bucks.
So what's the value?
Well, it's the software, and the global network.
If you just wanna buy all the parts and build your own little seismograph Pi, that's doable
for a lot less.
But the Raspberry Shake is more than that.
The Shake hardware's been tested and validated against multi-thousand dollar gear like those
Trilliums in SLU's vault.
Also the software that runs on the Shake is maintained, and that costs money.
Plus ShakeNet, the global network of Raspberry Shakes, requires servers and maintenance,
and the team behind it hasn't been idle either.
In the past few years since they first built the Raspberry Shake, the team is continually
making their software better.
They even built this mobile app that lets me monitor my Shake anywhere, in real-time,
and they're continuing to build out their APIs for seismology around the globe.
So the four hundred bucks isn't just the price for the hardware, it's the price to be part
of a global seismic network.
And if you're wondering if it works?
Well, it does!
In fact, using the data from my sensor that's in ShakeNet, Dr. Herrmann actually pulled
up an earthquake that happened right by my house a few weeks ago!
That's right, this graph, built using some software Dr. Herrmann wrote, is the first
real earthquake I measured, from April 29.
These two spikes are the P and S waves, and it's amazing being able to see exactly what
over 4,000 other St. Louisans felt during that small earthquake.
And Dr. Herrmann has his own Raspberry Shake on a mantle at his house, and here's the graph
from his Shake.
Dr. Herrmann's software can also pull data from any Raspberry Shake in a predefined radius
and put them together on a graph, like this.
And I don't know who owns R474C or RA111, but you can see how the earthquake took a
lot longer to get to those two locations, and how the way the earth moved changed, based
on geography.
And heck, while I was writing this script, another earthquake happened in Southern Illinois
that my shake clearly picked up, though it was a lot quieter relative to the day-to-day
noises in the house.
But who cares about any of this?
Can a global network of these things do anything to prevent the loss of life or property because
of an earthquake?
Well, actually, yes.
Individual earthquakes can cause millions, or even billions of dollars of damage.
And in some areas, like around Oklahoma, where underground wastewater disposal caused a huge
increase in human-induced earthquakes, it's important to hold corporations accountable
for the environmental impact they have.
And earthquake sensor networks can help researchers study the frequency of earthquakes, and also
quickly estimate what kind of emergency response—if any—is needed.
Where the modern estimates or the present day estimates coming in from Shake Map from
the US Geological Survey, there is a very rapid estimate of just how many people could
have been killed.
So if you got so many people killed, that also means you're going to have so many people
homeless.
And that information can then be used to marshall global response to a disaster, so that you
can get in medical teams, you can get in equipment, you can get in everything to sustain life
like water and everything else.
So a lot of what we did, you know, we're still doing research to learn about the Earth, to
learn about earthquakes using the earthquake data.
But we're also contributing to a global disaster response.
And besides accountability and disaster response, seismologists can help inform building codes.
Then, new buildings in earthquake-prone areas can be built to withstand stronger earthquakes,
and help reduce the damage and human casualties caused by earthquakes.
And there are many other uses for seismic data.
At one level, you might have engineers that are interested in just what happens in the
upper 30 meters of the Earth.
That has to do with the hard rock round motion coming up with the surface.
It's modified by the soils you build on top of the soils.
Build your building strong.
Okay.
Another level of Seismology is you're trying to find something underground.
And so you might want to look down maybe 4 or 5 kilometers.
That would be the expiration industry for oil and natural gas.
Another part of Seismology might be interested in earthquake studies, another part might
be interested in volcanoes.
And then of course, there's a whole group that's interested in underground nuclear explosions.
So in this country, the US Geological Survey worries about earthquakes, National Oceanographic
and Atmospheric Agency worries about tsunamis, which also generates seismic waves.
And then the Air Force Technical Application Center is worried about underground nuclear
explosions.
And that last part, the AFTAC, operates the U.S. Atomic Energy Detection System.
They use seismograph networks to detect large-scale explosions, and help enforce things like the
Partial Nuclear Test Ban Treaty.
So a simple little sensor like this one, when its part of a global network, can contribute
useful data to geophysicists around the world, and be used to preserve human life.
We can't predict earthquakes, and probably never will be able to, but having so much
more data, and making it easier to access, means researchers like Dr. Herrmann and the
new students he's taught over the years can make the aftermath much better.
You can find out more about the Raspberry Shake, and all the different models they have
available, at raspberryshake.com.
Huge thanks to them, and to Dr. Bob Herrmann and SLU for teaching me about seismology and
showing me their seismic vault, and until next time, I'm Jeff Geerling.