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earlier this year a 7.8 magnitude earthquake
hit turkey in Syria it was the deadliest day
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in modern history for both countries and more than
75,000 separate buildings were destroyed if you're
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wondering if it's somehow airag gun's fault the
answer is basically yes but also just this time
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a little bit no it does admittedly make sense
that these countries weren't totally prepared
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for an earthquake like this the last time this
region saw a larger earthquake was more than 80
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years ago but that doesn't mean that earthquakes
of this size are rare it's just as they happen
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in other parts of the world specifically here this
region is called the Pacific Ring of Fire and it's
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the most seismically active place on Earth why
it doesn't really matter it has to do with old
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rocks and stuff but all you need to know is that
if you're planning on building the largest city
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on Earth you should probably do it anywhere other
than in this red area here now unfortunately this
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video was slightly delayed and we didn't get it
out in time for the founding of Japanese Society
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14,000 years ago so they didn't get the memo and
now you have Tokyo the largest city in the world
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and home to 14 million people built on an island
that gets hit with earthquakes the same size
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as the one that leveled turkey every few years
sometimes multiple times per year and though these
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earthquakes do invariably lead to some casualties
and some destruction Tokyo isn't this but how well
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the main ingredients in any Municipal mering
is buildings and while the buildings in Tokyo
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look like the sort of buildings that might turn to
soup with enough vibration there's a lot going on
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behind the scenes to keep them in one piece every
building in Tokyo Falls under one of Japan's three
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different tiers of earthquake proofing except for
a small handful of buildings built before 1981 but
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these are pretty much all lowcost residential
buildings so fortunately the only ones who are
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going to die are poor people anyway we don't need
to worry about those buildings because they're
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all going to be gone soon enough whether Japan
wants them to or not so instead let's talk about
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the buildings that do fall under Japan's three
tiers of earthquake proofing the first and most
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basic set of Standards is called the taen and it
applies to every building constructed after 1981
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from simple detached houses to everything else
this mostly just dictates a building's General
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sturdiness having a certain thickness of walls
and a certain strength of beams and columns pretty
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much every low-rise building in Japan is built in
a frame of steel or wood you won't see the sort of
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stone houses you might find in Europe or America
because unlike a flexible wood frame a stone frame
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is either upright or it's not that being said this
tier is only the Baseline these buildings will
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still Shake during an earthquake and your Funko
pops are still at risk of falling off the shelf
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taan buildings are mostly built to resist the
smaller four to five magnitude earthquakes that
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Japan experiences every day and to avoid total
collapse in the event of something larger but
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for buildings taller than a simple detached house
or small business this might not cut it which is
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what the next tier of earthquake proofing is for
this tier called station are features you'll find
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in many of Tokyo's high-rise Office Buildings and
they're designed to counteract the sort of swing
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that might shake a house but top a skyscraper
this is typically done with a device called a
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seismic damper which can look like a whole bunch
of different things if your building's engineer is
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boring they'll install a bunch of giant industrial
Springs in your building's frame that essentially
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pulls it back uppr right when an earthquake
shakes It One Direction or another but if
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your building's engineer is cool they'll install
a giant swinging egg that weighs several hundred
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tons and swings through your building to remind
everyone that deadly city- ending earthquakes are
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inevitable this basically does the same thing as
the Springs by moving opposite to the building's
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frame and pulling its momentum backwards while
also keeping everyone in the building humble
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Japanese buildings have actually had some version
of this for well over a thousand years if you look
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at for example old Japanese pagodas you'll see
that they're built differently than Korean or
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Chinese pagodas they have a central wooden column
called ashin bashira that essentially acts as a
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seismic damper some buildings actually still use
this exact method like the Tokyo Sky Tree which
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is supported by a massive concrete shim bashira
running through the full height of the tower but
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the Sky Tree which is one of the tallest buildings
in the world needs more than just that to survive
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an earthquake that's why it's one of the 2600 or
so buildings in Tokyo designed for the third tier
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of earthquake resistance called mention these
buildings which are usually over 20 stories
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are constructed in such a way that they are almost
entirely isolated from the ground itself it sounds
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weird but pretty much all of Tokyo skyscrapers
aren't actually on the ground instead they're
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built on top of extremely thick rubber legs that
allow the building to sway independently from the
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earth and when combined with seismic dampers and
decent enough construction even the tallest of Sky
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trees can live to do whatever the Sky Tree does
another day now well-designed buildings are great
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and all but they're not worth much without
their Plucky sidekick responsible Municipal
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infrastructure Marvel might have turned me down
but I am right the city needs to be able to detect
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measure and respond to earthquakes in a matter
of seconds because here's a fun fact it's not
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actually possible to predict earthquakes before
they happen the forces that cause earthquakes
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build up really slowly over hundreds or thousands
of years so even a fairly accurate earthquake
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forecast is give or take a few centuries and
that doesn't really answer my question of do
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I have to go to work today or will I be dead by
noon anyway all that is to say once an earthquake
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has started every second matters and Tokyo is
designed to use those seconds well the entire
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country of Japan and much of its surrounding ocean
floor is covered in a network of 4,235 size MERS
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all of which are recording the Earth vibrations
around the clock and they're there to buy Tokyo
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and other Japanese cities about half a minute of
time before the actual earthquake hits to explain
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how this works I need to say science words for
like 15 seconds so just plug your ears if that
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goes against your morals basically an earthquake
happens in two waves there's the swave which is
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the thing that actually causes major tremors
and there's also a weaker but faster traveling
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p-wave which is like a polite little Messenger
to tell you that the s-wave is on its way to
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come mess your whole day up so when one of the
nodes in this massive countrysize grid of siiz
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nomers detects a p-wave Japan can immediately
calculate where the earthquake is coming from
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how strong it is and when it will hit which parts
of the country with these 30 or so seconds the
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government can activate pretty much every phone
and television in the country to tell people to
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take cover and even more pressingly they have
time to stop the trains that would otherwise
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be derailed in the earthquake and all that in
addition to being about 5,000 mi from Aragon's
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sphere of influence is why Tokyo is still here
today now I really only was able to scrape the
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surface of the ridiculous physics that go into
designing a building that won't fall over but if
00:06:12
you're interested in diving deeper I'd recommend
brilliant's course on the physics of the everyday
00:06:17
I'm not the most stem oriented person but I found
that this course really elegantly breaks down the
00:06:21
science behind a lot of normal things you might
idly wonder about like how do planes fly or what
00:06:26
makes refrigerators cold and as a hinted at
it also has a great little section about the
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physics of skyscrapers each lesson is quick
intuitive and interactive you're not going to
00:06:35
be slogging through any big blocks of text or
sitting at your computer for hours Brilliance
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courses are designed for you to learn for just a
few minutes each day at home or on the go and you
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can use it to teach yourself pretty much anything
under the stem umbrella they've got courses on
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AI language models multivariable calculus
quantitative Finance you name it it's the
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perfect way to get a little bit smarter every day
and if that sounds like a goal of yours I can't
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recommend brilliant enough to try everything
brilliant has to offer free for a full 30 days
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visit brilliant.org slhi or click on the link in
the description the first 2 of you will get 20%
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off brilliant's annual premium subscription
and you'll be supporting this channel too
