How earthquakes show us the inside of the Earth

It is pretty amazing how much we know about the Earth’s interior, given that we can only directly observe a tiny fraction of it. Due to our lack of access to the Earth’s interior, scientists must rely on indirect observations. One way they do this is by studying the movement of pressure waves as they travel through the interior of the Earth.
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[@bett1826]

0:00 introduction 0:16 The crust and how far we have gone 0:57 Seismology introduction 1:16 Body waves 1:30 P and S waves 2:46 How the P and S waves travel through different types of matter 4:12 What happens when Earthquakes occur 4:48 Seismic discontinuities 5:25 Discontinuities in order(Moho, asthenosphere, upper mantle, mantle/core boundary) 6:47 Shadow zones 7:11 How else scientists know about the Earth's interior 7:46 End Hope this helped :)

[@SciencePrimer]

Thank you!

[@abdullahabdulrahman5902]

Thank you 🙏

[@samuraihoodiegirl2983]

THANK U OMG

[@chubbieminami3274]

Hello from Japan. In 2015, we had a mildly big but weird feeling earthquake. The P wave was very long but the quake was pretty big. In Japan, when the P wave is pretty long, you know the quake is deep so I usually expect the S wave to be small. When they announced the details I got pretty excited because the quake was extremely deep. I am no scientist but studied geology so I knew it was a rare quake. In the beginning, they announced that it was 590 KM & 8.5M and I was pretty excited already. However, due to the change in density, they later corrected the numbers to 681 KM & 8.1M -- one of the deepest in the magnitude 8.0 category!!

[@Martin-iw1ll]

Why is it when p wave is long, the quake is deep? Does the earth change the frequency of the p waves?

[@chubbieminami3274]

@@Martin-iw1ll P wave travels about 2 times faster than the S wave. In shallow earthquakes you feel it almost at the same time. In the west coast of the U.S. you have different types of shallow earthquakes. Japan's quakes are usually deeper and not so shallow.

[@DrakeLarson-js9px]

This is an outstanding overview on this topic (seismic waves and the profiling methods of our inner-earth).

[@jamesharrell4360]

Made a subscriber outta me with this excellent, easy to understand, informative video. Great work. Appreciate it.

[@prof.simonen.brandao7699]

Thanks! I will use it in my classes in Brazil❤❤❤

[@SciencePrimer]

I love it. Thanks for letting me know

[@PoutsNKsul]

Excellent work. Very well explained. Thank you

[@arandomchannel56]

Best explanation ever on this topic. Thanks tons!

[@ewanbates599]

Thank you for your clear and concise explanation

[@nepenthe_1610]

Thank you! This was very helpful

[@vimalramachandran]

Well explained! Keep up the good work.

[@SciencePrimer]

Glad it was helpful. Thanks for commenting.

[@juvanllego6301]

Thanks you for this.... Now i have my report ❤

[@cherriesinsnow]

This has been a great help.

[@spblore]

Jus lyk a wow❤ explanation

[@VictorGreinvolfe48]

Having to watch this for online school, good stuff

[@Erzan391]

lol same

[@adventurekitty1016]

Nothing like me watching this stuff because I am trying to make an original character that can manipulate and generate vibrations(Much like Quake or Vibe in the Marvel and DC comics) as grounded as I can. I want just her powers to make sense realistically, like if someone had her powers irl.

[@davidaugustofc2574]

I don't know how this is gonna help me in mechanical engineering but I do find it super interesting.

[@BlackEyedGhost0]

In the inner core, the seismic waves appear to curve in the opposite direction, as if the center is less dense than the exterior. Why is that?

[@Grdnrjess8946]

Great video!!

[@SciencePrimer]

Thanks!

[@rjones6219]

Watching this video, just prompted a long forgotten memory. As a child in the early 50s, I used to read a comic, one of the stories was about a scientist who bored his way to the centre of the earth, in a special machine he developed. It had a sharp nose like one of those screw drills. He built into it a refrigeration system to keep the interior cool. (Must admit, even at that very early age, I was puzzled how he could keep the interior cool, with so much heat outside, where did he vent the heat to?).

[@kajalkiranpujhari3216]

Cleared my doubts👍👍

[@SciencePrimer]

Glad it was helpful. Thanks for commenting!

[@reetasingh4304]

Best seismic wave video

[@SciencePrimer]

Glad you think so!

[@shubhamshikher1326]

preparing for upsc ?

[@budgarner3522]

Indirect observations. Incredibly important fact. BS in Geology & Geophysics and 13+ years in O & G exploration, most geologists deal in direct observations when they can get their eyes and hands on them. The overwhelming investigations for the rest of geology and almost all of geophysics is INDIRECT. We really have to keep fine tuning our data and it's interpretation and even dumping it out and starting over in our minds if we are to come to better conclusions. Very nice work.

[@harithameka8328]

thanks for the video why p waves have high velocity in mantle

[@yoowee2056]

THANK YOU SO MUCHHHHHHH😀

[@NekoChxn]

Thank you

[@SciencePrimer]

You're welcome

[@davidthomas5174]

Amazing! I assume we would have no idea what the inner structure of earth is without seismic waves.

[@santaclause3487]

They don’t know

[@mohamedadnan3345]

@@santaclause3487 yes, we know

[@DannyTruthMagnified]

​@@mohamedadnan3345They know that the waves are passing through some solid and less dense (possibly liquid) objects. Outside of that, everything else is them guessing.

[@Martin-iw1ll]

I always thought p and s waves represented pressure and shear wave

[@ronilavi3621]

Thank you ! Great video ! Can you please refer me to an academic book that explains more?

[@SciencePrimer]

I don't have a specific recommendation for an accessible book about seismology. Most of the information I used for this video came from geology and plate tectonics textbooks. If you have access to a university library, you could take a look at what textbooks they have on the shelves.

[@osemank]

@@SciencePrimer I recently acquired a copy of "The Earth's Inner Core" by Hrvoje Thkalcic (publ. 2017). It is certainly "academic" and it pretty hard-core, mathematically. But the author also covers a lot of the history and there are loads of diagrams and graphs. Also, an extensive bibliography. I obtained a copy for £3.79 from eBay!! It's worth a look at that price.

[@muskanmishra5581]

👍clears many of my doubts

[@SciencePrimer]

Glad it was helpful. Thanks for commenting!

[@shubhamshikher1326]

preparing for upsc ?

[@izeddb6293]

What is the summary of the video?

[@SciencePrimer]

Here is a text version of the material if you find reading more helpful. scienceprimer.com/studying-inside-earth

[@lenymalvar3786]

Why seismic waves travel slowly?

[@cmrewind4771]

It's all about density of the materials they travel through

[@user-gk4qz9ku3s]

Hotter areas cause waves travel more slowly revealing the presence of hotspots partially molten areas such as the asthenosphere weakend but do not completely stop S waves molten regions cause P waves to slow down and completely stop S waves all of this predictable behaviors provide seismologist with information about the tegion of the Earth waves passed through after an earthquake Both S and Pwaves travel faster through more dense material and since density increases with that, waves speed up as they move deeper in the Earth. The change in density also causes the waves to travel in curved path as they move through the Earth. The curving of this wave is similar to the refraction that occurs when a light ray passes through and interface between two media like air to glass but rather than an abrupt change in direction . P and S waves undergo a gradual in direction as density changes gradually with dept.

[@sixthsenseamelia4695]

🌱🌏💚

[@maricellasac5943]

I go here because of modules

[@siyuziiiiii]

same

[@alecboterblom6684]

2:50 Cap

[@official_jasye6936]

its a hallow earth

[@santaclause3487]

They have no clue what the earth is made of. This is just making a guess

[@cmriess5367]

Good explanation I can use in class. But...pronunciation! "Hundred" is not pronounced 'Hunerd' !!

[@siyuziiiiii]

are u a teacher?

[@cmrewind4771]

@@siyuziiiiii Yes. How can you tell? LOL

[@Jesus_is_All_we_need]

🤣😂🥰🙏💝🙏

[@santaclause3487]

Wait, ur saying they measure waves from outside of earth, right through the middle, and then on the other side ? That makes no sense. U don’t know where the wave ends up too. This is all cap

[@DannyTruthMagnified]

Not necessarily. They have multiple seismic stations all over the world constantly tracking and measuring these waves so they can definitely keep track of where they are going, the issue is them playing basically a guessing game in trying to figure out what they are actually passing through inside the Earth.

[@DannyTruthMagnified]

@@charlesrichter3854 Well, it took 10 years for them to figure out that there isn't hundreds of mantle plumes filling the mantle of Earth's inner structure and that required thermal mapping to figure out. There is still a lot they don't fully understand.

[@aimbotboi3886]

yeet

[@zzy5951]

BOOOO

[@MakingworldBetter88]

lame