Jojo vs Earthquakes (part 3)

After few days being on high alert due to ONYOK, things have got quiet again. No disasters of huge proportion except for a lot of rain in different places of Mindanao. There were flooded area, they were landslides as well, but as far as it is known there was no casualties at all. Really, it is great news.

I can now come back to blogging and continue my journey with you to understand more what Earthquakes are all about.

In Jojo vs Earthquakes (Part 2), when I was developing a little on Plate Tectonic, and the "why we have earthquakes?", I superficially touched about the inside of our planet mentioning that I would go deeper for each layer composing the inner part of our planet. As it had been promised it has to be delivered, so here we are.

"What Is Below Our Feet Precisely?"

In simple terms, four big layers makes up our planet. From top to bottom they are :

• The Crust

• The Mantle

• The Outer Core

• The Inner Core

In this post let's stop on the first layer

THE CRUST LAYER

The Crust is a general term often used for the sake of simplicity, but even that is not totally precise. The more specific term is Lithosphere from which the Crust is simply the visible surface on which we live. I used those two terms inter-changeably in this post.

In many ways this layer is not really difficult to visualize since it is the one we walk on, we drive on, and where all living beings are living. On the Crust we have built our whole Human Civilization, that's where we grow our food, it is also where we find coal, diamonds, gold, iron, etc.  

The entire Lithosphere (remember the Crust is a simplistic term) is between 30 and 50km deep (70km in certain places). It seems a lot, but do we realize that compared to the rest of the planet the Crust is extremely thin?

A good analogy is the skin of an apple. Take an apple, and peel it. Once peeled cut the apple in two. Now take the skin you have peeled previously and compare the thickness of the peel with the thickness of one of the two half. Look at the difference. That's a good comparison between what the Crust is to the rest of the planet's inside. The Crust is like the skin of an apple, extremely thin. Another analogy could be that of an egg, the Crust being the shell of the egg. Compare to the inside, the shell is thin.

At first it does not make any difference to know this, but after a while, taking things in context, we can begin to realize that, considering the shear size of our planet in relation the smallness of the Crust, the power and energy inside our planet could destroy us easily. Compare to what is stored under our feet we humans are really nothing, and there is nothing we can do about it because we are the one living just above the burning cauldron. 

If the Crust was not broken here and there, the inside pressure of the Earth would wipe us out fast by exploding the surface. Our salvation comes through Plate Tectonic and the ability of the Continental Plates all over the world to move along. That mobility prevent any excessive pressure built-up against the Lithosphere.

Still, the Earthquakes are there to remember us that, although much pressure is release on a daily basis without us ever noticing it, not all the pressure is release equally on the Globe. Sometimes it is stuck along the Plate and after a while released in a big hick-up. As such, the Earthquakes are the main destructive power when it comes to the Crust itself on which we live.

However, beside the Earthquakes, the Crust is also pierced in many places. Those Earth's Piercing are the spot of what we call Volcanoes through which the magma can be spewed out. That same magma is the result of what is happening in the Mantle Layer. And that's what we will look into in the next post concerning the Mantle Layer.

Related Blog Topic
Africa Geography Blog

To learn more
Wikipedia - The Structure of the Earth
University of Colorado Boulder - The Earth's Inside
USGS - Inside the Earth
National Geographic for Kids - Structure of the Earth
Kid Geo - The Study of Our Earth
Georgia State University - Structure of the Earth

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