Doublet Earthquake

We just learned about the Blind Thrust.

Another type of earthquake is the Doublet Earthquake.

We learned before that most earthquakes have a big mainshock, with a smaller beginning called a foreshock, and a smaller quake after called the aftershock.

Sometimes two big earthquakes happen at the same time very near each other.
When this happens, it's like a double quake, just like the name doublet earthquake.
So when this happens there are two foreshocks, two mainshocks and two aftershocks.
It can be very hard for seismologists to figure out which quakes came from which fault.


(from: wikipedia - doublet earthquake)


Kid Facts - Blast from the past: Iron Ore

Blind Thrust

We just learned about the Thrust Fault where the earth slips in the reverse direction.

One type of earthquake is a Blind Thrust earthquake.

Usually earthquakes happen in places where there are faults that have been mapped out, so people know where they are and know what to expect.

Sometimes earthquakes happen in areas where people did not think there were any faults, so it is like a blind earthquake because no one was expecting it, and no one was looking there for an earthquake.


(from: wikipedia - blind thrust earthquake)


Kid Facts - Blast from the past: Heat Treatment

Thrust Fault

We just learned about the Aftershock that happens after the biggest part of the earthquake.

We've learned about the Dip Slip fault before.

Another fault type is a Thrust Fault.
This is a lot like the dip-slip, but the slip goes in the opposite direction.
Sometimes they even call it a reverse thrust fault.


(from: wikipedia - thrust fault)


Kid Facts - Blast from the past: Forge Welding

Aftershock

We just learned about the Foreshock and Mainshock of an earthquake.

After the Mainshock comes the Aftershock.

When the earthquake passes it's strongest part of the mainshock, any of the other quakes or ground shaking is part of the aftershock.

Separating the earthquake into the three parts (Foreshock, Mainshock and Aftershock) helps earthquake scientists study each part of the quake, and learn about why the earth acts the way it does.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Punching

Mainshock

We just learned about the Foreshock that happens before the biggest part of the earthquake.

The biggest part of the earthquake is called the Mainshock.
This is when the earthquake is at it's strongest force.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Swaging

Foreshock

We just learned about the Ring Fault.

Another part of earthquake science is the Foreshock.

Most earthquakes have multiple shocks, where the earth is shaking.
The first one that is smaller before the biggest one is called the foreshock.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Upsetting

Ring Fault

We just learned about the Listric Fault.

Another type of fault is a Ring Fault.

This fault is in a crater or a volcano, where the volcano has collapsed, or the ground caved in after getting hit by a meteorite.


(from: wikipedia - chesapeake bay impact crater)


Kid Facts - Blast from the past: Bending

Listric Fault

We just learned about the Oblique-Slip Fault.

Another earthquake fault is a Listric Fault.

This is like the Dip-Slip fault that we learned about before, but the fault line makes a curved line where the earth's crust slides down.

(from: wikipedia - fault (geology))


Kid Facts - Blast from the past: Drawing Down

Oblique-Slip Fault

We just learned about the Dip-Slip Fault.

Another type of earthquake fault is the Oblique-Slip Fault.

This is when two the tectonic plates move, and the earth's crust bumps into each other in both a Strike-Slip and Dip-Slip way.

That means the earth went side to side, and up and down.


(from: wikipedia - fault (geology))


Kid Facts - Blast from the past: Blizzard

Dip-slip Fault

We just learned about the Strike-slip fault.

Another type of earthquake fault is the Dip-slip fault.

This happens when the tectonic plates hit each other, and one of them slips down and the other slips up.


(from: wikipedia - fault (geology))



(from: wikipedia - fault (geology))


Kid Facts - Blast from the past: Fuller

Strike-Slip Fault

We just learned that a fault is when two tectonic plates crash into each other.

There are different types of faults, and different ways that the earth's crust moves during faults.
One type of fault is a Strike-slip fault, also known as a wrench fault, tear fault or transcurrent fault.

When an earthquake happens at one of these faults, the ground shifts side to side.
To show this, put your two hands in front of you on a table, with your palms flat on the table.
Have your hands touching at the sides of your thumbs and pointer fingers.
Slide your right hand forward away from you, and slide your left hand toward your body.
That is the same way the earth moves, slipping the two pieces of the earth's crust next to each other, but keeping them touching.

(from: wikipedia - fault (geology))


(from: wikipedia - fault (geology))


Kid Facts - Blast from the past: Tongs

Fault

We just learned about the Tectonic Plates.

Another part of earthquake science is a fault.

When the tectonic plates smash into each other, the place where the earth's crust touches from two different plates is called a fault.
When the plates move, not every part of the crust will run into other parts.
There are a bunch of different types of faults, depending on how the two pieces of crust run into each other.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Chisel

Tectonic Plates

We just learned about the earthquake Hypocenter.

Another part of earthquakes is the Tectonic Plates.

The scientist who study earthquakes have mapped out 15 big areas on the earth, on every continent and around the oceans.
These areas are called tectonic plates, and they move around little by little every year.
When one tectonic plate area moves, it bumps into another tectonic plate, and it causes an earthquake!

These plates are millions of miles wide, and over 60 miles deep.
Because they are so huge, when they bump into each other the earth crashing together has a lot of force and makes a big problem.


(from: wikipedia - list of tectonic plates)


Kid Facts - Blast from the past: Sledgehammer

Hypocenter

We just learned about the earthquake Epicenter.

Another important thing in earthquake science is the Hypocenter.

This is the spot underground where the earthquake first started.
The epicenter is right above the hypocenter, but at the surface of the earth.


(from: wikipedia - hypocenter)


Kid Facts - Blast from the past: Straight Peen Hammer

Epicenter

Let's keep learning about Earthquakes.

When an earthquake happens underground, the spot on the earth's surface above where the earthquake is strongest is called the epicenter.


(from: wikipedia - epicenter)


Kid Facts - Blast from the past: Cross Peen Hammer

Earthquakes

We've learned a whole lot about how to work with metal.
Everything from furnaces to get the metal from iron ore, to working with it on anvils, to using it on machines like lathes or mills.

Let's start learning a little bit about Earthquakes.
Earthquakes happen all over the world, even underwater!
There are scientific tools for predicting and measuring quakes, and there is a lot of scientific study over what makes an earthquake happen.

A scientist who studies earthquakes is called a seismologist.


(from: wikipedia - earthquake)


Kid Facts - Blast from the past: Ball Peen Hammer

Numerical Control - CNC

We just learned about Plasma Cutting.

Another tool for working with metal is CNC - Computer Numerical Control.

All of the different types of metal work that we've learned about like lathes, mills, drills and grinders can be controlled by a computer so that they can do the same work over and over, thousands of times without any mistakes.

The numerical control means that the computer is given numbers that tell it what parts to cut and how to cut them.


(from: wikipedia - numerical control)


Kid Facts - Blast from the past: Pritchel Hole

Plasma Cutting

We just learned about the Water Jet Cutting.

Another way to cut metals is Plasma Cutting using a Plasma Torch.

The plasma torch shoots a fast stream of gas through a nozzle that has electricity shooting across it.
This electricity ionizes the gas, meaning that it gets the tiny electrons in the gas all super excited and the gas gets super hot!

These plasma torches are super fast at cutting metals and other materials.


(from: wikipedia - plasma torch)



(from: wikipedia - plasma cutting)


Kid Facts - Blast from the past: Anvil - Hardy Hole

Water jet cutting

We just learned about Electrical Discharge Machining.

Another way to work with metal is water jet cutting.

A water jet cutting tool takes water and squirts it at super high speeds at a piece of metal, and the water is going so fast that it actually cuts the metal.

The tool that makes the water go fast actually uses a jewel like a sapphire, ruby or diamond to make a really small hole for the water to go through.
Water jets can be used to cut anything from glass, to rubber to wood or metal.

Sometimes if the water needs to cut something really hard the water gets mixed up with small pieces of hard crystals like garnet or aluminum oxide, and it gets rougher.
You can think of that like if someone mixed sand up in a squirtgun and shot it at you, it might sting more than just water in a squirtgun.


(from: wikipedia - water jet cutter)


(from: wikipedia - water jet cutter)


Kid Facts - Blast from the past: Anvil - Table

Electrical Discharge Machining

We just learned about the type of metal working called Stamping.

Another way to work with metal is called Electrical Discharge Machining or EDM for short.
It is also sometimes called spark machining, spark eroding, burning, die sinking, wire burning or wire erosion.

This is a way to cut some parts out of a piece of metal using electricity.
A special tool zaps a piece of metal with some electricity, and the power of the electricity is so strong it cuts into the metal.



(from: wikipedia - electrical discharge machining)


Kid Facts - Blast from the past: Anvil - Horn