Presentation on theme: "Faults By: Angie and Katherine. About 250 million years ago, the continents of Earth were grouped together in one continent called “Pangea.” It is just."— Presentation transcript:
Faults By: Angie and Katherine
About 250 million years ago, the continents of Earth were grouped together in one continent called “Pangea.” It is just like the shell of an egg. Earth’s crust
Land masses have moved and broken up and have reshaped the continents completely over millions of years ago. It is like an egg shell that is cracked and put back together again. It looks like the pieces of a jigsaw puzzle. Tectonic Plates
Earth and an egg The Earth’s tectonic plates and egg’s shell are very much alike.
Earth’s crust is broken into many tectonic plates. There are big and small plates. Earth’s tectonic plate map
The tectonic plates float around the mantle. Which causes the tectonic plates to move. What causes tectonic plates to move?
The stress that is built up causes faults or cracks in Earth’s crust. When one plate pushes against another, stress builds up. There are three kinds of stress. They are compression, tension, and shearing. Plate and Shake! Stress that pushes rock past one another.
A fault is a sudden break in the rocks that make up the Earth’s crust, also know as tectonic plates. What are Faults? Faults begin way below in the Earth. They start with a focus point. Then every year or so, it will grow an inch or two. BIG enough to be seen! Above the focus point is called an epicenter. The place is usually where most damage happens. Do you know what it means ?
Cracks from faults create fault lines. Some fault lines have split open the ground. Large fault lines go deep underground and can stretch along a whole continent. Many of earth’s major fault lines run along coastlines and across the ocean floor. The world’s biggest fault lines are found near the edges of the Earth’s plate. Fault Lines
San Andreas Fault Faults develop deep underground in the Earth’s crust. A few can be seen on the surface. One of the most famous is California’s San Andreas fault.
There are three different types of major faults. The Normal Fault The Strike-Slip Fault The Reverse Fault/Thrust Fault What types of faults are there?
A normal fault is a section of the crust when it moves apart, rocks are stretched until they snap. When they snap it causes one block to move down along a sloping crack. The Normal Fault See? This is hanging here. And this is hanging on top, like a foot on a big rock!
When rocks come together, they are compressed. One block moves along a sloping crack when the other block moves down. The Reverse/Thrust Fault Just like we said! They compress lots of energy together and one goes on top one another! footwall Hanging wall
The strike-slip fault happens when rocks grind against each other, they move horizontally past each other in opposite directions. Just like two lanes of cars, and they go opposite sides! The Strike-Slip Fault Do they look the same to you?
Results of the faults
The hanging wall drops, tension is the stress. Normal Fault Stress that pulls rocks apart
The hanging wall moves up relative to the footwall. Reverse fault Compression pushes rocks together
Strike-Slip fault Stress that pushes rock past one another The bed for planting slip apart. The fence was broken and offset 8 feet by the moving of a strike-slip fault.
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