Types of stress

There are 3 types of stress:

1. Tension 
2. Compression
3. Shearing

Tension pulls on the crust, stretching the so that it becomes thinner in the middle. Tension happens when two plates are moving apart. 

Compression squeezes rock until it folds or breaks. One plate pushing against another can compress rock like a giant trash compactor

Shearing is a mass of rock in two opposite directions. Shearing can cause rock to break and slip apart or to change its shape. 

Kinds of faults:

• When enough stress builds up in the rock, the rock breaks, creating a fault. Fault is a break in the rock of the crust where the rock surfaces slip past each other. 
• The rocks on both sides of a fault can move up and down or side to side. 
• Most faults occur along plate boundaries, where the forces of plate motion push or pull the crust so much that the crust breaks.
• There are three main types of faults: normal faults, reverse faults and strike- slip faults.

Reverse faults:

•  In places where the rock of crust of the crust is pushed together, compression causes reverse to form. 
• A reverse fault has the same structure as a normal fault, but the blocks move in the opposite direction. 
• The rock forming the hanging wall of a reverse faults produced part of the northern Rocky Mountains in the western United states and Canada. 
• A normal fault, one side of a reverse fault lies at an angle above the other side. 

Strike- slip faults:

• In places where plates move past each other, shearing creates strike- slip faults. 
• In a strike- slip faults, the rocks on either side of the fault slips past each other side- ways, with little up and down motion. 

Changing Earths Surface:

• The force produced by the movement of Earths plates can fold, stretch and uplift the crust. 
• Over millions of years, the forces of plate movement can change a flat plain into land- forms such as anticlines and synclines, folded mountains, fault- block mountains, and plateaus. 

Key questions:

 

what are the three main types of stress in rock? 

The three main types are tension, compression and shearing.

how does tension change the shape of Earths crust?

It pulls on the crust, stretching the so that it becomes thinner in the middle.

Compare the way that compression affects the crust to the way that tension effects the crust? 

 Compression squeezes rock until it folds or breaks and tension pulls on the crust, stretching the so that it becomes thinner in the middle. So the two do totally different things. 

What is a fault? 

 hen enough stress builds up in the rock, the rock breaks, creating a fault.

Why do faults often occur along plate boundaries?

Because its where the forces of plate motion push or pull the crust so much that the crust breaks.

What types of faults is formed when plates diverge, or pull apart? what type of faults is formed when plates are pushed together? 

It is normal faults and reverse faults. 

Name five kinds of landforms caused by plate movement? 

anticlines, synclines, folded mountains, fault- block mountains, and plateaus.