A normal fault occurs when rocks break and move because they are being pulled apart. As the area is stretched, the rocks move along the fault. Each movement causes an earthquake. This model demonstrates how a block of rock is extended by a normal fault.
- Photocopies of models
- Carefully cut out the larger block and construct, using glue where indicated. Do not yet glue along the area marked "In this area glue on the reverse side of this tab."
- Now cut out the smaller block and construct.
- Once the glue is dry, slide the flap of the larger block inside the smaller block and then glue on the reserve of the tab indicated, so that the two blocks are connected and yet the smaller block slides up and down on the larger block.
- To see how a normal fault works, slide the smaller block up so that the land surface is level. Measure the distance from one end of the model to the other.
- Now cause the fault to move by sliding the smaller block downwards.
- Measure the length of the model. You will see that movement along the normal fault has caused the area to become longer as it undergoes stretching.
Click for a printable version: Model of a Normal Fault.