Part 3

Exploration Phase

1. Have students develop a model of a strike-slip fault. Instructions to students:

   1. Locate points F and G on your model. Move the pieces of the model so that point F is next to point G.
   2. Have students draw an overhead view of the surface as it looks after movement along the fault.

Concept Development

1. Ask the following questions:

   1. If you were standing at point F and looking across the fault, which way did the block on the opposite side move?
   2. What happened to rock layers X, Y, and Z?
   3. Are the rock layers still continuous?
   4. What likely happened to the river? the road? the railroad tracks?
   5. If the scale used in this model is 1 mm = 2 m, how many meters did the earth move when the strike-slip fault caused point F to move alongside point G? (Note that this scale would make an unlikely size for the railroad track!) If there were a sudden horizontal shift of this magnitude it would be about five times the shift that occurred in the 1906 San Andreas fault as a result of the San Francisco earthquake.
   6. Is this type of fault caused by tension, compression or shearing?

2. Explain that this type of fault is known as a strike-slip fault.

3. Have students label their drawing "strike-slip fault".

4. Explain to the students that a strike-slip fault can be described as having right or left-lateral movement. If you look directly across the fault, the direction that the opposite side moved defines whether the movement is left-lateral or right-lateral. The San Andreas fult in California is a right-lateral strike-slip fault.