Step 3 is to determine the dip. This is a perpendicular line down the face of the incline toward the water in the example. You might say it is 35 degrees West of North. Step 4 is the measure the dip angle. The dip angle is the angle of the incline compared to the horizontal. You might say it is 65 degrees angulated with respect to the horizontal.
FAULTS AND JOINTS A joint is any separation of a block of wall where there has been no movement on either side of the crack. It takes pressure from gravity or from forces behind or beneath onehalf of the joint to create a fault. A fault is a good example of what happens when brittle rock fractures or breaks. You will see an offset at this point because the two halves didn't just break and stay in place. They broke and then moved in some direction away from each other. The reference point is the inclined plane. The block below the inclined plane is called the footwall, while the one above the inclined plane is the hanging wall. The hanging wall will either fall due to gravity or rise when a force thrusts it up the plane. A geologist's goal is to describe what has happened to the two halves. Note the inclined plane aspect of the images you look at in figure 52 as you think about which fault is which. Figure 52 shows you the different fault types in better detail:
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